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Sample records for nutrient deficiencies soil

  1. Combating Human Micronutrient Deficiencies through Soil Management Practices that Enhance Bioavailability of Nutrients to Plants

    ERIC Educational Resources Information Center

    O'Meara, Mary

    2009-01-01

    Micronutrient malnutrition affects the health and well being of 3 billion people globally. Identifying means to improve the micronutrient density in the edible portions of crops is an important way to combat nutrient deficiencies. By studying how plants obtain micronutrients from the soil, we can develop methods to enhance uptake. Although more…

  2. Diagnosing oceanic nutrient deficiency

    NASA Astrophysics Data System (ADS)

    Moore, C. Mark

    2016-11-01

    The supply of a range of nutrient elements to surface waters is an important driver of oceanic production and the subsequent linked cycling of the nutrients and carbon. Relative deficiencies of different nutrients with respect to biological requirements, within both surface and internal water masses, can be both a key indicator and driver of the potential for these nutrients to become limiting for the production of new organic material in the upper ocean. The availability of high-quality, full-depth and global-scale datasets on the concentrations of a wide range of both macro- and micro-nutrients produced through the international GEOTRACES programme provides the potential for estimation of multi-element deficiencies at unprecedented scales. Resultant coherent large-scale patterns in diagnosed deficiency can be linked to the interacting physical-chemical-biological processes which drive upper ocean nutrient biogeochemistry. Calculations of ranked deficiencies across multiple elements further highlight important remaining uncertainties in the stoichiometric plasticity of nutrient ratios within oceanic microbial systems and caveats with regards to linkages to upper ocean nutrient limitation. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  3. Utilizing ERTS imagery to detect plant diseases and nutrient deficiencies, soil types and soil moisture levels

    NASA Technical Reports Server (NTRS)

    Parks, W. L.; Sewell, J. I.; Hilty, J. W.; Rennie, J. C. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. ERTS-1 imagery may be used to delineate soil associations. It does have the capacity to divide soils into groups such that their land use and management would be similar. It offers definite potential for making grass flood-plain, wetland, river shoreline, and land use change surveys. Production of volume strata and forest type from the two usable bands of ERTS-1 imagery were of questionable value. No imagery was received for evaluation during the time of year when maine dwarf mosaic virus and southern corn leaf blight were active.

  4. Utilizing ERTS imagery to detect plant diseases and nutrient deficiencies, soil types and soil moisture levels

    NASA Technical Reports Server (NTRS)

    Parks, W. L. (Principal Investigator); Sewell, J. I.; Hilty, J. W.; Rennie, J. C.

    1973-01-01

    The author has identified the following significant results. The delineation of soil associations and detection of drainage patterns, erosion and sedimentation through the use of ERTS-1 imagery are shown. Corn blight and corn virus could not be detected from ERTS-1 and detection of forest composition was at a very low probability.

  5. Lead phytotoxicity in soils and nutrient solutions is related to lead induced phosphorus deficiency.

    PubMed

    Cheyns, Karlien; Peeters, Sofie; Delcourt, Dorien; Smolders, Erik

    2012-05-01

    This study was set up to relate lead (Pb) bioavailability with its toxicity to plants in soils. Tomato and barley seedlings were grown in six different PbCl(2) spiked soils (pH: 4.7-7.4; eCEC: 4.2-41.7 cmol(c)/kg). Soils were leached and pH corrected after spiking to exclude confounding factors. Plant growth was halved at 1600-6500 mg Pb/kg soil for tomato and at 1900-8300 mg Pb/kg soil for barley. These soil Pb threshold were unrelated to soil pH, organic carbon, texture or eCEC and neither soil solution Pb nor Pb(2+) ion activity adequately explained Pb toxicity among soils. Shoot phosphorus (P) concentrations significantly decreased with increasing soil Pb concentrations. Tomato grown in hydroponics at either varying P supply or at increasing Pb (equal initial P) illustrated that shoot P explained growth response in both scenarios. The results suggest that Pb toxicity is partially related to Pb induced P deficiency, likely due to lead phosphate precipitation.

  6. Utilization of ERTS data to detect plant diseases and nutrient deficiencies, soil types and moisture levels

    NASA Technical Reports Server (NTRS)

    Parks, W. L.; Sewell, J. I. (Principal Investigator); Hilty, J. W.; Rennie, J. C.

    1972-01-01

    The author has identified the following significant results. A significant finding is the identification and delineation of a large soil association in Obion County, West Tennessee. These data are now being processed through the scanner and computer and will be included in the next report along with pictures of printout and imagery. Channel 7 appears to provide the most useful imagery related to soil differences. Soil types have been identified through the use of aircraft imagery. However, a soil association map appears to be the best that space imagery will provide. The exception to this will be large areas of a uniform soil type as occurs in the great plains.

  7. Utilization of ERTS data to detect plant diseases and nutrient deficiencies, soil types and moisture levels

    NASA Technical Reports Server (NTRS)

    Parks, W. L. (Principal Investigator); Sewell, J. I.; Hilty, J. W.; Rennie, J. C.

    1973-01-01

    The author has identified the following significant results. A significant finding to date is the delineation of the Memphis soil association in Obion County, Dyer County, and in portions of Kentucky. This soil association was delineated mechanically through the use of imagery in the digital tape format, appropriate computer software, and an IBM/360/05 computer. The Waverly-Swamp association as well as the Obion River have been identified on the ERTS-1 imagery as well as on the computer printout. These findings demonstrate the feasibility of delineating major soil associations through vegetative cover common to the association. Channel 7 provides the most information for studies of this type. Computer density printouts assist markedly in making density separations and delineating major soil moisture differences; however, signatures for soil moisture classification for this area of mixed land uses in relatively small tracts have not yet been developed.

  8. Proteomics dissection of plant responses to mineral nutrient deficiency.

    PubMed

    Liang, Cuiyue; Tian, Jiang; Liao, Hong

    2013-02-01

    Plants require at least 17 essential nutrients to complete their life cycle. Except for carbon, hydrogen, and oxygen, other essential nutrients are mineral nutrients, which are mainly acquired from soils by roots. In natural soils, the availability of most essential mineral nutrients is very low and hard to meet the demand of plants. Developing crops with high nutrient efficiency is essential for sustainable agriculture, which requires more understandings of crop responses to mineral nutrient deficiency. Proteomic techniques provide a crucial and complementary tool to dissect molecular mechanisms underlying crop adaptation to mineral nutrient deficiency in the rapidly processing postgenome era. This review gives a comparative overview about identification of mineral nutrient deficiency responsive proteins using proteomic analysis, and discusses the current status for crop proteomics and its challenges to be integrated into systems biology approaches for developing crops with high mineral nutrient efficiency.

  9. Effects of soil applications of micro-nutrients and chelating agent citric acid on mineral nutrients in soybean seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Micro-nutrients deficiency in soil result in crop yield loss and poor seed quality. Correcting this deficiency is normally conducted by foliar or soil application. The objective of this research was to determine the effects of soil applications of five micro-nutrients (Mn, Cu, Zn, Mo, and B) with a ...

  10. Update of nutrient-deficiency anemia in elderly patients.

    PubMed

    Andrès, Emmanuel; Federici, Laure; Serraj, Khalid; Kaltenbach, Georges

    2008-11-01

    Anemia, defined as a hemoglobin level < 13 g/dL in men and < 12 g/dL in women, is an important healthcare concern among the elderly. Nutrient-deficiency anemia represents one third of all anemias in elderly patients. About two thirds of nutrient-deficiency anemia is associated with iron deficiency and most of those cases are the result of chronic blood loss from gastrointestinal lesions. The remaining cases of nutrient-deficiency anemia are usually associated with vitamin B12, most frequently related to food-cobalamin malabsorption, and/or folate deficiency and are easily treated (nutrient-deficiency replacement).

  11. Plasticity of the Arabidopsis root system under nutrient deficiencies.

    PubMed

    Gruber, Benjamin D; Giehl, Ricardo F H; Friedel, Swetlana; von Wirén, Nicolaus

    2013-09-01

    Plant roots show a particularly high variation in their morphological response to different nutrient deficiencies. Although such changes often determine the nutrient efficiency or stress tolerance of plants, it is surprising that a comprehensive and comparative analysis of root morphological responses to different nutrient deficiencies has not yet been conducted. Since one reason for this is an inherent difficulty in obtaining nutrient-deficient conditions in agar culture, we first identified conditions appropriate for producing nutrient-deficient plants on agar plates. Based on a careful selection of agar specifically for each nutrient being considered, we grew Arabidopsis (Arabidopsis thaliana) plants at four levels of deficiency for 12 nutrients and quantified seven root traits. In combination with measurements of biomass and elemental concentrations, we observed that the nutritional status and type of nutrient determined the extent and type of changes in root system architecture (RSA). The independent regulation of individual root traits further pointed to a differential sensitivity of root tissues to nutrient limitations. To capture the variation in RSA under different nutrient supplies, we used principal component analysis and developed a root plasticity chart representing the overall modulations in RSA under a given treatment. This systematic comparison of RSA responses to nutrient deficiencies provides a comprehensive view of the overall changes in root plasticity induced by the deficiency of single nutrients and provides a solid basis for the identification of nutrient-sensitive steps in the root developmental program.

  12. Responses of spinach to salinity and nutrient deficiency in growth, physiology and nutritional value

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salinity and nutrient depleted soil are major constraints to crop production, especially for vegetable crops. The effects of salinity and nutrient deficiency on spinach were evaluated in sand cultures under greenhouse conditions. Plants were watered every day with Hoagland nutrition solution, depriv...

  13. Soil Nutrient Assessment for Urban Ecosystems in Hubei, China

    PubMed Central

    Li, Zhi-guo; Zhang, Guo-shi; Liu, Yi; Wan, Kai-yuan; Zhang, Run-hua; Chen, Fang

    2013-01-01

    Recent urban landscape vegetation surveys conducted in many cities in China identified numerous plant nutrient deficiencies, especially in newly developed cities. Soil nutrients and soil nutrient management in the cities of Hubei province have not received adequate attention to date. The aims of this study were to characterize the available nutrients of urban soils from nine cities in Hubei province, China, and to assess how soil nutrient status is related to land use type and topography. Soil nutrients were measured in 405 sites from 1,215 soil samples collected from four land use types (park, institutional [including government building grounds, municipal party grounds, university grounds, and garden city institutes], residential, and roadside verges) and three topographies (mountainous [142–425 m a.s.l], hilly [66–112 m a.s.l], and plain [26–30 m a.s.l]). Chemical analyses showed that urban soils in Hubei had high pH and lower soil organic matter, available nitrogen (N), available phosphorus (P), and available boron (B) concentrations than natural soils. Nutrient concentrations were significantly different among land use types, with the roadside and residential areas having greater concentrations of calcium (Ca), sulfur (S), copper (Cu), manganese (Mn), and zinc (Zn) that were not deficient against the recommended ranges. Topographic comparisons showed statistically significant effects for 8 of the 11 chemical variables (p < 0.05). Concentrations of N, Ca, Mg, S, Cu, and Mn in plain cities were greater than those in mountainous cities and show a negative correlation with city elevation. These results provide data on urban soils characteristics in land use types and topography, and deliver significant information for city planners and policy makers. PMID:24086647

  14. Nutrient Limitation of Microbial Mediated Decomposition and Arctic Soil Chronology

    NASA Astrophysics Data System (ADS)

    Melle, C. J.; Darrouzet-Nardi, A.; Wallenstein, M. D.

    2012-12-01

    Soils of northern permafrost regions currently contain twice as much carbon as the entire Earth's atmosphere. Traditionally, environmental constraints have limited microbial activity resulting in restricted decomposition of soil organic matter in these systems and accumulation of massive amounts of soil organic carbon (SOC), however climate change is reducing the constraints of decomposition in arctic permafrost regions. Carbon cycling in nutrient poor, arctic ecosystems is tightly coupled to other biogeochemical cycles. Several studies have suggested strong nitrogen limitations of primary productivity and potentially warm-season microbial activity in these nutrient deficient soils. Nitrogen is required for microbial extracellular enzyme production which drives the decomposition of soil organic matter (SOM). Nitrogen limited arctic soils may also experience limitation via labile carbon availability despite the SOM rich environment due to low extracellular enzyme production. Few studies have directly addressed nutrient induced microbial limitation in SOC rich arctic tundra soils, and even less is known about the potential for nutrient co-limitation. Additionally, through the process of becoming deglaciated, sites within close proximity to one another may have experienced drastic differences in their effective soil ages due to the varied length of their active histories. Many soil properties and nutrient deficiencies are directly related to soil age, however this chronology has not previously been a focus of research on nutrient limitation of arctic soil microbial activity. Understanding of nutrient limitations, as well as potential co-limitation, on arctic soil microbial activity has important implications for carbon cycling and the ultimate fate of the current arctic SOC reservoir. Analyses of nutrient limitation on soils of a single site are not adequate for fully understanding the controls on soil microbial activity across a vast land mass with large variation in

  15. Analysis of field-scale spatial correlations and variations of soil nutrients using geostatistics.

    PubMed

    Liu, Ruimin; Xu, Fei; Yu, Wenwen; Shi, Jianhan; Zhang, Peipei; Shen, Zhenyao

    2016-02-01

    Spatial correlations and soil nutrient variations are important for soil nutrient management. They help to reduce the negative impacts of agricultural nonpoint source pollution. Based on the sampled available nitrogen (AN), available phosphorus (AP), and available potassium (AK), soil nutrient data from 2010, the spatial correlation, was analyzed, and the probabilities of the nutrient's abundance or deficiency were discussed. This paper presents a statistical approach to spatial analysis, the spatial correlation analysis (SCA), which was originally developed for describing heterogeneity in the presence of correlated variation and based on ordinary kriging (OK) results. Indicator kriging (IK) was used to assess the susceptibility of excess of soil nutrients based on crop needs. The kriged results showed there was a distinct spatial variability in the concentration of all three soil nutrients. High concentrations of these three soil nutrients were found near Anzhou. As the distance from the center of town increased, the concentration of the soil nutrients gradually decreased. Spatially, the relationship between AN and AP was negative, and the relationship between AP and AK was not clear. The IK results showed that there were few areas with a risk of AN and AP overabundance. However, almost the entire study region was at risk of AK overabundance. Based on the soil nutrient distribution results, it is clear that the spatial variability of the soil nutrients differed throughout the study region. This spatial soil nutrient variability might be caused by different fertilizer types and different fertilizing practices.

  16. Macro and micro nutrient uptake parameters and use efficiency in cacao genotypes influenced by deficient to excess levels of soil K

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cacao (Theobroma cacao L.) is an important economic crop for many of the tropical countries. Adequate levels of soil K are essential for good growth and achieving high cocoa bean yields. Soils under cacao invariably have low levels of plant available K to support good cacao growth. Growth chamber ex...

  17. Lichen substances prevent lichens from nutrient deficiency.

    PubMed

    Hauck, Markus; Willenbruch, Karen; Leuschner, Christoph

    2009-01-01

    The dibenzofuran usnic acid, a widespread cortical secondary metabolite produced by lichen-forming fungi, was shown to promote the intracellular uptake of Cu(2+) in two epiphytic lichens, Evernia mesomorpha and Ramalina menziesii, from acidic, nutrient-poor bark. Higher Cu(2+) uptake in the former, which produces the depside divaricatic acid in addition to usnic acid, suggests that this depside promotes Cu(2+) uptake. Since Cu(2+) is one of the rarest micronutrients, promotion of Cu(2+) uptake by lichen substances may be crucial for the studied lichens to survive in their nutrient-poor habitats. In contrast, study of the uptake of other metals in E. mesomorpha revealed that the intracellular uptake of Mn(2+), which regularly exceeds potentially toxic concentrations in leachates of acidic tree bark, was partially inhibited by the lichen substances produced by this species. Inhibition of Mn(2+) uptake by lichen substances previously has been demonstrated in lichens. The uptake of Fe(2+), Fe(3+), Mg(2+), and Zn(2+), which fail to reach toxic concentrations in acidic bark at unpolluted sites, although they are more common than Cu(2+), was not affected by lichen substances of E. mesomorpha.

  18. Application of root bioassays to detect nutrient deficiencies in fast-growing trees and agroforestry crops

    SciTech Connect

    Harrison, A.F.; Dighton, J.; Jones, H.E.

    1992-12-31

    A new method for the detection of nutrient deficiencies is outlined and recommended as an alternative to conventional soil and foliar analyses. Bioassays are conducted to measure the uptake and supply of the macronutrients. Examples are quoted of the successful use of this technique with Eucalyptus and Sitka spruce. The bioassays have been shown to give equally good results with a range of tree and ground crops.

  19. Spectra of normal and nutrient-deficient maize leaves

    NASA Technical Reports Server (NTRS)

    Al-Abbas, A. H.; Barr, R.; Hall, J. D.; Crane, F. L.; Baumgardner, M. F.

    1973-01-01

    Reflectance, transmittance and absorptance spectra of normal and six types of nutrient-deficient (N, P, K, S, Mg, and Ca) maize (Zea mays L.) leaves were analyzed at 30 selected wavelengths from 500 to 2600 nm. The analysis of variance showed significant differences in reflectance, transmittance and absorptance in the visible wavelengths among leaf numbers 3, 4, and 5, among the seven treatments, and among the interactions of leaf number and treatments. In the infrared wavelengths only treatments produced significant differences. The chlorophyll content of leaves was reduced in all nutrient-deficient treatments. Percent moisture was increased in S-, Mg-, and N-deficiencies. Polynomial regression analysis of leaf thickness and leaf moisture content showed that these two variables were significantly and directly related. Leaves from the P- and Ca-deficient plants absorbed less energy in the near infrared than the normal plants; S-, Mg-, K-, and N-deficient leaves absorbed more than the normal. Both S- and N-deficient leaves had higher temperatues than normal maize leaves.

  20. Artificial Soil With Build-In Plant Nutrients

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Allen, Earl; Henninger, Donald; Golden, D. C.

    1995-01-01

    Nutrients contained in sandlike material. Artificial soil provides nutrients to plants during several growing seasons without need to add fertilizer or nutrient solution. When watered, artificial soil slowly releases all materials a plant needs to grow. Developed as medium for growing crops in space. Also used to grow plants on Earth under controlled conditions or even to augment natural soil.

  1. Soil nutrient bioavailability and nutrient content of pine trees (Pinus thunbergii) in areas impacted by acid deposition in Korea.

    PubMed

    Yang, Jae E; Lee, Wi-Young; Ok, Yong Sik; Skousen, Jeffrey

    2009-10-01

    Acid deposition has caused detrimental effects on tree growth near industrial areas of the world. Preliminary work has indicated that concentrations of NO(3-), SO(4)(2-), F( - ) and Al in soil solutions were 2 to 33 times higher in industrial areas compared to non-industrial areas in Korea. This study evaluated soil nutrient bioavailability and nutrient contents of red pine (Pinus thunbergii) needles in forest soils of industrial and non-industrial areas of Korea. Results confirm that forest soils of industrial areas have been acidified mainly by deposition of sulfate, resulting in increases of Al, Fe and Mn and decreases of Ca, Mg and K concentrations in soils and soil solutions. In soils of industrial areas, the molar ratios of Ca/Al and Mg/Al in forest soils were <2, which can lead to lower levels and availability of nutrients for tree growth. The Ca/Al molar ratio of Pinus thunbergii needles on non-industrial sites was 15, while that of industrial areas was 10. Magnesium concentrations in needles of Pinus thunbergii were lower in soils of industrial areas and the high levels of acid cations such as Al and Mn in these soils may have antagonized the uptake of base cations like Mg. Continued acidification can further reduce uptake of base cations by trees. Results show that Mg deficiency and high concentrations of Al and Mn in soil solution can be limiting factors for Pinus thunbergii growth in industrial areas of Korea.

  2. Coping with uncertainty: Nutrient deficiencies motivate insect migration at a cost to immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Migration is often associated with movement away from areas with depleted nutrients or other resources, and yet migration itself is energetically demanding. Migrating Mormon crickets Anabrus simplex (Orthoptera: Tettigoniidae) lack nutrients, and supplementation of deficient nutrients slows migrator...

  3. Legume adaptation to sulfur deficiency revealed by comparing nutrient allocation and seed traits in Medicago truncatula.

    PubMed

    Zuber, Hélène; Poignavent, Germain; Le Signor, Christine; Aimé, Delphine; Vieren, Eric; Tadla, Charlène; Lugan, Raphaël; Belghazi, Maya; Labas, Valérie; Santoni, Anne-Lise; Wipf, Daniel; Buitink, Julia; Avice, Jean-Christophe; Salon, Christophe; Gallardo, Karine

    2013-12-01

    Reductions in sulfur dioxide emissions and the use of sulfur-free mineral fertilizers are decreasing soil sulfur levels and threaten the adequate fertilization of most crops. To provide knowledge regarding legume adaptation to sulfur restriction, we subjected Medicago truncatula, a model legume species, to sulfur deficiency at various developmental stages, and compared the yield, nutrient allocation and seed traits. This comparative analysis revealed that sulfur deficiency at the mid-vegetative stage decreased yield and altered the allocation of nitrogen and carbon to seeds, leading to reduced levels of major oligosaccharides in mature seeds, whose germination was dramatically affected. In contrast, during the reproductive period, sulfur deficiency had little influence on yield and nutrient allocation, but the seeds germinated slowly and were characterized by low levels of a biotinylated protein, a putative indicator of germination vigor that has not been previously related to sulfur nutrition. Significantly, plants deprived of sulfur at an intermediary stage (flowering) adapted well by remobilizing nutrients from source organs to seeds, ensuring adequate quantities of carbon and nitrogen in seeds. This efficient remobilization of photosynthates may be explained by vacuolar sulfate efflux to maintain leaf metabolism throughout reproductive growth, as suggested by transcript and metabolite profiling. The seeds from these plants, deprived of sulfur at the floral transition, contained normal levels of major oligosaccharides but their germination was delayed, consistent with low levels of sucrose and the glycolytic enzymes required to restart seed metabolism during imbibition. Overall, our findings provide an integrative view of the legume response to sulfur deficiency.

  4. Leaf mineral nutrient remobilization during leaf senescence and modulation by nutrient deficiency

    PubMed Central

    Maillard, Anne; Diquélou, Sylvain; Billard, Vincent; Laîné, Philippe; Garnica, Maria; Prudent, Marion; Garcia-Mina, José-Maria; Yvin, Jean-Claude; Ourry, Alain

    2015-01-01

    Higher plants have to cope with fluctuating mineral resource availability. However, strategies such as stimulation of root growth, increased transporter activities, and nutrient storage and remobilization have been mostly studied for only a few macronutrients. Leaves of cultivated crops (Zea mays, Brassica napus, Pisum sativum, Triticum aestivum, Hordeum vulgare) and tree species (Quercus robur, Populus nigra, Alnus glutinosa) grown under field conditions were harvested regularly during their life span and analyzed to evaluate the net mobilization of 13 nutrients during leaf senescence. While N was remobilized in all plant species with different efficiencies ranging from 40% (maize) to 90% (wheat), other macronutrients (K–P–S–Mg) were mobilized in most species. Ca and Mn, usually considered as having low phloem mobility were remobilized from leaves in wheat and barley. Leaf content of Cu–Mo–Ni–B–Fe–Zn decreased in some species, as a result of remobilization. Overall, wheat, barley and oak appeared to be the most efficient at remobilization while poplar and maize were the least efficient. Further experiments were performed with rapeseed plants subjected to individual nutrient deficiencies. Compared to field conditions, remobilization from leaves was similar (N–S–Cu) or increased by nutrient deficiency (K–P–Mg) while nutrient deficiency had no effect on Mo–Zn–B–Ca–Mn, which seemed to be non-mobile during leaf senescence under field conditions. However, Ca and Mn were largely mobilized from roots (-97 and -86% of their initial root contents, respectively) to shoots. Differences in remobilization between species and between nutrients are then discussed in relation to a range of putative mechanisms. PMID:26029223

  5. Leaf mineral nutrient remobilization during leaf senescence and modulation by nutrient deficiency.

    PubMed

    Maillard, Anne; Diquélou, Sylvain; Billard, Vincent; Laîné, Philippe; Garnica, Maria; Prudent, Marion; Garcia-Mina, José-Maria; Yvin, Jean-Claude; Ourry, Alain

    2015-01-01

    Higher plants have to cope with fluctuating mineral resource availability. However, strategies such as stimulation of root growth, increased transporter activities, and nutrient storage and remobilization have been mostly studied for only a few macronutrients. Leaves of cultivated crops (Zea mays, Brassica napus, Pisum sativum, Triticum aestivum, Hordeum vulgare) and tree species (Quercus robur, Populus nigra, Alnus glutinosa) grown under field conditions were harvested regularly during their life span and analyzed to evaluate the net mobilization of 13 nutrients during leaf senescence. While N was remobilized in all plant species with different efficiencies ranging from 40% (maize) to 90% (wheat), other macronutrients (K-P-S-Mg) were mobilized in most species. Ca and Mn, usually considered as having low phloem mobility were remobilized from leaves in wheat and barley. Leaf content of Cu-Mo-Ni-B-Fe-Zn decreased in some species, as a result of remobilization. Overall, wheat, barley and oak appeared to be the most efficient at remobilization while poplar and maize were the least efficient. Further experiments were performed with rapeseed plants subjected to individual nutrient deficiencies. Compared to field conditions, remobilization from leaves was similar (N-S-Cu) or increased by nutrient deficiency (K-P-Mg) while nutrient deficiency had no effect on Mo-Zn-B-Ca-Mn, which seemed to be non-mobile during leaf senescence under field conditions. However, Ca and Mn were largely mobilized from roots (-97 and -86% of their initial root contents, respectively) to shoots. Differences in remobilization between species and between nutrients are then discussed in relation to a range of putative mechanisms.

  6. Dysregulation of Nutrient Sensing and CLEARance in Presenilin Deficiency.

    PubMed

    Reddy, Kavya; Cusack, Corey L; Nnah, Israel C; Khayati, Khoosheh; Saqcena, Chaitali; Huynh, Tuong B; Noggle, Scott A; Ballabio, Andrea; Dobrowolski, Radek

    2016-03-08

    Attenuated auto-lysosomal system has been associated with Alzheimer disease (AD), yet all underlying molecular mechanisms leading to this impairment are unknown. We show that the amino acid sensing of mechanistic target of rapamycin complex 1 (mTORC1) is dysregulated in cells deficient in presenilin, a protein associated with AD. In these cells, mTORC1 is constitutively tethered to lysosomal membranes, unresponsive to starvation, and inhibitory to TFEB-mediated clearance due to a reduction in Sestrin2 expression. Normalization of Sestrin2 levels through overexpression or elevation of nuclear calcium rescued mTORC1 tethering and initiated clearance. While CLEAR network attenuation in vivo results in buildup of amyloid, phospho-Tau, and neurodegeneration, presenilin-knockout fibroblasts and iPSC-derived AD human neurons fail to effectively initiate autophagy. These results propose an altered mechanism for nutrient sensing in presenilin deficiency and underline an importance of clearance pathways in the onset of AD.

  7. NUTRIENT UPTAKE: A Microcomputer Program to Predict Nutrient Absorption from Soil by Roots.

    ERIC Educational Resources Information Center

    Oates, Kenneth; Barber, S. A.

    1987-01-01

    Discusses the use of a computer program designed to solve the mathematical model associated with soil nutrient uptake by plant roots and to predict the nutrient uptake. Describes a user-friendly personal computer version of this program. (TW)

  8. Nutrient status and plant growth effects of forest soils in the Basin of Mexico.

    PubMed

    Fenn, M E; Perea-Estrada, V M; de Bauer, L I; Pérez-Suárez, M; Parker, D R; Cetina-Alcalá, V M

    2006-03-01

    The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and Co, were higher at the high pollution sites. However, positive plant growth responses to P and sometimes to N, and results of wheat root elongation bioassays, suggest that heavy metal concentrations were not directly phytotoxic. Further studies are needed to determine if heavy metal toxicity to mycorrhizal symbionts of eucalyptus (Eucalyptus camaldulensis Dehnh.) from high pollution sites may explain the P deficiency and stunted growth. P deficiency is expected to limit the capacity for biotic N retention in N saturated forested watersheds in the Basin of Mexico dominated by Andisols.

  9. Spectral characteristics of normal and nutrient-deficient maize leaves

    NASA Technical Reports Server (NTRS)

    Al-Abbas, A. H.; Barr, R.; Hall, J. D.; Crane, F. L.; Baumgardner, M. F.

    1972-01-01

    Reflectance, transmittance and absorbance spectra of normal and six types of mineral-deficient (N,P,K,S,Mg and Ca) maize (Zea mays L.) leaves were analyzed at 30 selected wavelengths along the electromagnetic spectrum from 500 to 2600 nm. Chlorophyll content and percent leaf moisture were also determined. Leaf thermograms were obtained for normal, N- and S- deficient leaves. The results of the analysis of variance showed significant differences in reflectance, transmittance and absorbance in the visible wavelengths among leaf numbers 3, 4, and 5, among the seven nutrient treatments, and among the interactions of leaves and treatments. In the reflective infrared wavelengths only treatments produced significant differences. The chlorophyll content of leaves was reduced in all deficiencies in comparison to controls. Percent moisture was increased in S-, Mg- and N- deficiencies. Positive correlation (r = 0.707) between moisture content and percent absorption at both 1450 and 1930 nm were obtained. Polynomial regression analysis of leaf thickness and leaf moisture content showed that these two variables were significantly and directly related (r = 0.894).

  10. Effects of broiler litter application on nutrient accumulations in soil.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive nutrient accumulation in soils due to land application of broiler litter is a growing environmental concern. A four year study was conducted on a Pembroke silt loam soil (Mollic Paleudalf) cropped to orchardgrass (Dactylis glomerata L.) to evaluate accumulation of soil nutrients from broil...

  11. Effects of broiler litter application on nutrient accumulation in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive nutrient accumulation in soils due to land application of broiler litter is a growing environmental concern. A four-year study was conducted on a Pembroke silt loam soil (Mollic Paleudalf) cropped to orchardgrass (Dactylis glomerata L.) to evaluate accumulation of soil nutrients from broil...

  12. Relationships between soil physicochemical, microbiological properties, and nutrient release in buffer soils compared to field soils.

    PubMed

    Stutter, Marc I; Richards, Samia

    2012-01-01

    The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams.

  13. Variation in wood nutrients along a tropical soil fertility gradient.

    PubMed

    Heineman, Katherine D; Turner, Benjamin L; Dalling, James W

    2016-07-01

    Wood contains the majority of the nutrients in tropical trees, yet controls over wood nutrient concentrations and their function are poorly understood. We measured wood nutrient concentrations in 106 tree species in 10 forest plots spanning a regional fertility gradient in Panama. For a subset of species, we quantified foliar nutrients and wood density to test whether wood nutrients scale with foliar nutrients at the species level, or wood nutrient storage increases with wood density as predicted by the wood economics spectrum. Wood nutrient concentrations varied enormously among species from fourfold in nitrogen (N) to > 30-fold in calcium (Ca), potassium (K), magnesium (Mg) and phosphorus (P). Community-weighted mean wood nutrient concentrations correlated positively with soil Ca, K, Mg and P concentrations. Wood nutrients scaled positively with leaf nutrients, supporting the hypothesis that nutrient allocation is conserved across plant organs. Wood P was most sensitive to variation in soil nutrient availability, and significant radial declines in wood P indicated that tropical trees retranslocate P as sapwood transitions to heartwood. Wood P decreased with increasing wood density, suggesting that low wood P and dense wood are traits associated with tree species persistence on low fertility soils. Substantial variation among species and communities in wood nutrient concentrations suggests that allocation of nutrients to wood, especially P, influences species distributions and nutrient dynamics in tropical forests.

  14. Effect of soil in nutrient cycle assessment at dairy farms

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Maricke; de Boer, Imke; van Dam, Jos; van Middelaar, Corina; Stoof, Cathelijne

    2016-04-01

    Annual farm nutrient cycle assessments give valuable insight in the nutrient cycles and nutrient losses at dairy farms. It describes nutrient use efficiencies for the entire farm and for the underlying components cattle, manure, crops and soil. In many modelling studies, soil is kept as a constant factor, while soil quality is vital for soil functioning of the ecosystem. Improving soil quality will improve the nutrient cycle, and will also have positive effect on the soil functions crop production, water cycling and greenhouse gas mitigation. Spatial variation of soil properties within a farm, however, are not included in annual nutrient cycle assessments. Therefore it is impossible to identify fields where most profit can be gained by improving farm management at field level, and it is not possible to identify and to quantify nutrient flow path ways. The aim of this study is to develop a framework to improve the annual nutrient cycle assessment at Dutch dairy farms, by including soil properties and their spatial variation within farms. Soil type and soil quality will be described by visual soil assessment of soil quality characteristics. The visual observations will be linked to the nutrient cycle assessment, using soil-hydrological model SWAP. We will demonstrate how soil quality at field level can impact on crop production, eutrophication potential and greenhouse gas potential at farm level. Also, we will show how this framework can be used by farmers to improve their farm management. This new approach is focusing on annual nutrient cycle assessment, but could also be used in life cycle assessment. It will improve understanding of soil functioning and dairy farm management.

  15. Organic matter and nutrient accumulation in reclaimed kaolin mine soils of Georgia

    SciTech Connect

    Haddock, R.B.; Morris, L.A.; Hendrick, R.L.; Ogden, E.A.

    1996-12-31

    Deficiencies in soil nutrients, particularly nitrogen, commonly result from replacement of natural soil profiles by overburden low in organic matter and essential elements. Reclamation success depends largely upon creating nutrient reserves, establishing adequate nutrient cycles, and developing a functional soil profile. Loblolly pine (Pinus taeda L.) stand productivity and soil characteristics of reclaimed kaolin mines in Georgia were evaluated along a chronosequence. Estimated site index (age 25) ranged from 11.3 m on poor sites to 24.1 m on productive sites. Projected volume at age 25 ranged from 119 m{sup 3}/ha on poor sites to 280 m{sup 3}/ha on productive sites. These values indicate that growth on many mined lands is comparable to growth on adjacent non-mined lands. Soil profile development below the surface soil was nonexistent on all sites and differences in soil texture and color did not adequately explain observed differences in site productivity. Foliar deficiencies in phosphorus, potassium and several micronutrients suggest that availability of nutrients and potential mineralization explain the observed differences in site productivity.

  16. Soil Aeration deficiencies in urban sites

    NASA Astrophysics Data System (ADS)

    Weltecke, Katharina; Gaertig, Thorsten

    2010-05-01

    Soil aeration deficiencies in urban sites Katharina Weltecke and Thorsten Gaertig On urban tree sites reduction of soil aeration by compaction or sealing is an important but frequently underestimated factor for tree growth. Up to 50% of the CO2 assimilated during the vegetation period is respired in the root space (Qi et al. 1994). An adequate supply of the soil with oxygen and a proper disposal of the exhaled carbon dioxide are essential for an undisturbed root respiration. If the soil surface is smeared, compacted or sealed, soil aeration is interrupted. Several references show that root activity and fine root growth are controlled by the carbon dioxide concentration in soil air (Qi et al.1994, Burton et al. 1997). Gaertig (2001) found that decreasing topsoil gas permeability leads to reduced fine root density and hence to injury in crown structure of oaks. In forest soils a critical CO2 concentration of more than 0.6 % indicates a bad aeration status (Gaertig 2001). The majority of urban tree sites are compacted or sealed. The reduction of soil aeration may lead to dysfunctions in the root space and consequently to stress during periods of drought, which has its visible affects in crown structure. It is reasonable to assume that disturbances in soil aeration lead to reduced tree vigour and roadworthiness, resulting in high maintenance costs. The assessment of soil aeration in urban sites is difficult. In natural ecosystems the measurement of gas diffusivity and the gas-chromatical analysis of CO2 in soil air are accepted procedures in analyzing the state of aeration (Schack-Kirchner et al. 2001, Gaertig 2001). It has been found that these methods can also be applied for analyzing urban sites. In particular CO2 concentration in the soil atmosphere can be considered as a rapidly assessable, relevant and integrating indicator of the aeration situation of urban soils. This study tested the working hypothesis that soil aeration deficiencies lead to a decrease of fine

  17. Soil-Plant Nutrient Interactions on Manure-Enriched Calcareous Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient accumulations on heavily manured soils can trigger soil and plant nutrient interactions. The goal of the study was to determine the current impact of dairy manure applications on nutrient concentrations in soil and tissue for irrigated corn silage crops grown in Southern Idaho. At harvest,...

  18. Fiber optic spectrophotometry monitoring of plant nutrient deficiency under hydroponic culture conditions

    NASA Astrophysics Data System (ADS)

    Liew, Oi Wah; Boey, William S. L.; Asundi, Anand K.; Chen, Jun-Wei; He, Duo-Min

    1999-05-01

    In this paper, fiber optic spectrophotometry (FOSpectr) was adapted to provide early detection of plant nutrient deficiency by measuring leaf spectral reflectance variation resulting from nutrient stress. Leaf reflectance data were obtained form a local vegetable crop, Brassica chinensis var parachinensis (Bailey), grown in nitrate-nitrogen (N)- and calcium (Ca)- deficient hydroponics nutrient solution. FOSpectr analysis showed significant differences in leaf reflectance within the first four days after subjecting plants to nutrient-deficient media. Recovery of the nutrient-stressed plants could also be detected after transferring them back to complete nutrient solution. In contrast to FOSpectr, plant response to nitrogen and calcium deficiency in terms of reduced growth and tissue elemental levels was slower and less pronounced. Thus, this study demonstrated the feasibility of using FOSpectr methodology as a non-destructive alternative to augment current methods of plant nutrient analysis.

  19. Diet and hair loss: effects of nutrient deficiency and supplement use

    PubMed Central

    Guo, Emily L.; Katta, Rajani

    2017-01-01

    Patients presenting with hair loss should be screened by medical history, dietary history and physical exam for risk factors for nutrient deficiency. If warranted, laboratory studies may be performed. In patients with no risk factors, further laboratory evaluation searching for nutritional deficiencies is not warranted. For patients with nutritional deficiencies, it is clear that those deficiencies should be corrected. Further research is required to determine whether any benefit exists for nutrient supplementation in the absence of documented deficiency. At this time, patients must be informed that such research is lacking and that in fact some supplements carry the risk of worsening hair loss or the risk of toxicity. PMID:28243487

  20. Diet and hair loss: effects of nutrient deficiency and supplement use.

    PubMed

    Guo, Emily L; Katta, Rajani

    2017-01-01

    Patients presenting with hair loss should be screened by medical history, dietary history and physical exam for risk factors for nutrient deficiency. If warranted, laboratory studies may be performed. In patients with no risk factors, further laboratory evaluation searching for nutritional deficiencies is not warranted. For patients with nutritional deficiencies, it is clear that those deficiencies should be corrected. Further research is required to determine whether any benefit exists for nutrient supplementation in the absence of documented deficiency. At this time, patients must be informed that such research is lacking and that in fact some supplements carry the risk of worsening hair loss or the risk of toxicity.

  1. Nutrient omission in Bt cotton affects soil organic carbon and nutrients status

    NASA Astrophysics Data System (ADS)

    Aladakatti, Y. R.; Biradar, D. P.; Satyanarayana, T.; Majumdar, K.; Shivamurthy, D.

    2012-04-01

    Studies carried out at the University of Agricultural Sciences, Dharwad, India, in medium black soils assessed the effect of nutrient omission in Bt cotton and its effect on the soil organic carbon (SOC) and available nutrients at the end of second consecutive year of nutrient omission. The study also assessed the extent of contribution of the macro and micronutrients towards seed cotton yield. The experiment consisting 11 treatments omitting a nutrient in each treatment including an absolute control without any nutrients was conducted in a Randomised Block Design with three replications. Cotton crop sufficiently fertilized with macro and micro nutrients (165 : 75 : 120 NPK kg ha-1 and 20 kg each of CaSO4, and MgSO4, 10 kg of S, 20 kg each of ZnSO4, FeSO4 and 0.1 per cent Boron twice as foliar spray) was taken as a standard check to assess the contribution of each nutrient in various nutrient omission treatments. Soils of each treatment were analysed initially and after each crop of cotton for SOC and available nutrient status. Results indicated that the SOC decreased after each crop of cotton in absolute control where no nutrients were applied (0.50 % to 0.38 %) and also in the N omission treatment (0.50 % to 0.35 %). But there was no significant impact of omission of P, K and other nutrients on soil organic carbon. Soil available N, P and K in the soil were reduced as compared to the initial soil status after first and second crop of cotton in the respective treatment where these nutrients were omitted. The soil available N, P and K were reduced to the extent of 61 kg ha-1, 7.1 kg ha-1 and 161.9 kg ha-1 in the respective nutrient omission treatment at end of second crop of cotton as compared to the initial status of these nutrients in the soil. This might be due to the mining of these nutrients from the soil nutrient pool with out addition of these nutrients extraneously. The nutrient status of N, P and K remained almost similar in omission of other nutrients

  2. Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties

    EPA Science Inventory

    Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

  3. Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties.

    EPA Science Inventory

    Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

  4. Landscape influence on soil carbon and nutrient levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Past runoff, erosion, and management practices influence nutrient levels on the landscape. These starting levels affect future nutrient transport due to runoff, erosion, and leaching events. The purpose of this study was to examine closed-depression landscape effects on surface soil organic matter, ...

  5. [Changes of crop yield and soil fertility under long-term application of fertilizer and recycled nutrients in manure on a black soil III. Soil nutrient budget].

    PubMed

    Liu, Hongxiang; Wang, Delu; Wang, Shouyu; Meng, Kai; Han, Xiaozeng; Zhang, Lu; Shen, Shanmin

    2002-11-01

    The nutrient budget of fertilization models under different treatments was calculated using data from a field experiment over the period of 1985-1999. The results indicated that application of nitrogen fertilizer accelerated a large deficit of soil phosphorus, and the use of nitrogen and phosphorus accelerated the deficit of potassium. The experimental data demonstrated the appearance of a large area of soil deficit of phosphorus from 1970s and of potassium from 1980s in China. Nutrient recycled in farming system improved soil nutrient budget, but could not meet the nutrient requirements from high-yield crops. The use of recycled nutrients with an appropriate use of fertilizers according to the soil fertility could produce higher crop yields, balance soil nutrient budget, and not cause surplus nutrients to emit into environment.

  6. Spatial variability assessment of soil nutrients in an intense agricultural area, a case study of Rugao County in Yangtze River Delta Region, China

    NASA Astrophysics Data System (ADS)

    Zhao, Yongcun; Xu, Xianghua; Darilek, Jeremy Landon; Huang, Biao; Sun, Weixia; Shi, Xuezheng

    2009-05-01

    Topsoil samples (0-20 cm) ( n = 237) were collected from Rugao County, China. Geostatistical variogram analysis, sequential Gaussian simulation (SGS), and principal component (PC) analysis were applied to assess spatial variability of soil nutrients, identify the possible areas of nutrient deficiency, and explore spatial scale of variability of soil nutrients in the county. High variability of soil nutrient such as soil organic matter (SOM), total nitrogen (TN), available P, K, Fe, Mn, Cu, Zn, and B concentrations were observed. Soil nutrient properties displayed significant differences in their spatial structures, with available Cu having strong spatial dependence, SOM and available P having weak spatial dependence, and other nutrient properties having moderate spatial dependence. The soil nutrient deficiency, defined here as measured nutrient concentrations which do not meet the advisory threshold values specific to the county for dominant crops, namely rice, wheat, and rape seeds, was observed in available K and Zn, and the deficient areas covered 38 and 11%, respectively. The first three PCs of the nine soil nutrient properties explained 62.40% of the total variance. TN and SOM with higher loadings on PC1 are closely related to soil texture derived from different parent materials. The PC2 combined intermediate response variables such as available Zn and P that are likely to be controlled by land use and soil pH. Available B has the highest loading on PC3 and its variability of concentrations may be primarily ascribed to localized anthropogenic influence. The amelioration of soil physical properties (i.e. soil texture) and soil pH may improve the availability of soil nutrients and the sustainability of the agricultural system of Rugao County.

  7. Paradoxical nutritional deficiency in overweight and obesity: the importance of nutrient density.

    PubMed

    Markovic, Tania P; Natoli, Sharon J

    2009-02-02

    Overweight and obese patients may develop paradoxical nutritional deficiency from eating high-energy foods with a poor nutrient content. In such patients, this condition is probably under-recognised, and thus untreated. The nutrient density of foods has recently been defined by a score--the naturally nutrient-rich (NNR) score--which assesses the contribution a food makes to the nutrient intake of a 2000 calorie (8360 kJ) daily diet and includes 14 key macronutrients. NNR foods are whole foods that provide the highest nutrient-to-kilojoule ratio. An awareness of the importance of the nutrient density of foods can assist health practitioners to recognise and effectively manage paradoxical nutritional deficiency. Knowledge of the nutrient density of foods helps people wanting to reduce their kilojoule intake to maintain a nutritionally sound diet, providing adequate vitamins, minerals and macronutrients.

  8. Uncovering miRNAs involved in crosstalk between nutrient deficiencies in Arabidopsis.

    PubMed

    Liang, Gang; Ai, Qin; Yu, Diqiu

    2015-07-02

    Integrating carbon (C), nitrogen (N), and sulfur (S) metabolism is essential for the growth and development of living organisms. MicroRNAs (miRNAs) play key roles in regulating nutrient metabolism in plants. However, how plant miRNAs mediate crosstalk between different nutrient metabolic pathways is unclear. In this study, deep sequencing of Arabidopsis thaliana small RNAs was used to reveal miRNAs that were differentially expressed in response to C, N, or S deficiency. Comparative analysis revealed that the targets of the differentially expressed miRNAs are involved in different cellular responses and metabolic processes, including transcriptional regulation, auxin signal transduction, nutrient homeostasis, and regulation of development. C, N, and S deficiency specifically induced miR169b/c, miR826 and miR395, respectively. In contrast, miR167, miR172, miR397, miR398, miR399, miR408, miR775, miR827, miR841, miR857, and miR2111 are commonly suppressed by C, N, and S deficiency. In particular, the miRNAs that are induced specifically by a certain nutrient deficiency are often suppressed by other nutrient deficiencies. Further investigation indicated that the modulation of nutrient-responsive miRNA abundance affects the adaptation of plants to nutrient starvation conditions. This study revealed that miRNAs function as important regulatory nodes of different nutrient metabolic pathways.

  9. Diagnosis & Correction of Soil Nutrient Limitations in Intensively managed southern pine forests

    SciTech Connect

    University of Florida

    2002-10-25

    Forest productivity is one manner to sequester carbon and it is a renewable energy source. Likewise, efficient use of fertilization can be a significant energy savings. To date, site-specific use of fertilization for the purpose of maximizing forest productivity has not been well developed. Site evaluation of nutrient deficiencies is primarily based on empirical approaches to soil testing and plot fertilizer tests with little consideration for soil water regimes and contributing site factors. This project uses mass flow diffusion theory in a modeling context, combined with process level knowledge of soil chemistry, to evaluate nutrient bioavailability to fast-growing juvenile forest stands growing on coastal plain Spodosols of the southeastern U.S. The model is not soil or site specific and should be useful for a wide range of soil management/nutrient management conditions. In order to use the model, field data of fast-growing southern pine needed to be measured and used in the validation of the model. The field aspect of the study was mainly to provide data that could be used to verify the model. However, we learned much about the growth and development of fast growing loblolly. Carbon allocation patterns, root shoot relationships and leaf area root relationships proved to be new, important information. The Project Objectives were to: (1) Develop a mechanistic nutrient management model based on the COMP8 uptake model. (2) Collect field data that could be used to verify and test the model. (3) Model testing.

  10. Prehistoric agricultural depletion of soil nutrients in Hawai'i.

    PubMed

    Hartshorn, A S; Chadwick, O A; Vitousek, P M; Kirch, P V

    2006-07-18

    We investigated the fate of soil nutrients after centuries of indigenous dryland agriculture in Hawai'i using a coupled geochemical and archaeological approach. Beginning approximately 500 years ago, farmers began growing dryland taro and sweet potato on the leeward slopes of East Maui. Their digging sticks pierced a subsurface layer of cinders, enhancing crop access to the soil water stored below the intact cinders. Cultivation also catalyzed nutrient losses, directly by facilitating leaching of mobile nutrients after disturbing a stratigraphic barrier to vertical water movement, and indirectly by increasing mineral weathering and subsequent uptake and harvest. As a result, centuries of cultivation lowered volumetric total calcium, magnesium, sodium, potassium, and phosphorus content by 49%, 28%, 75%, 37%, and 32%, respectively. In the absence of written records, we used the difference in soil phosphorus to estimate that prehistoric yields were sufficient to meet local demand over very long time frames, but the associated acceleration of nutrient losses could have compromised subsequent yields.

  11. Substrate and nutrient limitation regulating microbial growth in soil

    NASA Astrophysics Data System (ADS)

    Bååth, Erland

    2015-04-01

    Microbial activity and growth in soil is regulated by several abiotic factors, including temperature, moisture and pH as the most important ones. At the same time nutrient conditions and substrate availability will also determine microbial growth. Amount of substrate will not only affect overall microbial growth, but also affect the balance of fungal and bacterial growth. The type of substrate will also affect the latter. Furthermore, according to Liebig law of limiting factors, we would expect one nutrient to be the main limiting one for microbial growth in soil. When this nutrient is added, the initial second liming factor will become the main one, adding complexity to the microbial response after adding different substrates. I will initially describe different ways of determining limiting factors for bacterial growth in soil, especially a rapid method estimating bacterial growth, using the leucine incorporation technique, after adding C (as glucose), N (as ammonium nitrate) and P (as phosphate). Scenarios of different limitations will be covered, with the bacterial growth response compared with fungal growth and total activity (respiration). The "degree of limitation", as well as the main limiting nutrient, can be altered by adding substrate of different stoichiometric composition. However, the organism group responding after alleviating the nutrient limitation can differ depending on the type of substrate added. There will also be situations, where fungi and bacteria appear to be limited by different nutrients. Finally, I will describe interactions between abiotic factors and the response of the soil microbiota to alleviation of limiting factors.

  12. Soil factors associated with zinc deficiency in crops and humans.

    PubMed

    Alloway, B J

    2009-10-01

    Zinc deficiency is the most ubiquitous micronutrient deficiency problem in world crops. Zinc is essential for both plants and animals because it is a structural constituent and regulatory co-factor in enzymes and proteins involved in many biochemical pathways. Millions of hectares of cropland are affected by Zn deficiency and approximately one-third of the human population suffers from an inadequate intake of Zn. The main soil factors affecting the availability of Zn to plants are low total Zn contents, high pH, high calcite and organic matter contents and high concentrations of Na, Ca, Mg, bicarbonate and phosphate in the soil solution or in labile forms. Maize is the most susceptible cereal crop, but wheat grown on calcareous soils and lowland rice on flooded soils are also highly prone to Zn deficiency. Zinc fertilizers are used in the prevention of Zn deficiency and in the biofortification of cereal grains.

  13. JAZ Repressors: Potential Involvement in Nutrients Deficiency Response in Rice and Chickpea.

    PubMed

    Singh, Ajit P; Pandey, Bipin K; Deveshwar, Priyanka; Narnoliya, Laxmi; Parida, Swarup K; Giri, Jitender

    2015-01-01

    Jasmonates (JA) are well-known phytohormones which play important roles in plant development and defense against pathogens. Jasmonate ZIM domain (JAZ) proteins are plant-specific proteins and act as transcriptional repressors of JA-responsive genes. JA regulates both biotic and abiotic stress responses in plants; however, its role in nutrient deficiency responses is very elusive. Although, JA is well-known for root growth inhibition, little is known about behavior of JAZ genes in response to nutrient deficiencies, under which root architectural alteration is an important adaptation. Using protein sequence homology and a conserved-domains approach, here we identify 10 novel JAZ genes from the recently sequenced Chickpea genome, which is one of the most nutrient efficient crops. Both rice and chickpea JAZ genes express in tissue- and stimuli-specific manners. Many of which are preferentially expressed in root. Our analysis further showed differential expression of JAZ genes under macro (NPK) and micronutrients (Zn, Fe) deficiency in rice and chickpea roots. While both rice and chickpea JAZ genes showed a certain level of specificity toward type of nutrient deficiency, generally majority of them showed induction under K deficiency. Generally, JAZ genes showed an induction at early stages of stress and expression declined at later stages of macro-nutrient deficiency. Our results suggest that JAZ genes might play a role in early nutrient deficiency response both in monocot and dicot roots, and information generated here can be further used for understanding the possible roles of JA in root architectural alterations for nutrient deficiency adaptations.

  14. Phytotoxicity studies with Lactuca sativa in soil and nutrient solution

    SciTech Connect

    Hulzebos, E.M.; Dirven-van Breemen, E.M.; Dis, W.A. van; Herbold, H.A.; Hoekstra, J.A.; Baerselman, R.; Gestel, C.A.M van ); Adema, D.M.M.; Henzen, L. )

    1993-06-01

    The toxicity of 76 priority pollutants to lettuce (Lactuca sativa) was determined in soil and in nutrient solution. In the first case a static and in the latter a semistatic exposure was established. Volatile and easily degradable compounds had high EC50 values in soil. In nutrient solution, however, several of these compounds were rather toxic. Quantitative structure activity relationships (QSARs) relating EC50 values to log K[sub ow] could be described for the toxicity in nutrient solution. Generally, the toxicity of the compounds increased with increasing lipophilicity. Deviations were caused by reactivity (N-containing compounds, double bonds in compounds), low lipophilicity, and EC50 values close to solubility. To relate toxicity in soil and nutrient solution, soil EC50 values were recalculated to values in the soil pore water using calculated adsorption coefficients. Estimated pore-water EC50 values showed a good correlation with values determined in nutrient solution but were not equal to these values. The differences can be attributed to differences in exposure.

  15. Underestimation of boreal soil carbon stocks by mathematical soil carbon models linked to soil nutrient status

    NASA Astrophysics Data System (ADS)

    Ťupek, Boris; Ortiz, Carina A.; Hashimoto, Shoji; Stendahl, Johan; Dahlgren, Jonas; Karltun, Erik; Lehtonen, Aleksi

    2016-08-01

    Inaccurate estimate of the largest terrestrial carbon pool, soil organic carbon (SOC) stock, is the major source of uncertainty in simulating feedback of climate warming on ecosystem-atmosphere carbon dioxide exchange by process-based ecosystem and soil carbon models. Although the models need to simplify complex environmental processes of soil carbon sequestration, in a large mosaic of environments a missing key driver could lead to a modeling bias in predictions of SOC stock change.We aimed to evaluate SOC stock estimates of process-based models (Yasso07, Q, and CENTURY soil sub-model v4) against a massive Swedish forest soil inventory data set (3230 samples) organized by a recursive partitioning method into distinct soil groups with underlying SOC stock development linked to physicochemical conditions.For two-thirds of measurements all models predicted accurate SOC stock levels regardless of the detail of input data, e.g., whether they ignored or included soil properties. However, in fertile sites with high N deposition, high cation exchange capacity, or moderately increased soil water content, Yasso07 and Q models underestimated SOC stocks. In comparison to Yasso07 and Q, accounting for the site-specific soil characteristics (e. g. clay content and topsoil mineral N) by CENTURY improved SOC stock estimates for sites with high clay content, but not for sites with high N deposition.Our analysis suggested that the soils with poorly predicted SOC stocks, as characterized by the high nutrient status and well-sorted parent material, indeed have had other predominant drivers of SOC stabilization lacking in the models, presumably the mycorrhizal organic uptake and organo-mineral stabilization processes. Our results imply that the role of soil nutrient status as regulator of organic matter mineralization has to be re-evaluated, since correct SOC stocks are decisive for predicting future SOC change and soil CO2 efflux.

  16. Plant invasion is associated with higher plant-soil nutrient concentrations in nutrient-poor environments.

    PubMed

    Sardans, Jordi; Bartrons, Mireia; Margalef, Olga; Gargallo-Garriga, Albert; Janssens, Ivan A; Ciais, Phillipe; Obersteiner, Michael; Sigurdsson, Bjarni D; Chen, Han Y H; Peñuelas, Josep

    2017-03-01

    Plant invasion is an emerging driver of global change worldwide. We aimed to disentangle its impacts on plant-soil nutrient concentrations. We conducted a meta-analysis of 215 peer-reviewed articles and 1233 observations. Invasive plant species had globally higher N and P concentrations in photosynthetic tissues but not in foliar litter, in comparison with their native competitors. Invasive plants were also associated with higher soil C and N stocks and N, P, and K availabilities. The differences in N and P concentrations in photosynthetic tissues and in soil total C and N, soil N, P, and K availabilities between invasive and native species decreased when the environment was richer in nutrient resources. The results thus suggested higher nutrient resorption efficiencies in invasive than in native species in nutrient-poor environments. There were differences in soil total N concentrations but not in total P concentrations, indicating that the differences associated to invasive plants were related with biological processes, not with geochemical processes. The results suggest that invasiveness is not only a driver of changes in ecosystem species composition but that it is also associated with significant changes in plant-soil elemental composition and stoichiometry.

  17. Ethylene and the Regulation of Physiological and Morphological Responses to Nutrient Deficiencies.

    PubMed

    García, María José; Romera, Francisco Javier; Lucena, Carlos; Alcántara, Esteban; Pérez-Vicente, Rafael

    2015-09-01

    To cope with nutrient deficiencies, plants develop both morphological and physiological responses. The regulation of these responses is not totally understood, but some hormones and signaling substances have been implicated. It was suggested several years ago that ethylene participates in the regulation of responses to iron and phosphorous deficiency. More recently, its role has been extended to other deficiencies, such as potassium, sulfur, and others. The role of ethylene in so many deficiencies suggests that, to confer specificity to the different responses, it should act through different transduction pathways and/or in conjunction with other signals. In this update, the data supporting a role for ethylene in the regulation of responses to different nutrient deficiencies will be reviewed. In addition, the results suggesting the action of ethylene through different transduction pathways and its interaction with other hormones and signaling substances will be discussed.

  18. Ethylene and the Regulation of Physiological and Morphological Responses to Nutrient Deficiencies

    PubMed Central

    García, María José; Romera, Francisco Javier; Lucena, Carlos; Alcántara, Esteban; Pérez-Vicente, Rafael

    2015-01-01

    To cope with nutrient deficiencies, plants develop both morphological and physiological responses. The regulation of these responses is not totally understood, but some hormones and signaling substances have been implicated. It was suggested several years ago that ethylene participates in the regulation of responses to iron and phosphorous deficiency. More recently, its role has been extended to other deficiencies, such as potassium, sulfur, and others. The role of ethylene in so many deficiencies suggests that, to confer specificity to the different responses, it should act through different transduction pathways and/or in conjunction with other signals. In this update, the data supporting a role for ethylene in the regulation of responses to different nutrient deficiencies will be reviewed. In addition, the results suggesting the action of ethylene through different transduction pathways and its interaction with other hormones and signaling substances will be discussed. PMID:26175512

  19. Bacterial Mobilization of Nutrients From Biochar-Amended Soils.

    PubMed

    Schmalenberger, A; Fox, A

    2016-01-01

    Soil amendments with biochar to improve soil fertility and increase soil carbon stocks have received some high-level attention. Physical and chemical analyses of amended soils and biochars from various feedstocks are reported, alongside some evaluations of plant growth promotion capabilities. Fewer studies investigated the soil microbiota and their potential to increase cycling and mobilization of nutrients in biochar-amended soils. This review is discussing the latest findings in the bacterial contribution to cycling and mobilizing nitrogen, phosphorus, and sulfur in biochar-amended soils and potential contributions to plant growth promotion. Depending on feedstock, pyrolysis, soil type, and plant cover, changes in the bacterial community structure were observed for a majority of the studies using amplicon sequencing or genetic fingerprinting methods. Prokaryotic nitrification largely depends on the availability of ammonium and can vary considerably under soil biochar amendment. However, denitrification to di-nitrogen and in particular, nitrous oxide reductase activity is commonly enhanced, resulting in reduced nitrous oxide emissions. Likewise, bacterial fixation of di-nitrogen appears to be regularly enhanced. A paucity of studies suggests that bacterial mobilization of phosphorus and sulfur is enhanced as well. However, most studies only tested for extracellular sulfatase and phosphatase activity. Further research is needed to reveal details of the bacterial nutrient mobilizing capabilities and this is in particular the case for the mobilization of phosphorus and sulfur.

  20. [Study on the polarized reflectance characteristics of single greenhouse tomato nutrient deficiency leaves].

    PubMed

    Zhu, Wen-Jing; Mao, Han-Ping; Liu, Hong-Yu; Zhang, Xiao-Dong; Ni, Ji-Heng

    2014-01-01

    In order to improve accuracy of quantitative analysis model for the greenhouse tomato nitrogen, phosphorus and potassium nutrient stress, and explore the advantages of polarization non-destructive detection in single-leaf plants scale, polarized reflectance characteristics of greenhouse nutrient deficiency tomato leaves in different growing seasons and different deficiency extents were both examined via means of polarized reflectance spectroscopy system, which was self-developed by the research group. The main factors with effects on the polarized reflectance characteristics of tomato leaves were discussed, such as incident zenith angle, azimuth angle, detection zenith angle, light source polarizer degree, and detector polarizer degree. Experiments were carried out to verify the optimum level of above five parameters by means of range analysis of orthogonal experiments, through that way we can know the best angle combination of five parameters. Based on the above analysis, the angle combination and sorting of detecting tomato nutrients deficiency leaves via means of polarization spectroscopy system were obtained as follows: incident zenith angle 60 degrees, light source polarizer degree 0 degrees, detection zenith angle 45 degrees, detector polarizer degree 45 degrees and azimuth angle 180 degrees. At the same time, both the spectra of nitrogen, phosphorus and potassium deficiency leaves in different growth stages and different deficiency extent leaves were compared with each other. Results show that there is a positive correlation between the greenhouse nutrient deficiency tomato leaves growth cycle and tomato leaves polarized reflectance spectra. Nutrient excess or nutrient deficiency can both lead to polarized reflectance decline and polarized reflectance decline extent of greenhouse tomato leaves is more obvious during the fruiting and harvest period. This paper has a certain theoretical and practical significance in the research on nutrition rapid detection on

  1. Transcriptional activities of methanogens and methanotrophs vary with methane emission flux in rice soils under chronic nutrient constraints of phosphorus and potassium

    NASA Astrophysics Data System (ADS)

    Sheng, Rong; Chen, Anlei; Zhang, Miaomiao; Whiteley, Andrew S.; Kumaresan, Deepak; Wei, Wenxue

    2016-12-01

    Nutrient status in soil is crucial for the growth and development of plants which indirectly or directly affect the ecophysiological functions of resident soil microorganisms. Soil methanogens and methanotrophs can be affected by soil nutrient availabilities and plant growth, which in turn modulate methane (CH4) emissions. Here, we assessed whether deficits in soil-available phosphorus (P) and potassium (K) modulated the activities of methanogens and methanotrophs in a long-term (20 year) experimental system involving limitation in either one or both nutrients. Results showed that a large amount of CH4 was emitted from paddy soil at rice tillering stage (flooding) while CH4 flux was minimum at ripening stage (drying). Compared to soils amended with NPK fertiliser treatment, the soils without P input significantly reduced methane flux rates, whereas those without K input did not. Under P limitation, methanotroph transcript copy number significantly increased in tandem with a decrease in methanogen transcript abundance, suggesting that P-deficiency-induced changes in soil physio-chemical properties, in tandem with rice plant growth, might constrain the activity of methanogens, whereas the methanotrophs might be adaptive to this soil environment. In contrast, lower transcript abundance of both methanogen and methanotrophs were observed in K-deficient soils. Assessments of community structures based upon transcripts indicated that soils deficient in P induced greater shifts in the active methanotrophic community than K-deficient soils, while similar community structures of active methanogens were observed in both treatments. These results suggested that the population dynamics of methanogens and methanotrophs could vary along with the changes in plant growth states and soil properties induced by nutrient deficiency.

  2. Effects of Phos-Chek® on soil nutrient availability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wildfire frequencies and intensities have been steadily increasing on western US landscapes. Phos-chek® is an aerially-applied fire retardant used to contain and control wildfires. Composed of ammonium and phosphate salts, Phos-chek® has the potential to increase soil nutrient availability of N and ...

  3. Temporal Changes in the Spatial Variability of Soil Nutrients

    SciTech Connect

    R. L. Hoskinson; J. R. Hess; R. S. Alessi

    1999-07-01

    This paper reports the temporal changes in the spatial variability of soil nutrient concentrations across a field during the growing season, over a four-year period. This study is part of the Site-Specific Technologies for Agriculture (SST4Ag) precision farming research project at the INEEL. Uniform fertilization did not produce a uniform increase in fertility. During the growing season, several of the nutrients and micronutrients showed increases in concentration although no additional fertilization had occurred. Potato plant uptake did not explain all of these changes. Some soil micronutrient concentrations increased above levels considered detrimental to potatoes, but the plants did not show the effects in reduced yield. All the nutrients measured changed between the last sampling in the fall and the first sampling the next spring prior to fertilization. The soil microbial community may play a major role in the temporal changes in the spatial variability of soil nutrient concentrations. These temporal changes suggest potential impact when determining fertilizer recommendations, and when evaluating the results of spatially varying fertilizer application.

  4. [Soil nutrients spatial variability and soil fertility suitability in Qujing tobacco-planting area].

    PubMed

    Li, Qiang; Zhou, Ji-heng; Yang, Rong-sheng; Zhang, Zheng-yan; Xie, Yan; Zhang, Yi-yang; Huang, Kua-ke; Li, Wei

    2011-04-01

    By adopting GPS technique, 2088 sampling sites were installed in the tobacco-planting area of Qujing City, Yunnan Province, with 0-20 cm soil samples collected to determine their main nutrients contents. The overall characteristics and spatial variability of the tobacco soil nutrients were analyzed by classic statistics and geo-statistics, and the soil fertility suitability in planting tobacco was evaluated by the methods of fuzzy mathematics. In the study area, soil pH and soil organic matter, available S, and water-soluble Cl contents were appropriate, soil total N and alkalihydrolyzable N contents were too high, soil available K, Ca, Mg, Cu, Fe, Zn, Mo, and Mn contents were abundant, soil available P content was at medium level, while soil total P and K and available B contents were insufficient. All the nutrient indices presented anisotropic distribution, among which, the spatial variability of soil available P and B was mainly caused by random factors, and that of other nutrients was caused by the co-effects of structural and random factors. The spatial distribution map of soil fertility suitability index (SFI) showed that there was no the excellent grade region for tobacco-planting, good grade region accounted for 8.0%, general grade region accounted for 51.6%, moderate grade region accounted for 39.0%, and low grade region accounted for 1.4%.

  5. Geographic variations of soil phosphorus induced by long-term land and manure nutrient management practices

    NASA Astrophysics Data System (ADS)

    Dao, Thanh

    2014-05-01

    Most natural and agricultural ecosystems are deficient in phosphorus (P), and supplemental P must be provided to attain optimal levels of agronomic production. Animal manure is often used to supply needed plant nutrients to enhance production of feed and fiber crops for human and livestock consumption. Soils have been treated with large amounts of P-enriched manure, and have shown elevated P levels in watersheds where there is a high density of intensive confined animal agriculture. Long-term additions can have lasting effects on the geographic distribution of soil microbes associated with the turnover of major soil nutrients, in particular non-mobile one such as P. We determined the distribution of soil P forms in a 10-ha no-till field that received annual additions of dairy manure at 0, 15, and 30 kg P ha-1 at the field scale for 16 consecutive years. Spectroscopic analyses of the near-surface zone were performed by X-ray fluorescence in soil cores taken to a depth of 0.2 m. Geostatistical methods were used to determine the spatial structure of the soil compositional data. Soil X-ray fluorescence spectral attributes were obtained based on a set of five parallel transects established across five experimental blocks, i.e., a 5 × 5 rectangular grid pattern. Three subsets of each soil attribute were identified for the three rates of manure addition. Long-term manure addition, albeit liquid manure, resulted in significant variability in soil P distribution in the near surface zone. The heterogeneity persisted over years of continuous no-tillage management. Therefore, a high density of geo-referenced soil measurements must be made to estimate the status of a required plant nutrient, especially a non-mobile nutrient in soil. A large number of timely measurements would require a rapid geo-referenced soil sensing spectroscopic method such as X-ray fluorescence to manage in near real-time the observed spatial variability of manure-treated fields.

  6. [Soil Microorganism Characteristics and Soil Nutrients of Different Wetlands in Sanjinag Plain, Northeast China].

    PubMed

    Xiao, Ye; Huang, Zhi-gang; Wu, Hai-tao; Lü, Xian-guo

    2015-05-01

    Four typical wetland types (i.e. wetlands with the following dominant plant species: Calamagrostis angustifolia + Salix brachypoda, Calamagrostis angustifolia, Carex lasiocarpa and Phragmites australis) of the Honghe reserve in Sanjiang Plain were studied to investigate the distribution of soil microorganism quantity and enzyme activity and their relationships with soil nutrients. The results showed that in 0-30 cm soil layer of these four wetlands: (1) Contents of soil total organic carbon, total nitrogen and total phosphorus decreased with the increase of soil depth, while available nitrogen, phosphorus and potassium did not exhibit regularly changes. Moreover, there were significantly different for soil nutrient contents among different wetland types (P < 0.05). (2) The number of soil microorganism was bacteria > actinomycetes > fungi, furthermore, the number of three microbial colonies all decreased with the increase of soil depth. Total soil microbial number of C. angustifolia wetland was the highest and that of C. lasiocarpa wetland was the lowest. (3) Soil invertase and cellulase activities decreased with soil depth, while soil catalase activity showed no consistent changes. Three kinds of enzyme activities in C. angustifolia + S. brachypoda and C. angustifolia wetlands were significantly higher than those of C. lasiocarpa and P. australis wetlands (P < 0.05). (4) The correlation analysis showed that soil bacteria, fungi and cellulose activity had a significant correlation with indicators of soil nutrients. But there was no correlation between actinomyces, invertase and available potassium, as well as between catalase and available potassium, available phosphorus. Overall, soil microorganism and enzyme activities are important indicators for reflecting the status of soil nutrients.

  7. Complications, reoperations, and nutrient deficiencies two years after sleeve gastrectomy.

    PubMed

    Pech, Nicole; Meyer, Frank; Lippert, Hans; Manger, Thomas; Stroh, Christine

    2012-01-01

    Background. The aim of this study was to investigate patient outcomes and nutritional deficiencies following sleeve gastrectomy (SG) during a follow-up of two years. Methods. Over a period of 56 months, all consecutive patients who underwent SG were documented in this prospective, single-center, observational study. The study endpoints included operative time, complication rates, nutritional deficiencies and percentage of excess weight loss (%EWL). Results. From September 26, 2005 to May 28, 2009, 82 patients (female : male = 48 : 34) with a mean age of 43.3 years (range: 22-64) and a preoperative BMI of 52.5 kg/m² (range: 36.8-77.0) underwent SG. Major complications were observed in 9.8% of the patients, with 1 death. During follow up 51.2% of patients were supplemented with iron, 36.6% with zinc, 37.8% with calcium, 26.8% with vitamin D, 46.3% with vitamin B12 and 41.5% with folic acid. %EWL was 54.3, 65.3 and 62.6% after 6, 12 and 24 months. Conclusion. SG as a single step procedure is an effective bariatric intervention. Nutritional deficiencies after SG can be detected by routine nutritional screening. Our results show that Vitamin B12 supplementation should suggest routinely after SG.

  8. [Response of fine roots to soil nutrient spatial heterogeneity].

    PubMed

    Wang, Qingcheng; Cheng, Yunhuan

    2004-06-01

    The spatial heterogeneity is the complexity and variation of systems or their attributes, and the heterogeneity of soil nutrients is ubiquitous in all natural ecosystems. The scale of spatial heterogeneity varies considerably among different ecosystems, from tens of centimeters to hundred meters. Some of the scales can be detected by individual plant. Because the growth of individual plants can be strongly influenced by soil heterogeneity, it follows that the inter-specific competition should also be affected. During the long process of evolution, plants developed various plastic responses with their root system, including morphological, physiological and mycorrhizal plasticity, to maximize the nutrient acquisition from heterogeneous soil resources. Morphological plasticity, an adjustment in root system spatial allocation and architecture in response to spatial heterogeneous distribution of available soil resources, has been most intensively studied, and root proliferation in nutrient rich patches has been certified for many species. The species that do respond may have an increased rate of nutrient uptake, leading to a competitive advantage. Scale and precision are two important features employed in describing the size and foraging behavior of root system. It was hypothesized that scale and precision is negatively related, i. e., the species with high scale of root system tend to be a less precise forager. The outcomes of different research work have been diverse, far from reaching a consensus. Species with high scale are not necessarily less precise in fine root allocation, and vice versa. The proliferation of fine root in enriched micro-sites is species dependent, and also affected by other factors, such as patch attributes (size and nutrients concentration), nutrients, and overall soil fertility. Beside root proliferation in nutrient enriched patches, plants can also adapt themselves to the heterogeneous soil environment by altering other root characteristics

  9. Nutrient deficiency in the production of artemisinin, dihydroartemisinic acid, and artemisinic acid in Artemisia annua L.

    PubMed

    Ferreira, Jorge F S

    2007-03-07

    Artemisia annua became a valuable agricultural crop after the World Health Organization recommended artemisinin as a component of ACT (artemisinin-combination based therapies) for malaria in 2001. A cloned, greenhouse-grown, A. annua (Artemis) subjected to an acidic soil and macronutrient deficit was evaluated for artemisinin production. Lack of lime (L) and macronutrients (N, P, and K) reduced leaf biomass accumulation. When L was provided (pH 5.1), the highest average leaf biomass was achieved with the "complete" (+N, +P, +K, and +L) treatment (70.3 g/plant), and the least biomass was achieved with the untreated (-N, -P, -K, and -L) treatment (6.18 g/plant). The nutrient least required for biomass accumulation per plant (g) was K (49.0 g), followed by P (36.5 g) and N (14.3 g). The artemisinin concentration (g/100 g) was significantly higher (75.5%) in -K plants when compared to plants under the complete treatment (1.62 vs 0.93%). Although the artemisinin total yield (g/plant) was 21% higher in -K plants, it was not significantly different from plants under the complete treatment (0.80 vs 0.66 g/plant). There were no marked treatment effects for concentration (g/100 g) or yield (g/plant) of both dihydroartemisinic acid and artemisinic acid, although higher levels were achieved in plants under the complete or -K treatments. There was a positive and significant correlation between artemisinin and both artemisinic acid and dihydroartemisin acid, in g/100 g and g/plant. This is the first report where potassium deficiency significantly increases the concentration (g/100 g) of artemisinin. Thus, under a mild potassium deficiency, A. annua farmers could achieve similar gains in artemisinin/ha, while saving on potassium fertilization, increasing the profitability of artemisinin production.

  10. 7 CFR 205.203 - Soil fertility and crop nutrient management practice standard.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... nutrients and soil fertility through rotations, cover crops, and the application of plant and animal... 7 Agriculture 3 2012-01-01 2012-01-01 false Soil fertility and crop nutrient management practice... Requirements § 205.203 Soil fertility and crop nutrient management practice standard. (a) The producer...

  11. 7 CFR 205.203 - Soil fertility and crop nutrient management practice standard.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... nutrients and soil fertility through rotations, cover crops, and the application of plant and animal... 7 Agriculture 3 2011-01-01 2011-01-01 false Soil fertility and crop nutrient management practice... Requirements § 205.203 Soil fertility and crop nutrient management practice standard. (a) The producer...

  12. 7 CFR 205.203 - Soil fertility and crop nutrient management practice standard.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... nutrients and soil fertility through rotations, cover crops, and the application of plant and animal... 7 Agriculture 3 2014-01-01 2014-01-01 false Soil fertility and crop nutrient management practice... Requirements § 205.203 Soil fertility and crop nutrient management practice standard. (a) The producer...

  13. 7 CFR 205.203 - Soil fertility and crop nutrient management practice standard.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... nutrients and soil fertility through rotations, cover crops, and the application of plant and animal... 7 Agriculture 3 2013-01-01 2013-01-01 false Soil fertility and crop nutrient management practice... Requirements § 205.203 Soil fertility and crop nutrient management practice standard. (a) The producer...

  14. 7 CFR 205.203 - Soil fertility and crop nutrient management practice standard.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... nutrients and soil fertility through rotations, cover crops, and the application of plant and animal... 7 Agriculture 3 2010-01-01 2010-01-01 false Soil fertility and crop nutrient management practice... Requirements § 205.203 Soil fertility and crop nutrient management practice standard. (a) The producer...

  15. Reprogramming of root epidermal cells in response to nutrient deficiency.

    PubMed

    Perry, P; Linke, B; Schmidt, W

    2007-02-01

    Post-embryonic development of the root system is highly plastic to environmental cues, compensating for the sessile lifestyle of plants. The fate of epidermal cells of Arabidopsis roots is particularly responsive to nutritional signals, leading to an increase in the root's surface area in the absence of the essential but immobile minerals iron, phosphate and manganese. The resulting phenotype is characteristic of the respective condition. Growth under nutrient starvation affects the expression of genes involved in cell specification, indicating that environmental signals are perceived at an early stage of cell development. Cell fate decisions are controlled at different levels, probably integrated at the level of chromatin organization.

  16. The relative importance of vertical soil nutrient heterogeneity, and mean and depth-specific soil nutrient availabilities for tree species richness in tropical forests and woodlands.

    PubMed

    Shirima, Deo D; Totland, Ørjan; Moe, Stein R

    2016-11-01

    The relative importance of resource heterogeneity and quantity on plant diversity is an ongoing debate among ecologists, but we have limited knowledge on relationships between tree diversity and heterogeneity in soil nutrient availability in tropical forests. We expected tree species richness to be: (1) positively related to vertical soil nutrient heterogeneity; (2) negatively related to mean soil nutrient availability; and (3) more influenced by nutrient availability in the upper than lower soil horizons. Using a data set from 60, 20 × 40-m plots in a moist forest, and 126 plots in miombo woodlands in Tanzania, we regressed tree species richness against vertical soil nutrient heterogeneity, both depth-specific (0-15, 15-30, and 30-60 cm) and mean soil nutrient availability, and soil physical properties, with elevation and measures of anthropogenic disturbance as co-variables. Overall, vertical soil nutrient heterogeneity was the best predictor of tree species richness in miombo but, contrary to our prediction, the relationships between tree species richness and soil nutrient heterogeneity were negative. In the moist forest, mean soil nutrient availability explained considerable variations in tree species richness, and in line with our expectations, these relationships were mainly negative. Soil nutrient availability in the top soil layer explained more of the variation in tree species richness than that in the middle and lower layers in both vegetation types. Our study shows that vertical soil nutrient heterogeneity and mean availability can influence tree species richness at different magnitudes in intensively utilized tropical vegetation types.

  17. Active Layer Soil Carbon and Nutrient Mineralization, Barrow, Alaska, 2012

    DOE Data Explorer

    Stan D. Wullschleger; Holly M. Vander Stel; Colleen Iversen; Victoria L. Sloan; Richard J. Norby; Mallory P. Ladd; Jason K. Keller; Ariane Jong; Joanne Childs; Deanne J. Brice

    2015-10-29

    This data set consists of bulk soil characteristics as well as carbon and nutrient mineralization rates of active layer soils manually collected from the field in August, 2012, frozen, and then thawed and incubated across a range of temperatures in the laboratory for 28 day periods in 2013-2015. The soils were collected from four replicate polygons in each of the four Areas (A, B, C, and D) of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Soil samples were coincident with the established Vegetation Plots that are located in center, edge, and trough microtopography in each polygon. Data included are 1) bulk soil characteristics including carbon, nitrogen, gravimetric water content, bulk density, and pH in 5-cm depth increments and also by soil horizon, 2) carbon, nitrogen, and phosphorus mineralization rates for soil horizons incubated aerobically (and in one case both aerobically and anaerobically) for 28 days at temperatures that included 2, 4, 8, and 12 degrees C. Additional soil and incubation data are forthcoming. They will be available when published as part of another paper that includes additional replicate analyses.

  18. Risks and benefits of gardening in urban soil; heavy metals and nutrient content in Los Angeles Community Gardens

    NASA Astrophysics Data System (ADS)

    Clarke, L. W.; Jenerette, D.; Bain, D. J.

    2012-12-01

    The availability of soil nutrients and heavy metals in urban community gardens can influence health of crops and participants. Interactions between garden history, management, and soils are understudied in cities. In July 2011, we collected soil samples from 45 plots at 6 Los Angeles community gardens. For comparison, 3 samples were collected from uncultivated garden soils and 3 more from outside soils. Samples were then tested for major nutrients- Nitrogen(N), Potassium (K), and Phosphorous (P)- and organic matter (SOM). We also measured concentrations of 29 metals in 3 gardens using Inductively Coupled Plasma- Atomic Emission Spectroscopy. Potassium and phosphorus exceeded optimum levels in all plots, with some over twice the maximum recommended levels. Over-fertilized soils may contribute to local watershed pollution and crop micronutrient deficiencies. Low soil SOM was observed in gardens in impoverished neighborhoods, possibly due to low quality amendments. Our metals analysis showed dangerous levels of lead (Pb)-- up to 1700 ppm in outside soils and 150 ppm in garden soils-- near older gardens, indicating lead deposition legacies. California lead safety standards indicate that children should not play near soils with Pb above 200 ppm, indicating need for long term monitoring of lead contaminated gardens. Arsenic (As) levels exceeded federal risk levels (0.3 ppm) and average CA background levels (2 ppm) in all areas, with some gardens exceeding 10 ppm. Heavy metal legacies in gardens may pose risks to participants with prolonged exposure and remediation of soils may be necessary.

  19. [Effects of biochar on soil nutrients leaching and potential mechanisms: A review].

    PubMed

    Liu, Yu-xue; Lyu, Hao-hao; Shi, Yan; Wang, Yao-feng; Zhong, Zhe-ke; Yang, Sheng-mao

    2015-01-01

    Controlling soil nutrient leaching in farmland ecosystems has been a hotspot in the research field of agricultural environment. Biochar has its unique physical and chemical properties, playing a significant role in enhancing soil carbon storage, improving soil quality and increasing crop yield. As a kind of new exogenous material, biochar has the potential in impacting soil nutrient cycling directly or indirectly, and has profound influences on soil nutrient leaching. This paper analyzed the intrinsic factors affecting how biochar affects soil nutrient leaching, such as the physical and chemical properties of biochar, and the interaction between biochar and soil organisms. Then the latest literatures regarding the external factors, including biochar application rates, soil types, depth of soil layer, fertilization conditions and temporal dynamics, through which biochar influences soil nutrient (especially nitrogen and phosphorus) leaching were reviewed. On that basis, four related action mechanisms were clarified, including direct adsorption of nutrients by biochar due to its micropore structure or surface charge, influencing nutrient leaching through increasing soil water- holding capacity, influencing nutrient cycling through the interaction with soil microbes, and preferential transport of absorbed nutrients by fine biochar particles. At last future research directions for better understanding the interactions between biochar and nutrient leaching in the soil were proposed.

  20. Plant nutrients do not covary with soil nutrients under changing climatic conditions

    NASA Astrophysics Data System (ADS)

    Luo, Wentao; Elser, James J.; Lü, Xiao-Tao; Wang, Zhengwen; Bai, Edith; Yan, Caifeng; Wang, Chao; Li, Mai-He; Zimmermann, Niklaus E.; Han, Xingguo; Xu, Zhuwen; Li, Hui; Wu, Yunna; Jiang, Yong

    2015-08-01

    Nitrogen (N) and phosphorus (P) play vital roles in plant growth and development. Yet how climate regimes and soil fertility influence plant N and P stoichiometry is not well understood, especially in the belowground plant parts. Here we investigated plant aboveground and belowground N and P concentrations ([N] and [P]) and their stoichiometry in three dominant genera along a 2200 km long climatic gradient in northern China. Results showed that temperature explained more variation of [N] and [P] in C4 plants, whereas precipitation exerted a stronger influence on [N] and [P] in C3 plants. Both plant aboveground and belowground [N] and [P] increased with decreasing precipitation, and increasing temperatures yet were negatively correlated with soil [N] and [P]. Plant N:P ratios were unrelated with all climate and soil variables. Plant aboveground and belowground [N] followed an allometric scaling relationship, but the allocation of [P] was isometric. These results imply that internal processes stabilize plant N:P ratios and hence tissue N:P ratios may not be an effective parameter for predicting plant nutrient limitation. Our results also imply that past positive relationships between plant and nutrient stocks may be challenged under changing climatic conditions. While any modeling would need to be able to replicate currently observed relationships, it is conceivable that some relationships, such as those between temperature or rainfall and carbon:nutrient ratios, should be different under changing climatic conditions.

  1. It is elemental: soil nutrient stoichiometry drives bacterial diversity.

    PubMed

    Delgado-Baquerizo, Manuel; Reich, Peter B; Khachane, Amit N; Campbell, Colin D; Thomas, Nadine; Freitag, Thomas E; Abu Al-Soud, Waleed; Sørensen, Søren; Bardgett, Richard D; Singh, Brajesh K

    2017-03-01

    It is well established that resource quantity and elemental stoichiometry play major roles in shaping below and aboveground plant biodiversity, but their importance for shaping microbial diversity in soil remains unclear. Here, we used statistical modeling on a regional database covering 179 locations and six ecosystem types across Scotland to evaluate the roles of total carbon (C), nitrogen (N) and phosphorus (P) availabilities and ratios, together with land use, climate and biotic and abiotic factors, in determining regional scale patterns of soil bacterial diversity. We found that bacterial diversity and composition were primarily driven by variation in soil resource stoichiometry (total C:N:P ratios), itself linked to different land uses, and secondarily driven by other important biodiversity drivers such as climate, soil spatial heterogeneity, soil pH, root influence (plant-soil microbe interactions) and microbial biomass (soil microbe-microbe interactions). In aggregate, these findings provide evidence that nutrient stoichiometry is a strong predictor of bacterial diversity and composition at a regional scale.

  2. Proposed chemical mechanismsManagement practices impacts soil nutrients and bacterial populations in backgrounding beef feedlot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive beef backgrounding often accumulate manure born soil nutrients, microbes, and pharmaceuticals at different site locations. Unless properly managed, such waste materials can pollute surrounding soil and water sources. Soil sampling from these sites helps determining waste material levels bu...

  3. Soil nutrients influence spatial distributions of tropical trees species

    USGS Publications Warehouse

    John, R.; Dalling, J.W.; Harms, K.E.; Yavitt, J.B.; Stallard, R.F.; Mirabello, M.; Hubbell, S.P.; Valencia, R.; Navarrete, H.; Vallejo, M.; Foster, R.B.

    2007-01-01

    The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757-1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant-soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36-51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant-soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species. ?? 2007 by The National Academy of Sciences of the USA.

  4. BOREAS TE-1 SSA-Fen Soil Profile Nutrient Data

    NASA Technical Reports Server (NTRS)

    Papagno, Andrea; Anderson, Darwin; Newcomer, Jeffrey A. (Editor); Hall, Forrest G. (Editor)

    2000-01-01

    The BOREAS TE-1 team collected various data to characterize the soil-plant systems in the BOREAS SSA. Particular emphasis was placed on nutrient biochemistry, the stores and transfers of organic carbon, and how the characteristics were related to measured methane fluxes. The overall traniect in the Prince Albert National Park (Saskatchewan, Canada) included the major plant communities and related soils that occurred in that section of the boreal forest. Soil physical, chemical, and biological measurements along the transect were used to characterize the static environment, which allowed them to be related to methane fluxes. Chamber techniques were used to provide a measure of methane production/uptake. Chamber measurements coupled with flask sampling were used to determine the seasonality of methane fluxes. This particular data set contains soil profile measurements of various nutrients at the SSA-Fen site. The data were collected from 23-May to 21-Oct- 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  5. Comparison of plant nutrient and environmental soil tests to predict Pb in urban soils.

    PubMed

    Minca, Kristen Kathleen; Basta, Nicholas Thomas

    2013-02-15

    Most urban soils are not tested for Pb because of the high costs associated with sampling and laboratory analysis of soil contaminants. However, soil testing for plant nutrients is inexpensive and routinely performed for agricultural soils used for food production. The objectives of this study are to determine the ability of 1 M HNO(3), Mehlich 3, and Modified Morgan soil tests to predict total Pb and other contaminants in urban soils. Total Pb was determined from 65 urban vacant residential lots being considered for urban gardens and food production in Cleveland, OH. Extractable Pb was determined using common soil nutrient test methods Mehlich 3 and Modified Morgan extraction, and a 1M HNO(3) extraction. Significant linear regressions between total Pb and Mehlich 3 (r(2)=0.83), 1M HNO(3) (r(2)=0.92), and Modified Morgan (r(2)=0.77) in study soils were found. Most commercial and university soil testing labs use Mehlich 3 which could be implemented as a screening tool for soil Pb, Cu, and Zn. The Mehlich 3 soil test is widely used and is relatively inexpensive (<$15). Our results show that total Pb can be conservatively estimated by the following equation Total Pb (mg kg(-1))=Mehlich 3 Pb (mg kg(-1))×2.

  6. Woody encroachment reduces nutrient limitation and promotes soil carbon sequestration

    PubMed Central

    Blaser, Wilma J; Shanungu, Griffin K; Edwards, Peter J; Olde Venterink, Harry

    2014-01-01

    During the past century, the biomass of woody species has increased in many grassland and savanna ecosystems. As many of these species fix nitrogen symbiotically, they may alter not only soil nitrogen (N) conditions but also those of phosphorus (P). We studied the N-fixing shrub Dichrostachys cinerea in a mesic savanna in Zambia, quantifying its effects upon pools of soil N, P, and carbon (C), and availabilities of N and P. We also evaluated whether these effects induced feedbacks upon the growth of understory vegetation and encroaching shrubs. Dichrostachys cinerea shrubs increased total N and P pools, as well as resin-adsorbed N and soil extractable P in the top 10-cm soil. Shrubs and understory grasses differed in their foliar N and P concentrations along gradients of increasing encroachment, suggesting that they obtained these nutrients in different ways. Thus, grasses probably obtained them mainly from the surface upper soil layers, whereas the shrubs may acquire N through symbiotic fixation and probably obtain some of their P from deeper soil layers. The storage of soil C increased significantly under D. cinerea and was apparently not limited by shortages of either N or P. We conclude that the shrub D. cinerea does not create a negative feedback loop by inducing P-limiting conditions, probably because it can obtain P from deeper soil layers. Furthermore, C sequestration is not limited by a shortage of N, so that mesic savanna encroached by this species could represent a C sink for several decades. We studied the effects of woody encroachment on soil N, P, and C pools, and availabilities of N and P to Dichrostachys cinerea shrubs and to the understory vegetation. Both N and P pools in the soil increased along gradients of shrub age and cover, suggesting that N fixation by D. cinerea did not reduce the P supply. This in turn suggests that continued growth and carbon sequestration in this mesic savanna ecosystems are unlikely to be constrained by nutrient

  7. Soil bacterial community composition altered by increased nutrient availability in Arctic tundra soils.

    PubMed

    Koyama, Akihiro; Wallenstein, Matthew D; Simpson, Rodney T; Moore, John C

    2014-01-01

    The pool of soil organic carbon (SOC) in the Arctic is disproportionally large compared to those in other biomes. This large quantity of SOC accumulated over millennia due to slow rates of decomposition relative to net primary productivity. Decomposition is constrained by low temperatures and nutrient concentrations, which limit soil microbial activity. We investigated how nutrients limit bacterial and fungal biomass and community composition in organic and mineral soils within moist acidic tussock tundra ecosystems. We sampled two experimental arrays of moist acidic tussock tundra that included fertilized and non-fertilized control plots. One array included plots that had been fertilized annually since 1989 and the other since 2006. Fertilization significantly altered overall bacterial community composition and reduced evenness, to a greater degree in organic than mineral soils, and in the 1989 compared to the 2006 site. The relative abundance of copiotrophic α-Proteobacteria and β-Proteobacteria was higher in fertilized than control soils, and oligotrophic Acidobacteria were less abundant in fertilized than control soils at the 1989 site. Fungal community composition was less sensitive to increased nutrient availability, and fungal responses to fertilization were not consistent between soil horizons and sites. We detected two ectomycorrhizal genera, Russula and Cortinarius spp., associated with shrubs. Their relative abundance was not affected by fertilization despite increased dominance of their host plants in the fertilized plots. Our results indicate that fertilization, which has been commonly used to simulate warming in Arctic tundra, has limited applicability for investigating fungal dynamics under warming.

  8. Nutrient deficiencies modify the ionomic composition of plant tissues: a focus on cross-talk between molybdenum and other nutrients in Brassica napus.

    PubMed

    Maillard, Anne; Etienne, Philippe; Diquélou, Sylvain; Trouverie, Jacques; Billard, Vincent; Yvin, Jean-Claude; Ourry, Alain

    2016-10-01

    The composition of the ionome is closely linked to a plant's nutritional status. Under certain deficiencies, cross-talk induces unavoidable accumulation of some nutrients, which upsets the balance and modifies the ionomic composition of plant tissues. Rapeseed plants (Brassica napus L.) grown under controlled conditions were subject to individual nutrient deficiencies (N, K, P, Ca, S, Mg, Fe, Cu, Zn, Mn, Mo, or B) and analyzed by inductively high-resolution coupled plasma mass spectrometry to determine the impact of deprivation on the plant ionome. Eighteen situations of increased uptake under mineral nutrient deficiency were identified, some of which have already been described (K and Na, S and Mo, Fe, Zn and Cu). Additionally, as Mo uptake was strongly increased under S, Fe, Cu, Zn, Mn, or B deprivation, the mechanisms underlying the accumulation of Mo in these deficient plants were investigated. The results suggest that it could be the consequence of multiple metabolic disturbances, namely: (i) a direct disturbance of Mo metabolism leading to an up-regulation of Mo transporters such as MOT1, as found under Zn or Cu deficiency, which are nutrients required for synthesis of the Mo cofactor; and (ii) a disturbance of S metabolism leading to an up-regulation of root SO4(2-) transporters, causing an indirect increase in the uptake of Mo in S, Fe, Mn, and B deficient plants.

  9. Root Nutrient Foraging1

    PubMed Central

    Giehl, Ricardo F.H.; von Wirén, Nicolaus

    2014-01-01

    During a plant's lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant's nutritional status. PMID:25082891

  10. Root nutrient foraging.

    PubMed

    Giehl, Ricardo F H; von Wirén, Nicolaus

    2014-10-01

    During a plant's lifecycle, the availability of nutrients in the soil is mostly heterogeneous in space and time. Plants are able to adapt to nutrient shortage or localized nutrient availability by altering their root system architecture to efficiently explore soil zones containing the limited nutrient. It has been shown that the deficiency of different nutrients induces root architectural and morphological changes that are, at least to some extent, nutrient specific. Here, we highlight what is known about the importance of individual root system components for nutrient acquisition and how developmental and physiological responses can be coupled to increase nutrient foraging by roots. In addition, we review prominent molecular mechanisms involved in altering the root system in response to local nutrient availability or to the plant's nutritional status.

  11. Identification of nutrient deficiency in maize and tomato plants by in vivo chlorophyll a fluorescence measurements.

    PubMed

    Kalaji, Hazem M; Oukarroum, Abdallah; Alexandrov, Vladimir; Kouzmanova, Margarita; Brestic, Marian; Zivcak, Marek; Samborska, Izabela A; Cetner, Magdalena D; Allakhverdiev, Suleyman I; Goltsev, Vasilij

    2014-08-01

    The impact of some macro (Ca, S, Mg, K, N, P) and micro (Fe) nutrients deficiency on the functioning of the photosynthetic machinery in tomato (Solanum lycopersicum L.) and maize (Zea mays L.) plants grown in hydroponic cultures were investigated. Plants grown on a complete nutrient solution (control) were compared with those grown in a medium, which lacked one of macro- or microelements. The physiological state of the photosynthetic machinery in vivo was analysed after 14-days of deficient condition by the parameters of JIP-test based on fast chlorophyll a fluorescence records. In most of the nutrient-deficient samples, the decrease of photochemical efficiency, increase in non-photochemical dissipation and decrease of the number of active photosystem II (PSII) reaction centres were observed. However, lack of individual nutrients also had nutrient-specific effects on the photochemical processes. In Mg and Ca-deficient plants, the most severe decrease in electron donation by oxygen evolving complex (OEC) was indicated. Sulphur deficiency caused limitation of electron transport beyond PSI, probably due to decrease in the PSI content or activity of PSI electron acceptors; in contrary, Ca deficiency had an opposite effect, where the PSII activity was affected much more than PSI. Despite the fact that clear differences in nutrient deficiency responses between tomato and maize plants were observed, our results indicate that some of presented fluorescence parameters could be used as fluorescence phenotype markers. The principal component analysis of selected JIP-test parameters was presented as a possible species-specific approach to identify/predict the nutrient deficiency using the fast chlorophyll fluorescence records.

  12. Emerging Trends in Epigenetic Regulation of Nutrient Deficiency Response in Plants.

    PubMed

    Sirohi, Gunjan; Pandey, Bipin K; Deveshwar, Priyanka; Giri, Jitender

    2016-03-01

    Diverse environmental stimuli largely affect the ionic balance of soil, which have a direct effect on growth and crop yield. Details are fast emerging on the genetic/molecular regulators, at whole-genome levels, of plant responses to mineral deficiencies in model and crop plants. These genetic regulators determine the root architecture and physiological adaptations for better uptake and utilization of minerals from soil. Recent evidence also shows the potential roles of epigenetic mechanisms in gene regulation, driven by minerals imbalance. Mineral deficiency or sufficiency leads to developmental plasticity in plants for adaptation, which is preceded by a change in the pattern of gene expression. Notably, such changes at molecular levels are also influenced by altered chromatin structure and methylation patterns, or involvement of other epigenetic components. Interestingly, many of the changes induced by mineral deficiency are also inheritable in the form of epigenetic memory. Unravelling these mechanisms in response to mineral deficiency would further advance our understanding of this complex plant response. Further studies on such approaches may serve as an exciting interaction model of epigenetic and genetic regulations of mineral homeostasis in plants and designing strategies for crop improvement.

  13. Nutrient use preferences among soil Streptomyces suggest greater resource competition in monoculture than polyculture plant communities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient use overlap among sympatric Streptomyces populations is correlated with pathogen inhibitory capacity, yet there is little information on either the factors that influence nutrient use overlap among coexisting populations or the diversity of nutrient use among soil Streptomyces. We examined ...

  14. Soil nutrient dynamics in small beef cattle backgrounding feedlot on karst environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef cattle backgrounding feedlot systems that grow out weaned calves for feedlot finishing can become potential diffuse sources of manure derived soil nutrients. Better understanding of these nutrient concentrations and their distribution will aid in development of effective nutrient management gui...

  15. Carbon storage in seagrass soils: long-term nutrient history exceeds the effects of near-term nutrient enrichment

    NASA Astrophysics Data System (ADS)

    Armitage, A. R.; Fourqurean, J. W.

    2015-10-01

    The carbon sequestration potential in coastal soils is linked to aboveground and belowground plant productivity and biomass, which in turn, is directly and indirectly influenced by nutrient input. We evaluated the influence of long-term and near-term nutrient input on aboveground and belowground carbon accumulation in seagrass beds, using a nutrient enrichment (nitrogen and phosphorus) experiment embedded within a naturally occurring, long-term gradient of phosphorus availability within Florida Bay (USA). We measured organic carbon stocks in soils and above- and belowground seagrass biomass after 17 months of experimental nutrient addition. At the nutrient-limited sites, phosphorus addition increased the carbon stock in aboveground seagrass biomass by more than 300 %; belowground seagrass carbon stock increased by 50-100 %. Soil carbon content slightly decreased (~ 10 %) in response to phosphorus addition. There was a strong but non-linear relationship between soil carbon and Thalassia testudinum leaf nitrogen: phosphorus (N : P) or belowground seagrass carbon stock. When seagrass leaf N : P exceeded a threshold of 75 : 1, or when belowground seagrass carbon stock was less than 100 g m-2, there was less than 3 % organic carbon in the sediment. Despite the marked difference in soil carbon between phosphorus-limited and phosphorus-replete areas of Florida Bay, all areas of the bay had relatively high soil carbon stocks near or above the global median of 1.8 % organic carbon. The relatively high carbon content in the soils indicates that seagrass beds have extremely high carbon storage potential, even in nutrient-limited areas with low biomass or productivity.

  16. Carbon storage in seagrass soils: long-term nutrient history exceeds the effects of near-term nutrient enrichment

    NASA Astrophysics Data System (ADS)

    Armitage, A. R.; Fourqurean, J. W.

    2016-01-01

    The carbon sequestration potential in coastal soils is linked to aboveground and belowground plant productivity and biomass, which in turn, is directly and indirectly influenced by nutrient input. We evaluated the influence of long-term and near-term nutrient input on aboveground and belowground carbon accumulation in seagrass beds, using a nutrient enrichment (nitrogen and phosphorus) experiment embedded within a naturally occurring, long-term gradient of phosphorus availability within Florida Bay (USA). We measured organic carbon stocks in soils and above- and belowground seagrass biomass after 17 months of experimental nutrient addition. At the nutrient-limited sites, phosphorus addition increased the carbon stock in aboveground seagrass biomass by more than 300 %; belowground seagrass carbon stock increased by 50-100 %. Soil carbon content slightly decreased ( ˜ 10 %) in response to phosphorus addition. There was a strong but non-linear relationship between soil carbon and Thalassia testudinum leaf nitrogen : phosphorus (N : P) or belowground seagrass carbon stock. When seagrass leaf N : P exceeded an approximate threshold of 75 : 1, or when belowground seagrass carbon stock was less than 100 g m-2, there was less than 3 % organic carbon in the sediment. Despite the marked difference in soil carbon between phosphorus-limited and phosphorus-replete areas of Florida Bay, all areas of the bay had relatively high soil carbon stocks near or above the global median of 1.8 % organic carbon. The relatively high carbon content in the soils indicates that seagrass beds have extremely high carbon storage potential, even in nutrient-limited areas with low biomass or productivity.

  17. Inorganic fertilizers after broiler litter amendment reduce surplus nutrients in orchardgrass soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The common producer practice to dispose of broiler litter at high rates to forage crops allow excessive accumulation of soil nutrients. A remediation study was developed to examine if inorganic fertilizer application over the residual fertility of broiler litter would reduce surplus soil nutrients i...

  18. Spatial distribution of livestock concentration areas and soil nutrients in pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock congregate at feeders, shades, or other sites in pastures, which severely disturbs soil and vegetation leading to erosion and nutrient runoff. Our objective was to determine the extent and spatial distribution of soil nutrients in livestock concentration areas in pastures. We georeferenced...

  19. Spatial distribution of livestock concentration areas and soil nutrients in pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock frequently congregate at feeders, shades, or other sites on pastures, which severely disturbs soil and vegetation leading to erosion and nutrient runoff. Our objective was to determine the extent and spatial distribution of soil nutrients in livestock concentration areas on pastures and qu...

  20. Nutrient losses from Fall and Winter-applied manure: Effects of timing and soil temperature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil temperature is a major environmental factor that affects both the infiltration of meltwater and precipitation, and nutrient cycling. The objectives of this study were to determine nutrient losses in runoff and leachate from fall and winter-applied dairy manure based on the soil temperature at t...

  1. Measurement of nutrients in green house soil with laser induced breakdown spectroscopy.

    PubMed

    Hussain, T; Gondal, M A; Yamani, Z H; Baig, M A

    2007-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of nutrients in the green house soil samples. We determined appropriate spectral signatures of vital nutrients and calibrated the method to measure the nutrients in a naturally fertilized plot, cultivated with tomato and cucumber plants. From the calibration curves we predicted the concentrations of important nutrients such as Ca, K, P, Mg, Fe, S, Ni and Ba in the soil. Our measurements proved that the LIBS method rapidly and efficiently measures soil nutrients with excellent detection limits of 12, 9, 7, 9, 7, 10, 8 and 12 mg/kg for Ca, K, P, Mg, Fe, S, Ni and Ba respectively with a precision of approximately 2%, The unique features of LIBS for rapid sample analysis demonstrated by this study suggests that this method offers promise for precision measurements of soil nutrients as compared to conventional methods in short span of time.

  2. Long-term effects of sustained beef feedlot manure application on soil nutrients, corn silage yield, and nutrient uptake.

    PubMed

    Ferguson, Richard B; Nienaber, John A; Eigenberg, Roger A; Woodbury, Brian L

    2005-01-01

    A field study was initiated in 1992 to investigate the long-term impacts of beef feedlot manure application (composted and uncomposted) on nutrient accumulation and movement in soil, corn silage yield, and nutrient uptake. Two application strategies were compared: providing the annual crop nitrogen (N) requirement (N-based rate) or crop phosphorus (P) removal (P-based rate), as well as a comparison to inorganic fertilizer. Additionally, effects of a winter cover crop were evaluated. Irrigated corn (Zea mays L.) was produced annually from 1993 through 2002. Average silage yield and crop nutrient removal were highest with N-based manure treatments, intermediate with P-based manure treatments, and least with inorganic N fertilizer. Use of a winter cover crop resulted in silage yield reductions in four of ten years, most likely due to soil moisture depletion in the spring by the cover crop. However, the cover crop did significantly reduce NO3-N accumulation in the shallow vadose zone, particularly in latter years of the study. The composted manure N-based treatment resulted in significantly greater soil profile NO3-N concentration and higher soil P concentration near the soil surface. The accounting procedure used to calculate N-based treatment application rates resulted in acceptable soil profile NO3-N concentrations over the short term. While repeated annual manure application to supply the total crop N requirement may be acceptable for this soil for several years, sustained application over many years carries the risk of unacceptable soil P concentrations.

  3. Sex-related differences in photoinhibition, photo-oxidative stress and photoprotection in stinging nettle (Urtica dioica L.) exposed to drought and nutrient deficiency.

    PubMed

    Simancas, Bárbara; Juvany, Marta; Cotado, Alba; Munné-Bosch, Sergi

    2016-03-01

    Dimorphic plant species can show distinct nutrient needs due to sex-related differences in nutrient allocation to reproductive structures, which can potentially affect their sensitivity to photoinhibition and photo-oxidative stress. Here, we investigated sex-related differences in the extent of photo-oxidative stress in male and female individuals of U. dioica exposed to a combination of severe drought and nutrient starvation. Male and female individuals of U. dioica subject to severe drought stress were exposed to various levels of nutrient availability. First, a set of plants grown under field conditions and exposed to summer drought was used to test the effects of nutrient supply (given as NPK fertilizer). Secondly, the effects of various phosphate concentrations in the nutrient solution were tested in drought-stressed potted plants. The Fv/Fm ratio (maximum efficiency of PSII photochemistry), photoprotection capacity (levels of carotenoids, including the xanthophyll cycle, and vitamins C and E), and the extent of lipid peroxidation (hydroperoxide levels) were measured. Results showed that an application of the NPK fertilizer to the soil had a positive effect on drought-stressed plants, reducing the extent of lipid peroxidation in both males and females. P deficiency led to residual photoinhibition, as indicated by significant reductions in the Fv/Fm ratio, and enhanced lipid peroxidation in females, but not in males. We conclude that (i) increased nutrient availability in the soil can alleviate photo-oxidative stress in drought-stressed U. dioica plants, and (ii) U. dioica plants show sexual secondary dimorphism in terms of photoinhibition and photo-oxidative stress, but this is only apparent when stress infringed on plants is very severe.

  4. [Spatial variability of soil moisture, nutrients, and productivity on slopeland in loessial semiarid region].

    PubMed

    Pan, Chengzhong; Shangguan, Zhouping

    2004-11-01

    For the sustainable development and ecological construction in the loessial semiarid region, it is important to describe the variability of slopeland soil properties and the affecting factors of slopeland productivity. In this study, soil samples were taken from eroded steep slopeland, and leaf area index (LAI) and above-ground biomass (AGB) were measured at the sampling locations. The soil water content (WC) of 2 m depth at 20 cm intervals, and the soil organic matter (OM), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN) and available phosphorus (AP) contents of 0-20 and 20-40 cm soil layers were determined in the laboratory. The results showed that the majority of the properties was normally distributed, and the nutrient contents were higher in 0-20 cm than in 20-40 cm layer, but the variations of soil nutrients were much smaller in 0-20 cm than in 20-40 cm layer. Soil nutrients had a significantly larger variation than soil moisture. Soil nutrient contents in 20-40 cm layer kept increasing from upslope to downslope, while those in 0-20 cm layer varied slightly. Slope topography had more obvious impact on soil organic matter, total nitrogen and available phosphorus than other affecting factors. Soil water and nutrient contents on the shallow gully trough were notably higher than those on the upslope, but above-ground biomass was less than that on the upslope. Though longitudinal slope (35 degrees-45 degrees) was obviously larger than the horizontal one (5 degrees-10 degrees), horizontal slope position had a greater influence on soil nutrients, but much weaker effect on soil moisture than longitudinal direction. There were significant correlations between 0-120 cm soil moisture and 20-40 cm soil nutrients, and among soil nutrients except 0-20 cm soil available phosphorus. Slopeland position had a great impact on soil moisture and nutrients, but soil moisture and/or nutrients had no significant impact on above-ground biomass.

  5. Effect of soil carbohydrates on nutrient availability in natural forests and cultivated lands in Sri Lanka

    NASA Astrophysics Data System (ADS)

    Ratnayake, R. R.; Seneviratne, G.; Kulasooriya, S. A.

    2013-05-01

    Carbohydrates supply carbon sources for microbial activities that contribute to mineral nutrient production in soil. Their role on soil nutrient availability has not yet been properly elucidated. This was studied in forests and cultivated lands in Sri Lanka. Soil organic matter (SOM) fractions affecting carbohydrate availability were also determined. Soil litter contributed to sugars of plant origin (SPO) in croplands. The negative relationship found between clay bound organic matter (CBO) and glucose indicates higher SOM fixation in clay that lower its availability in cultivated lands. In forests, negative relationships between litter and sugars of microbial origin (SMO) showed that litter fuelled microbes to produce sugars. Fucose and glucose increased the availability of Cu, Zn and Mn in forests. Xylose increased Ca availability in cultivated lands. Arabinose, the main carbon source of soil respiration reduced the P availability. This study showed soil carbohydrates and their relationships with mineral nutrients could provide vital information on the availability of limiting nutrients in tropical ecosystems.

  6. Autophagy regulates pancreatic beta cell death in response to Pdx1 deficiency and nutrient deprivation.

    PubMed

    Fujimoto, Kei; Hanson, Piia T; Tran, Hung; Ford, Eric L; Han, Zhiqiang; Johnson, James D; Schmidt, Robert E; Green, Karen G; Wice, Burton M; Polonsky, Kenneth S

    2009-10-02

    There are three types of cell death; apoptosis, necrosis, and autophagy. The possibility that activation of the macroautophagy (autophagy) pathway may increase beta cell death is addressed in this study. Increased autophagy was present in pancreatic islets from Pdx1(+/-) mice with reduced insulin secretion and beta cell mass. Pdx1 expression was reduced in mouse insulinoma 6 (MIN6) cells by delivering small hairpin RNAs using a lentiviral vector. The MIN6 cells died after 7 days of Pdx1 deficiency, and autophagy was evident prior to the onset of cell death. Inhibition of autophagy prolonged cell survival and delayed cell death. Nutrient deprivation increased autophagy in MIN6 cells and mouse and human islets after starvation. Autophagy inhibition partly prevented amino acid starvation-induced MIN6 cell death. The in vivo effects of reduced autophagy were studied by crossing Pdx1(+/-) mice to Becn1(+/-) mice. After 1 week on a high fat diet, 4-week-old Pdx1(+/-) Becn1(+/-) mice showed normal glucose tolerance, preserved beta cell function, and increased beta cell mass compared with Pdx1(+/-) mice. This protective effect of reduced autophagy had worn off after 7 weeks on a high fat diet. Increased autophagy contributes to pancreatic beta cell death in Pdx1 deficiency and following nutrient deprivation. The role of autophagy should be considered in studies of pancreatic beta cell death and diabetes and as a target for novel therapeutic intervention.

  7. Biochar soil amendment: Impact of soil types on heavy metal sorption-desorption behaviors and repeated nutrient leaching

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Depending on soil types, properties of chars especially pH and leachable organic/inorganic components can have varying impacts when used as a soil amendment. We have investigated sorption-desorption behaviors of metal contaminant of concern in shooting ranges and urban soils (Cu), nutrient supply (...

  8. Anaerobic soil disinfestation impact on soil nutrients dynamics and nitrous oxide emissions in fresh-market tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD) is proposed as a pre-plant, non-chemical soil disinfestation technique to control several soilborne phytosanitary issues. Limited information is available on the impact of ASD on soil fertility, plant growth, and potential nutrient loss. The objectives of the curr...

  9. Soil nutrient competition in earth system models: an important but underappreciated driver of plant responses to nutrient fertilization

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C.

    2015-12-01

    Earth System Models (ESMs) used to project future biosphere-climate feedbacks rely on predictions of terrestrial carbon dynamics. Furthermore, soil nutrient availability strongly modulates land surface carbon dynamics, including plant sequestration of atmospheric CO2. Plant growth under future environmental changes (e.g., nitrogen and phosphorus deposition) depends on how well plants compete with microbial and abiotic competitors. Here, we surveyed recent developments of nutrient competition representations in ESMs that participated in the CMIP5 project. We found that nutrient competition is over-simplified despite its ecological significance. Existing ESMs either assume that soil-decomposing microbes (1) outcompete plants or (2) are evenly competitive, both of which are inconsistent with theoretical understanding and field observations. We compiled and synthesized global data of forest carbon productivity in response to nitrogen and phosphorus fertilization experiments. Using this synthesis, we show that existing ESMs with the first and second competition schemes lead to underestimation and overestimation, respectively, of fertilization effects on plant growth. We reduced these systematic biases by applying a new competition scheme in CLM4.5 and the essentially equivalent ACME land model (ALMv0) based on the Equilibrium Chemistry Approximation, which is based on classical equilibrium chemical kinetics theory. This approach dynamically updates nutrient competitiveness among multiple consumers (e.g., plants, decomposing microbes, nitrifier, denitrifier, mineral surfaces) as a function of soil nutrient status. There has been a long-term debate regarding how to implement theoretically realistic and computationally efficient nutrient competition schemes in ESMs. Our approach reconciles the complex nature of ecosystem nutrient competition with a computationally tractable approach applicable to ESMs. More importantly, our results imply that previous estimates of plant

  10. Deficiencies and toxicities of trace elements and micronutrients in tropical soils: Limitations of knowledge and future research needs

    SciTech Connect

    Davies, B.E.

    1997-01-01

    This article reviews present knowledge concerning deficiencies and toxicities of trace elements and micronutrients in tropical soils. The myth that all tropical soils are highly leached and nutrient-poor is challenged. Continuing use of the term laterite by ecologists and geologists is criticized and adoption of plinthite is urged. The trace element content of plinthite and its possible influence on micronutrient availability are described. Micronutrient limitations of tropical agriculture are related to soil type and formation, and the special problem of aluminum toxicity in acid soils is discussed in both agricultural and ecological contexts. Studies of micronutrient cycling in tropical forests or savannas are needed to supplement the emerging picture of the complexities of major element cycles in these ecosystems.

  11. Phosphate addition enhanced soil inorganic nutrients to a large extent in three tropical forests.

    PubMed

    Zhu, Feifei; Lu, Xiankai; Liu, Lei; Mo, Jiangming

    2015-01-21

    Elevated nitrogen (N) deposition may constrain soil phosphorus (P) and base cation availability in tropical forests, for which limited evidence have yet been available. In this study, we reported responses of soil inorganic nutrients to full factorial N and P treatments in three tropical forests different in initial soil N status (N-saturated old-growth forest and two less-N-rich younger forests). Responses of microbial biomass, annual litterfall production and nutrient input were also monitored. Results showed that N treatments decreased soil inorganic nutrients (except N) in all three forests, but the underlying mechanisms varied depending on forests: through inhibition on litter decomposition in the old-growth forest and through Al(3+) replacement of Ca(2+) in the two younger forests. In contrast, besides great elevation in soil available P, P treatments induced 60%, 50%, 26% increases in sum of exchangeable (K(+)+Ca(2+)+Mg(2+)) in the old-growth and the two younger forests, respectively. These positive effects of P were closely related to P-stimulated microbial biomass and litter nutrient input, implying possible stimulation of nutrient return. Our results suggest that N deposition may result in decreases in soil inorganic nutrients (except N) and that P addition can enhance soil inorganic nutrients to support ecosystem processes in these tropical forests.

  12. Studies on nutrient uptake of rice and characteristics of soil microorganisms in a long-term fertilization experiments for irrigated rice.

    PubMed

    Zhang, Qi-chun; Wang, Guang-huo

    2005-02-01

    The ecosystem characteristics of soil microorganism and the nutrient uptake of irrigated rice were investigated in a split-block experiment with different fertilization treatments, including control (no fertilizer application), PK, NK, NP, NPK fertilization, in the main block, and conventional rice and hybrid rice comparison, in the sub block. Average data of five treatments in five years indicated that the indigenous N supply (INS) capacity ranged from 32.72 to 93.21 kg/ha; that indigenous P supply (IPS) capacity ranged from 7.42 to 32.25 kg/ha; and that indigenous K supply (IKS) capacity ranged from 16.24 to 140.51 kg/ha, which showed that soil available nutrient pool depletion might occur very fast and that P, K deficiency has become a constraint to increasing yields of consecutive crops grown without fertilizer application. It was found that soil nutrient deficiency and unbalanced fertilization to rice crop had negative effect on the diversity of the microbial community and total microbial biomass in the soil. The long-term fertilizer experiment (LTFE) also showed that balanced application of N, P and K promoted microbial biomass growth and improvement of community composition. Unbalanced fertilization reduced microbial N and increased C/N ratio of the microbial biomass. Compared with inbred rice, hybrid rice behavior is characterized by physiological advantage in nutrient uptake and lower internal K use efficiency.

  13. Soil Organic Carbon and Nutrient Dynamics in Reclaimed Appalachian Mine Soil

    NASA Astrophysics Data System (ADS)

    Acton, P.; Fox, J.; Campbell, J. E.; Rowe, H. D.; Jones, A.

    2011-12-01

    Past research has shown that drastically disturbed and degraded soils can offer a high potential for soil organic carbon and aboveground carbon sequestration. Little work has been done on both the functioning of soil carbon accumulation and turnover in reclaimed surface mining soils. Reclamation practices of surface coal mine soils in the Southern Appalachian forest region of the United States emphasizes heavy compaction of surface material to provide slope stability and reduce surface erosion, and topsoil is not typically added. An analysis of the previously collected data has provided a 14 year chronosequence of SOC uptake and development in the soil column and revealed that these soils are sequestering carbon at a rate of 1.3 MgC ha-1 yr-1, which is 1.6 to 3 times less than mining soils reported for other regions. Results of bulk density analysis indicate a contrast between 0 - 10 cm (1.51 g cm-3) and 10 - 50 cm (2.04 g cm-3) depth intervals. Aggregate stability was also quantified as well as dynamic soil texture measurements. With this analysis, it has been established that these soils are well below their potential in terms of the ability to store and cycle carbon and other nutrients as well their ability to sustain a fully-functioning forested ecosystem typical for the region. We are taking an integrated approach that relies on ecological observations for present conditions combined with computational modeling to understand long-term soil organic carbon (SOC) accumulation and turnover in regards to SOC sequestration potential and quantification of specific processes by which these soils develop. A dual-isotope end-member model, utilizing the carbon 13 and nitrogen 15 stable isotopes, is being developed to provide greater input into the mathematical separation of organic carbon derived from new soil inputs and existing coal carbon. Soils from the study sites have been isolated into three distinct size pools, and elemental and isotopic analysis of these samples

  14. Impacts of soil petroleum contamination on nutrient release during litter decomposition of Hippophae rhamnoides.

    PubMed

    Zhang, Xiaoxi; Liu, Zengwen; Luc, Nhu Trung; Yu, Qi; Liu, Xiaobo; Liang, Xiao

    2016-03-01

    Petroleum exploitation causes contamination of shrub lands close to oil wells. Soil petroleum contamination affects nutrient release during the litter decomposition of shrubs, which influences nutrient recycling and the maintenance of soil fertility. Hence, this contamination may reduce the long-term growth and stability of shrub communities and consequently, the effects of phytoremediation. Fresh foliar litter of Hippophae rhamnoides, a potential phytoremediating species, was collected for this study. The litter was placed in litterbags and then buried in different petroleum-polluted soil media (the petroleum concentrations were 15, 30, and 45 g kg(-1) dry soil, which were considered as slightly, moderately and seriously polluted soil, respectively) for a decomposition test. The impacts of petroleum contamination on the release of nutrients (including N, P, K, Cu, Zn, Fe, Mn, Ca and Mg) were assessed. The results showed that (1) after one year of decomposition, the release of all nutrients was accelerated in the slightly polluted soil. In the moderately polluted soil, P release was accelerated, while Cu, Zn and Mn release was inhibited. In the seriously polluted soil, Cu and Zn release was accelerated, while the release of the other nutrients was inhibited. (2) The effect of petroleum on nutrient release from litter differed in different periods during decomposition; this was mainly due to changes in soil microorganisms and enzymes under the stress of petroleum contamination. (3) To maintain the nutrient cycling and the soil fertility of shrub lands, H. rhamnoides is only suitable for phytoremediation of soils containing less than 30 g kg(-1) of petroleum.

  15. Evidence for Cross-Tolerance to Nutrient Deficiency in Three Disjunct Populations of Arabidopsis lyrata ssp. lyrata in Response to Substrate Calcium to Magnesium Ratio

    PubMed Central

    Veatch-Blohm, Maren E.; Roche, Bernadette M.; Campbell, MaryJean

    2013-01-01

    Species with widespread distributions that grow in varied habitats may consist of ecotypes adapted to a particular habitat, or may exhibit cross-tolerance that enables them to exploit a variety of habitats. Populations of Arabidopsis lyrata ssp. lyrata (L.) O’Kane & Al-Shehbaz grow in a wide variety of edaphic settings including serpentine soil, limestone sand, and alluvial flood plains. While all three of these environments share some stressors, a crucial difference among these environments is soil calcium to magnesium ratio, which ranges from 25∶1 in the limestone sand to 0.2∶1 in serpentine soil. The three populations found on these substrates were subjected to three different Ca to Mg ratios under controlled environmental conditions during germination and rosette growth. Response to Ca to Mg ratio was evaluated through germination success and radicle growth rate, rosette growth rate, and the content of Ca and Mg in the rosette. All three populations were particularly efficient in fueling growth under nutrient deficiency, with the highest nutrient efficiency ratio for Ca under Ca deficiency and for Mg under Mg deficiency. Although the serpentine population had significantly higher leaf Ca to Mg ratio than the limestone or flood plain populations under all three Ca to Mg ratios, this increase did not result in any advantage in growth or appearance of the serpentine plants, during early life stages before the onset of flowering, even in the high Mg substrate. The three populations showed no population by substrate interaction for any of the parameters measured indicating that these populations may have cross-tolerance to substrate Ca to Mg ratio. PMID:23650547

  16. Evidence for cross-tolerance to nutrient deficiency in three disjunct populations of Arabidopsis lyrata ssp. lyrata in response to substrate calcium to magnesium ratio.

    PubMed

    Veatch-Blohm, Maren E; Roche, Bernadette M; Campbell, Maryjean

    2013-01-01

    Species with widespread distributions that grow in varied habitats may consist of ecotypes adapted to a particular habitat, or may exhibit cross-tolerance that enables them to exploit a variety of habitats. Populations of Arabidopsis lyrata ssp. lyrata (L.) O'Kane & Al-Shehbaz grow in a wide variety of edaphic settings including serpentine soil, limestone sand, and alluvial flood plains. While all three of these environments share some stressors, a crucial difference among these environments is soil calcium to magnesium ratio, which ranges from 25:1 in the limestone sand to 0.2:1 in serpentine soil. The three populations found on these substrates were subjected to three different Ca to Mg ratios under controlled environmental conditions during germination and rosette growth. Response to Ca to Mg ratio was evaluated through germination success and radicle growth rate, rosette growth rate, and the content of Ca and Mg in the rosette. All three populations were particularly efficient in fueling growth under nutrient deficiency, with the highest nutrient efficiency ratio for Ca under Ca deficiency and for Mg under Mg deficiency. Although the serpentine population had significantly higher leaf Ca to Mg ratio than the limestone or flood plain populations under all three Ca to Mg ratios, this increase did not result in any advantage in growth or appearance of the serpentine plants, during early life stages before the onset of flowering, even in the high Mg substrate. The three populations showed no population by substrate interaction for any of the parameters measured indicating that these populations may have cross-tolerance to substrate Ca to Mg ratio.

  17. Linking spatial patterns of soil redistribution traced with 137Cs and soil nutrients in a Mediterranean mountain agroecosystem (NE Spain)

    NASA Astrophysics Data System (ADS)

    Quijano, Laura; Gaspar, Leticia; Navas, Ana

    2016-04-01

    Mediterranean mountain agroecosystems are prone to soil loss mainly due to the accelerated erosion as a consequence of human induced changes from agriculture and grazing practices over the last centuries and the climatic conditions (i.e. irregular and scarce precipitations and drought periods). Soil erosion leads to soil degradation inducing the loss of soil functions. The progressive decline of soil functions thereof soil quality is associated to a decrease of soil productivity and can threat the sustainability of cultivated soils. The use of fallout 137Cs as a soil movement tracer provides useful data to identify areas where loss and gain of 137Cs occurs and that of soil. This study aims to address soil movement and soil nutrient dynamics closely related to the status of soil degradation. A rain-fed cereal field (1.6 ha) representative of Mediterranean mountain agricultural landscapes (42°25'41''N 1°13'8''W) was selected to examine the effects of soil redistribution processes on the spatial variability of soil organic carbon (SOC) and nitrogen (SON) and their relationships with soil properties and topographic characteristics. From the hydrological point of view, the field is isolated due to the effect of landscape features and man-made structures. Climate is continental Mediterranean with an average annual rainfall of 500 mm and soils are Calcisols. The reference inventories of 137Cs and soil nutrients were established from 21 soil samples collected in nearby undisturbed areas under typical Mediterranean vegetation cover. A total of 156 bulk soil samples (30-50 cm depth) and 156 topsoil samples (5 cm) were collected on a 10 m grid. 137Cs and soil nutrients loss and gain areas were identified by comparing the reference inventories with the values of inventories at the sampling points. A new approach to characterize and measure active (ACF) and stable (SCF) carbon fraction contents by using a dry combustion method based on the oxidation temperature of carbon

  18. Evaluation models for soil nutrient based on support vector machine and artificial neural networks.

    PubMed

    Li, Hao; Leng, Weijia; Zhou, Yibing; Chen, Fudi; Xiu, Zhilong; Yang, Dazuo

    2014-01-01

    Soil nutrient is an important aspect that contributes to the soil fertility and environmental effects. Traditional evaluation approaches of soil nutrient are quite hard to operate, making great difficulties in practical applications. In this paper, we present a series of comprehensive evaluation models for soil nutrient by using support vector machine (SVM), multiple linear regression (MLR), and artificial neural networks (ANNs), respectively. We took the content of organic matter, total nitrogen, alkali-hydrolysable nitrogen, rapidly available phosphorus, and rapidly available potassium as independent variables, while the evaluation level of soil nutrient content was taken as dependent variable. Results show that the average prediction accuracies of SVM models are 77.87% and 83.00%, respectively, while the general regression neural network (GRNN) model's average prediction accuracy is 92.86%, indicating that SVM and GRNN models can be used effectively to assess the levels of soil nutrient with suitable dependent variables. In practical applications, both SVM and GRNN models can be used for determining the levels of soil nutrient.

  19. Ecoenzymatic Stoichiometry of Microbial Organic Nutrient Acquisition in Soil and Sediment

    EPA Science Inventory

    Terrestrial soils and freshwater sediments contain reserves of organic carbon estimated at 1500 Pg and 0.2 Pg, respectively. Mineralization of this organic matter by heterotrophic microorganisms drives global carbon and nutrient cycles, controlling plant production and atmospher...

  20. Nutrient levels modify saltmarsh responses to increased inundation in different soil types.

    PubMed

    Wong, Joanne X W; Van Colen, Carl; Airoldi, Laura

    2015-03-01

    Saltmarshes have been depleted historically, and cumulative stressors threaten their future persistence. We examined experimentally how nutrient availability (high vs. low) affects the responses of Spartina maritima to increased inundation in two mineral soil types (low vs. medium organic). Increased inundation, one of the effects of accelerated sea level rise, had negative effects on most plant growth parameters, but the magnitude varied with soil and nutrient levels, and between plants from different locations. Average differences between inundation treatments were largest at high nutrient conditions in low organic matter soils. We conclude that saltmarsh vegetation would be more drastically affected by increased inundation in low than in medium organic matter soils, and especially in estuaries already under high nutrient availability. This knowledge enhances the prediction of changes at the foreshore of saltmarshes related to sea level rise, and the development of site-specific conservation strategies.

  1. Conversion of grazing land into Grevillea robusta plantation and exclosure: impacts on soil nutrients and soil organic carbon.

    PubMed

    Alem, Shiferaw; Pavlis, Jindrich

    2014-07-01

    Different studies have shown that the effect of land use conversion on soil nutrients and soil organic carbon (SOC) is variable, which indicates that more investigations that focus on different specific geographical locations and land use types are required. The objectives of this study were (1) to evaluate the effect of grazing land (GL) conversion into Grevillea robusta plantation and exclosure (EX) on soil nutrients and soil organic carbon (SOC) and (2) to examine the impact of soil organic matter (SOM) on soil nutrients. To achieve these objectives, soil samples were taken from a soil depth of 20 cm (n = 4) in each of the studied land areas. Each soil sample was analysed in a soil laboratory following a standard procedure. Analysis of variance (ANOVA) and Pearson's correlation coefficient were used for the data analysis. The result indicated that conversion of GL into EX improved the soil electrical conductivity (EC), exchangeable K, cation exchange capacity (CEC), total N and available P (p < 0.05), while the exchangeable Mg, SOC, available K and SOM were decreased (p < 0.05). Conversion of GL into G. robusta improved the soil EC, exchangeable (K, Ca, Mg), CEC, SOC, total N, available K and SOM (p < 0.05). There was a significant relationship between SOM and available P, total N, SOC and EC. There were no significant relationships between SOM and pH, available K and CEC. Finally, the results indicate that both land uses, established in acidic Nitosols, have variable impacts on soil chemical properties and that G. robusta plantation improved most of the soil nutrients and SOC much better than the EX land use.

  2. GLUT1 deficiency links nutrient availability and apoptosis during embryonic development.

    PubMed

    Jensen, Penny J; Gitlin, Jonathan D; Carayannopoulos, Mary O

    2006-05-12

    GLUT1 is essential for human brain development and function, as evidenced by the severe epileptic encephalopathy observed in children with GLUT1 deficiency syndrome resulting from inherited loss-of-function mutations in the gene encoding this facilitative glucose transporter. To further elucidate the pathophysiology of this disorder, the zebrafish orthologue of human GLUT1 was identified, and expression of this gene was abrogated during early embryonic development, resulting in a phenotype of aberrant brain organogenesis consistent with the observed expression of Glut1 in the embryonic tectum and specifically rescued by human GLUT1 mRNA. Affected embryos displayed impaired glucose uptake concomitant with increased neural cell apoptosis and subsequent ventricle enlargement, trigeminal ganglion cell loss, and abnormal hindbrain architecture. Strikingly, inhibiting expression of the zebrafish orthologue of the proapoptotic protein Bad resulted in complete rescue of this phenotype, and this occurred even in the absence of restoration of apparent glucose uptake. Taken together, these studies describe a tractable system for elucidating the cellular and molecular mechanisms of Glut1 deficiency and provide compelling in vivo genetic evidence directly linking nutrient availability and activation of mitochondria-dependent apoptotic mechanisms during embryonic brain development.

  3. [Correlation analysis of nutrients and microorganisms in soils with polyphenols and total flavonoids of Houttuynia cordata].

    PubMed

    Wu, Dan; Luo, Shi-qiong; Yang, Zhan-nan; Ma, Jing; Hong, Liang

    2015-04-01

    The relationship of nutrients and microorganisms in soils with polyphenols and total flavonoids of Houttuynia cordata were investigated by measuring nutrients, enzyme activity, pH, concentrations of microbe phospholipid fatty acids (PLFAs) in soils, and determining concentrations of polyphenols and total flavonoids of H. cordata. The research is aimed to understand characteristics of the planting soils and improve the quality of cultivated H. cordata. The soils at different sample sites varied greatly in nutrients, enzyme activity, pH, microbic PLFAs and polyphenols and all flavonoids. The content of total PLFAs in sample sites was following: bacteria > fungi > actinomyces > nematode. The content of bacteria PLFAs was 37.5%-65.0% at different sample sites. Activities of polyphenol oxidease, concentrations of available P and content of PLFAs of bacteria, actinomyces and total microorganisms in soils were significantly and positively related to the concentrations of polyphenols and total flavonoids of H. cordata, respectively (P < 0.05) . The Content of fungi PLFAs in soils was significantly and negatively related to concentrations of polyphenols and total flavonoids of H. cordata, respectively (P < 0.05). This study provides evidence that effectiveness of the soil nutrient, which may be improved due to transformation of soil microorganisms and enzymes to N and P in the soils, was beneficial to adaptation of H. cordata adapted to different soil conditions, and significantly affects metabolic accumulation of polyphenols and flavonoids of H. cordata.

  4. Artificial neural network estimation of soil erosion and nutrient concentrations in runoff from land application areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transport of sediment and nutrients from land application areas is an environmental concern. New methods are needed for estimating soil and nutrient concentrations of runoff from cropland areas on which manure is applied. Artificial Neural Networks (ANN) trained with a Backpropagation (BP) algor...

  5. Soil nutrient evaluation from swine effluent application to five forage-system practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 3-yr study was conducted to investigate the impact of forage double-cropping on nutrient accumulation and leaching in Mantachie fine loam soil fertilized with swine (Sus scrofa domesticus) waste lagoon effluent as the sole source of plant nutrients. Plots of Tifton 44 bermudagrass [Cynodon dactylo...

  6. Evolution of root plasticity responses to variation in soil nutrient distribution and concentration.

    PubMed

    Grossman, Judah D; Rice, Kevin J

    2012-12-01

    Root plasticity, a trait that can respond to selective pressure, may help plants forage for nutrients in heterogeneous soils. Agricultural breeding programs have artificially selected for increased yield under comparatively homogeneous soil conditions, potentially decreasing the capacity for plasticity in crop plants like barley (Hordeum vulgare). However, the effects of domestication on the evolution of root plasticity are essentially unknown. Using a split container approach, we examined the differences in root plasticity among three domestication levels of barley germplasm (wild, landrace, and cultivar) grown under different concentrations and distribution patterns of soil nutrients. Domestication level, nutrient concentration, and nutrient distribution interactively affected average root diameter; differential root allocation (within-plant plasticity) was greatest in wild barley (Hordeum spontaneum), especially under low nutrient levels. Correlations of within-plant root plasticity and plant size were most pronounced in modern cultivars under low-nutrient conditions. Barley plants invested more resources to root systems when grown in low-nutrient soils and allocated more roots to higher-nutrient locations. Root plasticity in barley is scale dependent and varies with domestication level. Although wild barley harbors a greater capacity for within-plant root plasticity than domesticated barley, cultivars exhibited the greatest capacity to translate within-plant plasticity into increased plant size.

  7. Soil fertility in deserts: a review on the influence of biological soil crusts and the effect of soil surface disturbance on nutrient inputs and losses

    USGS Publications Warehouse

    Reynolds, R.; Phillips, S.; Duniway, M.; Belnap, J.

    2003-01-01

    Sources of desert soil fertility include parent material weathering, aeolian deposition, and on-site C and N biotic fixation. While parent materials provide many soil nutrients, aeolian deposition can provide up to 75% of plant-essential nutrients including N, P, K, Mg, Na, Mn, Cu, and Fe. Soil surface biota are often sticky, and help retain wind-deposited nutrients, as well as providing much of the N inputs. Carbon inputs are from both plants and soil surface biota. Most desert soils are protected by cyanobacterial-lichen-moss soil crusts, chemical crusts and/or desert pavement. Experimental disturbances applied in US deserts show disruption of soil surfaces result in decreased N and C inputs from soil biota by up to 100%. The ability to glue aeolian deposits in place is compromised, and underlying soils are exposed to erosion. The ability to withstand wind increases with biological and physical soil crust development. While most undisturbed sites show little sediment production, disturbance by vehicles or livestock produce up to 36 times more sediment production, with soil movement initiated at wind velocities well below commonly-occurring wind speeds. Soil fines and flora are often concentrated in the top 3 mm of the soil surface. Winds across disturbed areas can quickly remove this material from the soil surface, thereby potentially removing much of current and future soil fertility. Thus, disturbances of desert soil surfaces can both reduce fertility inputs and accelerate fertility losses.

  8. Plant Foliar Response to Soil Nutrient Availability Across Contrasting Geologic Settings

    NASA Astrophysics Data System (ADS)

    Castle, S. C.; Neff, J. C.

    2007-12-01

    Rock derived mineral nutrients such as P, Ca, Mg, Mn, and K play a significant, but poorly understood role in the structure and function of temperate forest ecosystems. Though these nutrients are not necessarily limiting to plant growth, they are essential to plant physiological functioning. In this study, we test the hypothesis that foliar nutrients are a proxy for soil nutrient availability across sites of different underlying geologies. Specifically, we focus on the plant nutrient-use strategies of rock derived nutrients (P and K) and how they relate to soil nutrient status. In order to assess the responses of plant species to nutrient availability, we monitored above ground net primary productivity (current annual increment + litterfall), plant chemistry, and soil nutrients for a period of 24 months. This research was completed in the San Juan Mountain region of southern Colorado, where there is a high local diversity of bedrock geochemistry. Within this region, two small sub-alpine basins were chosen; a sedimentary basin composed of Mesozoic cyclic limestone, sandstone & shale and a volcanic basin composed of Tertiary rhyolite. Across these basins, geology played a significant role in explaining the variability of rock derived nutrient availability. Initial results suggest that differences in bedrock geochemistry have little influence on the aboveground net primary production (ANPP) of plants or on the chemistry of foliar materials. This inflexibility of foliar chemistry to variations in nutrient availability suggests that genetic and physiologic controls play a strong role in determining the chemical content of plant materials. An alternative hypothesis is that deposition of eolian mineral dust into subalpine systems could play a role in offsetting the reliance of vegetation on deeper bedrock derived nutrient sources. An investigation is currently underway to assess the contribution of eolian dust derived nutrients to plant nutrition using Sr as a geochemical

  9. Nutrient and toxic element soil concentrations during repeated mineral and compost fertilization treatments in a Mediterranean agricultural soil.

    PubMed

    Baldantoni, Daniela; Morra, Luigi; Saviello, Giovanni; Alfani, Anna

    2016-12-01

    Agricultural soils of semi-arid Mediterranean areas are often subjected to depletion of their chemical, physical, and biological properties. In this context, organic fertilization, in addition to providing nutrients for a longer time in respect to mineral fertilization, improves many other characteristics related to soil fertility. Moreover, the combined use of organic and mineral fertilizers may promote a more sustainable crop production. However, a concern on the long-term use of organic fertilizers arises in relation to the possible accumulation of toxic elements in soil and their transfer to human beings. For this reason, a long-term study on nutrient and toxic element total concentrations and availabilities during fertilization treatments was carried out. In particular, mineral NPK fertilized soils, soils amended with biowaste compost, soils amended with biowaste compost plus mineral nitrogen, and unfertilized soils were analyzed for 11 chemical elements. The results highlighted that temporal variations in total and bioavailable concentrations of both nutrients and toxic elements, occurring also in unfertilized soils, are wider than those related to fertilization treatments. Anyway, soil amendments with biowaste compost, alone or in combination with mineral fertilizers, reduce Cu bioavailability but improve K, Fe, Mn, and Zn availabilities, excluding at the same time a long-term accumulation in soil. Total and bioavailable toxic element concentrations (apart from available Cd) do not vary in relation to fertilization treatments.

  10. [Study on nutrient and salinity in soil covered with different vegetations in Shuangtaizi estuarine wetlands].

    PubMed

    Song, Xiao-Lin; Lü, Xian-Guo; Zhang, Zhong-Sheng; Chen, Zhi-Ke; Liu, Zheng-Mao

    2011-09-01

    Nutrient elements and salinity in soil covered by different vegetations including Phragmites australis (Clay.) Trin., Typha orientalis Presl., Puccinellia distans Parl, and Suaeda salsa in Shuangtaizi estuarine wetlands were investigated to study their distribution characteristics and to reveal the nutrient element variation during the vegetation succession processes. Results indicated that total potassium, total phosphorus and salinity were different significantly in soil between different plant communities while available phosphorus, total nitrogen, available nitrogen, available potassium, total sulfur, iron and soil organic carbon were different insignificantly. Correlation analysis suggested that soil organic carbon were related significantly to total nitrogen, available phosphorus, available potassium, which implied that decomposition of plant litter might be the mail source of soil nitrogen and available nutrient. Salinity was significantly related to total phosphorus and iron in soil. In Shuangtaizi estuarine wetland soil, ratios of carbon to nitrogen (R(C/N)) was in the range of 12.21-26.33 and the average value was 18.21, which was higher than 12.0. It indicated that soil organic carbon in Shuangtaizi estuarine mainly came from land but not ocean and plants contributed the most of soil organic matters. There was no significant difference in R(C/N) between soil from the four plant communities (F = 1.890, p = 0.151). R(C/N) was related significantly to sol salinity (r = 0.346 3, p = 0.035 8) and was increasing with soil salinity.

  11. Detecting nutrients deficiencies of oil palm trees using remotely sensed data

    NASA Astrophysics Data System (ADS)

    Marzukhi, Faradina; Liyana Elahami, Aina; Norashikin Bohari, Sharifah

    2016-06-01

    Oil palm plantation management involve crucial role for the farmers. The remote sensing imagery has widely used nowadays in order to monitor oil palm tree in plantation. To pact with the problem, the use of vegetation indices analysis on satellite image on plantation will examine the ability of spectral data in determining the greenness of the trees. Vegetation Indices are used for estimating the crops and vegetation variables by using visible and nearinfrared region (NIR) from the electromagnetic spectrum. The healthy tree will display very low reflectance and transmitted in visible region and very high reflectance transmitted in NIR. The chlorophyll absorption in reflectance and normalizes pigment chlorophyll vegetation indexes will show a loss of chlorophyll pigment compared to healthy oil palm trees. Besides, pH. value and soil nutrient will be examined to determine their effect towards the trees. In addition, the laboratory test sample is done to analyse the pH. value and major nutrient status of nitrogen (N), phosphorus (P) and potassium (K) together with their relationship with the remotely sensed data.

  12. Effects of Nutrient Enrichment on Microbial Communities and Carbon Cycling in Wetland Soils

    NASA Astrophysics Data System (ADS)

    Hartman, W.; Neubauer, S. C.; Richardson, C. J.

    2013-12-01

    Soil microbial communities are responsible for catalyzing biogeochemical transformations underlying critical wetland functions, including cycling of carbon (C) and nutrients, and emissions of greenhouse gasses (GHG). Alteration of nutrient availability in wetland soils may commonly occur as the result of anthropogenic impacts including runoff from human land uses in uplands, alteration of hydrology, and atmospheric deposition. However, the impacts of altered nutrient availability on microbial communities and carbon cycling in wetland soils are poorly understood. To assess these impacts, soil microbial communities and carbon cycling were determined in replicate experimental nutrient addition plots (control, +N, +P, +NP) across several wetland types, including pocosin peat bogs (NC), freshwater tidal marshes (GA), and tidal salt marshes (SC). Microbial communities were determined by pyrosequencing (Roche 454) extracted soil DNA, targeting both bacteria (16S rDNA) and fungi (LSU) at a depth of ca. 1000 sequences per plot. Wetland carbon cycling was evaluated using static chambers to determine soil GHG fluxes, and plant inclusion chambers were used to determine ecosystem C cycling. Soil bacterial communities responded to nutrient addition treatments in freshwater and tidal marshes, while fungal communities did not respond to treatments in any of our sites. We also compared microbial communities to continuous biogeochemical variables in soil, and found that bacterial community composition was correlated only with the content and availability of soil phosphorus, while fungi responded to phosphorus stoichiometry and soil pH. Surprisingly, we did not find a significant effect of our nutrient addition treatments on most metrics of carbon cycling. However, we did find that several metrics of soil carbon cycling appeared much more related to soil phosphorus than to nitrogen or soil carbon pools. Finally, while overall microbial community composition was weakly correlated with

  13. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens.

    PubMed

    Gharajehdaghipour, Tazarve; Roth, James D; Fafard, Paul M; Markham, John H

    2016-04-05

    Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ(15)N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.

  14. Soil Microbial and Enzymatic Responses to Complex and Labile Nutrient Inputs

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Vitousek, P. M.

    2003-12-01

    Microbial extracellular enzymes are essential for converting complex organic compounds into smaller molecules that are available for plant and microbial uptake. However, enzyme production represents a substantial resource cost for microbes, and microbes may be under selection to produce enzymes only when benefits exceed costs. We predicted that soil enzyme activities would be highest when complex substrates were abundant, but available nutrients were scarce (large potential benefit from enzyme production). We also predicted that rates of nutrient and carbon mineralization would correspond to observed shifts in enzyme activities. To test these predictions, we added insoluble and available carbon, nitrogen, and phosphorus substrates to soil incubations and measured enzyme activities, CO2 respiration, microbial biomass, and nutrient mineralization. Labile carbon additions increased respiration rates and microbial biomass, while labile nutrient additions were taken up by microbes but did not increase respiration rates. Labile carbon + nitrogen additions increased acid phosphatase activity, while labile nitrogen additions suppressed aminopeptidase activity. Insoluble nutrients caused major increases in enzyme and microbial activities only when added in combination with complementary labile nutrients (e.g. insoluble carbon + available nitrogen and phosphorus). These results indicate that microbes respond to soil nutrient status by changing patterns of extracellular enzyme production. Such changes can allow microbes to access nutrients in complex molecules, but may be limited by the availability of resources to build enzymes.

  15. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens

    NASA Astrophysics Data System (ADS)

    Gharajehdaghipour, Tazarve; Roth, James D.; Fafard, Paul M.; Markham, John H.

    2016-04-01

    Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra.

  16. Arctic foxes as ecosystem engineers: increased soil nutrients lead to increased plant productivity on fox dens

    PubMed Central

    Gharajehdaghipour, Tazarve; Roth, James D.; Fafard, Paul M.; Markham, John H.

    2016-01-01

    Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact can be even greater in environments with low nutrients and productivity, such as Arctic tundra. We estimated the effects of Arctic fox (Vulpes lagopus) denning on soil nutrient dynamics and vegetation production near Churchill, Manitoba in June and August 2014. Soils from fox dens contained higher nutrient levels in June (71% more inorganic nitrogen, 1195% more extractable phosphorous) and in August (242% more inorganic nitrogen, 191% more extractable phosphorous) than adjacent control sites. Inorganic nitrogen levels decreased from June to August on both dens and controls, whereas extractable phosphorous increased. Pup production the previous year, which should enhance nutrient deposition (from urine, feces, and decomposing prey), did not affect soil nutrient concentrations, suggesting the impact of Arctic foxes persists >1 year. Dens supported 2.8 times greater vegetation biomass in August, but δ15N values in sea lyme grass (Leymus mollis) were unaffected by denning. By concentrating nutrients on dens Arctic foxes enhance nutrient cycling as an ecosystem service and thus engineer Arctic ecosystems on local scales. The enhanced productivity in patches on the landscape could subsequently affect plant diversity and the dispersion of herbivores on the tundra. PMID:27045973

  17. Root growth and plant biomass in Lolium perenne exploring a nutrient-rich patch in soil.

    PubMed

    Nakamura, Ryoji; Kachi, Naoki; Suzuki, Jun-Ichirou

    2008-11-01

    We investigated soil exploration by roots and plant growth in a heterogeneous environment to determine whether roots can selectively explore a nutrient-rich patch, and how nutrient heterogeneity affects biomass allocation and total biomass before a patch is reached. Lolium perenne L. plants were grown in a factorial experiment with combinations of fertilization (heterogeneous and homogeneous) and day of harvest (14, 28, 42, or 56 days after transplanting). The plant in the heterogeneous treatment was smaller in its mean total biomass, and allocated more biomass to roots. The distributions of root length and root biomass in the heterogeneous treatment did not favor the nutrient-rich patch, and did not correspond to the patchy distribution of inorganic nitrogen. Specific root length (length/biomass) was higher and root elongation was more extensive both laterally and vertically in the heterogeneous treatment. These characteristics may enable plants to acquire nutrients efficiently and increase the probability of encountering nutrient-rich patches in a heterogeneous soil. However, heterogeneity of soil nutrients would hold back plant growth before a patch was reached. Therefore, although no significant selective root placement in the nutrient-rich patch was observed, plant growth before reaching nutrient-rich patches differed between heterogeneous and homogeneous environments.

  18. Species-soil associations, disturbance, and nutrient cycling in an Australian tropical rainforest.

    PubMed

    Gleason, Sean Michael; Read, Jennifer; Ares, Adrian; Metcalfe, Daniel J

    2010-04-01

    Resource availability and disturbance are important factors that shape the composition, structure, and functioning of ecosystems. We investigated the effects of soil fertility and disturbance on plant-soil interactions and nutrient cycling in a diverse tropical rainforest. Our goal was to determine how common soil specialisation is among species and how plant-soil interactions affect ecosystem functioning in the presence of disturbance. Most species (59%) showed significant fidelity to either fertile (basalt) or infertile (schist) soils. Obligate schist specialists (six species) contributed 39 and 37% to total stand-level basal area and aboveground net primary productivity, respectively. High nutrient use efficiency of schist specialists reduced the rates of within-stand nutrient cycling through the production of nutrient-poor plant tissues and litter. Although forests on schist soils had higher basal area and similar rates of productivity to forests on basalt, uptake of Mg, K, P, and N were markedly less on schist than on basalt, particularly after a cyclone disturbance. Stands on schist soils were also less affected by the cyclone and, as a result, contributed less (ca. 50%) Mg, K, P, and N inputs to the forest floor (via litterfall) than stands on basalt soils. System "openness" (i.e. the risk of nutrient loss) from cyclone-affected basalt forests was minimised by high rates of uptake following disturbance and large effective cation exchange capacities of soils. Soil-plant-disturbance interactions are likely to engender different fitness-enhancing strategies on fertile and infertile soils, possibly leading to the development and/or maintenance of diversity in rainforests.

  19. Costs of Nutrient Losses in Priceless Soils Eroded From the Highlands of Northwestern Ethiopia

    NASA Astrophysics Data System (ADS)

    Gebreselassie, Yihenew; Belay, Yihenew

    2014-05-01

    Soils formation is a geomorphic process that takes place through the interaction of soil forming factors in several hundreds and thousands of years. However, land degradation and soil erosion is consistently taking place in the horn of Africa washing away this priceless product in short period of time. The scale of the problem dramatically increased due to the increase in deforestation, overgrazing, over-cultivation, inappropriate farming practices, and increasing human population. Several research results were published in the region showing the extent of land degradation and soil loss. However, little attempt has been done to estimate the nutrient loss in monitory terms which made it difficult for policy makers to properly understand the extent of the problem. A study was, therefore, conducted in 2011 to estimate soil and nutrient losses caused by water erosion and predict nutrient replacement costs on different land use types and slope classes at Harfetay watershed, Northwestern Ethiopia. The revised soil loss equation (RUSLE) was used to estimate the soil loss from the different land uses and slope classes in watershed. Moreover, nutrient loss from similar units was calculated by multiplying the in situ nutrient concentration of soil samples by the estimated soil loss using RUSLE. The replacement costs of nutrient losses were calculated by multiplying the nutrient loss with the price of available nutrients in urea and diammonium phosphate. The estimate of the RUSLE indicated that the average soil losses in the study watershed were 119 tons ha-1 year-1 for non-conserved crop land, 23 tons for conserved farmlands, 23 tons for forest and shrub lands, 19 tons for grazing lands, and 6 tons for plantation forest. The mean soil loss for lower slope classes (<15%), middle slope classes (15-30%) and upper slope classes (>30%) were 30.11, 48.09 and 57.22 tons ha-1 year-1, respectively. The highest losses of total nitrogen (154.7 kg ha-1 year-1), available phosphorus (1

  20. Impact of FGD gypsum on soil fertility and plant nutrient uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of FGD gypsum is thought to improve soil productivity and increase plant production. Thus, a study was conducted to evaluate the effects of FGD gypsum on yield, plant nutrient uptake and soil productivity. The study was conducted on an established bermudagrass pasture. Poultry litter was applied...

  1. Mycorrhiza and heavy metal resistant bacteria enhance growth, nutrient uptake and alter metabolic profile of sorghum grown in marginal soil.

    PubMed

    Dhawi, Faten; Datta, Rupali; Ramakrishna, Wusirika

    2016-08-01

    The main challenge for plants growing in nutrient poor, contaminated soil is biomass reduction, nutrient deficiency and presence of heavy metals. Our aim is to overcome these challenges using different microbial combinations in mining-impacted soil and focus on their physiological and biochemical impacts on a model plant system, which has multiple applications. In the current study, sorghum BTx623 seedlings grown in mining-impacted soil in greenhouse were subjected to plant growth promoting bacteria (PGPB or B) alone, PGPB with arbuscular mycorrhizal fungi (My), My alone and control group with no treatment. Root biomass and uptake of most of the elements showed significant increase in all treatment groups in comparison with control. Mycorrhiza group showed the best effect followed by My + B and B groups for uptake of majority of the elements by roots. On the contrary, biomass of both shoot and root was more influenced by B treatment than My + B and My treatments. Metabolomics identified compounds whose levels changed in roots of treatment groups significantly in comparison to control. Upregulation of stearic acid, sorbitol, sebacic acid and ferulic acid correlated positively with biomass and uptake of almost all elements. Two biochemical pathways, fatty acid biosynthesis and galactose metabolism, were regulated in all treatment groups. Three common pathways were upregulated only in My and My + B groups. Our results suggest that PGPB enhanced metabolic activities which resulted in increase in element uptake and sorghum root biomass whether accompanied with mycorrhiza or used solely.

  2. Carbon sequestration and plant nutrients in soil in different land types in Thingvellir Iceland

    NASA Astrophysics Data System (ADS)

    Svavarsdóttir, María; Gísladóttir, Guðrún; Mankasingh, Utra

    2015-04-01

    Special properties of volcanic soils (andisol) that is most common in Iceland can sequestrate considerably more carbon (C) that other types of soils. A mellow developed andisol with natural ecosystem such as birch forest or grass- and heathland is presumably to be fertile and sequestrate a lot of carbon. Coniferous tree species have been imported to Iceland for large scale utilisation in Icelandic forestry and is therefore an imported species/ecosystem. Abroad it has been noticed that coniferous trees acidify soil and change the properties of the soil so other species cannot thrive in it. The Icelandic Forest service is aiming tenfold the coverage of forests in Iceland before the year 2100 but about 50% of tree species that the institution uses is coniferous species. It is therefore important to research the soil due to the plant types that are planted in the soil. The aim of this project is to compare soil properties, soil nutrients and soil sequestration in heathland, birch forest and coniferous forest in Thingvellir national park in Iceland. Heathland and birch forest represent the natural ecosystem but coniferous forest imported ecosystem. Carbon (C) in soil will be measured, proportion of carbon and nitrogen (C:N), respiration from soil (CO2) and live green biomass and organic matter in the soil. The speed of decomposition of organic matter will be estimated. Important nutrients, pH and cation exchange capacity will be measured among other physical properties as bulk density, grain size and water holding capacity of the soil.

  3. Exploiting genotypic variation in plant nutrient accumulation to alleviate micronutrient deficiency in populations.

    PubMed

    Genc, Yusuf; Humphries, Julia M; Lyons, Graham H; Graham, Robin D

    2005-01-01

    More than 2 billion people consume diets that are less diverse than 30 years ago, leading to deficiencies in micronutrients, especially iron (Fe), zinc (Zn), selenium (Se), iodine (I), and also vitamin A. A strategy that exploits genetic variability to breed staple crops with enhanced ability to fortify themselves with micronutrients (genetic biofortification) offers a sustainable, cost-effective alternative to conventional supplementation and fortification programs. This is more likely to reach those most in need, has the added advantages of requiring no change in current consumer behaviour to be effective, and is transportable to a range of countries. Research by our group, along with studies elsewhere, has demonstrated conclusively that substantial genotypic variation exists in nutrient (e.g. Fe, Zn) and nutrient promotor (e.g. inulin) concentrations in wheat and other staple foods. A rapid screening technique has been developed for lutein content of wheat and triticale, and also for pro-vitamin A carotenoids in bread wheat. This will allow cost-effective screening of a wider range of genotypes that may reveal greater genotypic variation in these traits. Moreover, deeper understanding of genetic control mechanisms and development of molecular markers will facilitate breeding programs. We suggest that a combined strategy utilising plant breeding for higher micronutrient density; maximising the effects of nutritional promoters (e.g. inulin, vitamin C) by promoting favourable dietary combinations, as well as by plant breeding; and agronomic biofortification (e.g. adding iodide or iodate as fertiliser; applying selenate to cereal crops by spraying or adding to fertiliser) is likely to be the most effective way to improve the nutrition of populations. Furthermore, the importance of detecting and exploiting beneficial interactions is illustrated by our discovery that in Fe-deficient chickens, circulating Fe concentrations can be restored to normal levels by lutein

  4. Controls of bedrock geochemistry on soil and plant nutrients in Southeastern Utah

    USGS Publications Warehouse

    Neff, J.C.; Reynolds, R.; Sanford, R.L.; Fernandez, D.; Lamothe, P.

    2006-01-01

    The cold deserts of the Colorado Plateau contain numerous geologically and geochemically distinct sedimentary bedrock types. In the area near Canyonlands National Park in Southeastern Utah, geochemical variation in geologic substrates is related to the depositional environment with higher concentrations of Fe, Al, P, K, and Mg in sediments deposited in alluvial or marine environments and lower concentrations in bedrock derived from eolian sand dunes. Availability of soil nutrients to vegetation is also controlled by the formation of secondary minerals, particularly for P and Ca availability, which, in some geologic settings, appears closely related to variation of CaCO3 and Ca-phosphates in soils. However, the results of this study also indicate that P content is related to bedrock and soil Fe and Al content suggesting that the deposition history of the bedrock and the presence of P-bearing Fe and Al minerals, is important to contemporary P cycling in this region. The relation between bedrock type and exchangeable Mg and K is less clear-cut, despite large variation in bedrock concentrations of these elements. We examined soil nutrient concentrations and foliar nutrient concentration of grasses, shrubs, conifers, and forbs in four geochemically distinct field sites. All four of the functional plant groups had similar proportional responses to variation in soil nutrient availability despite large absolute differences in foliar nutrient concentrations and stoichiometry across species. Foliar P concentration (normalized to N) in particular showed relatively small variation across different geochemical settings despite large variation in soil P availability in these study sites. The limited foliar variation in bedrock-derived nutrients suggests that the dominant plant species in this dryland setting have a remarkably strong capacity to maintain foliar chemistry ratios despite large underlying differences in soil nutrient availability. ?? 2006 Springer Science

  5. Farmers' Perception of Integrated Soil Fertility and Nutrient Management for Sustainable Crop Production: A Study of Rural Areas in Bangladesh

    ERIC Educational Resources Information Center

    Farouque, Md. Golam; Takeya, Hiroyuki

    2007-01-01

    This study aimed to determine farmers' perception of integrated soil fertility and nutrient management for sustainable crop production. Integrated soil fertility (ISF) and nutrient management (NM) is an advanced approach to maintain soil fertility and to enhance crop productivity. A total number of 120 farmers from eight villages in four districts…

  6. Biochar application to sandy and loamy soils for agricultural nutrient management

    NASA Astrophysics Data System (ADS)

    Gronwald, Marco; Don, Axel; Tiemeyer, Baerbel; Helfrich, Mirjam

    2014-05-01

    Soil fertility of agricultural soils is challenged by nutrients losses and increasing soil acidification. Furthermore, leached nutrients negatively affect the quality of ground and surface water 1]. In addition to the possible soil carbon sequestration by applying biochars, many positive soil-improving properties are attributed to biochars. The application of biochars to agricultural - especially sandy - soils could reduce leaching of nutrients and may improve their availability 1,2]. Thus, biochar application to agricultural fields could be an ecologically and economically viable option to improve soils' fertility. However, biochar properties strongly depend on their feedstock and production process 3]. Various types of biochars (pyrolysis char, hydrochar (produced at 200 and 250° C); feedstocks: digestate, Miscanthus and wood chips) were used to determine sorption kinetics and sorption isotherms for the major nutrients Ca, Mg, K, NH4 and NO3 as a function of biochar types in different soil substrates (sand, loess). In addition, the biochars were washed to create free binding sites on the chars' surface that simulate aged char. We compared the simulated aged char with biochars that was aged in-situ at a field experiment for seven months. The first results showed that pyrochars have the largest retention potential for NO3 and hydrochars have retention potential for NH4. Washing of biochars turned them from a PO4 and NH4 source into an adsorber, especially for hydrochars. Highest leaching was observed for biochars from digestates likely due to the high nutrient content of digestates. But the different ions may lead to pH-dependent interactions between each other and the chars' surface that override the adsoption effects. In this context, cation-bridge and ligand bindings 4,5] need to be further investigated. Most of the fresh, unwashed biochars were a source of nutrients with hardly any detectable nutrient retention. Pyrochars showed the highest potential for anion

  7. Spatial variability of soil nutrient in paddy plantation: Sites FELCRA Seberang Perak

    NASA Astrophysics Data System (ADS)

    Kamarudin, H.; Adnan, N. A.; Mispan, M. R.; Athirah. A, A.

    2016-06-01

    The conventional methods currently used for rice cultivation in Malaysia are unable to give maximum yield although the yield production of paddy is increasing. This is due to the conversional method being unable to include soil properties as one of their parameters in agriculture management. Soil properties vary spatially in farm scale due to differences in topography, parent material, vegetation or land management and soil characteristics; also plantation productivity varies significantly over small spatial scales. Knowledge of spatial variability in soil fertility is important for site specific nutrient management. Analysis of spatial variability of soil nutrient of nitrogen (N), phosphorus (P) and potassium (K) were conducted in this study with the aid of GIS (i.e ArcGIS) and statistical softwares. In this study different temporal and depths of soil nutrient were extracted on the field and further analysis of N,P,K content were analysed in the chemical laboratory and using spatially technique in GIS sofware. The result indicated that for the Seberang Perak site of 58 hactares area, N and K are met minimum requirements nutrient content as outlines by the MARDI for paddy cultivation. However, P indicated poor condition in the study area; therefore the soil needs further attention and treatment.

  8. Elevated atmospheric CO{sub 2} and soil nutrients alter competitive performance of California annual grassland species

    SciTech Connect

    Reynolds, H.L.; Chapin, F.S. III; Field, C.B.

    1995-06-01

    Atmospheric CO{sub 2} and soil nutrients altered interspecific competitive performance of three grassland annuals, all exhibiting the C{sub 3} metabolic pathway. Plantago erecta, an herbaceous dicot dominant in low-fertility serpentine grassland, was the superior interspecific competitor at low soil nutrients. Bromus hordeaceus, an introduced grass dominant in higher fertility sandstone grassland, was the superior interspecific competitor at high soil nutrients. Interspecific competitive ability of Plantago was slightly enhanced under elevated CO{sub 2}, but only at high soil nutrients, whereas interspecific competitive ability of Bromus was stimulated under elevated CO{sub 2} at both low and high soil nutrients. Interspecific competitive ability of Lasthenia californica, another herbaceous dicot common in serpentine grassland, was low in all treatments, and tended to decrease with elevated CO{sub 2} at low soil nutrients. Our results suggest that elevated CO{sub 2} may shift plant species abundance of serpentine grassland in favor of Bromus hordeaceus.

  9. Production and diversity of volatile terpenes from plants on calcareous and siliceous soils: effect of soil nutrients.

    PubMed

    Ormeño, Elena; Baldy, Virginie; Ballini, Christine; Fernandez, Catherine

    2008-09-01

    Fertilizer effects on terpene production have been noted in numerous reports. In contrast, only a few studies have studied the response of leaf terpene content to naturally different soil fertility levels. Terpene content, as determined by gas chromatography/mass spectrometry/flame ionization detector, and growth of Pinus halepensis, Rosmarinus officinalis, and Cistus albidus were studied on calcareous and siliceous soils under field conditions. The effect of nitrogen (N) and extractable phosphorus (P(E)) from these soils on terpenes was also investigated since calcareous soils mainly differ from siliceous soils in their higher nutrient loadings. Rich terpene mixtures were detected. Twenty-one terpenes appeared in leaf extracts of R. officinalis and C. albidus and 20 in P. halepensis. Growth of all species was enhanced on calcareous soils, while terpene content showed a species-specific response to soil type. The total monoterpene content of P. halepensis and that of some major compounds (e.g., delta-terpinene) were higher on calcareous than on siliceous soils. A significant and positive relationship was found between concentration of N and P(E) and leaf terpene content of this species. These findings suggest that P. halepensis may respond to an environment characterized by increasing soil deposition, by allocating carbon resources to the synthesis of terpene defense metabolites without growth reduction. Results obtained for R. officinalis showed high concentrations of numerous major monoterpenes (e.g., myrcene, camphor) in plants growing on calcareous soils, while alpha-pinene, beta-caryophyllene, and the total sesquiterpene content were higher on siliceous soils. Finally, only alloaromadendrene and delta-cadinene of C. albidus showed higher concentrations on siliceous soils. Unlike P. halepensis, soil nutrients were not involved in terpene variation in calcareous and siliceous soils of these two shrub species. Possible ecological explanations on the effect of

  10. Solubility and Plant Availability of Nutrients as Affected by Soil Drainage Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn growth is affected due to oxygen deficiency and root death in a perched water table (PWT). The study objective was to evaluate a surface application of FGD gypsum (FGDG) and glyphosate (GLY) on nutrient uptake in corn with different drainage conditions. The experiment was conducted in greenhous...

  11. Nutrient and pollutant metals within earthworm residues are immobilized in soil during decomposition.

    PubMed

    Richardson, J B; Renock, D J; Görres, J H; Jackson, B P; Webb, S M; Friedland, A J

    2016-10-01

    Earthworms are known to bioaccumulate metals, making them a potential vector for metal transport in soils. However, the fate of metals within soil upon death of earthworms has not been characterized. We compared the fate of nutrient (Ca, Mg, Mn) and potentially toxic (Cu, Zn, Pb) metals during decomposition of Amynthas agrestis and Lumbricus rubellus in soil columns. Cumulative leachate pools, exchangeable pools (0.1 M KCl + 0.01 M acetic acid extracted), and stable pools (16 M HNO3 + 12 M HCl extracted) were quantified in the soil columns after 7, 21, and 60 days of decomposition. Soil columns containing A. agrestis and L. rubellus had significantly higher cumulative leachate pools of Ca, Mn, Cu, and Pb than Control soil columns. Exchangeable and stable pools of Cu, Pb, and Zn were greater for A. agrestis and L. rubellus soil columns than Control soil columns. However, we estimated that > 98 % of metals from earthworm residues were immobilized in the soil in an exchangeable or stable form over the 60 days using a mass balance approach. Micro-XRF images of longitudinal thin sections of soil columns after 60 days containing A. agrestis confirm metals immobilization in earthworm residues. Our research demonstrates that nutrient and toxic metals are stabilized in soil within earthworm residues.

  12. Extraradical mycelium of arbuscular mycorrhizal fungi radiating from large plants depresses the growth of nearby seedlings in a nutrient deficient substrate.

    PubMed

    Janoušková, Martina; Rydlová, Jana; Püschel, David; Száková, Jiřina; Vosátka, Miroslav

    2011-10-01

    The effect of arbuscular mycorrhiza (AM) on the interaction of large plants and seedlings in an early succession situation was investigated in a greenhouse experiment using compartmented rhizoboxes. Tripleurospermum inodorum, a highly mycorrhiza-responsive early coloniser of spoil banks, was cultivated either non-mycorrhizal or inoculated with AM fungi in the central compartment of the rhizoboxes. After two months, seedlings of T. inodorum or Sisymbrium loeselii, a non-host species colonising spoil banks simultaneously with T. inodorum, were planted in lateral compartments, which were colonised by the extraradical mycelium (ERM) of the pre-cultivated T. inodorum in the inoculated treatments. The experiment comprised the comparison of two AM fungal isolates and two substrates: spoil bank soil and a mixture of this soil with sand. As expected based on the low nutrient levels in the substrates, the pre-cultivated T. inodorum plants responded positively to mycorrhiza, the response being more pronounced in phosphorus uptake than in nitrogen uptake and growth. In contrast, the growth of the seedlings, both the host and the non-host species, was inhibited in the mycorrhizal treatments. Based on the phosphorus and nitrogen concentrations in the biomass of the experimental plants, this growth inhibition was attributed to nitrogen depletion in the lateral compartments by the ERM radiating from the central compartment. The results point to an important aspect of mycorrhizal effects on the coexistence of large plants and seedlings in nutrient deficient substrates.

  13. Soil Nutrient Depletion Is Associated with the Presence of Burkholderia pseudomallei

    PubMed Central

    Rongkard, Patpong; Oyuchua, Malinee; Amornchai, Premjit; Wuthiekanun, Vanaporn

    2016-01-01

    ABSTRACT Burkholderia pseudomallei is a soil-dwelling bacterium and the cause of melioidosis, which kills an estimated 89,000 people per year worldwide. Agricultural workers are at high risk of infection due to repeated exposure to the bacterium. Little is known about the soil physicochemical properties associated with the presence or absence of the organism. Here, we evaluated the soil physicochemical properties and presence of B. pseudomallei in 6,100 soil samples collected from 61 rice fields in Thailand. The presence of B. pseudomallei was negatively associated with the proportion of clay, proportion of moisture, level of salinity, percentage of organic matter, presence of cadmium, and nutrient levels (phosphorus, potassium, calcium, magnesium, and iron). The presence of B. pseudomallei was not associated with the level of soil acidity (P = 0.54). In a multivariable logistic regression model, the presence of B. pseudomallei was negatively associated with the percentage of organic matter (odds ratio [OR], 0.06; 95% confidence interval [CI], 0.01 to 0.47; P = 0.007), level of salinity (OR, 0.06; 95% CI, 0.01 to 0.74; P = 0.03), and percentage of soil moisture (OR, 0.81; 95% CI, 0.66 to 1.00; P = 0.05). Our study suggests that B. pseudomallei thrives in rice fields that are nutrient depleted. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas. IMPORTANCE Burkholderia pseudomallei is an environmental Gram-negative bacillus and the cause of melioidosis. Humans acquire the disease following skin inoculation, inhalation, or ingestion of the bacterium in the environment. The presence of B. pseudomallei in soil defines geographic regions where humans and livestock are at risk of melioidosis, yet little is known about the soil properties associated with the presence of the organism. We evaluated the soil properties and presence of B. pseudomallei in 61 rice fields in

  14. Comparison of methods for nutrient measurement in calcareous soils: Ion-exchange resin bag, capsule, membrane, and chemical extractions

    USGS Publications Warehouse

    Sherrod, S.K.; Belnap, J.; Miller, M.E.

    2002-01-01

    Four methods for measuring quantities of 12 plant-available nutrients were compared using three sandy soils in a series of three experiments. Three of the methods use different ion-exchange resin forms-bags, capsules, and membranes-and the fourth was conventional chemical extraction. The first experiment compared nutrient extraction data from a medium of sand saturated with a nutrient solution. The second and third experiments used Nakai and Sheppard series soils from Canyonlands National Park, which are relatively high in soil carbonates. The second experiment compared nutrient extraction data provided by the four methods from soils equilibrated at two temperatures, "warm" and "cold." The third experiment extracted nutrients from the same soils in a field equilibration. Our results show that the four extraction techniques are not comparable. This conclusion is due to differences among the methods in the net quantities of nutrients extracted from equivalent soil volumes, in the proportional representation of nutrients within similar soils and treatments, in the measurement of nutrients that were added in known quantities, and even in the order of nutrients ranked by net abundance. We attribute the disparities in nutrient measurement among the different resin forms to interacting effects of the inherent differences in resin exchange capacity, differences among nutrients in their resin affinities, and possibly the relatively short equilibration time for laboratory trials. One constraint for measuring carbonate-related nutrients in high-carbonate soils is the conventional ammonium acetate extraction method, which we suspect of dissolving fine CaCO3 particles that are more abundant in Nakai series soils, resulting in erroneously high Ca2+ estimates. For study of plant-available nutrients, it is important to identify the nutrients of foremost interest and understand differences in their resin sorption dynamics to determine the most appropriate extraction method.

  15. Plant species effects on soil nutrients and chemistry in arid ecological zones.

    PubMed

    Johnson, Brittany G; Verburg, Paul S J; Arnone, John A

    2016-09-01

    The presence of vegetation strongly influences ecosystem function by controlling the distribution and transformation of nutrients across the landscape. The magnitude of vegetation effects on soil chemistry is largely dependent on the plant species and the background soil chemical properties of the site, but has not been well quantified along vegetation transects in the Great Basin. We studied the effects of plant canopy cover on soil chemistry within five different ecological zones, subalpine, montane, pinyon-juniper, sage/Mojave transition, and desert shrub, in the Great Basin of Nevada all with similar underlying geology. Although plant species differed in their effects on soil chemistry, the desert shrubs Sarcobatus vermiculatus, Atriplex spp., Coleogyne ramosissima, and Larrea tridentata typically exerted the most influence on soil chemistry, especially amounts of K(+) and total nitrogen, beneath their canopies. However, the extent to which vegetation affected soil nutrient status in any given location was not only highly dependent on the species present, and presumably the nutrient requirements and cycling patterns of the plant species, but also on the background soil characteristics (e.g., parent material, weathering rates, leaching) where plant species occurred. The results of this study indicate that the presence or absence of a plant species, especially desert shrubs, could significantly alter soil chemistry and subsequently ecosystem biogeochemistry and function.

  16. Use of nutrient supplements to increase the microbial degradation of PAH in contaminated soils

    SciTech Connect

    Carmichael, L.M.; Pfaender, F.K.

    1994-12-31

    The microbial degradation of polycyclic aromatic hydrocarbons (PAH) is often low in soils due to unavailability of PAH and/or to conditions in the soil that are not favorable to microbial activity. As a result, successful bioremediation of PAH contaminated soils may require the addition of supplements to impact PAH availability or soil conditions. This paper reports on the addition of supplements (Triton X-100, Inopol, nutrient buffer, an organic nutrient solution, salicylic acid) on the fate of (9-{sup 14}C) phenanthrene, a model PAH, in creosote contaminated soils. Phenanthrene metabolism was assessed using a mass balance approach that accounts for metabolism of phenanthrene to CO{sub 2}, relative metabolite production, and uptake of phenanthrene into cells. Most of the supplements did not drastically alter the fate of phenanthrene in the contaminated soils. Additions of Inopol, however, increased phenanthrene mineralization, while salicylic acid decreased phenanthrene mineralization but greatly increased the production of polar and water soluble metabolites. All supplements (excluding salicylic acid and the organic nutrient solution) increased populations of heterotrophic microorganisms, as measured by plate counts. Phenanthrene degrader populations, however, were only slightly increased by additions of the nutrient buffer, as measured by the Most Probable Number assay.

  17. [An optical-fiber-sensor-based spectrophotometer for soil non-metallic nutrient determination].

    PubMed

    He, Dong-xian; Hu, Juan-xiu; Lu, Shao-kun; He, Hou-yong

    2012-01-01

    In order to achieve rapid, convenient and efficient soil nutrient determination in soil testing and fertilizer recommendation, a portable optical-fiber-sensor-based spectrophotometer including immersed fiber sensor, flat field holographic concave grating, and diode array detector was developed for soil non-metallic nutrient determination. According to national standard of ultraviolet and visible spectrophotometer with JJG 178-2007, the wavelength accuracy and repeatability, baseline stability, transmittance accuracy and repeatability measured by the prototype instrument were satisfied with the national standard of III level; minimum spectral bandwidth, noise and excursion, and stray light were satisfied with the national standard of IV level. Significant linear relationships with slope of closing to 1 were found between the soil available nutrient contents including soil nitrate nitrogen, ammonia nitrogen, available phosphorus, available sulfur, available boron, and organic matter measured by the prototype instrument compared with that measured by two commercial single-beam-based and dual-beam-based spectrophotometers. No significant differences were revealed from the above comparison data. Therefore, the optical-fiber-sensor-based spectrophotometer can be used for rapid soil non-metallic nutrient determination with a high accuracy.

  18. Nutrient movement in a 104-year old soil fertility experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alabama’s “Cullars Rotation” experiment (circa 1911) is the oldest, continuous soil fertility experiment in the southern U.S. Treatments include 5 K variables, P variables, S variables, soil pH variables and micronutrient variables in 14 treatments involving a 3-yr rotation of (1) cotton-winter legu...

  19. Effect of Water Logging Conditions on Solubility of Soil Nutrients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wide use of herbicides, fungicides, fertilizers, and soil amendments affect the rhizosphere biochemistry and ecology. Soils in the Midwest of the US tend to be saturated in the early spring when snow and ice melt, and frequent rain occurs. Saturated conditions also occur after heavy rainfall eve...

  20. Comprehensive biometric, biochemical and histopathological assessment of nutrient deficiencies in gilthead sea bream fed semi-purified diets.

    PubMed

    Ballester-Lozano, Gabriel F; Benedito-Palos, Laura; Estensoro, Itziar; Sitjà-Bobadilla, Ariadna; Kaushik, Sadasivam; Pérez-Sánchez, Jaume

    2015-09-14

    Seven isoproteic and isolipidic semi-purified diets were formulated to assess specific nutrient deficiencies in sulphur amino acids (SAA), n-3 long-chain PUFA (n-3 LC-PUFA), phospholipids (PL), P, minerals (Min) and vitamins (Vit). The control diet (CTRL) contained these essential nutrients in adequate amounts. Each diet was allocated to triplicate groups of juvenile gilthead sea bream fed to satiety over an 11-week feeding trial period. Weight gain of n-3 LC-PUFA, P-Vit and PL-Min-SAA groups was 50, 60-75 and 80-85 % of the CTRL group, respectively. Fat retention was decreased by all nutrient deficiencies except by the Min diet. Strong effects on N retention were found in n-3 LC-PUFA and P fish. Combined anaemia and increased blood respiratory burst were observed in n-3 LC-PUFA fish. Hypoproteinaemia was found in SAA, n-3 LC-PUFA, PL and Vit fish. Derangements of lipid metabolism were also a common disorder, but the lipodystrophic phenotype of P fish was different from that of other groups. Changes in plasma levels of electrolytes (Ca, phosphate), metabolites (creatinine, choline) and enzyme activities (alkaline phosphatase) were related to specific nutrient deficiencies in PL, P, Min or Vit fish, whereas changes in circulating levels of growth hormone and insulin-like growth factor I primarily reflected the intensity of the nutritional stressor. Histopathological scoring of the liver and intestine segments showed specific nutrient-mediated changes in lipid cell vacuolisation, inflammation of intestinal submucosa, as well as the distribution and number of intestinal goblet and rodlet cells. These results contribute to define the normal range of variation for selected biometric, biochemical, haematological and histochemical markers.

  1. The influence of microtopography on soil nutrients in created mitigation wetlands

    USGS Publications Warehouse

    Moser, K.F.; Ahn, C.; Noe, G.B.

    2009-01-01

    This study explores the relationship between microtopography and soil nutrients (and trace elements), comparing results for created and reference wetlands in Virginia, and examining the effects of disking during wetland creation. Replicate multiscale tangentially conjoined circular transects were used to quantify microtopography both in terms of elevation and by two microtopographic indices. Corresponding soil samples were analyzed for moisture content, total C and N, KCl-extractable NH4-N and NO3-N, and Mehlich-3 extractable P, Ca, Mg, K, Al, Fe, and Mn. Means and variances of soil nutrient/element concentrations were compared between created and natural wetlands and between disked and nondisked created wetlands. Natural sites had higher and more variable soil moisture, higher extractable P and Fe, lower Mn than created wetlands, and comparatively high variability in nutrient concentrations. Disked sites had higher soil moisture, NH4-N, Fe, and Mn than did nondisked sites. Consistently low variances (Levene test for inequality) suggested that nondisked sites had minimal nutrient heterogeneity. Across sites, low P availability was inferred by the molar ratio (Mehlich-3 [P/(Al + Fe)] < 0.06); strong intercorrelations among total C, total N, and extractable Fe, Al, and P suggested that humic-metal-P complexes may be important for P retention and availability. Correlations between nutrient/element concentrations and microtopographic indices suggested increased Mn and decreased K and Al availability with increased surface roughness. Disking appears to enhance water and nutrient retention, as well as nutrient heterogeneity otherwise absent from created wetlands, thus potentially promoting ecosystem development. ?? 2008 Society for Ecological Restoration International.

  2. [Assessment of soil nutrient status in urban green space of main cities in Hubei Province, China].

    PubMed

    Li, Zhi-guo; Zhang, Guo-Shi; Liu, Yi; Wan, Kai-Yuan; Zhang, Run-Hua; Chen, Fang

    2013-08-01

    According to the topography of the cities in Hubei Province, soil samples were collected from the urban green space in two mountainous cities (Enshi and Shiyan), three hilly cities (Jing-men, Xiangfan and Yichang), and five plain cities (Wuhan, Xiaogan, Xianning, Jingzhou, Suizhou and Huangshi). Within each city, subsoil samples were taken in accordance with four different types of land use, including park, residential, institutional (school, hospital and government, etc.), and roadside. In the main cities in Hubei, the soil pH of urban green space was averagely 7.9, being obviously higher than that of natural soils, while the soil organic matter content was rather low (6.8 g x kg(-1)). The soil available N and P contents were at a low level, while the soil available trace element (Ca, Mg, S, Fe, Cu, Mn, Zn and B) contents were moderate. Land use type had significant effects on the soil nutrient contents in plain cities. The soil pH in the residential green space was significantly higher than that in the park, roadside and institutional green space, while the contents of soil available trace elements (S, Cu, Mn and Zn) in roadside green space were significantly higher than those of green space in the other land use types. Park green space had the lowest soil nutrient contents. There existed significant differences in the soil nutrient contents among the cities with different topography. The soil organic matter, NH4-N, available K and P, and Ca, Mg, S, Fe, Cu and Mn contents were significantly higher in plain cities than in mountainous cities.

  3. Soil nutrients trump intraspecific effects on understory plant communities.

    PubMed

    Crutsinger, Gregory M; Carter, Benjamin E; Rudgers, Jennifer A

    2013-12-01

    Understanding the links between intraspecific genetic variation and patterns of diversity in associated communities has been the primary focus of community genetics or 'genes-to-ecosystem' research in ecology. While other ecological factors, such as the abiotic environment, have well-documented influences on communities, the relative contributions of genetic variation versus the environment to species interactions remains poorly explored. In this study, we use a common garden experiment to study a coastal dune plant community dominated by the shrub, Baccharis pilularis, which displays a morphological dimorphism in plant architecture. We found the differences in the understory plant community between erect and prostrate morphs of Baccharis to be statistically significant, but small relative to the impacts of nutrient additions (NPK and C additions), for the richness, cover, and biomass of the understory plant community. There were no significant interactions between Baccharis morphology and nutrient-addition treatments, suggesting the influence of nutrient addition was consistent between erect and prostrate morphs. Moreover, we found no difference in overall plant community composition between Baccharis morphs, while NPK additions led to shifts in understory community composition compared to unfertilized shrubs. In sum, our results indicate that nutrients are the more important factor governing understory plant community structure in a coastal dunes ecosystem followed by intraspecific variation in dominant shrub architecture. Our results address a growing call to understand the extended consequences of intraspecific variation across heterogeneous environments in terrestrial ecosystems.

  4. [Effects of different land use types on soil nutrients in karst region of Northwest Guangxi].

    PubMed

    Xu, Lian-Fang; Wang, Ke-Lin; Zhu, Han-Hua; Hou, Ya; Zhang, Wei

    2008-05-01

    Selecting the main land use types (shrub land, secondary forest land, orchard, pasture land, and upland) at the peak-cluster depression in karst region of Northwest Guangxi as test objects, this paper studied the effects of different land use types on soil nutrients. The results showed that, the contents of soil organic matter (SOM), total N, and available N were 86%-155%, 62% -119%, and 66%-215% higher in shrub land and secondary forest land than in orchard, pasture land, and upland, respectively, i. e., increased with the decrease of land use intensity. The contents of soil total P and K were mainly controlled by their origins, but less affected by land use type. Soil available P content was mainly affected by fertilization, while soil available K content was controlled by vegetation cover and water- and soil loss. Land use type was the dominant factor affecting the contents of soil SOM, total N, and available N, P and K. Extensive cultivation could decrease soil nutrient contents and lead to the degradation of cropland soil, while ecological restoration could improve soil fertility. Therefore, in karst region, the measures as changing extensive cultivation into intensive farming, applying organic fertilizers, balance fertilization, and "Grain for Green Project" for > or = 25 degrees slope should be taken to recover and rebuild the eco-environment, and keep the sustainable utilization of land resources.

  5. Summer cover crops and soil amendments to improve growth and nutrient uptake of okra

    SciTech Connect

    Wang, Q.R.; Li, Y.C.; Klassen, W.

    2006-04-15

    A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on 'Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudan-grass (Sorghum bicolor x S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash), coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. The results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.

  6. [Scale-dependency of spatial variability of soil available nutrients].

    PubMed

    Yang, Qi-Yong; Yang, Jing-Song; Liu, Guang-Ming

    2011-02-01

    With the support of GIS and by using classical statistics and geostatistics methods, the spatial variability of soil available P (AP) and available K (AK) in cultivated lands in Yucheng City of Shandong Province was approached at county and township scales. The results showed that both the soil AP and AK followed the logarithmic normal distribution, with the coefficient of variation (CV) at the two scales being 26.5% - 36.6% and presenting a moderate variation. With the decrease of the scale, the CV of the soil AP and AK increased. Both the soil AP and AK were spatially correlated with scale. At county scale, the soil AP and AK had a larger spatial correlation distance, being 9.0 km and 26.5 km, respectively; while at township scale, the soil AP and AK had a smaller spatial correlation distance, being 1.7 km and 2.8 km, respectively. The spatial distribution of the soil AP and AK at the two scales was obviously different, which was mainly affected by structural factors and random factors.

  7. Nutrient-limited biodegradation of PAH in various soil strata at a creosote contaminated site.

    PubMed

    Breedveld, G D; Sparrevik, M

    2000-01-01

    The effects of nutrient addition on the in situ biodegradation of polycyclic aromatic hydrocarbons in creosote contaminated soil were studied in soil columns taken from various soil strata at a wood preserving plant in Norway. Three samples were used: one from the topsoil (0-0.5 m), one from an organic rich layer (2-2.5 m) and one from the sandy aquifer (4.5-5 m). The addition of inorganic nitrogen and phosphorous stimulated the degradation of polycyclic aromatic hydrocarbons (PAHs) in the top soil and the aquifer sand. These two soils, which differed strongly in contamination levels, responded similarly to nutrient addition with the corresponding degradation of 4-ring PAHs. The ratio between available nitrogen (N) and phosphorous (P) might explain the degree of degradation observed for the 4-ring PAHs. However, the degree of degradation of 3-ring PAHs did not significantly increase after nutrient addition. An increase in the respiration rate, after nutrient addition, could only be observed in the topsoil. In the aquifer sand, 4-ring PAH degradation was not accompanied by an increase in the respiration rate or the number of heterotrophic micro-organisms. PAH degradation in the organic layer did not respond to nutrient addition. This was probably due to the low availability of the contaminants for micro-organisms, as a result of sorption to the soil organic matter. Our data illustrate the need for a better understanding of the role of nutrients in the degradation of high molecular weight hydrocarbons for the successful application of bioremediation at PAH contaminated sites.

  8. Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe

    PubMed Central

    Leff, Jonathan W.; Jones, Stuart E.; Prober, Suzanne M.; Barberán, Albert; Borer, Elizabeth T.; Firn, Jennifer L.; Harpole, W. Stanley; Hobbie, Sarah E.; Hofmockel, Kirsten S.; Knops, Johannes M. H.; McCulley, Rebecca L.; La Pierre, Kimberly; Risch, Anita C.; Seabloom, Eric W.; Schütz, Martin; Steenbock, Christopher; Stevens, Carly J.; Fierer, Noah

    2015-01-01

    Soil microorganisms are critical to ecosystem functioning and the maintenance of soil fertility. However, despite global increases in the inputs of nitrogen (N) and phosphorus (P) to ecosystems due to human activities, we lack a predictive understanding of how microbial communities respond to elevated nutrient inputs across environmental gradients. Here we used high-throughput sequencing of marker genes to elucidate the responses of soil fungal, archaeal, and bacterial communities using an N and P addition experiment replicated at 25 globally distributed grassland sites. We also sequenced metagenomes from a subset of the sites to determine how the functional attributes of bacterial communities change in response to elevated nutrients. Despite strong compositional differences across sites, microbial communities shifted in a consistent manner with N or P additions, and the magnitude of these shifts was related to the magnitude of plant community responses to nutrient inputs. Mycorrhizal fungi and methanogenic archaea decreased in relative abundance with nutrient additions, as did the relative abundances of oligotrophic bacterial taxa. The metagenomic data provided additional evidence for this shift in bacterial life history strategies because nutrient additions decreased the average genome sizes of the bacterial community members and elicited changes in the relative abundances of representative functional genes. Our results suggest that elevated N and P inputs lead to predictable shifts in the taxonomic and functional traits of soil microbial communities, including increases in the relative abundances of faster-growing, copiotrophic bacterial taxa, with these shifts likely to impact belowground ecosystems worldwide. PMID:26283343

  9. Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe.

    PubMed

    Leff, Jonathan W; Jones, Stuart E; Prober, Suzanne M; Barberán, Albert; Borer, Elizabeth T; Firn, Jennifer L; Harpole, W Stanley; Hobbie, Sarah E; Hofmockel, Kirsten S; Knops, Johannes M H; McCulley, Rebecca L; La Pierre, Kimberly; Risch, Anita C; Seabloom, Eric W; Schütz, Martin; Steenbock, Christopher; Stevens, Carly J; Fierer, Noah

    2015-09-01

    Soil microorganisms are critical to ecosystem functioning and the maintenance of soil fertility. However, despite global increases in the inputs of nitrogen (N) and phosphorus (P) to ecosystems due to human activities, we lack a predictive understanding of how microbial communities respond to elevated nutrient inputs across environmental gradients. Here we used high-throughput sequencing of marker genes to elucidate the responses of soil fungal, archaeal, and bacterial communities using an N and P addition experiment replicated at 25 globally distributed grassland sites. We also sequenced metagenomes from a subset of the sites to determine how the functional attributes of bacterial communities change in response to elevated nutrients. Despite strong compositional differences across sites, microbial communities shifted in a consistent manner with N or P additions, and the magnitude of these shifts was related to the magnitude of plant community responses to nutrient inputs. Mycorrhizal fungi and methanogenic archaea decreased in relative abundance with nutrient additions, as did the relative abundances of oligotrophic bacterial taxa. The metagenomic data provided additional evidence for this shift in bacterial life history strategies because nutrient additions decreased the average genome sizes of the bacterial community members and elicited changes in the relative abundances of representative functional genes. Our results suggest that elevated N and P inputs lead to predictable shifts in the taxonomic and functional traits of soil microbial communities, including increases in the relative abundances of faster-growing, copiotrophic bacterial taxa, with these shifts likely to impact belowground ecosystems worldwide.

  10. Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

    USGS Publications Warehouse

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

  11. Soil Nutrient Depletion Is Associated with the Presence of Burkholderia pseudomallei.

    PubMed

    Hantrakun, Viriya; Rongkard, Patpong; Oyuchua, Malinee; Amornchai, Premjit; Lim, Cherry; Wuthiekanun, Vanaporn; Day, Nicholas P J; Peacock, Sharon J; Limmathurotsakul, Direk

    2016-12-15

    Burkholderia pseudomallei is a soil-dwelling bacterium and the cause of melioidosis, which kills an estimated 89,000 people per year worldwide. Agricultural workers are at high risk of infection due to repeated exposure to the bacterium. Little is known about the soil physicochemical properties associated with the presence or absence of the organism. Here, we evaluated the soil physicochemical properties and presence of B. pseudomallei in 6,100 soil samples collected from 61 rice fields in Thailand. The presence of B. pseudomallei was negatively associated with the proportion of clay, proportion of moisture, level of salinity, percentage of organic matter, presence of cadmium, and nutrient levels (phosphorus, potassium, calcium, magnesium, and iron). The presence of B. pseudomallei was not associated with the level of soil acidity (P = 0.54). In a multivariable logistic regression model, the presence of B. pseudomallei was negatively associated with the percentage of organic matter (odds ratio [OR], 0.06; 95% confidence interval [CI], 0.01 to 0.47; P = 0.007), level of salinity (OR, 0.06; 95% CI, 0.01 to 0.74; P = 0.03), and percentage of soil moisture (OR, 0.81; 95% CI, 0.66 to 1.00; P = 0.05). Our study suggests that B. pseudomallei thrives in rice fields that are nutrient depleted. Some agricultural practices result in a decline in soil nutrients, which may impact the presence and amount of B. pseudomallei bacteria in affected areas.

  12. [Effects of long-term tillage and rice straw returning on soil nutrient pools and Cd concentration].

    PubMed

    Tang, Wen-guang; Xiao, Xiao-ping; Tang, Hai-ming; Zhang, Hai-lin; Chen, Fu; Chen, Zhong-du; Xue, Jian-fu; Yang, Guang-li

    2015-01-01

    The objective of this study was to assess the effects of tillage and straw returning on soil nutrient and its pools, and soil Cd concentration, and to identify the strategies for rational tillage and remediation of Cd contaminated paddy fields. The experiment was established with no-tillage with straw retention (NTS) , rotary tillage with straw incorporation (RTS) , conventional plow tillage with straw incorporation (CTS), conventional plow tillage with straw removed ( CT) from 2005 to 2013. The results indicated that tillage and rice straw retention had a great impact on soil properties at 0-10 cm soil depth. The soil aeration, and concentrations of soil nutrient and soil Cd increased under CTS, CT, and RTS. Due to the shallow plow layers, soil nutrient pools and the Cd concentration in rice shoot decreased in long-term tilled soil. Under long-term no-tillage, the soil bulk, soil nutrient pools and Cd concentration in rice shoot increased, but concentrations of soil nutrients decreased. In addition, rice straw returning significantly increased the soil nutrient concentrations, cation exchange capacity, depth of plow layer, and soil nutrient pools. However, the Cd in the rice straw was also returned to the soil by rice straw returning, which would not benefit the remediation of soil Cd. Therefore, it is necessary to improve tillage and straw retention practices due to the disadvantages of long-term continuous single tillage method and rice straw returning practices. Some recommended managements (e.g., rotational tillage or subsoiling, reducing straw returning amount, and rotational straw returning) could be good options in enhancing soil fertility and remedying soil pollution.

  13. Genetic causes and gene–nutrient interactions in mammalian zinc deficiencies: acrodermatitis enteropathica and transient neonatal zinc deficiency as examples.

    PubMed

    Kasana, Shakhenabat; Din, Jamila; Maret, Wolfgang

    2015-01-01

    Discovering genetic causes of zinc deficiency has been a remarkable scientific journey. It started with the description of a rare skin disease, its treatment with various agents, the successful therapy with zinc, and the identification of mutations in a zinc transporter causing the disease. The journey continues with defining the molecular and cellular pathways that lead to the symptoms caused by zinc deficiency. Remarkably, at least two zinc transporters from separate protein families are now known to be involved in the genetics of zinc deficiency. One is ZIP4, which is involved in intestinal zinc uptake. Its mutations can cause acrodermatitis enteropathica (AE) with autosomal recessive inheritance. The other one is ZnT2, the transporter responsible for supplying human milk with zinc. Mutations in this transporter cause transient neonatal zinc deficiency (TNZD) with symptoms similar to AE but with autosomal dominant inheritance. The two diseases can be distinguished in affected infants. AE is fatal if zinc is not supplied to the infant after weaning, whereas TNZD is a genetic defect of the mother limiting the supply of zinc in the milk, and therefore the infant usually will obtain enough zinc once weaned. Although these diseases are relatively rare, the full functional consequences of the numerous mutations in ZIP4 and ZnT2 and their interactions with dietary zinc are not known. In particular, it remains unexplored whether some mutations cause milder disease phenotypes or increase the risk for other diseases if dietary zinc requirements are not met or exceeded. Thus, it is not known whether widespread zinc deficiency in human populations is based primarily on a nutritional deficiency or determined by genetic factors as well. This consideration becomes even more significant with regard to mutations in the other 22 human zinc transporters, where associations with a range of diseases, including diabetes, heart disease, and mental illnesses have been observed

  14. Establishment of five cover crops and total soil nutrient extraction in a humid tropical soil in the Peruvian Amazon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to evaluate the establishment of five cover crops and their potential to increase soil fertility through nutrient extraction, an experiment was installed in the Research Station of Choclino, San Martin, Peru. Five cover crops were planted: Arachis pintoi Krapov. & W.C. Greg, Calopogonium m...

  15. Leaf nitrogen and phosphorus of temperate desert plants in response to climate and soil nutrient availability.

    PubMed

    He, Mingzhu; Dijkstra, Feike A; Zhang, Ke; Li, Xinrong; Tan, Huijuan; Gao, Yanhong; Li, Gang

    2014-11-06

    In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0-10 cm), middle (10-40 cm) and deep soil layers (40-100 cm), at 52 sites in a temperate desert of northwest China. Leaf P and N:P ratios varied markedly among life forms. Leaf P was higher in annuals and perennials than in shrubs. Leaf N and P showed a negative relationship with mean annual temperature (MAT) and no relationship with mean annual precipitation (MAP), but a positive relationship with soil P. Leaf P of shrubs was positively related to soil P in the deep soil. Our study indicated that leaf N and P across the three life forms were influenced by soil P. Deep-rooted plants may enhance the availability of P in the surface soil facilitating growth of shallow-rooted life forms in this N and P limited system, but further research is warranted on this aspect.

  16. Bacteria and fungi can contribute to nutrients bioavailability and aggregate formation in degraded soils.

    PubMed

    Rashid, Muhammad Imtiaz; Mujawar, Liyakat Hamid; Shahzad, Tanvir; Almeelbi, Talal; Ismail, Iqbal M I; Oves, Mohammad

    2016-02-01

    Intensive agricultural practices and cultivation of exhaustive crops has deteriorated soil fertility and its quality in agroecosystems. According to an estimate, such practices will convert 30% of the total world cultivated soil into degraded land by 2020. Soil structure and fertility loss are one of the main causes of soil degradation. They are also considered as a major threat to crop production and food security for future generations. Implementing safe and environmental friendly technology would be viable solution for achieving sustainable restoration of degraded soils. Bacterial and fungal inocula have a potential to reinstate the fertility of degraded land through various processes. These microorganisms increase the nutrient bioavailability through nitrogen fixation and mobilization of key nutrients (phosphorus, potassium and iron) to the crop plants while remediate soil structure by improving its aggregation and stability. Success rate of such inocula under field conditions depends on their antagonistic or synergistic interaction with indigenous microbes or their inoculation with organic fertilizers. Co-inoculation of bacteria and fungi with or without organic fertilizer are more beneficial for reinstating the soil fertility and organic matter content than single inoculum. Such factors are of great importance when considering bacteria and fungi inocula for restoration of degraded soils. The overview of presented mechanisms and interactions will help agriculturists in planning sustainable management strategy for reinstating the fertility of degraded soil and assist them in reducing the negative impact of artificial fertilizers on our environment.

  17. Leaf nitrogen and phosphorus of temperate desert plants in response to climate and soil nutrient availability

    PubMed Central

    He, Mingzhu; Dijkstra, Feike A.; Zhang, Ke; Li, Xinrong; Tan, Huijuan; Gao, Yanhong; Li, Gang

    2014-01-01

    In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0–10 cm), middle (10–40 cm) and deep soil layers (40–100 cm), at 52 sites in a temperate desert of northwest China. Leaf P and N:P ratios varied markedly among life forms. Leaf P was higher in annuals and perennials than in shrubs. Leaf N and P showed a negative relationship with mean annual temperature (MAT) and no relationship with mean annual precipitation (MAP), but a positive relationship with soil P. Leaf P of shrubs was positively related to soil P in the deep soil. Our study indicated that leaf N and P across the three life forms were influenced by soil P. Deep-rooted plants may enhance the availability of P in the surface soil facilitating growth of shallow-rooted life forms in this N and P limited system, but further research is warranted on this aspect. PMID:25373739

  18. Nutrient limitation in soils and trees of a treeline ecotone in Rolwaling Himal, Nepal

    NASA Astrophysics Data System (ADS)

    Drollinger, Simon; Müller, Michael; Schickhoff, Udo; Böhner, Jürgen; Scholten, Thomas

    2015-04-01

    At a global scale, tree growth and thus the position of natural alpine treelines is limited by low temperatures. At landscape and local scales, however, the treeline position depends on multiple interactions of influencing factors and mechanisms. The aim of our research is to understand local scale effects of soil properties and nutrient cycling on tree growth limitation, and their interactions with other abiotic and biotic factors, in a near-natural alpine treeline ecotone of Rolwaling Himal, Nepal. In total 48 plots (20 m x 20 m) were investigated. Three north-facing slopes were separated in four different altitudinal zones with the characteristic vegetation of tree species Rhododendron campanulatum, Abies spectabilis, Betula utilis, Sorbus microphylla and Acer spec. We collected 151 soil horizon samples (Ah, Ae, Bh, Bs), 146 litter layer samples (L), and 146 decomposition layer samples (Of) in 2013, as well as 251 leaves from standing biomass (SB) in 2013 and 2014. All samples were analysed for exchangeable cations or nutrient concentrations of C, N, P, K, Mg, Ca, Mn, Fe and Al. Soil moisture, soil and surface air temperatures were measured by 34 installed sensors. Precipitation and air temperatures were measured by three climate stations. The main pedogenic process is leaching of dissolved organic carbon, aluminium and iron from topsoil to subsoil. Soil types are classified as podzols with generally low nutrient concentrations. Soil acidity is extremely high and humus quality of mineral soils is poor. Our results indicate multilateral interactions and a great spatial variability of essential nutrients within the treeline ecotone. Both, soil nutrients and leave macronutrient concentrations of nitrogen (N), magnesium (Mg), potassium (K) decrease significantly with elevation in the treeline ecotone. Besides, phosphorus (P) foliar concentrations decrease significantly with elevation. Based on regression analyses, low soil temperatures and malnutrition most likely

  19. Dust and nutrient enrichment by wind erosion from Danish soils in dependence of tillage direction

    NASA Astrophysics Data System (ADS)

    Mohammadian Behbahani, Ali; Fister, Wolfgang; Heckrath, Goswin; Kuhn, Nikolaus J.

    2016-04-01

    Wind erosion is a selective process, which promotes erosion of fine particles. Therefore, it can be assumed that increasing erosion rates are generally associated with increasing loss of dust sized particles and nutrients. However, this selective process is strongly affected by the orientation and respective trapping efficiency of tillage ridges and furrows. Since tillage ridges are often the only protection measure available on poorly aggregated soils in absence of a protective vegetation cover, it is very important to know which orientation respective to the dominant wind direction provides best protection. This knowledge could be very helpful for planning erosion protection measures on fields with high wind erosion susceptibility. The main objective of this study, therefore, was to determine the effect of tillage direction on dust and nutrient mobilization by wind, using wind tunnel simulations. In order to assess the relationship between the enrichment ratio of specific particle sizes and the amount of eroded nutrients, three soils with loamy sand texture, but varying amounts of sand-sized particles, were selected. In addition, a soil with slightly less sand, but much higher organic matter content was chosen. The soils were tested with three different soil surface scenarios - flat surface, parallel tillage, perpendicular tillage. The parallel tillage operation experienced the greatest erosion rates, independent of soil type. Particles with D50 between 100-155 μm showed the greatest risk of erosion. However, due to a greater loss of dust sized particles from perpendicularly tilled surfaces, this wind-surface arrangement showed a significant increase in nutrient enrichment ratio compared to parallel tillage and flat surfaces. The main reason for this phenomenon is most probably the trapping of larger particles in the perpendicular furrows. This indicates that the highest rate of soil protection does not necessarily coincide with lowest soil nutrient losses and

  20. Soil carbon fractions under maize-wheat system: effect of tillage and nutrient management.

    PubMed

    Sandeep, S; Manjaiah, K M; Pal, Sharmistha; Singh, A K

    2016-01-01

    Soil organic carbon plays a major role in sustaining agroecosystems and maintaining environmental quality as it acts as a major source and sink of atmospheric carbon. The present study aims to assess the impact of agricultural management practices on soil organic carbon pools in a maize-wheat cropping system of Indo-Gangetic Plains, India. Soil samples from a split plot design with two tillage systems (bed planting and conventional tillage) and six nutrient treatments (T1 = control, T2 = 120 kg urea-N ha(-1), T3 = T2 (25 % N substituted by FYM), T4 = T2 (25 % N substituted by sewage sludge), T5 = T2 + crop residue, T6 = 100 % organic source (50 % FYM + 25 % biofertilizer + 25 % crop residue) were used for determining the organic carbon pools. Results show that there was a significant improvement in Walkley and Black carbon in soil under integrated and organic nutrient management treatments. KMnO4-oxidizable carbon content of soil varied from 0.63 to 1.50 g kg(-1) in soils and was found to be a better indicator for monitoring the impact of agricultural management practices on quality of soil organic carbon than microbial biomass carbon. Tillage and its interaction were found to significantly influence only those soil organic carbon fractions closely associated with aggregate stability viz, labile polysaccharides and glomalin. The highest amount of C4-derived carbon was found to be in plots receiving recommended doses of N as urea (29 %) followed by control plots (25 %). The carbon management index ranged between 82 to 195 and was better in integrated nutrient sources than ones receiving recommended doses of nutrients through mineral fertilizers alone.

  1. Heterogeneity of soil nutrients and subsurface biota in a dryland ecosystem

    USGS Publications Warehouse

    Housman, D.C.; Yeager, C.M.; Darby, B.J.; Sanford, R.L.; Kuske, C.R.; Neher, D.A.; Belnap, J.

    2007-01-01

    Dryland ecosystems have long been considered to have a highly heterogeneous distribution of nutrients and soil biota, with greater concentrations of both in soils under plants relative to interspace soils. We examined the distribution of soil resources in two plant communities (dominated by either the shrub Coleogyne ramosissima or the grass Stipa hymenoides) at two locations. Interspace soils were covered either by early successional biological soil crusts (BSCs) or by later successional BSCs (dominated by nitrogen (N)-fixing cyanobacteria and lichens). For each of the 8 plant type??crust type??locations, we sampled the stem, dripline, and 3 interspace distances around each of 3 plants. Soil analyses revealed that only available potassium (Kav) and ammonium concentrations were consistently greater under plants (7 of 8 sites and 6 of 8 sites, respectively). Nitrate and iron (Fe) were greater under plants at 4 sites, while all other nutrients were greater under plants at less than 50% of the sites. In contrast, calcium, copper, clay, phosphorus (P), and zinc were often greater in the interspace than under the plants. Soil microbial biomass was always greater under the plant compared to the interspace. The community composition of N-fixing bacteria was highly variable, with no distinguishable patterns among microsites. Bacterivorous nematodes and rotifers were consistently more abundant under plants (8 and 7 sites, respectively), and fungivorous and omnivorous nematodes were greater under plants at 5 of the 8 sites. Abundance of other soil biota was greater under plants at less than 50% of the sites, but highly correlated with the availability of N, P, Kav, and Fe. Unlike other ecosystems, the soil biota was only infrequently correlated with organic matter. Lack of plant-driven heterogeneity in soils of this ecosystem is likely due to (1) interspace soils covered with BSCs, (2) little incorporation of above-ground plant litter into soils, and/or (3) root deployment

  2. [Effects of rhizosphere soil permeability on water and nutrient uptake by maize].

    PubMed

    Niu, Wen-quan; Guo, Chao

    2010-11-01

    Aimed to better understand the significance of soil microenvironment in crop growth, a pot experiment was conducted to investigate the effects of rhizosphere soil permeability on the water and nutrient uptake by maize. Under three irrigation levels (600, 400, and 200 ml per pot), three treatments of soil aeration (no tube aeration as the control, tube aeration every two days, and tube aeration every four days) were installed, and the physiological indices of maize were measured. Under the same irrigation levels, soil aeration increased the plant height, leaf area, chlorophyll contents, promoted nutrient adsorption and increased root vitality markedly. At elongation stage, treatment tube aeration every four days had the highest root vitality (8.24 mg x g(-1) x h(-1)) under the irrigation level 600 ml per pot, being significantly higher (66.7%) than that (4.94 mg x g(-1) x h(-1)) of the control. Soil aeration had no significant effects on the transpiration rate of maize, indicating that rhizosphere soil aeration could raise water and nutrient use efficiency, and improve maize growth.

  3. [Status and changes of soil nutrients in rhizosphere of Abelmoschus manihot different planting age].

    PubMed

    Tang, Li-Xia; Tan, Xian-He; Zhang, Yu; Liu, Xiao-Ning

    2013-11-01

    Using soil chemical analysis method and combining with ICP-AES determination of mineral nutrition element content in rhizosphere soil of different planting age Abelmoschus Corolla Results show that along with the increase of planting age, the nitrogen (total N), available P and organic matter in rhizosphere soil of Abelmoschus Corolla content declined year by year and the soil got acidification. Heavy metal element content in agricultural land does not exceed national standards, but the content of element mercury (Hg) in rhizosphere soil of different planting age Abelmoschus Corolla declined. Request of microelement such as manganese (Mn) and zinc (Zn) had a increase tendency, but the content of magnesium (Mg) and sodium (Na) increased, and other nutrient elements had no changed rules or unchanged apparently. Consequently, exploring the change rules of different planting age Abelmoschus Corolla soil in rhizosphere as theoretical guidance of rational fertilization and subducting continuous cropping obstscles.

  4. Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation.

    PubMed

    Jiang, Ying; Brassington, Kirsty J; Prpich, George; Paton, Graeme I; Semple, Kirk T; Pollard, Simon J T; Coulon, Frédéric

    2016-10-01

    The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.

  5. Microprofiling of nitrogen patches in paddy soil: Analysis of spatiotemporal nutrient heterogeneity at the microscale.

    PubMed

    Li, Yilin; Kronzucker, Herbert J; Shi, Weiming

    2016-06-06

    Flooded paddy soil ecosystems in the tropics support the cultivation of the majority of the world's leading crop, rice, and nitrogen (N) availability in the paddy-soil rooting zone limits rice production more than any other nutritional factor. Yet, little is known about the dynamic response of paddy soil to N-fertiliser application, in terms of horizontal and vertical patchiness in N distribution and transformation. Here, we present a microscale analysis of the profile of ammonium (NH4(+)) and nitrate (NO3(-)), nitrification, oxygen (O2water and O2soil), and pH (pHwater and pHsoil) in paddy soils, collected from two representative rice-production areas in subtropical China. NH4(+) and NO3(-) exhibited dramatic spatiotemporal profiles within N patches on the microscale. We show that pHsoil became constant at 1.0-3.5 mm depth, and O2soil became undetectable at 1.7-4.0 mm. Fertiliser application significantly increased pH, and decreased O2, within N patches. Path analysis showed that the factors governing nitrification scaled in the order: pHwater > pHsoil > NH4(+) > O2water > NO3(-) > O2soil. We discuss the soil properties that decide the degree of nutrient patchiness within them and argue that such knowledge is critical to intelligent appraisals of nutrient-use efficiencies in the field.

  6. Inorganic Nutrients Increase Humification Efficiency and C-Sequestration in an Annually Cropped Soil

    PubMed Central

    Richardson, Alan E.; Wade, Len J.; Conyers, Mark; Kirkegaard, John A.

    2016-01-01

    Removing carbon dioxide (CO2) from the atmosphere and storing the carbon (C) in resistant soil organic matter (SOM) is a global priority to restore soil fertility and help mitigate climate change. Although it is widely assumed that retaining rather than removing or burning crop residues will increase SOM levels, many studies have failed to demonstrate this. We hypothesised that the microbial nature of resistant SOM provides a predictable nutrient stoichiometry (C:nitrogen, C:phosphorus and C:sulphur–C:N:P:S) to target using supplementary nutrients when incorporating C-rich crop residues into soil. An improvement in the humification efficiency of the soil microbiome as a whole, and thereby C-sequestration, was predicted. In a field study over 5 years, soil organic-C (SOC) stocks to 1.6 m soil depth were increased by 5.5 t C ha-1 where supplementary nutrients were applied with incorporated crop residues, but were reduced by 3.2 t C ha-1 without nutrient addition, with 2.9 t C ha-1 being lost from the 0–10 cm layer. A net difference of 8.7 t C ha-1 was thus achieved in a cropping soil over a 5 year period, despite the same level of C addition. Despite shallow incorporation (0.15 m), more than 50% of the SOC increase occurred below 0.3 m, and as predicted by the stoichiometry, increases in resistant SOC were accompanied by increases in soil NPS at all depths. Interestingly the C:N, C:P and C:S ratios decreased significantly with depth possibly as a consequence of differences in fungi to bacteria ratio. Our results demonstrate that irrespective of the C-input, it is essential to balance the nutrient stoichiometry of added C to better match that of resistant SOM to increase SOC sequestration. This has implications for global practices and policies aimed at increasing SOC sequestration and specifically highlight the need to consider the hidden cost and availability of associated nutrients in building soil-C. PMID:27144282

  7. Facilitated Bioavailability of PAHs to Native Soil Bacteria Promoted by Nutrient Addition

    NASA Astrophysics Data System (ADS)

    Pignatello, J. J.; Li, J.

    2006-12-01

    Facilitated bioavailability refers to the ability of an organism to have access to pools of non-labile chemical. Mechanisms proposed for this ability include release of biosurfactants, direct mining of adsorbed chemical, alteration of interfacial chemistry, and passive effects of attached biofilms on molecular diffusion. We investigated the biodegradation by indigenous organisms of a set of 16 standard polycyclic aromatic hydrocarbons (PAHs) in coal tar contaminated soil from a manufactured gas plant site in Connecticut in well- mixed aerobic reactors containing various additives over a 93-106 day period. Parallel desorption experiments were conducted in the presence of a biocide and an excess of Tenax-TA adsorbent beads to simulate desorption to infinite dilution (i.e., maximal concentration gradient for diffusion). Both biotransformation and desorption decreased with PAH ring size, as expected. Biodegradation by native organisms was strongly accelerated by addition of inorganic nutrients (N, P, K, and trace metals). In the absence of added nutrients, the biodegradation resistant fraction correlated well with the desorption resistant fraction. However, in the presence of added nutrients, the extent of biodegradation was greater than the extent of desorption except for the largest compounds, which neither degraded nor desorbed. The ability of nutrients to accelerate degradation of bioavailable PAHs by native cells indicates that the persistence of PAHs for many decades at this site is likely due to nutrient-limited natural attenuation. The surprising result of this study is that application of nutrients promotes `facilitated bioavailability' of PAHs in this soil to indigenous microorganisms.

  8. 57Fe Mössbauer spectroscopy investigations of iron oxidation states in the Harmattan dust nutrient contribution to West African soils

    NASA Astrophysics Data System (ADS)

    Adetunji, Jacob

    2014-12-01

    A variety of investigations have been carried out on Harmattan dust over many decades demonstrating the continuing importance of the Harmattan dust phenomenon. The investigations have included elemental enrichment factors, mineralogical nutrient input through dust deposition on the soil, meteorological studies, etc. Harmattan dust is important, not only for its impact on radio communication and low visibility in the shipping lanes over the Atlantic, but also on the livelihood and health of people living in countries over which the dust-laden Harmattan wind blows. However, so far, the aspect of nutrient mineral deposition on the soil has not been thoroughly investigated and requires attention, since the majority of people living in West Africa rely heavily on agriculture. It is therefore relevant to know the useful nutrients in the Harmattan dust deposited on soils of the region. This study is therefore aimed at determining the ferric-ferrous ratio of the iron-bearing minerals contained in the Harmattan dust, so their nutritional contribution can be considered. The Mössbauer technique is a powerful tool for studying the ferric-ferrous ratio and has therefore been used, for the first time, to determine the oxidation states of iron in the dust samples. The results of the analysis show that the Harmattan dust is seriously deficient in ferrous iron, which is the more soluble Fe-ion, needed in the soil for healthy crops and plants in general.

  9. Contaminant immobilization and nutrient release by carbonized biomass in water and soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chars contain functional surface groups such as carboxylic, phenolic, hydroxyl, carbonyl, and quinones, in addition to porous structures that can impact essential soil properties such as cation exchange capacity (CEC), pH, and retention of water, nutrients, and pesticides. Physical and chemical pro...

  10. Soil erosion and nutrient runoff in corn silage with kura clover living mulch and winter rye

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) silage is a productive and popular forage crop that can exacerbate soil loss, surface water runoff, and nonpoint source nutrient pollution from agricultural fields. The objective of this research was to compare the effects of using kura clover (Trifolium ambiguum M. Bieb.) living ...

  11. Nutrient dynamics from broiler litter applied to no-till cotton in an upland soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface-applying broiler litter to a no-till cotton field increases the potential for loss of manure nutrients from the fields in runoff events and volitization of the NH4-N. An experiment was conducted on an upland Atwood silt loam soil (fine-silty, mixed, thermic Typic Paleududalfs) at the Pontoto...

  12. Soils, slopes and source rocks: Application of a soil chemistry model to nutrient delivery to rift lakes

    NASA Astrophysics Data System (ADS)

    Harris, Nicholas B.; Tucker, Gregory E.

    2015-06-01

    The topographic evolution of rift basins may be critical to the deposition of lacustrine source rocks such as the organic-rich Lower Cretaceous shales of the South Atlantic margin. Soils have been proposed as a key link between topography and source rock deposition by providing nutrients for the algae growth in rift lakes. Decreasing topographic relief from active rift to late rift has several effects on soils: soils become thicker and finer, erosion of dead surface and soil organic matter decreases, and the fractionation of precipitation between runoff and infiltration may favor increased infiltration. This hypothesis is tested by application of CENTURY, a complex box model that simulates transfer of nutrients within soil pools. The model is first applied to a rainforest soil, with several parameters individually varied. Infiltration experiments show that the concentrations of C, N and P in groundwater decrease rapidly as infiltration decreases, whether due to increased slope or to decreased precipitation. Increased erosion of surface plant litter and topsoil results in substantially decreased nutrient concentrations in groundwater. Increased sand content in soil causes an increase in nutrient concentration. We integrate these variables in analyzing topographic swathes from the Rio Grande Rift, comparing the southern part of the rift, where topography is relatively old and reduced, to the northern rift. C and P concentrations in groundwater increase as slope gradient decreases, resulting in substantially larger C and P concentrations in groundwater in the southern rift than the northern rift. Nitrogen concentrations in groundwater depends on whether infiltration varies as a function of slope gradient; in experiments where the fraction of infiltrated precipitation decreased with increasing slope, N concentrations was also substantially higher in the southern rift; but in experiments where that fraction was held constant, N concentrations was lower in the southern

  13. Soil Hydrologic Response and Nutrient Movement in Three Small Tropical Catchments

    NASA Astrophysics Data System (ADS)

    Pullen, N. H.; Hamann, H. B.; Stallard, R. F.

    2004-12-01

    The movement of water over and through soils by storm-generated flowpaths in tropical forests not only mediates nutrient movement and physical weathering, but also potentially influences vegetation growth and dynamics with seasonally dry or saturated soil conditions. However, few small-scale catchment studies (10-1000ha) have produced a comprehensive, standardized dataset on soil hydrologic properties among tropical forest catchments, due in part to complexities within tropical systems, and to inconsistencies in methods, data collection, and/or analyses. In response, this study has utilized the global, standardized network of forest dynamics plots of the Center for Tropical Forest Science (CTFS) for the rapid assessment of soil saturated hydraulic conductivity (Ks) and the water chemistry from storm-generated flowpaths. Ks measurements at varying depths help in testing Elsenbeer's (2001) functional classification continuum of tropical forest soilscapes and resulting hydrologic flowpaths. In Barro Colorado Island, Panama, Ks decreased rapidly with soil depth where horizontal surface and near-surface flowpaths were most prevalent. Ks measurements in Yasuni National Park, Ecuador indicated limited vertical movement of water at depths >15cm due to an impermeable soil layer. Ks measurements from Lambir Hills National Park, Malaysia, represented both ends of the continuum due to variability in soil type and lithology. In relation to soil hydrology and hydrological flowpaths, runoff chemistry at Yasuni reveals a general pattern of increased nutrient export as water moves through the canopy and over the soil surface, with concentrations of K+ increasing significantly in throughfall, and concentrations of both K+, and NO3- remaining high in overland flow. The results from the composite overland flow samples may indicate a more open nutrient cycle in tropical forest environments than has been suggested from earlier studies using radioactively labeled isotopes.

  14. Microbial respiration per unit microbial biomass increases with carbon-to-nutrient ratios in soils

    NASA Astrophysics Data System (ADS)

    Spohn, Marie; Chodak, Marcin

    2015-04-01

    The ratio of carbon-to-nutrient in forest floors is usually much higher than the ratio of carbon-to-nutrient that soil microorganisms require for their nutrition. In order to understand how this mismatch affects carbon cycling, the respiration rate per unit soil microbial biomass carbon - the metabolic quotient (qCO2) - was studied. This was done in a field study (Spohn and Chodak, 2015) and in a meta-analysis of published data (Spohn, 2014). Cores of beech, spruce, and mixed spruce-beech forest soils were cut into slices of 1 cm from the top of the litter layer down to 5 cm in the mineral soil, and the relationship between the qCO2 and the soil carbon-to-nitrogen (C:N) and the soil carbon-to-phosphorus (C:P) ratio was analyzed. We found that the qCO2 was positively correlated with soil C:N ratio in spruce soils (R = 0.72), and with the soil C:P ratio in beech (R = 0.93), spruce (R = 0.80) and mixed forest soils (R = 0.96). We also observed a close correlation between the qCO2 and the soil C concentration in all three forest types. Yet, the qCO2 decreased less with depth than the C concentration in all three forest types, suggesting that the change in qCO2 is not only controlled by the soil C concentration. We conclude that microorganisms increase their respiration rate per unit biomass with increasing soil C:P ratio and C concentration, which adjusts the substrate to their nutritional demands in terms of stoichiometry. In an analysis of literature data, I tested the effect of the C:N ratio of soil litter layers on microbial respiration in absolute terms and per unit microbial biomass C. For this purpose, a global dataset on the microbial respiration rate per unit microbial biomass C - termed the metabolic quotient (qCO2) - was compiled form literature data. It was found that the qCO2 in the soil litter layers was positively correlated with the litter C:N ratio and negatively related with the litter nitrogen (N) concentration. The positive relation between the qCO2

  15. Soil nutrient additions increase invertebrate herbivore abundances, but not herbivory, across three grassland systems.

    PubMed

    La Pierre, Kimberly J; Smith, Melinda D

    2016-02-01

    Resource availability may influence invertebrate communities, with important consequences for ecosystem function, such as biomass production. We assessed: (1) the effects of experimental soil nutrient additions on invertebrate abundances and feeding rates and (2) the resultant changes in the effects of invertebrates on aboveground plant biomass at three grassland sites spanning the North American Central Plains, across which plant tissue chemistry and biomass vary. Invertebrate communities and rates of herbivory were sampled within a long-term nutrient-addition experiment established at each site along the broad Central Plains precipitation gradient. Additionally, the effects of invertebrates on aboveground plant biomass were determined under ambient and elevated nutrient conditions. At the more mesic sites, invertebrate herbivore abundances increased and their per capita rate of herbivory decreased with nutrient additions. In contrast, at the semi-arid site where plant biomass is low and plant nutrient concentrations are high, invertebrate herbivore abundances did not vary and per capita rates of herbivory increased with nutrient additions. No change in the effect of invertebrate herbivores on aboveground plant biomass was observed at any of the sites. In sum, nutrient additions induced shifts in both plant biomass and leaf nutrient content, which altered invertebrate abundances and feeding rate. However, due to the inverse relationship between changes in herbivore abundance and per capita rates of herbivory, nutrient additions did not alter the effect of invertebrates on aboveground biomass. Overall, we suggest that this inverse response of herbivore abundance and per capita feeding rate may buffer ecosystems against changes in invertebrate damage in response to fluctuations in nutrient levels.

  16. Nutrient Enrichment Mediates the Relationships of Soil Microbial Respiration with Climatic Factors in an Alpine Meadow.

    PubMed

    Zong, Ning; Jiang, Jing; Shi, Peili; Song, Minghua; Shen, Zhenxi; Zhang, Xianzhou

    2015-01-01

    Quantifying the effects of nutrient additions on soil microbial respiration (R m) and its contribution to soil respiration (R s) are of great importance for accurate assessment ecosystem carbon (C) flux. Nitrogen (N) addition either alone (coded as LN and HN) or in combination with phosphorus (P) (coded as LN + P and HN + P) were manipulated in a semiarid alpine meadow on the Tibetan Plateau since 2008. Either LN or HN did not affect R m, while LN + P enhanced R m during peak growing periods, but HN + P did not affect R m. Nutrient addition also significantly affected R m /R s, and the correlations of R m /R s with climatic factors varied with years. Soil water content (Sw) was the main factor controlling the variations of R m /R s. During the years with large rainfall variations, R m /R s was negatively correlated with Sw, while, in years with even rainfall, R m/R s was positively correlated with Sw. Meanwhile, in N + P treatments the controlling effects of climatic factors on R m /R s were more significant than those in CK. Our results indicate that the sensitivity of soil microbes to climatic factors is regulated by nutrient enrichment. The divergent effects of Sw on R m /R s suggest that precipitation distribution patterns are key factors controlling soil microbial activities and ecosystem C fluxes in semiarid alpine meadow ecosystems.

  17. Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils.

    PubMed

    Grau, Oriol; Peñuelas, Josep; Ferry, Bruno; Freycon, Vincent; Blanc, Lilian; Desprez, Mathilde; Baraloto, Christopher; Chave, Jérôme; Descroix, Laurent; Dourdain, Aurélie; Guitet, Stéphane; Janssens, Ivan A; Sardans, Jordi; Hérault, Bruno

    2017-03-23

    Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground biomass), and dynamics (growth, mortality, aboveground wood productivity) of nutrient-poor tropical forests. Most variables did not covary with site-level changes in soil nutrient content, indicating that nutrient-cycling mechanisms other than the direct absorption from soil (e.g. the nutrient uptake from litter, the resorption, or the storage of nutrients in the biomass), may strongly control forest structure and dynamics. Ecosystem-level adaptations to low soil nutrient availability and long-term low levels of disturbance may help to account for the lower productivity and higher accumulation of biomass in nutrient-poor forests compared to nutrient-richer forests.

  18. Nutrient-cycling mechanisms other than the direct absorption from soil may control forest structure and dynamics in poor Amazonian soils

    PubMed Central

    Grau, Oriol; Peñuelas, Josep; Ferry, Bruno; Freycon, Vincent; Blanc, Lilian; Desprez, Mathilde; Baraloto, Christopher; Chave, Jérôme; Descroix, Laurent; Dourdain, Aurélie; Guitet, Stéphane; Janssens, Ivan A.; Sardans, Jordi; Hérault, Bruno

    2017-01-01

    Tropical forests store large amounts of biomass despite they generally grow in nutrient-poor soils, suggesting that the role of soil characteristics in the structure and dynamics of tropical forests is complex. We used data for >34 000 trees from several permanent plots in French Guiana to investigate if soil characteristics could predict the structure (tree diameter, density and aboveground biomass), and dynamics (growth, mortality, aboveground wood productivity) of nutrient-poor tropical forests. Most variables did not covary with site-level changes in soil nutrient content, indicating that nutrient-cycling mechanisms other than the direct absorption from soil (e.g. the nutrient uptake from litter, the resorption, or the storage of nutrients in the biomass), may strongly control forest structure and dynamics. Ecosystem-level adaptations to low soil nutrient availability and long-term low levels of disturbance may help to account for the lower productivity and higher accumulation of biomass in nutrient-poor forests compared to nutrient-richer forests. PMID:28332608

  19. Comparison of ion-exchange resin counterions in the nutrient measurement of calcareous soils: Implications for correlative studies of plant-soil relationships

    USGS Publications Warehouse

    Sherrod, S.K.; Belnap, J.; Miller, M.E.

    2003-01-01

    For more than 40 years, ion-exchange resins have been used to characterize nutrient bioavailability in terrestrial and aquatic ecosystems. To date, however, no standardized methodology has been developed, particularly with respect to the counterions that initially occupy resin exchange sites. To determine whether different resin counterions yield different measures of soil nutrients and rank soils differently with respect to their measured nutrient bioavailability, we compared nutrient measurements by three common counterion combinations (HCl, HOH, and NaHCO3). Five sandy calcareous soils were chosen to represent a range of soil characteristics at Canyonlands National Park, Utah, and resin capsules charged with the different counterions equilibrated in saturated pastes of these soils for one week. Data were converted to proportions of total ions of corresponding charge for ANOVA. Results from the different methods were not comparable with respect to any nutrient. Of eleven nutrients measured, all but iron (Fe2+), manganese (Mn2+), and zinc (Zn2+) differed significantly (p ??? 0.05) as a function of soil x counterion interactions; Fe2+ and Zn2+ varied as functions of counterion alone. Of the counterion combinations, HCl-resins yielded the most net ion exchange with all measured nutrients except Na+, NH4+, and HPO42-, the three of which desorbed in the greatest quantities from HOH-resins. Conventional chemical extractions using ammonium acetate generally yielded high proportional values of Ca2+, K+, and Na+. Further, among-soil rankings of nutrient bioavailability varied widely among methods. This study highlights the fact that various ion-exchange resin techniques for measuring soil nutrients may have differential effects on the soil-resin environment and yield data that should not be compared nor considered interchangeable. The most appropriate methods for characterizing soil-nutrient bioavailability depends on soil characteristics and likely on the physiological

  20. Carbon-Degrading Enzyme Activities Stimulated by Increased Nutrient Availability in Arctic Tundra Soils

    PubMed Central

    Koyama, Akihiro; Wallenstein, Matthew D.; Simpson, Rodney T.; Moore, John C.

    2013-01-01

    Climate-induced warming of the Arctic tundra is expected to increase nutrient availability to soil microbes, which in turn may accelerate soil organic matter (SOM) decomposition. We increased nutrient availability via fertilization to investigate the microbial response via soil enzyme activities. Specifically, we measured potential activities of seven enzymes at four temperatures in three soil profiles (organic, organic/mineral interface, and mineral) from untreated native soils and from soils which had been fertilized with nitrogen (N) and phosphorus (P) since 1989 (23 years) and 2006 (six years). Fertilized plots within the 1989 site received annual additions of 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. Within the 2006 site, two fertilizer regimes were established – one in which plots received 5 g N⋅m-2⋅year-1 and 2.5 g P⋅m-2⋅year-1 and one in which plots received 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. The fertilization treatments increased activities of enzymes hydrolyzing carbon (C)-rich compounds but decreased phosphatase activities, especially in the organic soils. Activities of two enzymes that degrade N-rich compounds were not affected by the fertilization treatments. The fertilization treatments increased ratios of enzyme activities degrading C-rich compounds to those for N-rich compounds or phosphate, which could lead to changes in SOM chemistry over the long term and to losses of soil C. Accelerated SOM decomposition caused by increased nutrient availability could significantly offset predicted increased C fixation via stimulated net primary productivity in Arctic tundra ecosystems. PMID:24204773

  1. [Effects of nighttime warming on winter wheat root growth and soil nutrient availability].

    PubMed

    Zhang, Ming-Qian; Chen, Jin; Guo, Jia; Tian, Yun-Lu; Yang, Shi-Jia; Zhang, Li; Yang, Bing; Zhang, Wei-Jian

    2013-02-01

    Climate warming has an obvious asymmetry between day and night, with a greater increment of air temperature at nighttime than at daytime. By adopting passive nighttime warming (PNW) system, a two-year field experiment of nighttime warming was conducted in the main production areas of winter wheat in China (Shijiazhuang of Hebei Province, Xuzhou of Jiangsu Province, Xuchang of Henan Province, and Zhenjiang of Jiangsu Province) in 2009 and 2010, with the responses of soil pH and available nutrient contents during the whole growth periods and of wheat root characteristics at heading stage determined. As compared with the control (no nighttime warming), nighttime warming decreased the soil pH and available nutrient contents significantly, and increased the root dry mass and root/shoot ratio to a certain extent. During the whole growth period of winter wheat, nighttime warming decreased the soil pH in Shijiazhuang, Xuzhou, Xuchang, and Zhenjiang averagely by 0.4%, 0.4%, 0.7%, and 0.9%, the soil alkaline nitrogen content averagely by 8.1%, 8.1%, 7.1%, and 6.0%, the soil available phosphorus content averagely by 15.7%, 12.1%, 19.6%, and 25.8%, and the soil available potassium content averagely by 11.5%, 7.6%, 7.6% , and 10.1%, respectively. However, nighttime warming increased the wheat root dry mass at heading stage in Shijiazhuang, Xuzhou, and Zhenjiang averagely by 31. 5% , 27.0%, and 14.5%, and the root/shoot ratio at heading stage in Shijiazhuang, Xuchang, and Zhenjiang averagely by 23.8%, 13.7% and 9.7%, respectively. Our results indicated that nighttime warming could affect the soil nutrient supply and winter wheat growth via affecting the soil chemical properties.

  2. [Nutrient spatial variability of tobacco soil restoration area and fertility suitability level evaluation].

    PubMed

    Xu, Da-Bing; Deng, Jian-Qiang; Liu, Dong-Bi; Si, Guo-Han; Peng, Cheng-Lin; Yuan, Jia-Fu; Zhao, Shu-Jun; Wang, Rui

    2014-03-01

    By using geographic information system technology (GIS) and geostatistics methods, this paper studied the spatial variability of soil properties and available nutrients in the new regulation area units located in Qingjiangyuan modern tobacco agriculture science and technology park (Enshi, Hubei), suburb of Enshi City and the Baiyang base of Lichuan City, and further evaluation of the soil fertility suitability index (SFI) was carried out by use fuzzy mathematics. The results indicated that the effects of land restoration on the soil available phosphorus content variability and spatial distribution were very obvious, possibly due to the landform characteristics and restoration extent. The effect of land restoration on soil pH was small, however, serious soil acidification was detected in the soil sampled from Baiyang (pH < 5.5). Low SFI was found in 77.6%, 17.1% and 31.4% of the soils taken from the suburb, Baiyang and Qingjiangyuan, respectively. In conclusion, attentions should be paid on soil acidification in Baiyang, soil fertility and equalization in the suburb, and soil fertility in the region of Qingjiangyuan with low SFI.

  3. Aspen Increase Soil Moisture, Nutrients, Organic Matter and Respiration in Rocky Mountain Forest Communities

    PubMed Central

    Buck, Joshua R.; St. Clair, Samuel B.

    2012-01-01

    Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlake National Forest, Utah, USA. Soil measurements were collected in adjacent forest stands that were characterized as aspen dominated, mixed, conifer dominated or open meadow, which includes the range of vegetation conditions that exist in seral aspen forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than mixed and conifer dominated stands and meadows. Specifically, total N, NO3 and NH4 were nearly two-fold higher in soil underneath aspen dominated stands. Soil moisture was significantly higher in aspen stands and meadows in early summer but converged to similar levels as those found in mixed and conifer dominated stands in late summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. These results suggest that changes in disturbance regimes or climate scenarios that favor conifer expansion or loss of aspen will decrease soil resource availability, which is likely to have important feedbacks on plant community development. PMID:23285012

  4. Influence of soil pH in vegetative filter strips for reducing soluble nutrient transport.

    PubMed

    Rahmana, Atikur; Rahmana, Shafiqur; Cihacek, Larry

    2014-08-01

    Low efficacy of vegetative filter strips (VFS) in reducing soluble nutrients has been reported in research articles. Solubility of phosphorus and nitrogen compounds is largely affected by pH of soil. Changing soil pH may result in a decrease in soluble nutrient transportation through VFS. This study was conducted to evaluate the effect of pH levels of VFS soil on soluble nutrient transport reduction from manure-borne runoff. Soil (loamy sand texture; bulk density 1.3 g cm-3) was treated with calcium carbonate to change pH at different pH treatment levels (5.5-6.5, 6.5-7.5, and 7.5-8.5), soil was packed into galvanized metal boxes, and tall fescue grasses were established in the boxes to simulate VFS. Boxes were placed in an open environment, tilted to a 3.0% slope, and 44.0 L manure-amended water was applied through the VFS by a pump at a rate of 1.45 L min-1. Water samples were collected at the inlet and outlet as well as from the leachate. Samples were analysed for ortho-phosphorus, ammonium nitrogen, nitrate nitrogen, and potassium. Highest transport reductions in ortho-phosphorus (42.4%) and potassium (20.5%) were observed at pH range 7.5-8.5. Ammonium nitrogen transport reduction was the highest at pH level of 6.5-7.5 and was 26.1%. Surface transport reduction in nitrate nitrogen was 100%, but leachate had the highest concentration of nitrate nitrogen. Mass transport reduction also suggested that higher pH in the VFS soil are effective in reducing some soluble nutrients transport.

  5. Ca, Sr and Ba stable isotopes reveal the fate of soil nutrients along a tropical climosequence

    USGS Publications Warehouse

    Bullen, Thomas D.; Chadwick, Oliver A.

    2016-01-01

    Nutrient biolifting is an important pedogenic process in which plant roots obtain inorganic nutrients such as phosphorus (P) and calcium (Ca) from minerals at depth and concentrate those nutrients at the surface. Here we use soil chemistry and stable isotopes of the alkaline earth elements Ca, strontium (Sr) and barium (Ba) to test the hypothesis that biolifting of P has been an important pedogenic process across a soil climosequence developed on volcanic deposits at Kohala Mountain, Hawaii. The geochemical linkage between these elements is revealed as generally positive site-specific relationships in soil mass gains and losses, particularly for P, Ba and Ca, using the ratio of immobile elements titanium and niobium (Ti/Nb) to link individual soil samples to a restricted compositional range of the chemically and isotopically diverse volcanic parent materials. At sites where P is enriched in surface soils relative to abundances in deeper soils, the isotope compositions of exchangeable Ca, Sr and Ba in the shallowest soil horizons (< 10 cm depth) are lighter than those of the volcanic parent materials and trend toward those of plants growing on fresh volcanic deposits. In contrast the isotope composition of exchangeable Ba in deeper soil horizons (> 10 cm depth) at those sites is consistently heavier than the volcanic parent materials. The isotope compositions of exchangeable Ca and Sr trend toward heavier compositions with depth more gradually, reflecting increasing leakiness from these soils in the order Ba < Sr < Ca and downward transfer of light biocycled Ca and Sr to deeper exchange sites. Given the long-term stability of ecosystem properties at the sites where P is enriched in surface soils, a simple box model demonstrates that persistence of isotopically light exchangeable Ca, Sr and Ba in the shallowest soil horizons requires that the uptake flux to plants from those near-surface layers is less than the recycling flux returned to the surface as

  6. Biochar-induced changes in soil hydraulic conductivity and dissolved nutrient fluxes constrained by laboratory experiments.

    PubMed

    Barnes, Rebecca T; Gallagher, Morgan E; Masiello, Caroline A; Liu, Zuolin; Dugan, Brandon

    2014-01-01

    The addition of charcoal (or biochar) to soil has significant carbon sequestration and agronomic potential, making it important to determine how this potentially large anthropogenic carbon influx will alter ecosystem functions. We used column experiments to quantify how hydrologic and nutrient-retention characteristics of three soil materials differed with biochar amendment. We compared three homogeneous soil materials (sand, organic-rich topsoil, and clay-rich Hapludert) to provide a basic understanding of biochar-soil-water interactions. On average, biochar amendment decreased saturated hydraulic conductivity (K) by 92% in sand and 67% in organic soil, but increased K by 328% in clay-rich soil. The change in K for sand was not predicted by the accompanying physical changes to the soil mixture; the sand-biochar mixture was less dense and more porous than sand without biochar. We propose two hydrologic pathways that are potential drivers for this behavior: one through the interstitial biochar-sand space and a second through pores within the biochar grains themselves. This second pathway adds to the porosity of the soil mixture; however, it likely does not add to the effective soil K due to its tortuosity and smaller pore size. Therefore, the addition of biochar can increase or decrease soil drainage, and suggests that any potential improvement of water delivery to plants is dependent on soil type, biochar amendment rate, and biochar properties. Changes in dissolved carbon (C) and nitrogen (N) fluxes also differed; with biochar increasing the C flux from organic-poor sand, decreasing it from organic-rich soils, and retaining small amounts of soil-derived N. The aromaticity of C lost from sand and clay increased, suggesting lost C was biochar-derived; though the loss accounts for only 0.05% of added biochar-C. Thus, the direction and magnitude of hydraulic, C, and N changes associated with biochar amendments are soil type (composition and particle size) dependent.

  7. Biochar-Induced Changes in Soil Hydraulic Conductivity and Dissolved Nutrient Fluxes Constrained by Laboratory Experiments

    PubMed Central

    Barnes, Rebecca T.; Gallagher, Morgan E.; Masiello, Caroline A.; Liu, Zuolin; Dugan, Brandon

    2014-01-01

    The addition of charcoal (or biochar) to soil has significant carbon sequestration and agronomic potential, making it important to determine how this potentially large anthropogenic carbon influx will alter ecosystem functions. We used column experiments to quantify how hydrologic and nutrient-retention characteristics of three soil materials differed with biochar amendment. We compared three homogeneous soil materials (sand, organic-rich topsoil, and clay-rich Hapludert) to provide a basic understanding of biochar-soil-water interactions. On average, biochar amendment decreased saturated hydraulic conductivity (K) by 92% in sand and 67% in organic soil, but increased K by 328% in clay-rich soil. The change in K for sand was not predicted by the accompanying physical changes to the soil mixture; the sand-biochar mixture was less dense and more porous than sand without biochar. We propose two hydrologic pathways that are potential drivers for this behavior: one through the interstitial biochar-sand space and a second through pores within the biochar grains themselves. This second pathway adds to the porosity of the soil mixture; however, it likely does not add to the effective soil K due to its tortuosity and smaller pore size. Therefore, the addition of biochar can increase or decrease soil drainage, and suggests that any potential improvement of water delivery to plants is dependent on soil type, biochar amendment rate, and biochar properties. Changes in dissolved carbon (C) and nitrogen (N) fluxes also differed; with biochar increasing the C flux from organic-poor sand, decreasing it from organic-rich soils, and retaining small amounts of soil-derived N. The aromaticity of C lost from sand and clay increased, suggesting lost C was biochar-derived; though the loss accounts for only 0.05% of added biochar-C. Thus, the direction and magnitude of hydraulic, C, and N changes associated with biochar amendments are soil type (composition and particle size) dependent

  8. Land application of tylosin and chlortetracycline swine manure: Impacts to soil nutrients and soil microbial community structure.

    PubMed

    Stone, James J; Dreis, Erin K; Lupo, Christopher D; Clay, Sharon A

    2011-01-01

    The land application of aged chortetracycle (CTC) and tylosin-containing swine manure was investigated to determine associated impacts to soil microbial respiration, nutrient (phosphorus, ammonium, nitrate) cycling, and soil microbial community structure under laboratory conditions. Two silty clay loam soils common to southeastern South Dakota were used. Aerobic soil respiration results using batch reactors containing a soil-manure mixture showed that interactions between soil, native soil microbial populations, and antimicrobials influenced CO(2) generation. The aged tylosin treatment resulted in the greatest degree of CO(2) inhibition, while the aged CTC treatment was similar to the no-antimicrobial treatment. For soil columns in which manure was applied at a one-time agronomic loading rate, there was no significant difference in soil-P behavior between either aged CTC or tylosin and the no-antimicrobial treatment. For soil-nitrogen (ammonium and nitrate), the aged CTC treatment resulted in rapid ammonium accumulation at the deeper 40cm soil column depth, while nitrate production was minimal. The aged CTC treatment microbial community structure was different than the no-antimicrobial treatment, where amines/amide and carbohydrate chemical guilds utilization profile were low. The aged tylosin treatment also resulted in ammonium accumulation at 40 cm column depth, however nitrate accumulation also occurred concurrently at 10 cm. The microbial community structure for the aged tylosin was also significantly different than the no-antimicrobial treatment, with a higher degree of amines/amides and carbohydrate chemical guild utilization compared to the no-antimicrobial treatment. Study results suggest that land application of CTC and tylosin-containing manure appears to fundamentally change microbial-mediated nitrogen behavior within soil A horizons.

  9. Aeolian nutrient fluxes following wildfire in sagebrush steppe: Implications for soil carbon storage

    USGS Publications Warehouse

    Hasselquist, N.J.; Germino, M.J.; Sankey, J.B.; Ingram, L.J.; Glenn, N.F.

    2011-01-01

    Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m????'1 d????'1 and 19 g N m????'1 d????'1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes. ?? 2011 Author(s).

  10. Comparison of ion-exchange resin counterions in the nutrient measurement of calcareous soils: implications for correlative studies of plant-soil relationships

    USGS Publications Warehouse

    Sherrod, S.K.; Belnap, Jayne; Miller, M.E.

    2003-01-01

    For more than 40 years, ion-exchange resins have been used to characterize nutrient bioavailability in terrestrial and aquatic ecosystems. To date, however, no standardized methodology has been developed, particularly with respect to the counterions that initially occupy resin exchange sites. To determine whether different resin counterions yield different measures of soil nutrients and rank soils differently with respect to their measured nutrient bioavailability, we compared nutrient measurements by three common counterion combinations (HCl, HOH, and NaHCO3). Five sandy calcareous soils were chosen to represent a range of soil characteristics at Canyonlands National Park, Utah, and resin capsules charged with the different counterions equilibrated in saturated pastes of these soils for one week. Data were converted to proportions of total ions of corresponding charge for ANOVA. Results from the different methods were not comparable with respect to any nutrient. Of eleven nutrients measured, all but iron (Fe2+), manganese (Mn2+), and zinc (Zn2+) differed significantly (pa??0.05) as a function of soilcounterion interactions; Fe2+ and Zn2+ varied as functions of counterion alone. Of the counterion combinations, HCl-resins yielded the most net ion exchange with all measured nutrients except Na+, and the three of which desorbed in the greatest quantities from HOH-resins. Conventional chemical extractions using ammonium acetate generally yielded high proportional values of Ca2+, K+, and Na+. Further, among-soil rankings of nutrient bioavailability varied widely among methods. This study highlights the fact that various ion-exchange resin techniques for measuring soil nutrients may have differential effects on the soil-resin environment and yield data that should not be compared nor considered interchangeable. The most appropriate methods for characterizing soil-nutrient bioavailability depends on soil characteristics and likely on the physiological uptake mechanisms of

  11. Nutrient input and removal trends for agricultural soils in nine geographic regions in Arkansas.

    PubMed

    Slaton, Nathan A; Brye, Kristofor R; Daniels, Mike B; Daniel, Tommy C; Norman, Richard J; Miller, David M

    2004-01-01

    Knowledge of the balance between nutrient inputs and removals is required for identifying regions that possess an excess or deficit of nutrients. This assessment describes the balance between the agricultural nutrient inputs and removals for nine geographical districts within Arkansas from 1997 to 2001. The total N, P, and K inputs were summed for each district and included inorganic fertilizer and collectable nutrients excreted as poultry, turkey, dairy, and hog manures. Nutrients removed by harvested crops were summed and subtracted from total nutrient inputs to calculate the net nutrient balance. The net balances for N, P, and K were distributed across the hectarage used for row crop, hay, pasture, or combinations of these land uses. Row-crop agriculture predominates in the eastern one-third and animal agriculture predominates in the western two-thirds of Arkansas. Nutrients derived from poultry litter accounted for >92% of the total transportable manure N, P, and K. The three districts in the eastern one-third of Arkansas contained 95% of the row-crop hectarage and had net N and P balances that were near zero or negative. The six districts in the western two-thirds of Arkansas accounted for 89 to 100% of the animal populations, had positive net balances for N and P, and excess P ranged from 1 to 9 kg P ha(-1) when distributed across row-crop, hay, and pasture hectarage. Transport of excess nutrients, primarily in poultry litter, outside of the districts in western Arkansas is needed to achieve a balance between soil inputs and removals of P and N.

  12. Soil, water, and nutrient losses from management alternatives for degraded pasture in Brazilian Atlantic Rainforest biome.

    PubMed

    Rocha Junior, Paulo Roberto da; Andrade, Felipe Vaz; Mendonça, Eduardo de Sá; Donagemma, Guilherme Kangussú; Fernandes, Raphael Bragança Alves; Bhattharai, Rabin; Kalita, Prasanta Kumar

    2017-04-01

    The objective of this study was to evaluate sediment, water and nutrient losses from different pasture managements in the Atlantic Rainforest biome. A field study was carried out in Alegre Espiríto Santo, Brazil, on a Xanthic Ferralsol cultivated with braquiaria (Brachiaria brizantha). The six pasture managements studied were: control (CON), chisel (CHI), fertilizer (FER), burned (BUR), plowing and harrowing (PH), and integrated crop-livestock (iCL). Runoff and sediment samples were collected and analyzed for calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P) and organic carbon contents. Soil physical attributes and above and below biomass were also evaluated. The results indicated that higher water loss was observed for iCL (129.90mm) and CON (123.25mm) managements, and the sediment losses were higher for CON (10.24tha(-1)) and BUR (5.20tha(-1)) managements when compared to the other managements. Majority of the nutrients losses occurred in dissolved fraction (99% of Ca, 99% of Mg, 96% of K, and 65% of P), whereas a significant fraction of organic carbon (80%) loss occurred in a particulate form. Except for P, other nutrients (Ca, Mg and K) and organic carbon losses were higher in coarse sediment compared to fine sediment. The greater losses of sediment, organic carbon, and nutrients were observed for CON followed by BUR management (p<0.05). Our findings indicated that the traditional pasture management adopted in the Atlantic Rainforest needs to be rethought and burned management should be avoided. Based on the water, soil, and nutrient losses from various practices, to reduce pasture degradation, farmers should adopt edaphic practices by applying lime and fertilize to improve pasture growth and soil cover, and reducing soil erosion in the hilly Brazilian Atlantic Rainforest biome.

  13. Linking spatial patterns of leaf litterfall and soil nutrients in a tropical forest: a neighborhood approach.

    PubMed

    Uriarte, María; Turner, Benjamin L; Thompson, Jill; Zimmerman, Jess K

    2015-10-01

    Leaf litter represents an important link between tree community composition, forest productivity and biomass, and ecosystem processes. In forests, the spatial distribution of trees and species-specific differences in leaf litter production and quality are likely to cause spatial heterogeneity in nutrient returns to the forest floor and, therefore, in the redistribution of soil nutrients. Using mapped trees and leaf litter data for 12 tree species in a subtropical forest with a well-documented history of land use, we: (1) parameterized spatially explicit models of leaf litter biomass and nutrient deposition; (2) assessed variation in leaf litter inputs across forest areas with different land use legacies; and (3) determined the degree to which the quantity and quality of leaf litter inputs and soil physical characteristics are associated with spatial heterogeneity in soil nutrient ratios (C:N and N:P). The models captured the effects of tree size and location on spatial variation in leaf litterfall (R² = 0.31-0.79). For all 12 focal species, most of the leaf litter fell less than 5 m away from the source trees, generating fine- scale spatial heterogeneity in leaf litter inputs. Secondary forest species, which dominate areas in earlier successional stages, had lower leaf litter C:N ratios and produced less litter biomass than old-growth specialists. In contrast, P content and N:P ratios did not vary consistently among successional groups. Interspecific variation in leaf litter quality translated into differences in the quantity and quality (C:N) of total leaf litter biomass inputs and among areas with different land use histories. Spatial variation in leaf litter C:N inputs was the major factor associated with heterogeneity in soil C:N ratios relative to soil physical characteristics. In contrast, spatial variation soil N:P was more strongly associated with spatial variation in topography than heterogeneity in leaf litter inputs. The modeling approach presented here

  14. A mechanistic soil biogeochemistry model with explicit representation of microbial and macrofaunal activities and nutrient cycles

    NASA Astrophysics Data System (ADS)

    Fatichi, Simone; Manzoni, Stefano; Or, Dani; Paschalis, Athanasios

    2016-04-01

    The potential of a given ecosystem to store and release carbon is inherently linked to soil biogeochemical processes. These processes are deeply connected to the water, energy, and vegetation dynamics above and belowground. Recently, it has been advocated that a mechanistic representation of soil biogeochemistry require: (i) partitioning of soil organic carbon (SOC) pools according to their functional role; (ii) an explicit representation of microbial dynamics; (iii) coupling of carbon and nutrient cycles. While some of these components have been introduced in specialized models, they have been rarely implemented in terrestrial biosphere models and tested in real cases. In this study, we combine a new soil biogeochemistry model with an existing model of land-surface hydrology and vegetation dynamics (T&C). Specifically the soil biogeochemistry component explicitly separates different litter pools and distinguishes SOC in particulate, dissolved and mineral associated fractions. Extracellular enzymes and microbial pools are explicitly represented differentiating the functional roles of bacteria, saprotrophic and mycorrhizal fungi. Microbial activity depends on temperature, soil moisture and litter or SOC stoichiometry. The activity of macrofauna is also modeled. Nutrient dynamics include the cycles of nitrogen, phosphorous and potassium. The model accounts for feedbacks between nutrient limitations and plant growth as well as for plant stoichiometric flexibility. In turn, litter input is a function of the simulated vegetation dynamics. Root exudation and export to mycorrhiza are computed based on a nutrient uptake cost function. The combined model is tested to reproduce respiration dynamics and nitrogen cycle in few sites where data were available to test plausibility of results across a range of different metrics. For instance in a Swiss grassland ecosystem, fine root, bacteria, fungal and macrofaunal respiration account for 40%, 23%, 33% and 4% of total belowground

  15. Managing soil nutrients with compost in organic farms of East Georgia

    NASA Astrophysics Data System (ADS)

    Ghambashidze, Giorgi

    2013-04-01

    Soil Fertility management in organic farming relies on a long-term integrated approach rather than the more short-term very targeted solutions common in conventional agriculture. Increasing soil organic matter content through the addition of organic amendments has proven to be a valuable practice for maintaining or restoring soil quality. Organic agriculture relies greatly on building soil organic matter with compost typically replacing inorganic fertilizers and animal manure as the fertility source of choice. In Georgia, more and more attention is paid to the development of organic farming, occupying less than 1% of total agricultural land of the country. Due to increased interest towards organic production the question about soil amendments is arising with special focus on organic fertilizers as basic nutrient supply sources under organic management practice. In the frame of current research two different types of compost was prepared and their nutritional value was studied. The one was prepared from organic fraction municipal solid waste and another one using fruit processing residues. In addition to main nutritional properties both composts were tested on heavy metals content, as one of the main quality parameter. The results have shown that concentration of main nutrient is higher in municipal solid waste compost, but it contains also more heavy metals, which is not allowed in organic farming system. Fruit processing residue compost also has lower pH value and is lower in total salt content being is more acceptable for soil in lowlands of East Georgia, mainly characterised by alkaline reaction. .

  16. Nutrient uptake by agricultural crops from biochar-amended soils: results from two field experiments in Austria

    NASA Astrophysics Data System (ADS)

    Karer, Jasmin; Zehetner, Franz; Kloss, Stefanie; Wimmer, Bernhard; Soja, Gerhard

    2013-04-01

    The use of biochar as soil amendment is considered as a promising agricultural soil management technique, combining carbon sequestration and soil fertility improvements. These expectations are largely founded on positive experiences with biochar applications to impoverished or degraded tropical soils. The validity of these results for soils in temperate climates needs confirmation from field experiments with typical soils representative for intensive agricultural production areas. Frequently biochar is mixed with other organic additives like compost. As these two materials interact with each other and each one may vary considerably in its basic characteristics, it is difficult to attribute the effects of the combined additive to one of its components and to a specific physico-chemical parameter. Therefore investigations of the amendment efficacy require the study of the pure components to characterize their specific behavior in soil. This is especially important for adsorption behavior of biochar for macro- and micronutrients because in soil there are multiple nutrient sinks that compete with plant roots for vital elements. Therefore this contribution presents results from a field amendment study with pure biochar that had the objective to characterize the macro- and microelement uptake of crops from different soils in two typical Austrian areas of agricultural production. At two locations in North and South-East Austria, two identical field experiments on different soils (Chernozem and Cambisol) were installed in 2011 with varying biochar additions (0, 30 and 90 t/ha) and two nitrogen levels. The biochar was a product from slow pyrolysis of wood (SC Romchar SRL). During the installation of the experiments, the biochar fraction of <2 mm was mixed with surface soil to a depth of 15 cm in plots of 33 m2 each (n=4). Barley (at the Chernozem soil) and maize (at the Cambisol) were cultivated according to standard agricultural practices. The highest crop yields at both

  17. Soil Chemical Weathering and Nutrient Budgets along an Earthworm Invasion Chronosequence in a Northern Minnesota Forest

    NASA Astrophysics Data System (ADS)

    Resner, K. E.; Yoo, K.; Sebestyen, S. D.; Aufdenkampe, A. K.; Lyttle, A.; Weinman, B. A.; Blum, A.; Hale, C. M.

    2011-12-01

    We are investigating the impact of exotic earthworms on the rate of nutrient and ion release from soil chemical weathering along an ~200 m invasion chronosequence in a northern Minnesota sugar maple forest. The earthworms belong to three ecological groups that represent different feeding and burrowing behaviors, all of which were introduced from Europe to the previously earthworm-free Great Lakes Region through fishing and agricultural activities. As earthworms digest and mix the soil, we hypothesize that they significantly alter chemical weathering processes by incorporating mineral surfaces to new geochemical environments in their intestines and at different soil depths. The effect of mixing on soil morphology is dramatic, but biogeochemical changes remain largely unknown and therefore are poorly coupled to the current and potential changes in forest ecosystems under the threat of exotic earthworms. We analyze the activities of short-lived isotopes 137-Cs and 210-Pb along with the inorganic chemistry of soil, water, and leaf litter across an invasion transect and link these measurements to the biomass and species composition of exotic earthworms. Earthworms vertically relocate minerals and organic matter largely within the top ~10 cm, which is reflected in the depth profiles of the short-lived isotopes. Among the inorganic nutrients analyzed, Ca is of particular interest due to sugar maple's aptitude for recycling Ca. Fractional mass loss values (tau) of Ca, relative to the soil's parent material, show an enrichment factor of 14 in the least invaded A horizon soils. However, such a high enrichment factor declines dramatically in the heavily invaded soils, suggesting that earthworm activities contribute to leaching Ca. In contrast, the enrichment factor of Fe increases with greater degrees of earthworm invasion, which is consistent with the extraction chemistry data showing greater quantities of pedogenic crystalline iron oxides and greater mineral specific

  18. Fire and soil-plant nutrient relations in a pine-wiregrass savanna on the coastal plain of North Carolina.

    PubMed

    Christensen, Norman L

    1977-01-01

    Changes in soil and plant nutrient conditions were evaluated following various burn and clip treatments in a longleaf pine-wiregrass savanna in Bladen Co., N.C., USA. Ground fires were found to add substantial quantities of N, P, K, Ca, and Mg to the soil, though not necessarily in forms immediately available to plants. Less than 1% of the total nitrogen in the charred residue (ash) is present as nitrate or ammonium. Considerable quantities of all nutrients examined were lost to the atmosphere during burning. Green leaf tissue in recently burned areas was consistently higher in N, P, K, Ca, and Mg compared to unburned areas. Howerver, when compared to similar tissues from clipped plots, burned area tissues were significantly higher in N, Ca, and Mg only. Data presented here suggest that tissue age significantly affects nutrient content and must be considered in any analysis of tissue nutrient content following burning. Within 4-6 months following fire, burned-area tissue nutrient content decreases to concentrations found in the unburned area. Burning resulted in initial enrichment of available soil nutrients including PO4, K(+), Ca(++), and Mg(++), however, NO3(-), and NH4(+) concentrations in burned soil were not significantly different from unbruned soil. Soil and plant nutrient changes in an area burned two years in succession indicate that repeated burning may diminish nutrient availability. Plant response to various nutrient enrichment treatments of the soil indicated that nitrogen is limiting growth in both burned and unburned soils and that burning may alter some factors other than nutrients which may retard plant growth in unburned areas.

  19. Precontact vegetation and soil nutrient status in the shadow of Kohala Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Chadwick, Oliver A.; Kelly, Eugene F.; Hotchkiss, Sara C.; Vitousek, Peter M.

    2007-09-01

    Humans colonized Hawaii about 1200 years ago and have progressively modified vegetation, particularly in mesic to dry tropical forests. We use δ 13C to evaluate the contribution of C 3 and C 4 plants to deep soil organic matter to reconstruct pre-human contact vegetation patterns along a wet to dry climate transect on Kohala Mountain, Hawaii Island. Precontact vegetation assemblages fall into three distinct zones: a wet C 3 dominated closed canopy forest where annual rainfall is > 2000 mm, a dry C 4 dominated grassland with annual rainfall < 500 mm, and a broad transition zone between these communities characterized by either C 3 trees with higher water-use efficiency than the rainforest trees or C 3 trees with a small amount of C 4 grasses intermixed. The likelihood of C 4 grass understory decreases with increasing rainfall. We show that the total concentration of rock-derived nutrients in the < 2-mm soil fraction differs in each of these vegetation zones. Nutrient losses are driven by leaching at high rainfall and by plant cycling and wind erosion at low rainfall. By contrast, nutrients are best preserved in surface soils of the intermediate rainfall zone, where rainfall supports abundant plant growth but does not contribute large amounts of water in excess of evapotranspiration. Polynesian farmers exploited these naturally enriched soils as they intensified their upland agricultural systems during the last three centuries before European contact.

  20. From agricultural use of sewage sludge to nutrient extraction: A soil science outlook.

    PubMed

    Kirchmann, Holger; Börjesson, Gunnar; Kätterer, Thomas; Cohen, Yariv

    2017-03-01

    The composition of municipal wastewater and sewage sludge reflects the use and proliferation of elements and contaminants within society. In Sweden, official statistics show that concentrations of toxic metals in municipal sewage sludge have steadily decreased, by up to 90 %, since the 1970s, due to environmental programmes and statutory limits on metals in sludge and soil. Results from long-term field experiments show that reduced metal pollution during repeated sewage sludge application has reversed negative trends in soil biology. Despite this Swedish success story, organic waste recycling from Swedish towns and cities to arable land is still limited to only about 20 % of the total amount produced. Resistance among industries and consumers to products grown on land treated with sewage sludge may not always be scientifically grounded; however, there are rational obstacles to application of sewage sludge to land based on its inherent properties rather than its content of pollutants. We argue that application of urban organic wastes to soil is an efficient form of recycling for small municipalities, but that organic waste treatment from large cities requires other solutions. The large volumes of sewage sludge collected in towns and cities are not equitably distributed back to arable land because of the following: (i) The high water and low nutrient content in sewage sludge make long-distance transportation too expensive; and (ii) the low plant availability of nutrients in sewage sludge results in small yield increases even after many years of repeated sludge addition. Therefore, nutrient extraction from urban wastes instead of direct organic waste recycling is a possible way forward. The trend for increased combustion of urban wastes will make ash a key waste type in future. Combustion not only concentrates the nutrients in the ash but also leads to metal enrichment; hence, direct application of the ash to land is most often not possible. However, inorganic

  1. Influence of Acacia trees on soil nutrient levels in arid lands

    NASA Astrophysics Data System (ADS)

    De Boever, Maarten; Gabriels, Donald; Ouessar, Mohamed; Cornelis, Wim

    2014-05-01

    The potential of scattered trees as keystone structures in restoring degraded environments is gaining importance. Scattered trees have strong influence on their abiotic environment, mainly causing changes in microclimate, water budget and soil properties. They often function as 'nursing trees', facilitating the recruitment of other plants. Acacia raddiana is such a keystone species which persists on the edge of the Sahara desert. The study was conducted in a forest-steppe ecosystem in central Tunisia where several reforestation campaigns with Acacia took place. To indentify the impact of those trees on soil nutrients, changes in nutrient levels under scattered trees of three age stages were examined for the upper soil layer (0-10 cm) at five microsites with increasing distance from the trunk. In addition, changes in soil nutrient levels with depth underneath and outside the canopy were determined for the 0-30 cm soil layer. Higher concentrations of organic matter (OM) were found along the gradient from underneath to outside the canopy for large trees compared to medium and small trees, especially at microsites close to the trunk. Levels of soluble K, electrical conductivity (EC), available P, OM, total C and N decreased whereas pH and levels of soluble Mg increased with increasing distance from tree. Levels of soluble Ca and Na remained unchanged along the gradient. At the microsite closest to the trunk a significant decrease in levels of soluble K, EC, OM, available P, total C and N, while a significant increase in pH was found with increasing depth. The concentration of other nutrients remained unchanged or declined not differently underneath compared to outside the canopy with increasing depth. Differences in nutrient levels were largely driven by greater inputs of organic matter under trees. Hence, Acacia trees can affect the productivity and reproduction of understory species with the latter in term an important source of organic matter. This positive feedback

  2. Land application of domestic effluent onto four soil types: plant uptake and nutrient leaching.

    PubMed

    Barton, L; Schipper, L A; Barkle, G F; McLeod, M; Speir, T W; Taylor, M D; McGill, A C; van Schaik, A P; Fitzgerald, N B; Pandey, S P

    2005-01-01

    Land application has become a widely applied method for treating wastewater. However, it is not always clear which soil-plant systems should be used, or why. The objectives of our study were to determine if four contrasting soils, from which the pasture is regularly cut and removed, varied in their ability to assimilate nutrients from secondary-treated domestic effluent under high hydraulic loadings, in comparison with unirrigated, fertilized pasture. Grassed intact soil cores (500 mm in diameter by 700 mm in depth) were irrigated (50 mm wk(-1)) with secondary-treated domestic effluent for two years. Soils included a well-drained Allophanic Soil (Typic Hapludand), a poorly drained Gley Soil (Typic Endoaquept), a well-drained Pumice Soil formed from rhyolitic tephra (Typic Udivitrand), and a well-drained Recent Soil formed in a sand dune (Typic Udipsamment). Effluent-irrigated soils received between 746 and 815 kg N ha(-1) and 283 and 331 kg P ha(-1) over two years of irrigation, and unirrigated treatments received 200 kg N ha(-1) and 100 kg P ha(-1) of dissolved inorganic fertilizer over the same period. Applying effluent significantly increased plant uptake of N and P from all soil types. For the effluent-irrigated soils plant N uptake ranged from 186 to 437 kg N ha(-1) yr(-1), while plant P uptake ranged from 40 to 88 kg P ha(-1) yr(-1) for the effluent-irrigated soils. Applying effluent significantly increased N leaching losses from Gley and Recent Soils, and after two years ranged from 17 to 184 kg N ha(-1) depending on soil type. Effluent irrigation only increased P leaching from the Gley Soil. All P leaching losses were less than 49 kg P ha(-1) after two years. The N and P leached from effluent treatments were mainly in organic form (69-87% organic N and 35-65% unreactive P). Greater N and P leaching losses from the irrigated Gley Soil were attributed to preferential flow that reduced contact between the effluent and the soil matrix. Increased N leaching from

  3. [Responses of Agriophyllum squarrosum phenotypic plasticity to the changes of soil nutrient and moisture contents and population density].

    PubMed

    Huang, Ying-xin; Zhao, Xue-yong; Zhang, Hong-xuan; Luo, Ya-yong; Mao, Wei

    2008-12-01

    This paper studied the phenotypic plasticity of Agriophyllum squarrosum under effects of soil nutrient and moisture contents and population density. The results showed that with the increase of soil nutrient content, the root/shoot ratio of A. squarrosum was decreased from 0.135 to 0.073. However, soil moisture content and population density had less effect on the root/shoot ratio. The plasticity of reproductive allocation of A. squarrosum as responding to the changes of soil nutrient and moisture contents was a "real plasticity", and the allocation was negatively correlated with soil nutrient content but positively correlated with soil moisture content. When soil nutrient content was high or moisture content was low, the reproductive allocation of A. squarrosum changed larger with plant size. Population density had no effects on the reproductive allocation, while plant size conditioned the allocation. Among the three test affecting factors, soil nutrient content had the greatest effects on the morphological characters and biomass of A. squarrosum.

  4. Bacterial Community Structure after Long-term Organic and Inorganic Fertilization Reveals Important Associations between Soil Nutrients and Specific Taxa Involved in Nutrient Transformations

    PubMed Central

    Li, Fang; Chen, Lin; Zhang, Jiabao; Yin, Jun; Huang, Shaomin

    2017-01-01

    Fertilization has a large impact on the soil microbial communities, which play pivotal roles in soil biogeochemical cycling and ecological processes. While the effects of changes in nutrient availability due to fertilization on the soil microbial communities have received considerable attention, specific microbial taxa strongly influenced by long-term organic and inorganic fertilization, their potential effects and associations with soil nutrients remain unclear. Here, we use deep 16S amplicon sequencing to investigate bacterial community characteristics in a fluvo-aquic soil treated for 24 years with inorganic fertilizers and organics (manure and straw)-inorganic fertilizers, and uncover potential links between soil nutrient parameters and specific bacterial taxa. Our results showed that combined organic-inorganic fertilization increased soil organic carbon (SOC) and total nitrogen (TN) contents and altered bacterial community composition, while inorganic fertilization had little impact on soil nutrients and bacterial community composition. SOC and TN emerged as the major determinants of community composition. The abundances of specific taxa, especially Arenimonas, Gemmatimonas, and an unclassified member of Xanthomonadaceae, were substantially increased by organic-inorganic amendments rather than inorganic amendments only. A co-occurrence based network analysis demonstrated that SOC and TN had strong positive associations with some taxa (Gemmatimonas and the members of Acidobacteria subgroup 6, Myxococcales, Betaproteobacteria, and Bacteroidetes), and Gemmatimonas, Flavobacterium, and an unclassified member of Verrucomicrobia were identified as the keystone taxa. These specific taxa identified above are implicated in the decomposition of complex organic matters and soil carbon, nitrogen, and phosphorus transformations. The present work strengthens our current understanding of the soil microbial community structure and functions under long-term fertilization

  5. [Spatial distribution patterns of soil nutrients and microbes in seasonal wet meadow in Zha-long wetland].

    PubMed

    Ma, Ling; Ding, Xin-hua; Gu, Wei; Ma, Wei

    2011-07-01

    This paper studied the spatial distribution patterns of soil nutrients and biological characteristics and related major affecting factors in seasonal wet meadow in Zhalong wetland. In the meadow, the soil nutrients, microbial communities, and microbial biomass carbon and nitrogen showed an obvious vertical distribution, but the soil enzyme activities had a complicated spatial distribution due to the effects of multi factors. Stepwise linear regression analysis showed that soil microbial biomass carbon and nitrogen had significant positive correlations with soil beta-glucosidase, urease, and phosphatase activities (P<0.05), soil organic carbon had significant correlations with soil actinomycetes and soil catalase activity (P<0.05), soil available K, total N, alkali-hydrolyzable N, and C/N ratio were significantly correlated with soil bacteria (P<0.05), actinomycetes (P<0.05), beta-glucosidase activity (P<0.05), and microbial biomass nitrogen (P<0.05) , respectively, whereas soil total P and pH had no significant correlations with soil microbial activity (P>0.05). Two models, one for soil nutrients evaluation and another for soil microbiological prediction, were constructed by principal component analysis.

  6. Potential enzyme activities altered by increased nutrient availability in Arctic tundra soils

    NASA Astrophysics Data System (ADS)

    Koyama, A.; Wallenstein, M. D.; Moore, J. C.; Simpson, R. T.

    2012-12-01

    The Arctic tundra is a biome affected most by global warming predicted in the future. Such warming is expected to increase nutrient availability to soil microbes which, in turn, may accelerate soil organic matter decomposition. We investigated how extra-cellular enzyme activities in soils were affected by increasing nutrient availability in an Arctic tundra ecosystem. Specifically, we measured potential activities of seven enzymes at three profiles (organic, organic/mineral interface, and mineral) of soils which had been fertilized in long- (23 years) and short-terms (six years), assayed at four temperatures. The long-term site had a high fertilization treatment (10g N m-2 year-1 and 5g P m-2 year-1) and control, and the short-term site had a low fertilization treatment (5g N m-2 year-1 and 2.5g P m-2 year-1) in addition to the high fertilization treatment and control. The fertilization treatments significantly altered most of the enzyme activities in both sites. The fertilization treatments increased activities of enzymes hydrolyzing products for C and nitrogen N sources, but decreased phosphatase activities. Such alterations were most pronounced in the organic soils. The fertilization treatments also increased ratios of total enzyme activities involved in hydrolysis for C products to those for N products. This result is consistent with an observation that long-term N and P fertilization decreased soil organic C in the same tundra ecosystem. Altered enzymatic stoichiometry with increased nutrient availability should be considered when modeling biogeochemical cycles in Arctic tundra ecosystems in response to warming predicted in the future.

  7. Soil nutrient changes following whole tree harvesting on three northern hardwood sites

    SciTech Connect

    Mroz, G.D.; Jurgensen, M.F.; Frederick, D.J.

    1985-01-01

    Three northern hardwood stands were clearcut to evaluate the effect of whole tree harvesting on sites of varying quality. Stands were growing on sandy, outwash soils and had red maple (Acer rubrum) site indices of 15, 19, and 20 and biomass values of 114, 165, and 181 Mg/ha. Harvesting did not alter extractable soil P levels significantly on any site. Forest floor weights decreased to similar values on all sites 1.5 years after harvest. Nitrogen losses of over 1.3 Mg/ha occurred in the top meter of soil on all sites. This was attributed to the mixing of the forest floor with the surface mineral soil by the full tree skidding and the subsequent leaching of mineralized N. Soil exchangeable K decreased more than 1 Mg/ha on all sites. Changes in Ca and Mg were much smaller on the low and medium than on the high site. These losses from surface soil horizons are higher than reported previously for clearcutting northern hardwoods on till soils. The greatest impact of whole tree harvest on soil nutrients occurred on the better sites in this study rather than on the poor quality site. (Refs. 33.).

  8. [Relationships between soil nutrient contents and soil enzyme activities in Pinus massoniana stands with different ages in Three Gorges Reservoir Area].

    PubMed

    Ge, Xiao-Gai; Xiao, Wen-Fa; Zeng, Li-Xiong; Huang, Zhi-Lin; Huang, Ling-Ling; Tan, Ben-Wang

    2012-02-01

    Based on the measurements of soil nutrient contents and enzyme activities and the canonical correspondence analysis (CCA), this paper studied the relationships between soil nutrient contents and soil enzyme activities in different age Pinus massoniana stands in Three Gorges Reservoir Area. Among the test stands, mature stand had the highest contents of organic matter, total nitrogen, ammonium nitrogen, and available phosphorus in 0-20 cm soil layer, followed by middle-aged stand, and nearly-mature stand. With the increase of the stand age, soil invertase activity increased after an initial decrease, cellulase and polyphenoloxidase activities decreased gradually, while urease and peroxidase activities decreased after an initial increase. CCA analysis showed that the effects of the main soil parameters on the soil enzyme activities in the stands ranked in the sequence of total nitrogen > organic matter > pH > bulk density > ammonium nitrogen > available phosphorus. Soil invertase activity had significant positive correlations with soil organic matter, total nitrogen, and total phosphorus, while soil peroxidase activity significantly negatively correlated with soil organic matter, total nitrogen, total phosphorus, and bulk density. The soil was rich in main nutrients, invertase activity was relatively high, while peroxidase activity was relatively low. The activities of soil invertase, cellulase and peroxidase could be used as the good biological indicators in evaluating soil quality and fertility.

  9. Microprofiling of nitrogen patches in paddy soil: Analysis of spatiotemporal nutrient heterogeneity at the microscale

    PubMed Central

    Li, Yilin; Kronzucker, Herbert J.; Shi, Weiming

    2016-01-01

    Flooded paddy soil ecosystems in the tropics support the cultivation of the majority of the world’s leading crop, rice, and nitrogen (N) availability in the paddy-soil rooting zone limits rice production more than any other nutritional factor. Yet, little is known about the dynamic response of paddy soil to N-fertiliser application, in terms of horizontal and vertical patchiness in N distribution and transformation. Here, we present a microscale analysis of the profile of ammonium (NH4+) and nitrate (NO3−), nitrification, oxygen (O2water and O2soil), and pH (pHwater and pHsoil) in paddy soils, collected from two representative rice-production areas in subtropical China. NH4+ and NO3− exhibited dramatic spatiotemporal profiles within N patches on the microscale. We show that pHsoil became constant at 1.0–3.5 mm depth, and O2soil became undetectable at 1.7–4.0 mm. Fertiliser application significantly increased pH, and decreased O2, within N patches. Path analysis showed that the factors governing nitrification scaled in the order: pHwater > pHsoil > NH4+ > O2water > NO3− > O2soil. We discuss the soil properties that decide the degree of nutrient patchiness within them and argue that such knowledge is critical to intelligent appraisals of nutrient-use efficiencies in the field. PMID:27265522

  10. Microprofiling of nitrogen patches in paddy soil: Analysis of spatiotemporal nutrient heterogeneity at the microscale

    NASA Astrophysics Data System (ADS)

    Li, Yilin; Kronzucker, Herbert J.; Shi, Weiming

    2016-06-01

    Flooded paddy soil ecosystems in the tropics support the cultivation of the majority of the world’s leading crop, rice, and nitrogen (N) availability in the paddy-soil rooting zone limits rice production more than any other nutritional factor. Yet, little is known about the dynamic response of paddy soil to N-fertiliser application, in terms of horizontal and vertical patchiness in N distribution and transformation. Here, we present a microscale analysis of the profile of ammonium (NH4+) and nitrate (NO3‑), nitrification, oxygen (O2water and O2soil), and pH (pHwater and pHsoil) in paddy soils, collected from two representative rice-production areas in subtropical China. NH4+ and NO3‑ exhibited dramatic spatiotemporal profiles within N patches on the microscale. We show that pHsoil became constant at 1.0–3.5 mm depth, and O2soil became undetectable at 1.7–4.0 mm. Fertiliser application significantly increased pH, and decreased O2, within N patches. Path analysis showed that the factors governing nitrification scaled in the order: pHwater > pHsoil > NH4+ > O2water > NO3‑ > O2soil. We discuss the soil properties that decide the degree of nutrient patchiness within them and argue that such knowledge is critical to intelligent appraisals of nutrient-use efficiencies in the field.

  11. Leaf structure vs. nutrient relationships vary with soil conditions in temperate shrubs and trees

    NASA Astrophysics Data System (ADS)

    Niinemets, Ülo; Kull, Kalevi

    2003-09-01

    Often there are significant positive interspecific relationships between leaf area per unit dry mass (SLA) and foliar phosphorus and nitrogen concentrations ([P] and [N]). Most of these studies have been conducted on moderately acidic soils, and little is known of the generality of these relations as potentially affected by soil characteristics. We investigated foliage mineral composition in relation to leaf structure in a wooded meadow on calcareous alkaline soil, in a bog on strongly acidic soil, and in a flood plain on moderately acidic soil. Foliar nutrient contents and fertilization experiments indicated that foliage physiological activity was co-limited by both P and N availabilities in the wooded meadow, by P in the bog, and by N in the flood plain. In the wooded meadow and in the bog, there were positive relationships between SLA and P concentration ([P]), and no relationship between SLA and nitrogen concentration [N]. Given that the fraction of support tissues generally increases with decreasing SLA, the requirement for mineral nutrients is lower at low SLA. Thus, these contrasting relations between mineral nutrients and SLA suggest that P was distributed in a more "optimal" manner among the leaves with varying structure than N in P-limited communities. In the flood plain, SLA was positively related to both [P] and [N], possibly manifesting a strategy to cope with N limitations by enhancing N turnover, and accordingly, greater P requirement for nucleic acid formation in N-limited soils. Total variation in foliar structural and chemical characteristics was similar in all sites, and was mainly determined by variation among the species. Part of this variability was explained by life form and plant size. [P] was higher in trees than in shrubs, and [P] and P/N ratio increased with increasing total plant height, indicating that P nutrition was improved relative to N nutrition with increasing plant size. Since the capture of less mobile soil elements such as P is

  12. Preference and performance of a willow-feeding leaf beetle: soil nutrient and flooding effects on host quality.

    PubMed

    Lower, Steven S; Kirshenbaum, Sheril; Orians, Colin M

    2003-08-01

    The distribution and abundance of herbivores on plants growing under different environmental conditions may depend upon preference and/or performance. Soil nutrients and water availability are key determinants of herbivore distribution, as both influence plant growth and tissue quality. However, the effects of water on plant quality may depend upon the availability of nutrients and vice versa. Surprisingly few studies have examined the interactions between the two. We investigated the effects of soil nutrient and water availability on (1) the growth and chemistry of the silky willow (Salix sericea Marshall), and (2) the preference and performance of the imported willow leaf beetle (Plagiodera versicolora Laichartig). We conducted two common garden experiments using a similar 2x2 fully factorial design with two levels of soil nutrients (low, high) and two levels of water availability (field capacity, flooded). In the first experiment (larval performance), larval development time and pupal weight were not influenced by nutrient or water availability to the plant. This occurred despite the fact that plants in the high nutrient treatments had higher protein concentration and lower foliar concentrations of the phenolic glycoside 2'-cinnamoylsalicortin. In the second experiment (adult preference), we caged four plants (one from each treatment) and released beetles into cages. We found that plant growth and leaf protein depended upon the interaction between nutrient and water availability. Plant growth was greatest in the high nutrient-field capacity treatment and leaf protein was greatest in the high nutrient-flooded treatment. In contrast, adults settled and oviposited preferentially on the high nutrient treatment under flooded conditions, but we found no evidence of interactions between nutrients and water on preference. Thus, at least under flooded conditions nutrients affect adult preference. We also found that foliar protein was correlated positively with adult

  13. Biochar and manure affect calcareous soil and corn silage nutrient concentrations and uptake.

    PubMed

    Lentz, R D; Ippolito, J A

    2012-01-01

    Carbon-rich biochar derived from the pyrolysis of biomass can sequester atmospheric CO, mitigate climate change, and potentially increase crop productivity. However, research is needed to confirm the suitability and sustainability of biochar application to different soils. To an irrigated calcareous soil, we applied stockpiled dairy manure (42 Mg ha dry wt) and hardwood-derived biochar (22.4 Mg ha), singly and in combination with manure, along with a control, yielding four treatments. Nitrogen fertilizer was applied when needed (based on preseason soil test N and crop requirements) in all plots and years, with N mineralized from added manure included in this determination. Available soil nutrients (NH-N; NO-N; Olsen P; and diethylenetriaminepentaacetic acid-extractable K, Mg, Na, Cu, Mn, Zn, and Fe), total C (TC), total N (TN), total organic C (TOC), and pH were evaluated annually, and silage corn nutrient concentration, yield, and uptake were measured over two growing seasons. Biochar treatment resulted in a 1.5-fold increase in available soil Mn and a 1.4-fold increase in TC and TOC, whereas manure produced a 1.2- to 1.7-fold increase in available nutrients (except Fe), compared with controls. In 2009 biochar increased corn silage B concentration but produced no yield increase; in 2010 biochar decreased corn silage TN (33%), S (7%) concentrations, and yield (36%) relative to controls. Manure produced a 1.3-fold increase in corn silage Cu, Mn, S, Mg, K, and TN concentrations and yield compared with the control in 2010. The combined biochar-manure effects were not synergistic except in the case of available soil Mn. In these calcareous soils, biochar did not alter pH or availability of P and cations, as is typically observed for acidic soils. If the second year results are representative, they suggest that biochar applications to calcareous soils may lead to reduced N availability, requiring additional soil N inputs to maintain yield targets.

  14. [Nutritional characteristics of Caragana jubata shrub and distribution patterns of soil nutrients in Luya Mountain].

    PubMed

    Zhang, Qiang; Cheng, Bin; Yang, Zhiping; Gao, Chunhua; Zhang, Yigong; Zhang, Lizheng

    2006-12-01

    The study on the nutrient components of Caragana jubata shrub and the distribution patterns of soil nutrients in Luya Mountain of Shanxi Province showed that C. jubata was a valuable feeding plant, which contained 20.27% of crude protein and 5.12% of ash with abundant Ca, Fe and Mn. The crude protein, ash, and mineral element contents increased from May and achieved the highest in July when C. jubata was at flowering stage, and then declined. To adapt to the habitat in subalpine meadow with high altitude, low temperature and thin soil layer, C. jubata had "fertility island" effect. The electric conductivity and the contents of organic matter, total N, available P and available K in the center of "fertility island" increased by 18.8%, 16.4%, 18.7%, 16.6% and 8.4%, respectively, compared with those in the edge of the "fertility island". The organic matter content and total N content in rhizosphere increased, while the contents of available nutrients such as P, K, Fe and Mn decreased, suggesting that C. jubata had high capability of N fixation and nutrients uptake.

  15. Runoff erosion and nutrient depletion in five Mediterranean soils of NE Spain under different land use.

    PubMed

    Pardini, Giovanni; Gispert, Maria; Dunjó, Gemma

    2003-06-20

    We investigated the influence of agricultural management and various plant covers related to the period of abandonment on soil properties, erosion and nutrient depletion in a typical Mediterranean area with sandy loam shallow soils. Cultivated soils (CS) with insufficient management, 5 year abandoned soils covered with meadow (A5), 25 year abandoned soils covered with dense scrubs (A25), 50 year abandoned soils covered with cork trees (A50) and soils in a 50 year pine reforested area (P50) were studied over a period of 6 months (May-October 1999). The soils were classified as Lithic Xerorthents. Both the differences in soil properties and response to rainfall events were mainly attributed to the different vegetation types and stages in land management. Principal components analysis (PCA) was performed on the results, by running the overall data determined after five rainfall events. The factors extracted by PCA of the samples by variables matrix represented the response of the environments to different rainfall intensities as a function of management or natural evolution after abandonment. CS environments showed the highest runoff and sediment yield as well as the highest amount of dissolved organic carbon (DOC) and nitrogen in runoff water. The sequence of abandonment (A5, A25 and A50) showed approximately the same runoff production, whereas eroded sediments (ES) and DOC were inversely correlated. Organic carbon in the ES and DOC in runoff water always increased with the period of abandonment, which accounted for consistent nutrient depletion. Nevertheless, the A50 environment (dominated by Quercus suber) showed the best soil properties, whilst the A25 environment with dense cover of Cistus monspeliensis and Calicotome espinosa seemed to cause a worsening effect on the soil's physical and chemical properties. This is probably because these environments are more severely damaged by wild fire occurrence. In terms of sediment yield, the P50 environment followed CS

  16. Dynamics of plant nutrients, utilization and uptake, and soil microbial community in crops under ambient and elevated carbon dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In natural settings such as under field conditions, the plant available soil nutrients in conjunction with other environmental factors such as, solar radiation, temperature, precipitation, and atmospheric carbon dioxide (CO2) concentration determine crop adaptation and productivity. Therefore, crop...

  17. Impact of hydrochar application on soil nutrient dynamics and plant availability

    NASA Astrophysics Data System (ADS)

    Bargmann, I.; Greef, J. M.; Kücke, M.

    2012-04-01

    In order to investigate potentials for the use of HTC-products (hydrochar) in agriculture, the influence of soil application of different hydrochars on soil nutrient dynamics as well as on plant growth and plant nutrient uptake was determined. Hydrochars were produced from sugar beet pulps and brewer's grains by carbonization at 190°C for 4 respectively 12 hours each. Incubation experiments with two soil types showed an increase of soil pH by 0.5 to 2.5 pH units, depending on the amount of hydrochar added and the process conditions (i.e. addition of calcium carbonate during production). The application of HTC to soil decreased the plant available nitrogen to almost zero in the first week after HTC-addition, followed by a slow re-release of nitrate in the following weeks. A similar immobilization of soluble phosphate was observed for one soil type, although to a lower extent. The plant availability of phosphorus in hydrochars and biochars is subject of current trials. Furthermore it is actually investigated to what extend the N immobilization is related to soil microbial activity. Germination tests with barley showed toxic effects of hydrochar application on germination, both by direct contact of grains with HTC as well as by release of gaseous compounds from HTC. Effects differ significantly for different parent materials and pretreatments (washing, drying, storage). The influence of HTC-addition to soil on plant growth and nutrient uptake was investigated in pot experiments with various crop species (barley, phaseolus bean, leek), comparing HTC from different parent materials and process parameters such as carbonization time. With increasing addition of HTC, the N availability was decreased and N contents in the plant were significantly lower compared with the untreated control. The plant growth response was different for each tested crop. On barley, leaf tip necroses were observed, but not on phaseolus. Biomass yield of barley and beans was generally increased

  18. Altitudinal patterns and controls of plant and soil nutrient concentrations and stoichiometry in subtropical China

    NASA Astrophysics Data System (ADS)

    He, Xianjin; Hou, Enqing; Liu, Yang; Wen, Dazhi

    2016-04-01

    Altitude is a determining factor of ecosystem properties and processes in mountains. This study investigated the changes in the concentrations of carbon (C), nitrogen (N), and phosphorus (P) and their ratios in four key ecosystem components (forest floor litter, fine roots, soil, and soil microorganisms) along an altitudinal gradient (from 50 m to 950 m a.s.l.) in subtropical China. The results showed that soil organic C and microbial biomass C concentrations increased linearly with increasing altitude. Similar trends were observed for concentrations of total soil N and microbial biomass N. In contrast, the N concentration of litter and fine roots decreased linearly with altitude. With increasing altitude, litter, fine roots, and soil C:N ratios increased linearly, while the C:N ratio of soil microbial biomass did not change significantly. Phosphorus concentration and C:P and N:P ratios of all ecosystem components generally had nonlinear relationships with altitude. Our results indicate that the altitudinal pattern of plant and soil nutrient status differs among ecosystem components and that the relative importance of P vs. N limitation for ecosystem functions and processes shifts along altitudinal gradients.

  19. Soil Bacterial Communities Respond to Mowing and Nutrient Addition in a Steppe Ecosystem

    PubMed Central

    Zhang, Ximei; Chen, Quansheng; Han, Xingguo

    2013-01-01

    In many grassland ecosystems, nitrogen (N) and phosphorus (P) are added to improve plant productivity, and the aboveground plant biomass is mowed and stored as hay for the bullamacow. Nutrient addition and mowing affect the biodiversity and ecosystem functioning, and most of the previous studies have primarily focused on their effects on macro-organisms, neglecting the responses of soil microbial communities. In this study, we examined the changes in three community attributes (abundance, richness, and composition) of the entire bacterial kingdom and 16 dominant bacterial phyla/classes in response to mowing, N addition, P addition, and their combinations, by conducting a 5-year experiment in a steppe ecosystem in Inner Mongolia, China. Overall, N addition had a greater effect than mowing and P addition on most of these bacterial groups, as indicated by changes in the abundance, richness and composition in response to these treatments. N addition affected these soil bacterial groups primarily through reducing soil pH and increasing available N content. Meanwhile, the 16 bacterial phyla/classes responded differentially to these experimental treatments, with Acidobacteria, Acidimicrobidae, Deltaproteobacteria, and Gammaproteobacteria being the most sensitive. The changes in the abundance, richness, and composition of various bacterial groups could imply some potential shift in their ecosystem functions. Furthermore, the important role of decreased soil pH caused by N addition in affecting soil bacterial communities suggests the importance of restoring acidified soil to maintain soil bacterial diversity. PMID:24391915

  20. Farm management, not soil microbial diversity, controls nutrient loss from smallholder tropical agriculture

    PubMed Central

    Wood, Stephen A.; Almaraz, Maya; Bradford, Mark A.; McGuire, Krista L.; Naeem, Shahid; Neill, Christopher; Palm, Cheryl A.; Tully, Katherine L.; Zhou, Jizhong

    2015-01-01

    Tropical smallholder agriculture is undergoing rapid transformation in nutrient cycling pathways as international development efforts strongly promote greater use of mineral fertilizers to increase crop yields. These changes in nutrient availability may alter the composition of microbial communities with consequences for rates of biogeochemical processes that control nutrient losses to the environment. Ecological theory suggests that altered microbial diversity will strongly influence processes performed by relatively few microbial taxa, such as denitrification and hence nitrogen losses as nitrous oxide, a powerful greenhouse gas. Whether this theory helps predict nutrient losses from agriculture depends on the relative effects of microbial community change and increased nutrient availability on ecosystem processes. We find that mineral and organic nutrient addition to smallholder farms in Kenya alters the taxonomic and functional diversity of soil microbes. However, we find that the direct effects of farm management on both denitrification and carbon mineralization are greater than indirect effects through changes in the taxonomic and functional diversity of microbial communities. Changes in functional diversity are strongly coupled to changes in specific functional genes involved in denitrification, suggesting that it is the expression, rather than abundance, of key functional genes that can serve as an indicator of ecosystem process rates. Our results thus suggest that widely used broad summary statistics of microbial diversity based on DNA may be inappropriate for linking microbial communities to ecosystem processes in certain applied settings. Our results also raise doubts about the relative control of microbial composition compared to direct effects of management on nutrient losses in applied settings such as tropical agriculture. PMID:25926815

  1. Soil nutrient heterogeneity modulates ecosystem responses to changes in the identity and richness of plant functional groups.

    PubMed

    García-Palacios, Pablo; Maestre, Fernando T; Gallardo, Antonio

    2011-03-01

    Recent research has shown that biodiversity may has its greatest impact on ecosystem functioning in heterogeneous environments. However, the role of soil heterogeneity as a modulator of ecosystem responses to changes in biodiversity remains poorly understood, as few biodiversity studies have explicitly considered this important ecosystem feature.We conducted a microcosm experiment over two growing seasons to evaluate the joint effects of changes in plant functional groups (grasses, legumes, non-legume forbs and a combination of them), spatial distribution of soil nutrients (homogeneous and heterogeneous) and nutrient availability (50 and 100 mg of nitrogen [N] added as organic material) on plant productivity and surrogates of carbon, phosphorous and N cycling (β-glucosidase and acid phosphatase enzymes and in situ N availability, respectively).Soil nutrient heterogeneity interacted with nutrient availability and plant functional diversity to determine productivity and nutrient cycling responses. All the functional groups exhibited precise root foraging patterns. Above- and belowground productivity increased under heterogeneous nutrient supply. Surrogates of nutrient cycling were not directly affected by soil nutrient heterogeneity. Regardless of their above- and belowground biomass, legumes increased the availability of soil inorganic N and the activity of the acid phosphatase and β-glucosidase enzymes.Our study emphasizes the role of soil nutrient heterogeneity as a modulator of ecosystem responses to changes in functional diversity beyond the species level. Functional group identity, rather than richness, can play a key role in determining the effects of biodiversity on ecosystem functioning.Synthesis. Our results highlight the importance of explicitly considering soil heterogeneity in diversity-ecosystem functioning experiments, where the identity of the plant functional group is of major importance. Such consideration will improve our ability to fully

  2. Soil nutrient heterogeneity modulates ecosystem responses to changes in the identity and richness of plant functional groups

    PubMed Central

    García-Palacios, Pablo; Maestre, Fernando T.; Gallardo, Antonio

    2015-01-01

    Summary Recent research has shown that biodiversity may has its greatest impact on ecosystem functioning in heterogeneous environments. However, the role of soil heterogeneity as a modulator of ecosystem responses to changes in biodiversity remains poorly understood, as few biodiversity studies have explicitly considered this important ecosystem feature. We conducted a microcosm experiment over two growing seasons to evaluate the joint effects of changes in plant functional groups (grasses, legumes, non-legume forbs and a combination of them), spatial distribution of soil nutrients (homogeneous and heterogeneous) and nutrient availability (50 and 100 mg of nitrogen [N] added as organic material) on plant productivity and surrogates of carbon, phosphorous and N cycling (β-glucosidase and acid phosphatase enzymes and in situ N availability, respectively). Soil nutrient heterogeneity interacted with nutrient availability and plant functional diversity to determine productivity and nutrient cycling responses. All the functional groups exhibited precise root foraging patterns. Above- and belowground productivity increased under heterogeneous nutrient supply. Surrogates of nutrient cycling were not directly affected by soil nutrient heterogeneity. Regardless of their above- and belowground biomass, legumes increased the availability of soil inorganic N and the activity of the acid phosphatase and β-glucosidase enzymes. Our study emphasizes the role of soil nutrient heterogeneity as a modulator of ecosystem responses to changes in functional diversity beyond the species level. Functional group identity, rather than richness, can play a key role in determining the effects of biodiversity on ecosystem functioning. Synthesis. Our results highlight the importance of explicitly considering soil heterogeneity in diversity-ecosystem functioning experiments, where the identity of the plant functional group is of major importance. Such consideration will improve our ability to

  3. Predictable bacterial composition and hydrocarbon degradation in Arctic soils following diesel and nutrient disturbance

    PubMed Central

    Bell, Terrence H; Yergeau, Etienne; Maynard, Christine; Juck, David; Whyte, Lyle G; Greer, Charles W

    2013-01-01

    Increased exploration and exploitation of resources in the Arctic is leading to a higher risk of petroleum contamination. A number of Arctic microorganisms can use petroleum for growth-supporting carbon and energy, but traditional approaches for stimulating these microorganisms (for example, nutrient addition) have varied in effectiveness between sites. Consistent environmental controls on microbial community response to disturbance from petroleum contaminants and nutrient amendments across Arctic soils have not been identified, nor is it known whether specific taxa are universally associated with efficient bioremediation. In this study, we contaminated 18 Arctic soils with diesel and treated subsamples of each with monoammonium phosphate (MAP), which has successfully stimulated degradation in some contaminated Arctic soils. Bacterial community composition of uncontaminated, diesel-contaminated and diesel+MAP soils was assessed through multiplexed 16S (ribosomal RNA) rRNA gene sequencing on an Ion Torrent Personal Genome Machine, while hydrocarbon degradation was measured by gas chromatography analysis. Diversity of 16S rRNA gene sequences was reduced by diesel, and more so by the combination of diesel and MAP. Actinobacteria dominated uncontaminated soils with <10% organic matter, while Proteobacteria dominated higher-organic matter soils, and this pattern was exaggerated following disturbance. Degradation with and without MAP was predictable by initial bacterial diversity and the abundance of specific assemblages of Betaproteobacteria, respectively. High Betaproteobacteria abundance was positively correlated with high diesel degradation in MAP-treated soils, suggesting this may be an important group to stimulate. The predictability with which bacterial communities respond to these disturbances suggests that costly and time-consuming contaminated site assessments may not be necessary in the future. PMID:23389106

  4. Effects of thinning, residue mastication, and prescribed fire on soil and nutrient budgets in a Sierra Nevada mixed conifer forest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of thinning followed by residue mastication (THIN), prescribed fire (BURN), and thinning plus residue mastication plus burning (T+B) on nutrient budgets and resin-based (plant root simulator [PRS] probe) measurements of soil nutrient availability in a mixed-conifer forest were measured. ...

  5. Long-term effects of organic and inorganic nutrient sources on soil organic carbon and major nutrients in Vertisols

    NASA Astrophysics Data System (ADS)

    Aladakatti, Y. R.; Hallikeri, S. S.; Nandagavi, R. A.

    2012-04-01

    Field experiment conducted over 10 years at the University of Agricultural Sciences, Dharwad, India, assessed the long-term effects of various sources of organics (farmyard manure {FYM}, vermicompost and cotton crop residue) in conjunction with graded levels of inorganic fertilizers on the soil organic carbon (SOC), available major nutrients and seed cotton yield in cotton- (groundnut - winter Sorghum) rotation system. Main plots comprised FYM (10 Mg/ha), vermicompost (2.5 Mg/ha), cotton crop residue (2.5 Mg/ha) and combination of these organics in various proportions with an absolute control (no organics). No inorganic fertilizes, 50 and 100 % of the recommended dose of fertilizers (RDF) were assigned to the sub plots. The organics were applied every year during rainy season and the inorganic fertilizers as per the University recommended dose to each crop. Initial SOC, available N, P and K were 0.68%, 220, 22.5 and 403 kg/ha, respectively. Results indicated that at the end of tenth year of crop rotation, application of FYM, vermicompost and cotton crop residue either alone or in combination increased the SOC (0.68 to 0.81%), available N (220 to 308 kg/ha), P (22.5 to 33.0 kg/ha) and K (403 to 530 kg/ha) compared to the control plot where no organics were applied. SOC in the control treatment decreased to 0.52% at the end of tenth year from 0.68%. Averaged over five cropping cycles, application of FYM gave significantly higher yields of seed cotton, groundnut pods and sorghum grain over all other organic sources. During fifth cycle of cotton crop or 10th year of rotation, application of FYM along with 100% RDF resulted in the highest productivity and was similar to FYM + 50 % RDF, indicating a saving of 50% chemical fertilizer in these crops. Combination of cotton crop residue and vermicompost were next best alternative sources of organics after FYM in order of preference. Our studies suggest that in the scarcity of good quality manure such as FYM, cotton crop

  6. Enhancement and inhibition of microbial activity in hydrocarbon- contaminated arctic soils: Implications for nutrient-amended bioremediation

    USGS Publications Warehouse

    Braddock, J.F.; Ruth, M.L.; Catterall, P.H.; Walworth, J.L.; McCarthy, K.A.

    1997-01-01

    Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) end low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semivolatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) and low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus

  7. Mountain pine beetle disturbance effects on soil respiration and nutrient pools

    NASA Astrophysics Data System (ADS)

    Trahan, N. A.; Moore, D. J.; Brayden, B. H.; Dynes, E.; Monson, R. K.

    2011-12-01

    Over the past decade, the mountain pine beetle Dendroctonos ponderosae has infested more than 86 million hectares of high elevation forest in the Western U.S.A. While bark beetles are endemic to western forests and important agents of regeneration, the current mountain pine beetle outbreak is larger than any other on record and the resulting tree mortality has significant consequences for nutrient cycling and regional carbon exchange. We established decade-long parallel disturbance chronosequences in two lodgepole pine (Pinus contorta) forests in Colorado: one composed of mountain pine beetle killed lodgepole stands and one consisting of trees where beetle mortality was simulated by stem girdling. Over the 2010 and 2011 growing season we measured plot level soil respiration fluxes, as well as soil extractable dissolved organic carbon, nitrogen, microbial biomass carbon and nitrogen, and pools of ammonium, nitrate and inorganic phosphorus. We show that soil respiration sharply declines with gross primary productivity after tree mortality, but rebounds during the next 4 years, then declines again from 6-8 years post-disturbance. Soil extractable dissolved organic carbon, microbial biomass carbon, and inorganic phosphorous pools follow the pattern observed in soil respiration fluxes across disturbance age classes for both sites, while patterns in total dissolved nitrogen exhibit site specific variation. Levels of detectable soil nitrate were low and did not significantly change across the chronosequence, while soil ammonium increased in a similar pattern with soil moisture in disturbed plots. These patterns in soil respiration and nutrient pools reflect the loss of autotrophic respiration and rhizodeposition immediately after tree mortality, followed by a pulse in soil efflux linked to the decomposition of older, less labile carbon pools. This pulse is likely controlled by the fall rate of litter, coarse woody debris and the relative impact of post-disturbance water

  8. Nutrient leaching, soil pH and changes in microbial community increase with time in lead-contaminated boreal forest soil at a shooting range area.

    PubMed

    Selonen, Salla; Setälä, Heikki

    2017-02-01

    Despite the known toxicity of lead (Pb), Pb pellets are widely used at shotgun shooting ranges over the world. However, the impacts of Pb on soil nutrients and soil microbes, playing a crucial role in nutrient cycling, are poorly understood. Furthermore, it is unknown whether these impacts change with time after the cessation of shooting. To shed light on these issues, three study sites in the same coniferous forest in a shooting range area were studied: an uncontaminated control site and an active and an abandoned shooting range, both sharing a similar Pb pellet load in the soil, but the latter with a 20-year longer contamination history. Soil pH and nitrate concentration increased, whilst soil phosphate concentration and fungal phospholipid fatty acid (PLFA) decreased due to Pb contamination. Our results imply that shooting-derived Pb can influence soil nutrients and microbes not only directly but also indirectly by increasing soil pH. However, these mechanisms cannot be differentiated here. Many of the Pb-induced changes were most pronounced at the abandoned range, and nutrient leaching was increased only at that site. These results suggest that Pb disturbs the structure and functions of the soil system and impairs a crucial ecosystem service, the ability to retain nutrients. Furthermore, the risks of shooting-derived Pb to the environment increase with time.

  9. In situ electrokinetic control of moisture and nutrients in unsaturated soils

    SciTech Connect

    Lindgren, E.R.; Brady, P.V.

    1994-12-31

    Many DOE facilities have unsaturated soils contaminated with metals and organic solvents. Because of the large volumes, in situ remediation is often the most economically attractive remediation technique. The success of many in situ treatment technologies depends critically on the degree to which the movement of water and desired ions can be engineered in the vadose zone. Bioremediation efforts in the vadose zone are limited by the ability to provide moisture and nutrients to contaminant-metabolizing microorganisms. An in situ electrokinetic remediation process has been developed at Sandia National Laboratories (SNL) for use in unsaturated soils, and is presently undergoing field demonstration. The electrokinetic process is not limited by low soil permeabilities and, therefore, provides a level of control not achievable by hydraulic means. Moisture is added to the subsurface in a controlled fashion such that the field capacity is never exceeded, preventing the unwanted mobilization of dissolved contaminants by saturated wetting fronts. The Sandia electrokinetic process can potentially transport both water and nutrients for bioremediation efforts and is compatible with vapor phase in situ techniques such as bioventing. The approach should as bioventing. The approach should lend itself to the directed transport of biodegradable chelating agents and complexed metals from contaminated soils.

  10. Soil-type influences human selenium status and underlies widespread selenium deficiency risks in Malawi.

    PubMed

    Hurst, Rachel; Siyame, Edwin W P; Young, Scott D; Chilimba, Allan D C; Joy, Edward J M; Black, Colin R; Ander, E Louise; Watts, Michael J; Chilima, Benson; Gondwe, Jellita; Kang'ombe, Dalitso; Stein, Alexander J; Fairweather-Tait, Susan J; Gibson, Rosalind S; Kalimbira, Alexander A; Broadley, Martin R

    2013-01-01

    Selenium (Se) is an essential human micronutrient with critical roles in immune functioning and antioxidant defence. Estimates of dietary Se intakes and status are scarce for Africa although crop surveys indicate deficiency is probably widespread in Malawi. Here we show that Se deficiency is likely endemic in Malawi based on the Se status of adults consuming food from contrasting soil types. These data are consistent with food balance sheets and composition tables revealing that >80% of the Malawi population is at risk of dietary Se inadequacy. Risk of dietary Se inadequacy is >60% in seven other countries in Southern Africa, and 22% across Africa as a whole. Given that most Malawi soils cannot supply sufficient Se to crops for adequate human nutrition, the cost and benefits of interventions to alleviate Se deficiency should be determined; for example, Se-enriched nitrogen fertilisers could be adopted as in Finland.

  11. Soil-type influences human selenium status and underlies widespread selenium deficiency risks in Malawi

    PubMed Central

    Hurst, Rachel; Siyame, Edwin W. P.; Young, Scott D.; Chilimba, Allan D. C.; Joy, Edward J. M.; Black, Colin R.; Ander, E. Louise; Watts, Michael J.; Chilima, Benson; Gondwe, Jellita; Kang'ombe, Dalitso; Stein, Alexander J.; Fairweather-Tait, Susan J.; Gibson, Rosalind S.; Kalimbira, Alexander A.; Broadley, Martin R.

    2013-01-01

    Selenium (Se) is an essential human micronutrient with critical roles in immune functioning and antioxidant defence. Estimates of dietary Se intakes and status are scarce for Africa although crop surveys indicate deficiency is probably widespread in Malawi. Here we show that Se deficiency is likely endemic in Malawi based on the Se status of adults consuming food from contrasting soil types. These data are consistent with food balance sheets and composition tables revealing that >80% of the Malawi population is at risk of dietary Se inadequacy. Risk of dietary Se inadequacy is >60% in seven other countries in Southern Africa, and 22% across Africa as a whole. Given that most Malawi soils cannot supply sufficient Se to crops for adequate human nutrition, the cost and benefits of interventions to alleviate Se deficiency should be determined; for example, Se-enriched nitrogen fertilisers could be adopted as in Finland. PMID:23478344

  12. Aeolian nutrient fluxes following wildfire in sagebrush steppe: Implications for soil carbon storage

    USGS Publications Warehouse

    Hasselquist, N.J.; Germino, M.J.; Sankey, J.B.; Ingram, L.J.; Glenn, N.F.

    2011-01-01

    Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes occurring in the saltation zone during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m????'1 d????'1 and 19 g N m????'1 d????'1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes. ?? Author(s) 2011. CC Attribution 3.0 License.

  13. Anaerobic Soil Disinfestation (ASD) Combined with Soil Solarization as a Methyl Bromide Alternative: Vegetable Crop Performance and Soil Nutrient Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil treatment by anaerobic soil disinfestation (ASD) combined with soil solarization can effectively control soilborne plant pathogens and plant-parasitic nematodes in specialty crop production systems. At the same time, research is limited on the impact of soil treatment by ASD + solarization on c...

  14. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands

    PubMed Central

    Baptista, Isaurinda; Ritsema, Coen; Geissen, Violette

    2015-01-01

    Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges) on nitrogen (N) and phosphorus (P) losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice) were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1) than of PO4-P (0.02-0.07 mg L-1), and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1) than of NO3-N (1.30-8.51 mg g-1). The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1) and PO4-P (0.2, 0.1 and 0.4 kg ha-1) than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum), but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively). T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges) is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant) could be a

  15. Effect of Integrated Water-Nutrient Management Strategies on Soil Erosion Mediated Nutrient Loss and Crop Productivity in Cabo Verde Drylands.

    PubMed

    Baptista, Isaurinda; Ritsema, Coen; Geissen, Violette

    2015-01-01

    Soil erosion, runoff and related nutrient losses are a big risk for soil fertility in Cabo Verde drylands. In 2012, field trials were conducted in two agro-ecological zones to evaluate the effects of selected techniques of soil-water management combined with organic amendments (T1: compost/manure + soil surfactant; T2: compost/animal or green manure + pigeon-pea hedges + soil surfactant; T3: compost/animal or green manure + mulch + pigeon-pea hedges) on nitrogen (N) and phosphorus (P) losses in eroded soil and runoff and on crop yields. Three treatments and one control (traditional practice) were tested in field plots at three sites with a local maize variety and two types of beans. Runoff and eroded soil were collected after each erosive rain, quantified, and analysed for NO3-N and PO4-P concentrations. In all treatments runoff had higher concentrations of NO3-N (2.20-4.83 mg L-1) than of PO4-P (0.02-0.07 mg L-1), and the eroded soil had higher content of PO4-P (5.27-18.8 mg g-1) than of NO3-N (1.30-8.51 mg g-1). The control had significantly higher losses of both NO3-N (5.4, 4.4 and 19 kg ha-1) and PO4-P (0.2, 0.1 and 0.4 kg ha-1) than the other treatments. T3 reduced soil loss, runoff and nutrient losses to nearly a 100% while T1 and T2 reduced those losses from 43 to 88%. The losses of NO3-N and PO4-P were highly correlated with the amounts of runoff and eroded soil. Nutrient losses from the applied amendments were low (5.7% maximum), but the losses in the control could indicate long-term nutrient depletion in the soil (19 and 0.4 kg ha-1 of NO3-N and PO4-P, respectively). T1-T3 did not consistently increase crop yield or biomass in all three sites, but T1 increased both crop yield and biomass. We conclude that T3 (combining crop-residue mulch with organic amendment and runoff hedges) is the best treatment for steep slope areas but, the pigeon-pea hedges need to be managed for higher maize yield. T1 (combining organic amendment with soil surfactant) could be a

  16. Stimulation of hybrid poplar growth in petroleum-contaminated soils through oxygen addition and soil nutrient amendments.

    PubMed

    Rentz, Jeremy A; Chapman, Brad; Alvarez, Pedro J J; Schnoor, Jerald L

    2003-01-01

    Hybrid poplar trees (Populus deltoides x nigra DN34) were grown in a green-house using hydrocarbon-contaminated soil from a phytoremediation demonstration site in Health, Ohio. Two independent experiments investigated the effect of nutrient addition on poplar growth and the importance of oxygen addition to root development and plant growth. Biomass measurements, poplar height, and leaf color were used as indicators of plant health in the selection of a 10/5/5 NPK fertilizer applied at 1121 kg/ha (112 kg-N, 24.4 kg-P, 46.5 kg-K per ha) to enhance hybrid poplar growth at the Health site. Five passive methods of oxygen delivery were examined, including aeration tubes, gravel addition, and an Oxygen Release Compound (ORC). When ORC was placed in coffee filters above hydrocarbon-contaminated soil, a statistically significant increase of 145% was observed in poplar biomass growth, relative to unamended controls. The ORC in filters also stimulated significant increases in root density. A 15.2-cm interval of soil directly below ORC addition exhibited an increase from 2.6 +/- 1.0 mg/cm3 to 4.8 +/- 1.0 mg/cm3, showing stimulation of root growth in hydrocarbon-stained soil. The positive response of hybrid poplars to oxygen amendments suggests that overcoming oxygen limitation to plants should be considered in phytoremediation projects when soil contamination exerts a high biochemical oxygen demand, such as in former refinery sites.

  17. Relationships between nutrient-related plant traits and combinations of soil N and P fertility measures.

    PubMed

    Fujita, Yuki; van Bodegom, Peter M; Witte, Jan-Philip M

    2013-01-01

    Soil fertility and nutrient-related plant functional traits are in general only moderately related, hindering the progress in trait-based prediction models of vegetation patterns. Although the relationships may have been obscured by suboptimal choices in how soil fertility is expressed, there has never been a systematic investigation into the suitability of fertility measures. This study, therefore, examined the effect of different soil fertility measures on the strength of fertility-trait relationships in 134 natural plant communities. In particular, for eight plot-mean traits we examined (1) whether different elements (N or P) have contrasting or shared influences, (2) which timescale of fertility measures (e.g. mineralization rates for one or five years) has better predictive power, and (3) if integrated fertility measures explain trait variation better than individual fertility measures. Soil N and P had large mutual effects on leaf nutrient concentrations, whereas they had element-specific effects on traits related to species composition (e.g. Grime's CSR strategy). The timescale of fertility measures only had a minor impact on fertility-trait relationships. Two integrated fertility measures (one reflecting overall fertility, another relative availability of soil N and P) were related significantly to most plant traits, but were not better in explaining trait variation than individual fertility measures. Using all fertility measures together, between-site variations of plant traits were explained only moderately for some traits (e.g. 33% for leaf N concentrations) but largely for others (e.g. 66% for whole-canopy P concentration). The moderate relationships were probably due to complex regulation mechanisms of fertility on traits, rather than to a wrong choice of fertility measures. We identified both mutual (i.e. shared) and divergent (i.e. element-specific and stoichiometric) effects of soil N and P on traits, implying the importance of explicitly

  18. Soil nutrient budgets following projected corn stover harvest for biofuel production in the conterminous United States

    USGS Publications Warehouse

    Tan, Zhengxi; Liu, Shuguang

    2015-01-01

    Increasing demand for food and biofuel feedstocks may substantially affect soil nutrient budgets, especially in the United States where there is great potential for corn (Zea mays L) stover as a biofuel feedstock. This study was designed to evaluate impacts of projected stover harvest scenarios on budgets of soil nitrogen (N), phosphorus (P), and potassium (K) currently and in the future across the conterminous United States. The required and removed N, P, and K amounts under each scenario were estimated on the basis of both their average contents in grain and stover and from an empirical model. Our analyses indicate a small depletion of soil N (−4 ± 35 kg ha−1) and K (−6 ± 36 kg ha−1) and a moderate surplus of P (37 ± 21 kg ha−1) currently on the national average, but with a noticeable variation from state to state. After harvesting both grain and projected stover, the deficits of soil N, P, and K were estimated at 114–127, 26–27, and 36–53 kg ha−1 yr−1, respectively, in 2006–2010; 131–173, 29–32, and 41–96 kg ha−1 yr−1, respectively, in 2020; and 161–207, 35–39, and 51–111 kg ha−1 yr−1, respectively, in 2050. This study indicates that the harvestable stover amount derived from the minimum stover requirement for maintaining soil organic carbon level scenarios under current fertilization rates can be sustainable for soil nutrient supply and corn production at present, but the deficit of P and K at the national scale would become larger in the future.

  19. Impact of cattle congregation sites on soil nutrients and soil compaction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study determined the impact of grazing cattle on the changes in soil quality around and beneath cattle congregation sites (mineral feeders, water troughs, and shades). Baseline soil samples around and beneath three congregations sites in established (>10 yr) grazed beef cattle pastures at the U...

  20. Soil Carbon and Nutrient Changes Associated with Deforestation for Pasture in Southern Costa Rica

    NASA Technical Reports Server (NTRS)

    Huth, Timothy J.; Porder, Stephen; Chaves, Joaquin; Whiteside, Jessica H.

    2012-01-01

    We assessed the effects of deforestation on soil carbon (C) and nutrient stocks in the premontane landscape near Las Cruces Biological Station in southern Costa Rica, where forests were cleared for pasture in the mid-1960s. We excavated six soil pits to a depth of 1 m in both pasture and primary forest, and found that C stocks were 20 kg C per square meters in both settings. Nevertheless, soil delta C-13 suggests 50 percent of the forest-derived soil C above 40 cm depth has turned over since deforestation. Soil nitrogen (N) and phosphorus (P) stocks derived from the soil pits were not significantly different between land uses (P = 0.43 and 0.61, respectively). At a larger spatial scale, however, the ubiquity of ruts produced by cattle-induced erosion indicates that there are substantial soil effects of grazing in this steep landscape. Ruts averaged 13 cm deep and covered 45 percent of the landscape, and thus are evidence of the removal of 0.7 Mg C/ ha/yr, and 70, 9 and 40 kg/ha/yr of N, P and potassium (K), respectively. Subsoils in this region are 10 times less C- and N-rich, and 2 times less P- and K-rich than the topsoil. Thus, rapid topsoil loss may lead to a decline in pasture productivity in the coming decades. These data also suggest that the soil C footprint of deforestation in this landscape may be determined by the fate of soil C as it is transported downstream, rather than C turnover in situ.

  1. Impact of climate change on water balance, and nutrient leaching of (pre-) alpine grassland soils

    NASA Astrophysics Data System (ADS)

    Fu, Jin; Lu, Haiyan; Butterbach-bahl, Klaus; Kiese, Ralf

    2013-04-01

    On a global perspective terrestrial biosphere hosts significant pools of carbon and nitrogen. Due to cool and moist climatic conditions alpine grassland soils of moderate elevation (app. 1000m) in particular, are rich in soil organic carbon and associated nitrogen. In the framework of an in-situ climate change experiment we test the hypothesis that soil organic carbon and nitrogen are either volatilized (GHG emissions) or leached with seepage water due to increase in air temperature as induced by climate change. The infrastructure of the in-situ climate change experiment was funded by Helmholtz society and BMBF and allowed IMK-IFU to install a lysimeter network with undisturbed intact grassland soil cores (diameter approx. 1 m, depth 1.4 m, 2-3 t of soil) at three sites (Graswang 860m, Rottenbuch 750m, Fendt 600m) differing in altitude and climate. The lysimeter network consisting of a total of 36 lysimeters is operated since September 2011 and is run for climate change research with a long term perspective (>10years). Lysimeters were partly moved along the altitudinal gradient, with some soil cores still staying at sites as controls and some others translocated from higher elevation to sites at lower elevation with higher temperatures and slightly lower mean annual rainfall. The different components of the water balance i.e. precipitation, evapotranspiration and groundwater recharge of each lysimeter are measured by precision weighing of the lysimeters and a separate container for collection of seepage water at the lower boundary condition (1.4m). In addition, soil moisture (volumetric water content as well as water tension) and temperature are measured with sensors installed in 10, 30, 50, 140cm soil depth. Soil water in 10, 30, 50 and 140cm soil depth is drawn into glass bottles by under-pressurized suction cups. Water samples are collected regularly any 2 weeks and more often (e.g. 3 times a week) during fertilization events, and analyzed for nutrient

  2. Wading bird guano enrichment of soil nutrients in tree islands of the Florida Everglades.

    PubMed

    Irick, Daniel L; Gu, Binhe; Li, Yuncong C; Inglett, Patrick W; Frederick, Peter C; Ross, Michael S; Wright, Alan L; Ewe, Sharon M L

    2015-11-01

    Differential distribution of nutrients within an ecosystem can offer insight of ecological and physical processes that are otherwise unclear. This study was conducted to determine if enrichment of phosphorus (P) in tree island soils of the Florida Everglades can be explained by bird guano deposition. Concentrations of total carbon, nitrogen (N), and P, and N stable isotope ratio (δ(15)N) were determined on soil samples from 46 tree islands. Total elemental concentrations and δ(15)N were determined on wading bird guano. Sequential chemical extraction of P pools was also performed on guano. Guano contained between 53.1 and 123.7 g-N kg(-1) and 20.7 and 56.7 g-P kg(-1). Most of the P present in guano was extractable by HCl, which ranged from 82 to 97% of the total P. Total P of tree islands classified as having low or high P soils averaged 0.71 and 40.6 g kg(-1), respectively. Tree island soil with high total P concentration was found to have a similar δ(15)N signature and total P concentration as bird guano. Phosphorus concentrations and δ(15)N were positively correlated in tree island soils (r = 0.83, p< 0.0001). Potential input of guano with elevated concentrations of N and P, and (15)N enriched N, relative to other sources suggests that guano deposition in tree island soils is a mechanism contributing to this pattern.

  3. Contaminant immobilization and nutrient release by biochar soil amendment: roles of natural organic matter.

    PubMed

    Uchimiya, Minori; Lima, Isabel M; Klasson, K Thomas; Wartelle, Lynda H

    2010-08-01

    Contamination of soil interstitial waters by labile heavy metals such as Cu(II), Cd(II), and Ni(II) is of worldwide concern. Carbonaceous materials such as char and activated carbon have received considerable attention in recent years as soil amendment for both sequestering heavy metal contaminants and releasing essential nutrients like sulfur. Information is currently lacking in how aging impacts the integrity of biochars as soil amendment for both agricultural and environmental remediation purposes. Major contributors to biochar aging in soils are: sorption of environmental constituents, especially natural organic matter (NOM), and oxidation. To investigate the impact of NOM and organic fractions of chars, we employed broiler litter-derived chars and steam-activated carbons that underwent varying degrees of carbonization, in the presence and absence of NOM having known carboxyl contents. For aging by oxidation, we employed phosphoric acid activated carbons that underwent varying degrees of oxidation during activation. The results suggest that the organic fractions of biochars, and NOM having high carboxyl contents can mobilize Cu(II) retained by alkaline soil. Base treatment of broiler litter-derived char formed at low pyrolysis temperature (350 degrees C) improved the immobilization of all heavy metals investigated, and the extent of immobilization was similar to, or slightly greater than pecan shell-derived phosphoric acid activated carbons. Portions of total sulfur were released in soluble form in soil amended with broiler litter-derived carbons, but not pecan shell-derived phosphoric acid activated carbons.

  4. Metaproteogenomics reveals the soil microbial communities active in nutrient cycling processes under different tree species

    NASA Astrophysics Data System (ADS)

    Keiblinger, Katharina Maria; Masse, Jacynthe; Zühlke, Daniela; Riedel, Katharina; Zechmeister-Boltenstern, Sophie; Prescott, Cindy E.; Grayston, Sue

    2016-04-01

    Tree species exert strong effects on microbial communities in litter and soil and may alter rates of soil processes fundamental to nutrient cycling and carbon fluxes (Prescott and Grayston 2013). However, the influence of tree species on decomposition processes are still contradictory and poorly understood. An understanding of the mechanisms underlying plant influences on soil processes is important for our ability to predict ecosystem response to altered global/environmental conditions. In order to link microbial community structure and function to forest-floor nutrient cycling processes, we sampled forest floors under western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii) and Sitka spruce (Picea sitchensis) grown in nutrient-poor sites in common garden experiments on Vancouver island (Canada). We measured forest-floor total N, total C, initial NH4+ and NO3- concentrations, DOC, Cmic and Nmic. Gross rates of ammonification and NH4+ consumption were measured using the 15N pool-dilution method. Organic carbon quality was assessed through FTIR analyses. Microbial community structure was analysed by a metaproteogenomic approach using 16S and ITS amplification and sequencing with MiSeq platform. Proteins were extracted and peptides characterized via LC-MS/MS on a Velos Orbitrap to assess the active microbial community. Different microbial communities were active under the three tree species and variation in process rates were observed and will be discussed. This research provides new insights on microbial processes during organic matter decomposition. The metaproteogenomic approach enables us to investigate these changes with respect to possible effects on soil C-storage at even finer taxonomic resolution.

  5. Short-term grazing exclusion has no impact on soil properties and nutrients of degraded alpine grassland in Tibet, China

    NASA Astrophysics Data System (ADS)

    Lu, X.; Yan, Y.; Sun, J.; Zhang, X.; Chen, Y.; Wang, X.; Cheng, G.

    2015-11-01

    Since the 1980s, alpine grasslands have been seriously degraded on the Tibetan Plateau. Grazing exclusion by fencing has been widely adopted to restore degraded grasslands. To clarify the effect of grazing exclusion on soil quality, we investigated soil properties and nutrients by comparing free-grazing (FG) and grazing exclusion (GE) grasslands in Tibet. Soil properties - including soil bulk density, pH, particle size distributions, and proportion of aggregates - showed no significant difference between FG and GE plots. Soil organic carbon, soil available nitrogen, and available phosphorus contents did not differ with grazing exclusion treatments in both the 0-15 and 15-30 cm layer. However, soil total nitrogen and total phosphorus contents were remarkably reduced due to grazing exclusion at 0-15 cm depth. Furthermore, growing season temperature and/or growing season precipitation had significant effects on almost all soil property and nutrient indicators. This study demonstrates that grazing exclusion had no impact on most soil properties and nutrients in Tibet. Additionally, the potential shift of climate conditions should be considered when recommending any policy designed for restoration of degraded soil in alpine grasslands in the future. Nevertheless, because the results of the present study come from a short-term (6-8 years) grazing exclusion, the assessments of the ecological effects of the grazing exclusion management strategy on soil quality of degraded alpine grasslands in Tibet still need long-term continued research.

  6. Short-term grazing exclusion has no impact on soil properties and nutrients of degraded alpine grassland in Tibet, China

    NASA Astrophysics Data System (ADS)

    Lu, X.; Yan, Y.; Sun, J.; Zhang, X.; Chen, Y.; Wang, X.; Cheng, G.

    2015-08-01

    Since the 1980s, alpine grasslands have been seriously degraded on the Tibetan Plateau. Grazing exclusion by fencing has been widely adopted to restore degraded grasslands. To clarify the effect of grazing exclusion on soil quality, we investigated soil properties and nutrients by comparing free grazing (FG) and grazing exclusion (GE) grasslands in Tibet. Soil properties, including soil bulk density, pH, particle size distributions, and proportion of aggregates, were not significant different between FG and GE plots. Soil organic carbon, soil available nitrogen, available phosphorus contents did not differ with grazing exclusion treatments in both 0-15 and 15-30 cm layer. However, soil total nitrogen and total phosphorus contents were remarkably reduced due to grazing exclusion at the 0-15 cm depth. Furthermore, growing season temperature and/or growing season precipitation had significant effects on almost all soil properties and nutrients indicators. This study demonstrates that grazing exclusion had no impact on most soil properties and nutrients in Tibet. Additionally, the potential shift of climate conditions should be considered when recommend any policies designed for alpine grasslands degraded soil restoration in the future. Nevertheless, because the results of the present study come from short term (6-8 years) grazing exclusion, the assessments of the ecological effects of the grazing exclusion management strategy on soil quality of degraded alpine grasslands in Tibet still need long term continued research.

  7. Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests

    DOE PAGES

    Zhu, Q.; Riley, W. J.; Tang, J.; ...

    2016-01-18

    Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3− and POx; representing the sum of PO43−, HPO42− and H2PO4−) and five potential competitors (plantmore » roots, decomposing microbes, nitrifiers, denitrifiers and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus and NH4+ pools at a tropical forest site (Tapajos). The overall model uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer–substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results also imply that under strong nutrient limitation, relative competitiveness depends strongly on the competitor functional traits (affinity and nutrient carrier enzyme abundance). We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately replicated the experimentally observed

  8. Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C. D.

    2016-01-01

    Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3- and POx; representing the sum of PO43-, HPO42- and H2PO4-) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus and NH4+ pools at a tropical forest site (Tapajos). The overall model uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer-substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results also imply that under strong nutrient limitation, relative competitiveness depends strongly on the competitor functional traits (affinity and nutrient carrier enzyme abundance). We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii and Puerto Rico) not used in model development or calibration. Under soil inorganic nitrogen and phosphorus elevated conditions, the model accurately

  9. Dynamics of the biological properties of soil and the nutrient release of Amorpha fruticosa L. litter in soil polluted by crude oil.

    PubMed

    Zhang, Xiaoxi; Liu, Zengwen; Luc, Nhu Trung; Liang, Xiao; Liu, Xiaobo

    2015-11-01

    Litter from Amorpha fruticosa, a potential phytoremediating plant, was collected and used in a decomposition experiment that involved the litterbag in soil polluted by crude oil. The dynamics of the biological properties of soil and the nutrient release of the litter were detected. The results indicated that (1) in lightly polluted soil (LP, petroleum concentration was 15 g kg(-1)), the bacteria (including actinomycetes), and fungi populations were significant higher than those in unpolluted soil (CK) at the 1st month after pollution, and the bacteria (including actinomycetes) populations were higher than those in the CK at the 6th and 12th months. In moderately polluted soil (MP, 30 g kg(-1)), the bacteria (including actinomycetes) populations were higher than those in the CK at the 1st and 6th months, whereas only the actinomycetes population was greater than that in the CK at the 12th month. In seriously polluted soil (SP, 45 g kg(-1)), only the fungi population was higher than that in the CK at the 6th month. (2) The activities of soil protease, carboxymethyl cellulase, and sucrase were generally inhibited in polluted soil. Peroxidase activity was generally inhibited in the LP and MP soil, and polyphenol oxidase activity was inhibited in the SP soil at 6-12 months. (3) At the end of litter decomposition, the LP soil significantly increased the release rate of all nutrients, except for K. The MP soil reduced the release rate of Fe and Mn, whereas it increased that of C and Cu. The SP soil decreased the release rate of all nutrients except for Cu and Zn. In conclusion, SP by crude oil would lead to limitations in the release of nutrients from the litter and to decreases in the community stability of a phytoremediating plant. A. fruticosa could only be used in phytoremediation of polluted soil at concentrations below 45 g kg(-1) (crude).

  10. The influence of soil pH and humus content on received by Mehlich 3 method nutrients analysis results

    NASA Astrophysics Data System (ADS)

    Tonutare, Tonu; Krebstein, Kadri; Rodima, Ako; Kõlli, Raimo; Künnapas, Allan; Rebane, Jaanus; Penu, Priit; Vennik, Kersti; Soobik, Liina

    2015-04-01

    Soils provide vital ecosystem functions, playing an important role in our economy and in healthy living environment. However, soils are increasingly degrading in Europe and at the global level. Knowledge about the content of major plant available nutrients, i.e. calcium, magnesium, potassium and phosphorus, plays an important role in the sustainable soil management. Mobility of nutrients depends directly on the environmental conditions, two of the most important factors are the pH and organic matter content. Therefore it is essential to have correct information about the content and behaviour of the above named elements in soil, both from the environmental and agronomical viewpoint. During the last decades several extracting solutions which are suitable for the evaluation of nutrient status of soils have been developed for this purpose. One of them is called Mehlich 3 which is widely used in USA, Canada and some European countries (e.g. Estonia, Czech Republic) because of its suitability to extract several major plant nutrients from the soil simultaneously. There are several different instrumental methods used for the analysis of nutrient elements in the soil extract. Potassium, magnesium and calcium are widely analysed by the AAS (atomic absorption spectroscopic) method or by the ICP (inductively coupled plasma) spectroscopic methods. Molecular spectroscopy and ICP spectroscopy were used for the phosphorus determination. In 2011 a new multielemental instrumental method MP-AES (microwave plasma atomic emission spectroscopy) was added to them. Due to its lower detection limits and multielemental character, compared with AAS, and lower exploitation costs, compared with ICP, the MP-AES has a good potential to achieve a leading position in soil nutrient analysis in the future. The objective of this study was to investigate: (i) the impact of soil pH and humus content and (ii) applicability of MP-AES instrumental method for the determination of soil nutrients extracted

  11. Effects of Savanna trees on soil nutrient limitation and carbon-sequestration potential in dry season

    NASA Astrophysics Data System (ADS)

    Becker, Joscha; Gütlein, Adrian; Sierra Cornejo, Natalia; Kiese, Ralf; Hertel, Dietrich; Kuzyakov, Yakov

    2016-04-01

    Semi-arid savannah ecosystems are under strong pressure from climate and land-use changes, especially around populous areas like Mt. Kilimanjaro region. Savannah vegetation consists of grassland with isolated trees and is therefore characterized by high spatial variation of canopy cover and aboveground biomass. Both are major regulators for soil ecological parameters and soil-atmospheric trace gas exchange (CO2, N2O, CH4), especially in water limited environments. The spatial distribution of these parameters and the connection between above and belowground processes are important to understand and predict ecosystem changes and estimate its vulnerability. Our objective was to determine spatial trends and changes of soil parameters and trace-gas fluxes and relate their variability to the vegetation structure. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca). For each tree, we selected transects with total nine sampling points under and outside the crown. At each sampling point we measured soil and plant biomass carbon (C) and nitrogen (N) content, δ13C, microbial biomass C and N, soil respiration, available nutrients, pH, cation exchange capacity (CEC) as well as belowground biomass, soil temperature and soil water content. Contents and stocks of C and N fractions, Ca2+, K+ and total CEC decreased up to 50% outside the crown. This was unaffected by the tree species, tree size or other tree characteristics. Water content was below the permanent wilting point and independent from tree cover. In all cases tree litter inputs had far a closer C:N ratio than C4-grass litter. Microbial C:N ratio and CO2 efflux was about 30% higher in open area and strongly dependent on mineral N availability. This indicates N limitation and low microbial C use efficiency in soil under open area. We conclude that the spatial structure of aboveground biomass in savanna ecosystems leads to a spatial redistribution of nutrient

  12. Nitrogen fertilizer enhances growth and nutrient uptake of Medicago sativa inoculated with Glomus tortuosum grown in Cd-contaminated acidic soil.

    PubMed

    Liu, Mohan; Sun, Jian; Li, Yang; Xiao, Yan

    2017-01-01

    This study aimed to explore whether nitrogen availability could influence mycorrhizal function and their associations with host plants in Cd-contaminated acidic soils or not. A greenhouse pot experiment was conducted to assess the effects of mycorrhizal inoculation (non-mycorrhizal inoculation (NM), Glomus aggregatum (Ga), G. tortuosum (Gt) and G. versiforme (Gv)) and inorganic N amendment on the growth, nutrient and Cd uptake of Medicago sativa grown in Cd-contaminated acidic soils (10 mg Cd kg(-1) soil). AMF inoculations significantly increased the shoot and total biomass and decreased the shoot Cd concentration in comparison to plants uninoculated. N addition increased markedly concentration and content of N and decreased those of P in plants at all inoculation treatments. Shoot K, Na and Mg concentration in plants inoculated with Ga and Gv were decreased by N addition, whereas shoot K, Na, Ca and Mg concentration in plants inoculated with Gt were not negatively affected. It was observed that N addition only increased mycorrhizal colonization, shoot biomass, shoot K, Ca and Mg content of plants inoculated with Gt. Irrespective of N addition, plants with Gt inoculation got the maximum shoot and root P concentration and content, as well as P/Cd concentration molar ratio among all inoculation treatment. Neither AMF nor N fertilizer contributed to the decrease of soil exchangeable Cd and increase of soil pH. These results suggested that N fertilizer only elevated plant performance of alfalfa with Gt inoculation grown in acidic soil, by diluting Cd concentration and alleviating of nutrient deficiency, especially P.

  13. Composting of biochars improves their sorption properties, retains nutrients during composting and affects greenhouse gas emissions after soil application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar application to soils has been suggested to elevate nutrient sorption, improve soil fertility and reduce net greenhouse gas (GHG) emissions. We examined the impact of composting biochar together with a biologically active substrate (i.e., livestock manure-straw mixture). We hypothesized that ...

  14. Soil microbial and nutrient responses to 7 years of seasonally altered precipitation in a Chihuahuan Desert grassland.

    PubMed

    Bell, Colin W; Tissue, David T; Loik, Michael E; Wallenstein, Matthew D; Acosta-Martinez, Veronica; Erickson, Richard A; Zak, John C

    2014-05-01

    Soil microbial communities in Chihuahuan Desert grasslands generally experience highly variable spatiotemporal rainfall patterns. Changes in precipitation regimes can affect belowground ecosystem processes such as decomposition and nutrient cycling by altering soil microbial community structure and function. The objective of this study was to determine if increased seasonal precipitation frequency and magnitude over a 7-year period would generate a persistent shift in microbial community characteristics and soil nutrient availability. We supplemented natural rainfall with large events (one/winter and three/summer) to simulate increased precipitation based on climate model predictions for this region. We observed a 2-year delay in microbial responses to supplemental precipitation treatments. In years 3-5, higher microbial biomass, arbuscular mycorrhizae abundance, and soil enzyme C and P acquisition activities were observed in the supplemental water plots even during extended drought periods. In years 5-7, available soil P was consistently lower in the watered plots compared to control plots. Shifts in soil P corresponded to higher fungal abundances, microbial C utilization activity, and soil pH. This study demonstrated that 25% shifts in seasonal rainfall can significantly influence soil microbial and nutrient properties, which in turn may have long-term effects on nutrient cycling and plant P uptake in this desert grassland.

  15. Seasonal greenhouse gas and soil nutrient cycling in semi-arid native and non-native perennial grass pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research indicates that a difference occurs in native and non-native grass species in regard to drivers of greenhouse gas (GHG, (carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O))) emissions from soil. Drivers of soil nutrients could help establish best management practices to mit...

  16. Fertilizer and soil management practices for improving the efficiency of nutrient uptake and use in northern highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highbush blueberry is a long-lived perennial crop well-adapted to acidic soils. Plants acquire primarily NH4-N and tolerate relatively low concentrations of P and cations in the soil and high concentrations of plant available metals such as Al and Mn. Recently, we found that optimal leaf nutrient co...

  17. Soil nutrient-landscape relationships in a lowland tropical rainforest in Panama

    USGS Publications Warehouse

    Barthold, F.K.; Stallard, R.F.; Elsenbeer, H.

    2008-01-01

    Soils play a crucial role in biogeochemical cycles as spatially distributed sources and sinks of nutrients. Any spatial patterns depend on soil forming processes, our understanding of which is still limited, especially in regards to tropical rainforests. The objective of our study was to investigate the effects of landscape properties, with an emphasis on the geometry of the land surface, on the spatial heterogeneity of soil chemical properties, and to test the suitability of soil-landscape modeling as an appropriate technique to predict the spatial variability of exchangeable K and Mg in a humid tropical forest in Panama. We used a design-based, stratified sampling scheme to collect soil samples at 108 sites on Barro Colorado Island, Panama. Stratifying variables are lithology, vegetation and topography. Topographic variables were generated from high-resolution digital elevation models with a grid size of 5 m. We took samples from five depths down to 1 m, and analyzed for total and exchangeable K and Mg. We used simple explorative data analysis techniques to elucidate the importance of lithology for soil total and exchangeable K and Mg. Classification and Regression Trees (CART) were adopted to investigate importance of topography, lithology and vegetation for the spatial distribution of exchangeable K and Mg and with the intention to develop models that regionalize the point observations using digital terrain data as explanatory variables. Our results suggest that topography and vegetation do not control the spatial distribution of the selected soil chemical properties at a landscape scale and lithology is important to some degree. Exchangeable K is distributed equally across the study area indicating that other than landscape processes, e.g. biogeochemical processes, are responsible for its spatial distribution. Lithology contributes to the spatial variation of exchangeable Mg but controlling variables could not be detected. The spatial variation of soil total K

  18. Soil Iron Content as a Predictor of Carbon and Nutrient Mobilization in Rewetted Fens

    PubMed Central

    Emsens, Willem-Jan; Aggenbach, Camiel J. S.; Schoutens, Ken; Smolders, Alfons J. P.; Zak, Dominik; van Diggelen, Rudy

    2016-01-01

    Rewetted, previously drained fens often remain sources rather than sinks for carbon and nutrients. To date, it is poorly understood which soil characteristics stimulate carbon and nutrient mobilization upon rewetting. Here, we assess the hypothesis that a large pool of iron in the soil negatively affects fen restoration success, as flooding-induced iron reduction (Fe3+ to Fe2+) causes a disproportionate breakdown of organic matter that is coupled with a release of inorganic compounds. We collected intact soil cores in two iron-poor and two iron-rich drained fens, half of which were subjected to a rewetting treatment while the other half was kept drained. Prolonged drainage led to the mobilization of nitrate (NO3-, > 1 mmol L-1) in all cores, regardless of soil iron content. In the rewetted iron-rich cores, a sharp increase in pore water iron (Fe) concentrations correlated with concentrations of inorganic carbon (TIC, > 13 mmol L-1) and dissolved organic carbon (DOC, > 16 mmol L-1). Additionally, ammonium (NH4+) accumulated up to phytotoxic concentrations of 1 mmol L-1 in the pore water of the rewetted iron-rich cores. Disproportionate mobilization of Fe, TIC, DOC and NH4+ was absent in the rewetted iron-poor cores, indicating a strong interaction between waterlogging and iron-mediated breakdown of organic matter. Concentrations of dissolved phosphorus (P) rose slightly in all cores upon rewetting, but remained low throughout the experiment. Our results suggest that large pools of iron in the top soil of drained fens can hamper the restoration of the fen’s sink-service for ammonium and carbon upon rewetting. We argue that negative effects of iron should be most apparent in fens with fluctuating water levels, as temporary oxygenation allows frequent regeneration of Fe3+. We conclude that rewetting of iron-poor fens may be more feasible for restoration. PMID:27050837

  19. Biomass production, nutrient cycling, and carbon fixation by Salicornia brachiata Roxb.: A promising halophyte for coastal saline soil rehabilitation.

    PubMed

    Rathore, Aditya P; Chaudhary, Doongar R; Jha, Bhavanath

    2016-08-02

    In order to increase our understanding of the interaction of soil-halophyte (Salicornia brachiata) relations and phytoremediation, we investigated the aboveground biomass, carbon fixation, and nutrient composition (N, P, K, Na, Ca, and Mg) of S. brachiata using six sampling sites with varying characteristics over one growing season in intertidal marshes. Simultaneously, soil characteristics and nutrient concentrations were also estimated. There was a significant variation in soil characteristics and nutrient contents spatially (except pH) as well as temporally. Nutrient contents in aboveground biomass of S. brachiata were also significantly differed spatially (except C and Cl) as well as temporally. Aboveground biomass of S. brachiata ranged from 2.51 to 6.07 t/ha at maturity and it was positively correlated with soil electrical conductivity and available Na, whereas negatively with soil pH. The K/Na ratio in plant was below one, showing tolerance to salinity. The aboveground C fixation values ranged from 0.77 to 1.93 C t/ha at all six sampling sites. This study provides new understandings into nutrient cycling-C fixation potential of highly salt-tolerant halophyte S. brachiata growing on intertidal soils of India. S. brachiata have a potential for amelioration of the salinity due to higher Na bioaccumulation factor.

  20. Scale-location specific relations between soil nutrients and topographic factors in the Fen River Basin, Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Zhu, Hongfen; Bi, Rutian; Duan, Yonghong; Xu, Zhanjun

    2016-09-01

    Understanding scale- and location-specific variations of soil nutrients in cultivated land is a crucial consideration for managing agriculture and natural resources effectively. In the present study, wavelet coherency was used to reveal the scale-location specific correlations between soil nutrients, including soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), and available potassium (AK), as well as topographic factors (elevation, slope, aspect, and wetness index) in the cultivated land of the Fen River Basin in Shanxi Province, China. The results showed that SOM, TN, AP, and AK were significantly inter-correlated, and that the scales at which soil nutrients were correlated differed in different landscapes, and were generally smaller in topographically rougher terrain. All soil nutrients but TN were significantly influenced by the wetness index at relatively large scales (32-72 km) and AK was significantly affected by the aspect at large scales at partial locations, showing localized features. The results of this study imply that the wetness index should be taken into account during farming practices to improve the soil nutrients of cultivated land in the Fen River Basin at large scales.

  1. Examining soil erosion and nutrient accumulation in forested and agriculture lands of the low mountainous area of Northern Vietnam

    NASA Astrophysics Data System (ADS)

    Pham, A. T.; Gomi, T.; Takahisa, F.; Phung, K. V.

    2011-12-01

    We examined soil erosion and nutrient accumulations in the Xuanmai area located in the low mountainous region of Northern Vietnam, based on field investigations and remote sensing approaches. The study area had been degraded by land-use change from forest to agriculture in the last 20 years. In contrast, around the study area, the Vietnam government promoted reforestation projects. Such changes in land-use conditions, which may or may not be associated with vegetation ground cover conditions, potentially alter soil erosion and nutrient accumulation. We selected 10 dominant land-use types including forested land (e.g., Pinus massoniana and Acacia mangium plantation) agriculture land (e.g., Cassava), and bare land. We established three 1 x 1 m plots in each land-use type in September 2010. Vegetation biomass, litter cover, soil erosion (height of soil pedestal), and soil physical (soil bulk density and particle size distribution) and chemical properties (Total soil carbon, nitrate, and phosphorus) were measured. Height of soil pedestal can be a record of soil erosion by rain splash during rainy periods from April to August (prior to our field study). We also conducted remote sensing analysis using Landsat TM images obtained in 1993, 2000, and 2007 for identifying temporal patterns of land-use types. We found that the intensity of soil erosion depended primary on current vegetation ground cover condition with no regard of land-use. Hence, nutrient accumulation varied among vegetation ground cover and soil erosion. Remote sensing analysis suggested that shrub and bare lands had been altered from forested land more recently. Our finding suggested that variability of soil nutrient conditions can be associated with long-term soil erosion and production processes. Findings of our study are that: (1) current vegetation and litter ground cover affected the amount of surface soil erosion, and (2) legacy of land-use can be more critical for soil nutrient accumulation. Both

  2. Effect of Fertilization on Soil Fertility and Nutrient Use Efficiency at Potatoes

    NASA Astrophysics Data System (ADS)

    Neshev, Nesho; Manolov, Ivan

    2016-04-01

    The effect of fertilization on soil fertility, yields and nutrient use efficiency of potatoes grown under field experimental conditions was studied. The trail was conducted on shallow brown forest soil (Cambisols-coarse) during the vegetation periods of 2013 to 2015. The variants of the experiment were: control, N140; P80; K100; N140P80; N140K100; P80K100; N140P80K100; N140P80K100Mg33. The applied fertilization slightly decreased soil's pH after the harvest of potatoes compared to the soil pH their planting. Decreasing of pH was more severe at variant N (from 5,80 to 4,19 in 2014). The mineral nitrogen content in the soil after the harvest of potatoes was lower for the variants P, K and PK. The positive effect of fertilization on soil fertility after the end of the trails was more pronounced at variants NPK and NPKMg. The content of available nitrogen, phosphorus and potassium forms for these variants was the highest for each year. The highest content of mineral nitrogen was observed in 2013 (252,5 and 351,1 mg/1000g, respectively for variants NPK and NPKMg). It was due to extremely dry weather conditions during the vegetation in this year. Soil content of mineral N for the next two years was lower. The same tendency was observed for phosphorus and potassium was observed. In 2013 the P2O5 and K2O content in soil was the highest for the variants with full mineral fertilization - NPK (64,4 and 97,6 mg 100g-1 respectively for P2O5 and K2O) and NPKMg (65,2 and 88,0 mg 100g-1 respectively for P2O5 and K2O). The highest yields were recorded at variants NPK and NPKMg - 24,21 and 22,01 t ha-1, average for the studied period. The yield of variant NPK was 25 % higher than the yield from variant NP and 68 % higher than control. The partial factor productivity (PFPN, PFPP and PFPK) of the applied fertilizers was the highest at variant NPK. The PFPN (80,10 kg kg-1) for the yields of variant N was 57 % lower than the PFPN at variant NPK (180,36 kg kg-1). The PFPP and PFPK at

  3. Nutrient leaching and soil retention in mined land reclaimed with stabilized manure.

    PubMed

    Dere, Ashlee L; Stehouwer, Richard C; Aboukila, Emad; McDonald, Kirsten E

    2012-01-01

    Two environmental problems in Pennsylvania are degraded mined lands and excess manure nutrients from intensive animal production. Manure could be used in mine reclamation, but the large application rates required for sustained biomass production could result in significant nutrient discharge. An abandoned mine site in Schuylkill County, Pennsylvania, was used to test manure nutrient stabilization by composting and by mixing with primary paper mill sludge (PMS). Reclamation treatments were lime and fertilizer, composted poultry manure (78 and 156 Mg ha), and poultry manure (50 Mg ha) mixed with PMS (103 and 184 Mg ha) to achieve C-to-N ratios of 20 and 29. Leachates were collected with zero-tension lysimeters, and during 3 yr following amendment application, <1% of added N leached from the compost treatments. The manure+PMS C:N 29 treatment leached more N than any other treatment (393 kg N ha during 3 yr, 12.4 times more N than compost treatments), mostly as pulses of NO in the first two fall seasons following reclamation. The manure+PMS C:N 20 treatment leached 107 kg N ha during 3 yr. Three years after amendment application, most of the N and P added with the manure-based amendments was retained in the mine soil even though net immobilization of N by PMS appeared to be limited to 3 mo following application. Composting or mixing PMS with manure to achieve a C-to-N ratio of 20 can effectively minimize N leaching, retain added N in mine soil, and provide greater improvement in soil quality than lime and fertilizer amendment.

  4. Interspecific variation in compensatory regrowth to herbivory associated with soil nutrients in three Ficus (Moraceae) saplings.

    PubMed

    Zhao, Jin; Chen, Jin

    2012-01-01

    Plant compensatory regrowth is an induced process that enhances plant tolerance to herbivory. Plant behavior against herbivores differs between species and depends on resource availability, thus making general predictions related to plant compensatory regrowth difficult. To understand how soil nutrients determine the degree of compensatory regrowth for different plant species, we selected saplings of three Ficus species and treated with herbivore insects and artificial injury in both glasshouse conditions and in the field at two soil nutrient levels. Compensatory regrowth was calculated by biomass, relative growth rate and photosynthetic characteristics. A similar pattern was found in both the glasshouse and in the field for species F. hispida, where overcompensatory regrowth was triggered only under fertile conditions, and full compensatory regrowth occurred under infertile conditions. For F. auriculata, overcompensatory regrowth was stimulated only under infertile conditions and full compensatory regrowth occurred under fertile conditions. Ficus racemosa displayed full compensatory regrowth in both soil nutrient levels, but without overcompensatory regrowth following any of the treatments. The three Ficus species differed in biomass allocation following herbivore damage and artificial injury. The root/shoot ratio of F. hispida decreased largely following herbivore damage and artificial injury, while the root/shoot ratio for F. auriculata increased against damage treatments. The increase of shoot and root size for F. hispida and F. auriculata, respectively, appeared to be caused by a significant increase in photosynthesis. The results indicated that shifts in biomass allocation and increased photosynthesis are two of the mechanisms underlying compensatory regrowth. Contrasting patterns among the three Ficus species suggest that further theoretical and empirical work is necessary to better understand the complexity of the plant responses to herbivore damage.

  5. A high loading overland flow system: Impacts on soil characteristics, grass constituents, yields and nutrient removal.

    PubMed

    Wen, C G; Chen, T H; Hsu, F H; Lu, C H; Lin, J B; Chang, C H; Chang, S P; Lee, C S

    2007-04-01

    The objectives of this paper are to determine effects of different grass species and their harvests on pollutant removal, elucidate impacts on soil characteristics and grass constituents, observe grass yield and quantify nutrient uptake by vegetation in an overland flow system (OLFS). Polluted creek water was applied to eight channels in the OLFS, which were planted with Paragrass, Nilegrass, Cattail, and Vetiver, with each two channels being randomly planted with a given grass species. The grass in one channel was harvested while that in the other channel was not. At a high rate of 27.8 m d(-1) hydraulic loading, the removal efficiencies of conventional pollutants such as BOD, COD, suspended solids (SS), and total coliforms in wastewater are not affected by the type of the grasses species, but those of nitrogen and phosphorus are affected by different species. Overall average removal efficiencies of BOD, COD, SS, ammonia, total nitrogen, total phosphorus and total coliforms through the OLFS are 42%, 48%, 78%, 47%, 40%, 33% and 89%, respectively. The concentration of nitrate, however, increases due to nitrification. Soil characteristics in OLFS have been changed significantly; specific conductivity, organic matter, exchangeable magnesium, extractable copper and zinc in soils all increase with time while pHs decrease. During the winter season, there is a significant accumulation of nitrate in grass with the subsequent reduction during the active growing season (Spring). The contents of nitrate and phosphorus in grass tissue are higher than those of grass in general pastureland, probably due to nutrient luxury uptake by grass. The overall grass yield, growth rate and nutrient uptake are quantified and implication of such high rate OLFS discussed.

  6. Reducing soil erosion and nutrient loss on sloping land under crop-mulberry management system.

    PubMed

    Fan, Fangling; Xie, Deti; Wei, Chaofu; Ni, Jiupai; Yang, John; Tang, Zhenya; Zhou, Chuan

    2015-09-01

    Sloping croplands could result in soil erosion, which leads to non-point source pollution of the aquatic system in the Three Gorges Reservoir Region. Mulberry, a commonly grown cash plant in the region, is traditionally planted in contour hedgerows as an effective management practice to control soil erosion and non-point source pollution. In this field study, surface runoff and soil N and P loss on sloping land under crop-mulberry management were investigated. The experiments consisted of six crop-mulberry treatments: Control (no mulberry hedgerow with mustard-corn rotation); T1 (two-row contour mulberry with mustard-corn rotation); T2 (three-row contour mulberry with mustard-corn rotation); T3 (border mulberry and one-row contour mulberry with mustard-corn rotation); T4 (border mulberry with mustard-corn rotation); T5 (two-row longitudinal mulberry with mustard). The results indicated that crop-mulberry systems could effectively reduce surface runoff and soil and nutrient loss from arable slope land. Surface runoff from T1 (342.13 m(3) hm(-2)), T2 (260.6 m(3) hm(-2)), T3 (113.13 m(3) hm(-2)), T4 (114 m(3) hm(-2)), and T5 (129 m(3) hm(-2)) was reduced by 15.4, 35.6, 72.0, 71.8, and 68.1%, respectively, while soil loss from T1 (0.21 t hm(-2)), T2 (0.13 t hm(-2)), T3 (0.08 t hm(-2)), T4 (0.11 t hm(-2)), and T5 (0.12 t hm(-2)) was reduced by 52.3, 70.5, 81.8, 75.0, and 72.7%, respectively, as compared with the control. Crop-mulberry ecosystem would also elevate soil N by 22.3% and soil P by 57.4%, and soil nutrient status was contour-line dependent.

  7. [Natural vegetation restoration and soil nutrient dynamics of abandoned farmlands in forest-steppe zone on Loess Plateau].

    PubMed

    Wen, Zhongming; Jiao, Feng; Liu, Baoyuan; Bu, Yaojun; Jiao, Juying

    2005-11-01

    To understand the relationship between plant community succession and soil nutrient dynamics is crucial in intervening vegetation succession. This paper reported the results from a study carried out in a forest-steppe zone on the Loess Plateau, with emphasis on the vegetation characteristics and soil nutrient dynamics duringvegetation restoration on abandoned farmlands of this area. The results showed that under zonal habitat conditions, natural vegetation succession would turn toward the original vegetation communities, but the expected shrub or trees communities didn't occur after 40 approximately 50 years, and Stipa bungeana, Artemisia sacrorum, Bothriochloa ischaemun, Stipa grandis and Lespedeza davurica communities were still the widely distributed communities. Vegetation restoration had a significant effect on soil nutrient dynamics. In general, soil nutrient contents increased with restoration time, and extremely significant changes occurred in soil organic matter, total N, available N, and available K (P< 0.001),while only significant changes in available P (0.05 < P < 0.01) and no significant change in total P (P > 0.05). Moreover, the changes were also found in soil profile. Statistical analysis showed that from surface layer (0 approximately 20 cm) to deeper layer (to 60 cm), extremely significant changes occurred in soil organic matter, total N, available N, available K and available P (P < 0.001), and significant change in total P (P< 0.05). Soil nutrients intended to accumulate in surface layer. Further linear correlation analysis showed that soil organic matter, total N, available N and available K were significantly correlated each other ( P< 0.001), but didn't show correlation with soil total P and available P.

  8. Interactive effects of soil temperature, atmospheric carbon dioxide and soil N on root development, biomass and nutrient uptake of winter wheat during vegetative growth.

    PubMed

    Gavito, M E; Curtis, P S; Mikkelsen, T N; Jakobsen, I

    2001-09-01

    Nutrient requirements for plant growth are expected to rise in response to the predicted changes in CO(2) and temperature. In this context, little attention has been paid to the effects of soil temperature, which limits plant growth at early stages in temperate regions. A factorial growth-room experiment was conducted with winter wheat, varying soil temperature (10 degrees C and 15 degrees C), atmospheric CO(2) concentration (360 and 700 ppm), and N supply (low and high). The hypothesis was that soil temperature would modify root development, biomass allocation and nutrient uptake during vegetative growth and that its effects would interact with atmospheric CO(2) and N availability. Soil temperature effects were confirmed for most of the variables measured and 3-factor interactions were observed for root development, plant biomass components, N-use efficiency, and shoot P content. Importantly, the soil temperature effects were manifest in the absence of any change in air temperature. Changes in root development, nutrient uptake and nutrient-use efficiencies were interpreted as counterbalancing mechanisms for meeting nutrient requirements for plant growth in each situation. Most variables responded to an increase in resource availability in the order: N supply >soil temperature >CO(2).

  9. Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau

    PubMed Central

    Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

    2015-01-01

    The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil “fertile islands” were formed, and the “fertile islands” were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous

  10. Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau.

    PubMed

    Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

    2015-01-01

    The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil "fertile islands" were formed, and the "fertile islands" were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub.

  11. Effects of Litter and Nutrient Additions on Soil Carbon Cycling in a Tropical Forest

    NASA Astrophysics Data System (ADS)

    Cusack, D. F.; Halterman, S.; Turner, B. L.; Tanner, E.; Wright, S. J.

    2014-12-01

    Soil carbon (C) dynamics present one of the largest sources of uncertainty in global C cycle models, with tropical forest soils containing some of the largest terrestrial C stocks. Drastic changes in soil C storage and loss are likely to occur if global change alters plant net primary production (NPP) and/or nutrient availability in these ecosystems. We assessed the effects of litter removal and addition, as well as fertilization with nitrogen (N), phosphorus (P), and/or potassium (K), on soil C stocks in a tropical seasonal forest in Panama after ten and sixteen years, respectively. We used a density fractionation scheme to assess manipulation effects on rapidly and slowly cycling pools of C. Soil samples were collected in the wet and dry seasons from 0-5 cm and 5-10 cm depths in 15- 45x45 m plots with litter removal, 2x litter addition, and control (n=5), and from 32- 40x40 m fertilization plots with factorial additions of N, P, and K. We hypothesized that litter addition would increase all soil C fractions, but that the magnitude of the effect on rapidly-cycling C would be dampened by a fertilization effect. Results for the dry season show that the "free light" C fraction, or rapidly cycling soil C pool, was significantly different among the three litter treatments, comprising 5.1 ± 0.9 % of total soil mass in the litter addition plots, 2.7 ± 0.3 % in control plots, and 1.0 ± 0.1 % in litter removal plots at the 0-5cm depth (means ± one standard error, p < 0.05). Bulk soil C results are similar to observed changes in the rapidly cycling C pool for the litter addition and removal. Fertilization treatments on average diminished this C pool size relative to control plots, although there was substantial variability among fertilization treatments. In particular, addition of N and P together did not significantly alter rapidly cycling C pool sizes (4.1 ± 1.2 % of total soil mass) relative to controls (3.5 ± 0.4 %), whereas addition of P alone resulted in

  12. Fly ash application in nutrient poor agriculture soils: impact on methanotrophs population dynamics and paddy yields.

    PubMed

    Singh, Jay Shankar; Pandey, Vimal Chandra

    2013-03-01

    There are reports that the application of fly ash, compost and press mud or a combination thereof, improves plant growth, soil microbial communities etc. Also, fly ash in combination with farmyard manure or other organic amendments improves soil physico-chemical characteristics, rice yield and microbial processes in paddy fields. However, the knowledge about the impact of fly ash inputs alone or in combination with other organic amendments on soil methanotrophs number in paddy soils is almost lacking. We hypothesized that fly ash application at lower doses in paddy agriculture soil could be a potential amendment to elevate the paddy yields and methanotrophs number. Here we demonstrate the impact of fly ash and press mud inputs on number of methanotrophs, antioxidants, antioxidative enzymatic activities and paddy yields at agriculture farm. The impact of amendments was significant for methanotrophs number, heavy metal concentration, antioxidant contents, antioxidant enzymatic activities and paddy yields. A negative correlation was existed between higher doses of fly ash-treatments and methanotrophs number (R(2)=0.833). The content of antioxidants and enzymatic activities in leaves of higher doses fly ash-treated rice plants increased in response to stresses due to heavy metal toxicity, which was negatively correlated with rice grain yield (R(2)=0.944) and paddy straw yield (R(2)=0.934). A positive correlation was noted between heavy metals concentrations and different antioxidant and enzymatic activities across different fly ash treated plots.The data of this study indicate that heavy metal toxicity of fly ash may cause oxidative stress in the paddy crop and the antioxidants and related enzymes could play a defensive role against phytotoxic damages. We concluded that fly ash at lower doses with press mud seems to offer the potential amendments to improving soil methanotrophs population and paddy crop yields for the nutrient poor agriculture soils.

  13. Impact of Freezing and Thawing on Soil Oxygen Dynamics and Nutrient Fluxes

    NASA Astrophysics Data System (ADS)

    Milojevic, T.; Rezanezhad, F.; Van Cappellen, P.; Smeaton, C. M.; Parsons, C. T.

    2015-12-01

    Freeze-thaw cycles (FTCs) influence the physical properties, microbial activity, biogeochemistry, nutrient and carbon cycling in soils, and regulate subsurface oxygen (O2) availability, affecting greenhouse gas exchanges between soils and the atmosphere. The ability to monitor changes in O2 levels, which are indicative of aerobic and anaerobic conditions, is key to understanding how changes in the frequency and amplitude of freeze-thaw cycles affect a soil's geochemical conditions and microbial activity. In this study, a highly instrumented soil column experiment was designed to accurately simulate freeze-thaw dynamics under controlled conditions. This design allowed us to reproduce realistic, time- and depth-dependent temperature gradients in the soil column. Continuous O2 levels throughout the soil column were monitored using high-resolution, luminescence-based, Multi Fiber Optode (MuFO) microsensors. Image-processing techniques were used to convert light intensity of high-resolution digital images of the sensor-emitted light into O2 concentrations. Water samples from various depths in the column were collected to monitor pore water composition changes. Headspace gas measurements were used to derive the effluxes of CO2 and CH4 during the experiment. The results indicate that the pulse of oxygen introduced by thawing caused partial and temporal oxidation of previously reduced sulfur and nitrogen species, leading to concomitant changes in pore water SO42- and NO3- concentrations. Pulsed CO2 emission to the headspace was observed at the onset of thawing, indicating that a physical ice barrier had formed during frozen conditions and prevented gas exchange between the soil and atmosphere. CO2 emission was due to a combination of the physical release of gases dissolved in pore water and entrapped below the frozen zone and changing microbial respiration in response to electron acceptor variability (O2, NO3-, SO42-).

  14. Exogenous nutrients and carbon resource change the responses of soil organic matter decomposition and nitrogen immobilization to nitrogen deposition.

    PubMed

    He, Ping; Wan, Song-Ze; Fang, Xiang-Min; Wang, Fang-Chao; Chen, Fu-Sheng

    2016-03-29

    It is unclear whether exogenous nutrients and carbon (C) additions alter substrate immobilization to deposited nitrogen (N) during decomposition. In this study, we used laboratory microcosm experiments and (15)N isotope tracer techniques with five different treatments including N addition, N+non-N nutrients addition, N+C addition, N+non-N nutrients+C addition and control, to investigate the coupling effects of non-N nutrients, C addition and N deposition on forest floor decomposition in subtropical China. The results indicated that N deposition inhibited soil organic matter and litter decomposition by 66% and 38%, respectively. Soil immobilized (15)N following N addition was lowest among treatments. Litter (15)N immobilized following N addition was significantly higher and lower than that of combined treatments during the early and late decomposition stage, respectively. Both soil and litter extractable mineral N were lower in combined treatments than in N addition treatment. Since soil N immobilization and litter N release were respectively enhanced and inhibited with elevated non-N nutrient and C resources, it can be speculated that the N leaching due to N deposition decreases with increasing nutrient and C resources. This study should advance our understanding of how forests responds the elevated N deposition.

  15. Exogenous nutrients and carbon resource change the responses of soil organic matter decomposition and nitrogen immobilization to nitrogen deposition

    PubMed Central

    He, Ping; Wan, Song-Ze; Fang, Xiang-Min; Wang, Fang-Chao; Chen, Fu-Sheng

    2016-01-01

    It is unclear whether exogenous nutrients and carbon (C) additions alter substrate immobilization to deposited nitrogen (N) during decomposition. In this study, we used laboratory microcosm experiments and 15N isotope tracer techniques with five different treatments including N addition, N+non-N nutrients addition, N+C addition, N+non-N nutrients+C addition and control, to investigate the coupling effects of non-N nutrients, C addition and N deposition on forest floor decomposition in subtropical China. The results indicated that N deposition inhibited soil organic matter and litter decomposition by 66% and 38%, respectively. Soil immobilized 15N following N addition was lowest among treatments. Litter 15N immobilized following N addition was significantly higher and lower than that of combined treatments during the early and late decomposition stage, respectively. Both soil and litter extractable mineral N were lower in combined treatments than in N addition treatment. Since soil N immobilization and litter N release were respectively enhanced and inhibited with elevated non-N nutrient and C resources, it can be speculated that the N leaching due to N deposition decreases with increasing nutrient and C resources. This study should advance our understanding of how forests responds the elevated N deposition. PMID:27020048

  16. How do Gradients in Mineralogy and Nutrient Availability Alter Links between Microbial Growth Efficiency and Soil Carbon Storage?

    NASA Astrophysics Data System (ADS)

    Cusack, D. F.; Reed, S.; Wieder, W. R.; Taylor, P.; Cleveland, C. C.; Chadwick, O.; Vitousek, P.

    2013-12-01

    Our understanding of the terrestrial carbon (C) balance depends on understanding how C is (1) partitioned by heterotrophic microbes to biomass vs. respiration (i.e. growth efficiency), and (2) stabilized and stored in soils. Microbial growth efficiency may also strongly influence soil C stabilization if microbial biomass is a dominant source of C to organo-mineral associations. We hypothesized that natural variation in nutrient availability, as well as addition of scarce nutrients, may alter growth efficiency such that soil C storage on mineral surfaces increases without increasing C losses via heterotrophic respiration. We predicted that nutrient poor sites with relatively high reactive mineral availability (i.e. not C-saturated) have the largest potential to store new microbial biomass C. To test our hypothesis we used a microbial radionuclide-labeling technique combined with long- and short-term nutrient additions to follow C through soils that vary in mineral composition and background nutrient availability. We collected mineral soils (0-10 cm depth) from 8 Hawaiian sites that provided maximum variation in nutrient availability, reactive mineral content, and background soil C. Soils were sieved, pooled by site, and homogenized prior to a laboratory addition of radio (14C)-labeled sucrose, including nitrogen (N) and/or phosphorus (P) additions in full factorial design. We followed the 14C into microbial biomass growth, into soil mineral fractions, and into 14C-respiration (CO2) over 24 hours. We say effects of laboratory fertilization and ecosystem conditions on microbial growth efficiency and C losses via CO2. Across the 8 diverse soils, the full addition of 14C-sucrose+NP increased cumulative loss of 14C-CO2 relative to addition of 14C-sucrose alone (p<0.05), with the effect becoming more pronounced over the course of the experiment. Addition of 14C-sucrose with one additional nutrient (N or P) did not increase 14C-CO2 across the 8 soils relative to 14C

  17. Multiple soil nutrient competition between plants, microbes, and mineral surfaces: model development, parameterization, and example applications in several tropical forests

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Riley, W. J.; Tang, J.; Koven, C. D.

    2015-03-01

    Soil is a complex system where biotic (e.g., plant roots, micro-organisms) and abiotic (e.g., mineral surfaces) consumers compete for resources necessary for life (e.g., nitrogen, phosphorus). This competition is ecologically significant, since it regulates the dynamics of soil nutrients and controls aboveground plant productivity. Here we develop, calibrate, and test a nutrient competition model that accounts for multiple soil nutrients interacting with multiple biotic and abiotic consumers. As applied here for tropical forests, the Nutrient COMpetition model (N-COM) includes three primary soil nutrients (NH4+, NO3-, and POx (representing the sum of PO43-, HPO42-, and H2PO4-)) and five potential competitors (plant roots, decomposing microbes, nitrifiers, denitrifiers, and mineral surfaces). The competition is formulated with a quasi-steady-state chemical equilibrium approximation to account for substrate (multiple substrates share one consumer) and consumer (multiple consumers compete for one substrate) effects. N-COM successfully reproduced observed soil heterotrophic respiration, N2O emissions, free phosphorus, sorbed phosphorus, and free NH4+ at a tropical forest site (Tapajos). The overall model posterior uncertainty was moderately well constrained. Our sensitivity analysis revealed that soil nutrient competition was primarily regulated by consumer-substrate affinity rather than environmental factors such as soil temperature or soil moisture. Our results imply that the competitiveness (from most to least competitive) followed this order: (1) for NH4+, nitrifiers ~ decomposing microbes > plant roots, (2) for NO3-, denitrifiers ~ decomposing microbes > plant roots, (3) for POx, mineral surfaces > decomposing microbes ~ plant roots. Although smaller, plant relative competitiveness is of the same order of magnitude as microbes. We then applied the N-COM model to analyze field nitrogen and phosphorus perturbation experiments in two tropical forest sites (in Hawaii

  18. Effects of experimentally modified soil temperatures and nutrient availability on growth and mycorrhization of Pinus cembra at the alpine treeline

    NASA Astrophysics Data System (ADS)

    Gruber, Andreas; Peintner, Ursula; Wieser, Gerhard; Oberhuber, Walter

    2015-04-01

    Soil temperature affects litter decomposition, nutrient uptake, root growth and respiration and it is suggested that soil temperature has direct impact on tree growth at the alpine treeline. We have evaluated the impact of experimentally modified soil temperatures and nutrient availability on growth and mycorrhization of Pinus cembra at the treeline in the Central Eastern Alps (c. 2150 m a.s.l., Tyrol, Austria). Soil temperature in the rooting zone of naturally grown c. 25 year old trees (n=6 trees per treatment) was altered by shading and heat-trapping using non-transparent and glasshouse foils mounted c. 20 cm above soil surface. Additional trees were selected for a nitrogen fertilisation treatment and as controls. During the study period, mean soil temperatures at 10 cm depth were reduced by c. 3°C at the cooled vs. warmed plots. Soil moisture was not influenced due to soil water transport along the slope. Results revealed that changed soil temperatures did not significantly affect tree growth, gas exchange, needle nutrient content and specific leaf area. We also found no significant difference in degree of mycorrhization or number of mycorrhized root tips between treatments. On the other hand, nitrogen fertilization and a reduction of interspecific root competition led to significantly raised radial stem growth. Results indicate that tree growth at the selected study area was not limited by soil temperature, while interspecific competition for nutrients among trees and low stature vegetation (dwarf shrubs, grasses) had significant impact. Therefore, we suggest that root competition with alpine grassland and dwarf-shrub communities will hamper temperature driven advance of alpine treeline in the course of climate warming. Acknowledgements This work was funded by the Austrian Science Fund (FWF Project No. P22836-B16, 'Growth response of Pinus cembra to experimentally modified soil temperatures at the treeline').

  19. Predictable communities of soil bacteria in relation to nutrient concentration and successional stage in a laboratory culture experiment.

    PubMed

    Song, Woojin; Kim, Mincheol; Tripathi, Binu M; Kim, Hyoki; Adams, Jonathan M

    2016-06-01

    It is difficult to understand the processes that structure immensely complex bacterial communities in the soil environment, necessitating a simplifying experimental approach. Here, we set up a microcosm culturing experiment with soil bacteria, at a range of nutrient concentrations, and compared these over time to understand the relationship between soil bacterial community structure and time/nutrient concentration. DNA from each replicate was analysed using HiSeq2000 Illumina sequencing of the 16S rRNA gene. We found that each nutrient treatment, and each time point during the experiment, produces characteristic bacterial communities that occur predictably between replicates. It is clear that within the context of this experiment, many soil bacteria have distinct niches from one another, in terms of both nutrient concentration, and successional time point since a resource first became available. This fine niche differentiation may in part help to explain the coexistence of a diversity of bacteria in soils. In this experiment, we show that the unimodal relationship between nutrient concentration/time and species diversity often reported in communities of larger organisms is also evident in microbial communities.

  20. Soil profile distribution of phosphorus and other nutrients following wetland conversion to beef cattle pasture.

    PubMed

    Sigua, Gilbert C; Kang, Woo-Jun; Coleman, Sam W

    2006-01-01

    Largely influenced by the passage of the Swamp Land Act of 1849, many wetlands were lost in the coastal plain region of the southeastern United States, primarily as a result of drainage for agricultural activities. To better understand the chemical response of soils during wetland conversion, soil core samples were collected from the converted beef cattle pastures and from the natural wetland at Plant City, FL in the summers of 2002 and 2003. Data collected from the natural wetland sites were used as reference data to detect potential changes in soil properties associated with the conversion of wetlands to improved beef cattle (Bos taurus) pastures from 1940 to 2003. The average concentration of total phosphorus (TP) in pasture soils (284 mg kg(-1)) was significantly (p soils (688 mg kg(-1)). Compared with the adjoining natural wetlands, the beef cattle pasture soils, 63 yr after being drained exhibited: (1) a decrease in TOC (-172 g kg(-1)), TN (-10 g kg(-1)), K (-0.7 mg kg(-1)), and Al (-130 mg kg(-1)); (2) an increase in soil pH (+1.8), Ca (+88 mg kg(-1)), Mg (+7.5 mg kg(-1)), Mn (+0.3 mg kg(-1)), and Fe (+6.9 mg kg(-1)); and (3) no significant change in Na, Zn, and Cu. Wetland soils had higher concentrations (mg kg(-1)) of Al-P (435), CaMg-P (42), FeMn-P (43), and Org-P (162) than those of 172, 11, 11, and 84 mg kg(-1), respectively, found in the pasture soils. The levels of water-soluble P and KCl-bound P were comparable between wetland and pasture soils in 2003. Results of this study therefore suggest that wetland conversion to beef cattle pastures did not function as a source of nutrients, especially P and N, even with manure and urine additions due to the presence of grazing cattle.

  1. [Effects of plateau zokor disturbance and restoration years on soil nutrients and microbial functional diversity in alpine meadow].

    PubMed

    Hu, Lei; Ade, Lu-ji; Zi, Hong-biao; Wang, Chang-ting

    2015-09-01

    To explore the dynamic process of restoration succession in degraded alpine meadow that had been disturbed by plateau zokors in the eastern Tibetan Plateau, we examined soil nutrients and microbial functional diversity using conventional laboratory analysis and the Biolog-ECO microplate method. Our study showed that: 1) The zokors disturbance significantly reduced soil organic matter, total nitrogen, available nitrogen and phosphorus contents, but had no significant effects on soil total phosphorus and potassium contents; 2) Soil microbial carbon utilization efficiency, values of Shannon, Pielou and McIntosh indexes increased with alpine meadow restoration years; 3) Principal component analysis (PCA) showed that carbohydrates and amino acids were the main carbon sources for maintaining soil microbial community; 4) Redundancy analysis ( RDA) indicated that soil pH, soil organic matter, total nitrogen, available nitrogen, and total potassium were the main factors influencing the metabolic rate of soil microbial community and microbial functional diversity. In summary, variations in soil microbial functional diversity at different recovery stages reflected the microbial response to aboveground vegetation, soil microbial composition and soil nutrients.

  2. Monitoring Citrus Soil Moisture and Nutrients Using an IoT Based System

    PubMed Central

    Zhang, Xueyan; Zhang, Jianwu; Li, Lin; Zhang, Yuzhu; Yang, Guocai

    2017-01-01

    Chongqing mountain citrus orchard is one of the main origins of Chinese citrus. Its planting terrain is complex and soil parent material is diverse. Currently, the citrus fertilization, irrigation and other management processes still have great blindness. They usually use the same pattern and the same formula rather than considering the orchard terrain features, soil differences, species characteristics and the state of tree growth. With the help of the ZigBee technology, artificial intelligence and decision support technology, this paper has developed the research on the application technology of agricultural Internet of Things for real-time monitoring of citrus soil moisture and nutrients as well as the research on the integration of fertilization and irrigation decision support system. Some achievements were obtained including single-point multi-layer citrus soil temperature and humidity detection wireless sensor nodes and citrus precision fertilization and irrigation management decision support system. They were applied in citrus base in the Three Gorges Reservoir Area. The results showed that the system could help the grower to scientifically fertilize or irrigate, improve the precision operation level of citrus production, reduce the labor cost and reduce the pollution caused by chemical fertilizer. PMID:28241488

  3. Monitoring Citrus Soil Moisture and Nutrients Using an IoT Based System.

    PubMed

    Zhang, Xueyan; Zhang, Jianwu; Li, Lin; Zhang, Yuzhu; Yang, Guocai

    2017-02-23

    Chongqing mountain citrus orchard is one of the main origins of Chinese citrus. Its planting terrain is complex and soil parent material is diverse. Currently, the citrus fertilization, irrigation and other management processes still have great blindness. They usually use the same pattern and the same formula rather than considering the orchard terrain features, soil differences, species characteristics and the state of tree growth. With the help of the ZigBee technology, artificial intelligence and decision support technology, this paper has developed the research on the application technology of agricultural Internet of Things for real-time monitoring of citrus soil moisture and nutrients as well as the research on the integration of fertilization and irrigation decision support system. Some achievements were obtained including single-point multi-layer citrus soil temperature and humidity detection wireless sensor nodes and citrus precision fertilization and irrigation management decision support system. They were applied in citrus base in the Three Gorges Reservoir Area. The results showed that the system could help the grower to scientifically fertilize or irrigate, improve the precision operation level of citrus production, reduce the labor cost and reduce the pollution caused by chemical fertilizer.

  4. Elemental uptake and distribution of nutrients in avocado mesocarp and the impact of soil quality.

    PubMed

    Reddy, Mageshni; Moodley, Roshila; Jonnalagadda, Sreekanth B

    2014-07-01

    The distribution of 14 elements (both essential and non-essential) in the Hass and Fuerte cultivars of avocados grown at six different sites in KwaZulu-Natal, South Africa, was investigated. Soils from the different sites were concurrently analysed for elemental concentration (both total and exchangeable), pH, organic matter and cation exchange capacity. In both varieties of the fruit, concentrations of the elements Cd, Co, Cr, Pb and Se were extremely low with the other elements being in decreasing order of Mg > Ca > Fe > Al > Zn > Mn > Cu > Ni > As. Nutritionally, avocados were found to be a good dietary source of the micronutrients Cu and Mn. In soil, Pb concentrations indicated enrichment (positive geoaccumuluation indices) but this did not influence uptake of the metal by the plant. Statistical analysis was done to evaluate the impact of soil quality parameters on the nutrient composition of the fruits. This analysis indicated the prevalence of complex metal interactions at the soil-plant interface that influenced their uptake by the plant. However, the plant invariably controlled metal uptake according to metabolic needs as evidenced by their accumulation and exclusion.

  5. Wolves modulate soil nutrient heterogeneity and foliar nitrogen by configuring the distribution of ungulate carcasses.

    PubMed

    Bump, Joseph K; Peterson, Rolf O; Vucetich, John A

    2009-11-01

    Mechanistic links between top terrestrial predators and biogeochemical processes remain poorly understood. Here we demonstrate that large carnivores configure landscape heterogeneity through prey carcass distribution. A 50-year record composed of > 3600 moose carcasses from Isle Royale National Park, Michigan, USA, showed that wolves modulate heterogeneity in soil nutrients, soil microbes, and plant quality by clustering prey carcasses over space. Despite being well utilized by predators, moose carcasses resulted in elevated soil macronutrients and microbial biomass, shifts in soil microbial composition, and elevated leaf nitrogen for at least 2-3 years at kill sites. Wolf-killed moose were deposited in some regions of the study landscape at up to 12x the rate of deposition in other regions. Carcass density also varied temporally, changing as much as 19-fold in some locations during the 50-year study period. This variation arises, in part, directly from variation in wolf hunting behavior. This study identifies a top terrestrial predator as a mechanism generating landscape heterogeneity, demonstrating reciprocal links between large carnivore behavior and ecosystem function.

  6. Effect of nanosilica and silicon sources on plant growth promoting rhizobacteria, soil nutrients and maize seed germination.

    PubMed

    Karunakaran, Gopalu; Suriyaprabha, Rangaraj; Manivasakan, Palanisamy; Yuvakkumar, Rathinam; Rajendran, Venkatachalam; Prabu, Periyasamy; Kannan, Narayanasamy

    2013-09-01

    The study was aimed at evaluating the effect of nanosilica and different sources of silicon on soil properties, total bacterial population and maize seed germination. Nanosilica was synthesised using rice husk and characterised. Silica powder was amorphous (50 nm) with >99.9% purity. Sodium silicate treated soil inhibited plant growth promoting rhizobacteria in contrast to nanosilica and other bulk sources. Surface property and effect of soil nutrient content of nanosilica treatment were improved. Colony forming unit (CFU) was doubled in the presence of nanosilica from 4 × 105 CFU (control) to 8 × 105 CFU per gram of soil. The silica and protein content of bacterial biomass clearly showed an increase in uptake of silica with an increase in nanosilica concentration. Nanosilica promoted seed germination percentage (100%) in maize than conventional Si sources. These studies show that nanosilica has favourable effect on beneficial bacterial population and nutrient value of soil.

  7. [Soil nutrient accumulation and its affecting factors during vegetation succession in karst peak-cluster depressions of South China].

    PubMed

    Zhang, Wei; Wang, Ke-Lin; Liu, Su-Juan; Ye, Ying-Ying; Pan, Fu-Jing; He, Xu-Yang

    2013-07-01

    Taking the typical karst peak-cluster depressions in Huanjiang County of northwest Guangxi as the objects, and by using the method of replacing time with space, an analysis was made on the dynamic changes of top soil (0-15 cm) nutrients and their dominant controlling factors during the process of vegetation succession. With the positive succession of vegetation (herb-shrub-secondary forest-primary forest), the soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents increased significantly, with the soil SOC, TN, and TP increased from 29.1 g x kg(-1), 2.48 g x kg(-1), and 0.72 g x kg(-1) in herb community to 73.9 g x kg(-1), 8.10 g x kg(-1), and 1.6 g x kg(-1) in primary forest, respectively, which indicated that the positive succession of vegetation was helpful to the soil nutrient accumulation. The soil cation exchange capacity (CEC) had close relationships with the soil SOC and TN, being the primary controlling factor for the accumulation of the soil C and N. The litter P content, C/P ratio, and N/P ratio were the major factors controlling the P accumulation in the topsoil. The litters higher P content and N/P ratio and smaller C/P ratio were helpful for the P accumulation. Topographic indices (slope, aspect, and rock exposure ratio) had little effects on the soil nutrients.

  8. Effect of nutrient deficiencies on in vitro Th1 and Th2 cytokine response of peripheral blood mononuclear cells to Plasmodium falciparum infection

    PubMed Central

    2010-01-01

    Background An appropriate balance between pro-inflammatory and anti-inflammatory cytokines that mediate innate and adaptive immune responses is required for effective protection against human malaria and to avoid immunopathology. In malaria endemic countries, this immunological balance may be influenced by micronutrient deficiencies. Methods Peripheral blood mononuclear cells from Tanzanian preschool children were stimulated in vitro with Plasmodium falciparum-parasitized red blood cells to determine T-cell responses to malaria under different conditions of nutrient deficiencies and malaria status. Results The data obtained indicate that zinc deficiency is associated with an increase in TNF response by 37%; 95% CI: 14% to 118% and IFN-γ response by 74%; 95% CI: 24% to 297%. Magnesium deficiency, on the other hand, was associated with an increase in production of IL-13 by 80%; 95% CI: 31% to 371% and a reduction in IFN-γ production. These results reflect a shift in cytokine profile to a more type I cytokine profile and cell-cell mediated responses in zinc deficiency and a type II response in magnesium deficiency. The data also reveal a non-specific decrease in cytokine production in children due to iron deficiency anaemia that is largely associated with malaria infection status. Conclusions The pathological sequels of malaria potentially depend more on the balance between type I and type II cytokine responses than on absolute suppression of these cytokines and this balance may be influenced by a combination of micronutrient deficiencies and malaria status. PMID:20546583

  9. Relative Roles of Soil Moisture, Nutrient Supply, Depth, and Mechanical Impedance in Determining Composition and Structure of Wisconsin Prairies

    PubMed Central

    Wernerehl, Robert W.; Givnish, Thomas J.

    2015-01-01

    Ecologists have long classified Midwestern prairies based on compositional variation assumed to reflect local gradients in moisture availability. The best known classification is based on Curtis’ continuum index (CI), calculated using the presence of indicator species thought centered on different portions of an underlying moisture gradient. Direct evidence of the extent to which CI reflects differences in moisture availability has been lacking, however. Many factors that increase moisture availability (e.g., soil depth, silt content) also increase nutrient supply and decrease soil mechanical impedance; the ecological effects of the last have rarely been considered in any ecosystem. Decreased soil mechanical impedance should increase the availability of soil moisture and nutrients by reducing the root costs of retrieving both. Here we assess the relative importance of soil moisture, nutrient supply, and mechanical impedance in determining prairie composition and structure. We used leaf δ13C of C3 plants as a measure of growing-season moisture availability, cation exchange capacity (CEC) x soil depth as a measure of mineral nutrient availability, and penetrometer data as a measure of soil mechanical impedance. Community composition and structure were assessed in 17 remnant prairies in Wisconsin which vary little in annual precipitation. Ordination and regression analyses showed that δ13C increased with CI toward “drier” sites, and decreased with soil depth and % silt content. Variation in δ13C among remnants was 2.0‰, comparable to that along continental gradients from ca. 500–1500 mm annual rainfall. As predicted, LAI and average leaf height increased significantly toward “wetter” sites. CI accounted for 54% of compositional variance but δ13C accounted for only 6.2%, despite the strong relationships of δ13C to CI and CI to composition. Compositional variation reflects soil fertility and mechanical impedance more than moisture availability. This

  10. Relative Roles of Soil Moisture, Nutrient Supply, Depth, and Mechanical Impedance in Determining Composition and Structure of Wisconsin Prairies.

    PubMed

    Wernerehl, Robert W; Givnish, Thomas J

    2015-01-01

    Ecologists have long classified Midwestern prairies based on compositional variation assumed to reflect local gradients in moisture availability. The best known classification is based on Curtis' continuum index (CI), calculated using the presence of indicator species thought centered on different portions of an underlying moisture gradient. Direct evidence of the extent to which CI reflects differences in moisture availability has been lacking, however. Many factors that increase moisture availability (e.g., soil depth, silt content) also increase nutrient supply and decrease soil mechanical impedance; the ecological effects of the last have rarely been considered in any ecosystem. Decreased soil mechanical impedance should increase the availability of soil moisture and nutrients by reducing the root costs of retrieving both. Here we assess the relative importance of soil moisture, nutrient supply, and mechanical impedance in determining prairie composition and structure. We used leaf δ13C of C3 plants as a measure of growing-season moisture availability, cation exchange capacity (CEC) x soil depth as a measure of mineral nutrient availability, and penetrometer data as a measure of soil mechanical impedance. Community composition and structure were assessed in 17 remnant prairies in Wisconsin which vary little in annual precipitation. Ordination and regression analyses showed that δ13C increased with CI toward "drier" sites, and decreased with soil depth and % silt content. Variation in δ13C among remnants was 2.0‰, comparable to that along continental gradients from ca. 500-1500 mm annual rainfall. As predicted, LAI and average leaf height increased significantly toward "wetter" sites. CI accounted for 54% of compositional variance but δ13C accounted for only 6.2%, despite the strong relationships of δ13C to CI and CI to composition. Compositional variation reflects soil fertility and mechanical impedance more than moisture availability. This study is the

  11. Peat humic substances enriched with nutrients for agricultural applications: competition between nutrients and non-essential metals present in tropical soils.

    PubMed

    Botero, Wander Gustavo; de Oliveira, Luciana Camargo; Rocha, Julio Cesar; Rosa, Andre Henrique; Dos Santos, Ademir

    2010-05-15

    Improved agricultural productivity, and reduction of environmental impacts, require studies of the interactions between different soil components. Fertilizers marketed as "organic" or "natural", such as peats or humic substances (HS) extracted from peats, are enriched with macro and micronutrients that, according to the manufacturers, are released to the plant in accordance with its needs. This work investigates the complexation capacity of HS for macro and micronutrient metal species, considering the competition, for HS complexation sites, between non-essential metals (aluminium and lead), present in the soil, and the nutrients. Humic substances were found to possess strong affinities for Pb(II) and Al(III), forming stable complexes, with concomitant release of complexed nutrients. Although HS are already used commercially as organic fertilizers, further studies of methods of HS enrichment, aimed at avoiding losses, are highly desirable from environmental and economic perspectives.

  12. Beneficial cyanobacteria and eubacteria synergistically enhance bioavailability of soil nutrients and yield of okra.

    PubMed

    Manjunath, Mallappa; Kanchan, Amrita; Ranjan, Kunal; Venkatachalam, Siddarthan; Prasanna, Radha; Ramakrishnan, Balasubramanian; Hossain, Firoz; Nain, Lata; Shivay, Yashbir Singh; Rai, Awadhesh Bahadur; Singh, Bijendra

    2016-02-01

    Microorganisms in the rhizosphere mediate the cycling of nutrients, their enhanced mobilisation and facilitate their uptake, leading to increased root growth, biomass and yield of plants. We examined the promise of beneficial cyanobacteria and eubacteria as microbial inoculants, applied singly or in combination as consortia or biofilms, to improve growth and yields of okra. Interrelationships among the microbial activities and the micro/macro nutrient dynamics in soils and okra yield characteristics were assessed along with the changes in the soil microbiome. A significant effect of microbial inoculation on alkaline phosphatase activity was recorded both at the mid-crop and harvest stages. Microbial biomass carbon values were highest due to the Anabaena sp. - Providencia sp. (CR1 + PR3) application. The yield of okra ranged from 444.6-478.4 g(-1) plant and a positive correlation (0.69) recorded between yield and root weight. The application of Azotobacter led to the highest root weight and yield. The concentration of Zn at mid-crop stage was 60-70% higher in the Azotobacter sp. and Calothrix sp. inoculated soils, as compared to uninoculated control. Iron concentration in soil was more than 2-3 folds higher than control at the mid-crop stage, especially due to the application of Anabaena-Azotobacter biofilm and Azotobacter sp. Both at the mid-crop and harvest stages, the PCR-DGGE profiles of eubacterial communities were similar among the uninoculated control, the Anabaena sp. - Providencia sp. (CW1 + PW5) and the Anabaena-Azotobacter biofilm treatments. Although the profiles of the Azotobacter, Calothrix and CR1 + PR3 treatments were identical at these stages of growth, the profile of CR1 + PR3 was clearly distinguishable. The performance of the inoculants, particularly Calothrix (T6) and consortium of Anabaena and Providencia (CR1 + PR3; T5), in terms of microbiological and nutrient data, along with generation of distinct PCR-DGGE profiles suggested their

  13. Influence of Organic Amendment and Compaction on Nutrient Dynamics in a Saturated Saline-Sodic Soil from the Riparian Zone.

    PubMed

    Miller, J J; Bremer, E; Curtis, T

    2016-07-01

    Cattle grazing in wet riparian pastures may influence nutrient dynamics due to nutrient deposition in feces and urine, soil compaction, and vegetation loss. We conducted a lab incubation study with a saline-sodic riparian soil to study nutrient (N, P, S, Fe, Mn, Cu, and Zn) dynamics in soil pore water using Plant Root Simulator (PRS) probes and release of nutrients into the overlying ponded water during flooding. The treatment factors were organic amendment (manure, roots, and unamended control), compaction (compacted, uncompacted), and burial time (3, 7, and 14 d). Amendment treatment had the greatest impact on nutrient dynamics, followed by burial time, whereas compaction had little impact. The findings generally supported our hypothesis that organic amendments should first increase nitrate loss, then increase Mn mobility, then Fe mobility and associated release of P, and finally increase sulfate loss. Declines in nitrate due to amendment addition were small because nitrate was at low levels in all treatments due to high denitrification potential instead of being released to soil pore water or overlying water. Addition of organic amendment strongly increased Mn and Fe concentrations in overlying water and of adsorbed Fe on PRS probes but only increased Mn on PRS probes on Day 3 due to subsequent displacement from ion exchange membranes. Transport of P to overlying water was increased by organic amendment addition but less so for manure than roots despite higher P on PRS probes. The findings showed that saline-sodic soils in riparian zones are generally a nutrient source for P and are a nutrient sink for N as measured using PRS probes after 3 to 7 d of flooding.

  14. Aeolian dust in Colorado Plateau soils: Nutrient inputs and recent change in source

    USGS Publications Warehouse

    Reynolds, R.; Belnap, Jayne; Lamothe, Paul; Luiszer, Fred

    2001-01-01

    Aeolian dust (windblown silt and clay) is an important component in arid-land ecosystems because it may contribute to soil formation and furnish essential nutrients. Few geologic surfaces, however, have been characterized with respect to dust-accumulation history and resultant nutrient enrichment. We have developed a combination of methods to identify the presence of aeolian dust in arid regions and to evaluate the roles of this dust in ecosystem processes. Unconsolidated sandy sediment on isolated surfaces in the Canyonlands region of the Colorado Plateau differs greatly in mineralogical and chemical composition from associated bedrock, mainly aeolian sandstone. Detrital magnetite in the surficial deposits produces moderately high values of magnetic susceptibility, but magnetite is absent in nearby bedrock. A component of the surficial deposits must be aeolian to account for the abundance of magnetite, which formed originally in far-distant igneous rocks. Particle-size analysis suggests that the aeolian dust component is typically as much as 20a??30%. Dust inputs have enriched the sediments in many elements, including P, Mg, Na, K, and Mo, as well as Ca, at sites where bedrock lacks calcite cement. Soil-surface biologic crusts are effective dust traps that apparently record a change in dust sources over the past several decades. Some of the recently fallen dust may result from human disturbance of land surfaces that are far from the Canyonlands, such as the Mojave Desert. Some land-use practices in the study area have the potential to deplete soil fertility by means of wind-erosion removal of aeolian silt.

  15. Trait-based community assembly of understory palms along a soil nutrient gradient in a lower montane tropical forest.

    PubMed

    Andersen, Kelly M; Endara, Maria Jose; Turner, Benjamin L; Dalling, James W

    2012-02-01

    Two opposing niche processes have been shown to shape the relationship between ecological traits and species distribution patterns: habitat filtering and competitive exclusion. Habitat filtering is expected to select for similar traits among coexisting species that share similar habitat conditions, whereas competitive exclusion is expected to limit the ecological similarity of coexisting species leading to trait differentiation. Here, we explore how functional traits vary among 19 understory palm species that differ in their distribution across a gradient of soil resource availability in lower montane forest in western Panama. We found evidence that habitat filtering influences species distribution patterns and shifts community-wide and intraspecific trait values. Differences in trait values among sites were more strongly related to soil nutrient availability than to variation in light or rainfall. Soil nutrient availability explained a significant amount of variation in site mean trait values for 4 of 15 functional traits. Site mean values of leaf nitrogen and phosphorus increased 37 and 64%, respectively, leaf carbon:nitrogen decreased 38%, and specific leaf area increased 29% with increasing soil nutrient availability. For Geonoma cuneata, the only species occurring at all sites, leaf phosphorus increased 34% and nitrogen:phosphorus decreased 42% with increasing soil nutrients. In addition to among-site variation, most morphological and leaf nutrient traits differed among coexisting species within sites, suggesting these traits may be important for niche differentiation. Hence, a combination of habitat filtering due to turnover in species composition and intraspecific variation along a soil nutrient gradient and site-specific niche differentiation among co-occurring species influences understory palm community structure in this lower montane forest.

  16. Can Tomato Inoculation with Trichoderma Compensate Yield and Soil Health Deficiency due to Soil Salinity?

    NASA Astrophysics Data System (ADS)

    Wagner, Karl; Apostolakis, Antonios; Daliakopoulos, Ioannis; Tsanis, Ioannis

    2016-04-01

    Soil salinity is a major soil degradation threat, especially for arid coastal environments where it hinders agricultural production and soil health. Protected horticultural crops in the Mediterranean region, typically under deficit irrigation and intensive cultivation practices, have to cope with increasing irrigation water and soil salinization. This study quantifies the beneficial effects of the Trichoderma harzianum (TH) on the sustainable production of Solanum lycopersicum (tomato), a major greenhouse crop of the RECARE project Case Study in Greece, the semi-arid coastal Timpaki basin in south-central Crete. 20 vigorous 20-day-old Solanum lycopersicum L. cv Elpida seedlings are treated with TH fungi (T) or without (N) and transplanted into 35 L pots under greenhouse conditions. Use of local planting soil with initial Electrical Conductivity (ECe) 1.8 dS m-1 and local cultivation practices aim to simulate the prevailing conditions at the Case Study. In order to simulate seawater intrusion affected irrigation, plants are drip irrigated with two NaCl treatments: slightly (S) saline (ECw = 1.1 dS m-1) and moderately (M) saline water (ECw = 3.5 dS m-1), resulting to very high and excessively high ECe, respectively. Preliminary analysis of below and aboveground biomass, soil quality, salinity, and biodiversity indicators, suggest that TH pre-inoculation of tomato plants at both S and M treatments improve yield, soil biodiversity and overall soil health.

  17. Nutrient management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient management has been defined as “the science and art directed to link soil, crop, weather and hydrologic factors with cultural, irrigation and soil and water conservation practices to achieve the goals of optimizing nutrient use efficiency, yields, crop quality, and economic returns, while r...

  18. Soil amendment using poplar woodchips to enhance the treatment of wastewater-originated nutrients.

    PubMed

    Meffe, Raffaella; de Miguel, Ángel; Martínez Hernández, Virtudes; Lillo, Javier; de Bustamante, Irene

    2016-09-15

    Vegetation filters, a nature based wastewater regeneration technology, have been reported as a feasible solution for small municipalities and scattered populations with limited access to sewage networks. However even when such a treatment is properly planned, the leaching of contaminants through the unsaturated zone may occur. The amendment of soil with a readily-labile source of carbon is supposed to ameliorate the removal of contaminants by stimulating microbial activity and enhancing sorption processes. In this study, lab-scale leaching column experiments were carried out to explore if the addition of woodchips to the soil could be a feasible strategy to be integrated in a vegetation filter. Two different types of arrangement of soil and woodchips layers were tested. The soil was collected from an operating vegetation filter treating wastewater of an office building characterised by a high nutrient load. Daily pulse of synthetic wastewater were applied into the columns and effluent samples were collected and analyzed for major ions, total nitrogen (NT), total phosphorous (PT) and chemical oxygen demand (COD). By the end of the experiment, NT, NO3-N and PT soil contents were also measured. Results indicate that amendments with woodchips enhance the elimination of wastewater-originated contaminants. NT removal in the columns with woodchips reaches a value of 99.4%. The main processes responsible for this elimination are NH4-N sorption and nitrification/denitrification. This latter fostered by the reduced redox conditions due to the enhanced microbial activity. High removal of PT (99%) is achieved independently of the woodchips presence due to retention and/or precipitation phenomena. The COD removal efficiency is not affected by the presence of the woodchips. The leaching of organic carbon occurs only during the experimental start-up period.

  19. Comparison between measurements of black carbon, charcoal and associated nutrients in western Amazonan soils

    NASA Astrophysics Data System (ADS)

    Zimmerman, A. R.; McMichael, C.; Hanlon, C.; Bush, M. B.

    2011-12-01

    To construct fire and climate history and human occupation records from soils and lake sediment profiles, climatologists and anthropologists have traditionally measured charcoal abundances by microscopic image analysis. In contrast, geochemists have developed methods of black carbon (BC) quantification using chemical extraction. We compared charcoal (>0.5 mm particle size) versus BC (measured via the CTO-340 method of Kuhlbusch, 1995) in multiple soil profiles from four western Amazon regions with evidence of pre-Columbian occupation. A secondary goal of this project was to understand the relative influence of climate and humans in the fire and ecological history of the Amazon. BC concentration in soils of the Amazon varied widely from an average of 0.5 mg g 1 in cores around Lake Gentry (southeastern Peru) to 5.5 mg g 1 around Lake Ayauchi (southeastern Ecuador), corresponding to the evidence of greater land use around the latter. Surprising, BC concentrations in habitation horizon soils at Quistococha, near Iquitos, Peru were similar to Lake Gentry, averaging about 0.6 mg g 1. However, BC as a percent of soil organic carbon (SOC) was much more uniform with an average of 12.0, 13.3, 14.6, and 13.0% in Quistococha, Gentry, Ayauchi, and Los Amigos (central-eastern Peru) soils, respectively, suggesting that the same processes that concentrate SOC also concentrate BC. BC may act to protect SOC via sorption or produce SOC via microbial community enhancement. These findings also show that BC is not regionally enriched as it might be were climate to be a predominant factor in BC production, and seem to track land use more closely. Charcoal and BC concentrations were linearly correlated in only about half the soil profiles and neither BC nor charcoal were consistently correlated with chemical anthropogenic indicators such as P or Ca within soil profiles or specific regions. However, there was a statistical covariance between each of these parameters suggesting that each

  20. MicroRNA expression profile in common bean (Phaseolus vulgaris) under nutrient deficiency stresses and manganese toxicity.

    PubMed

    Valdés-López, Oswaldo; Yang, S Samuel; Aparicio-Fabre, Rosaura; Graham, Peter H; Reyes, José Luis; Vance, Carroll P; Hernández, Georgina

    2010-08-01

    *MicroRNAs (miRNAs) play a pivotal role in post-transcriptional regulation of gene expression in plants. Information on miRNAs in legumes is as yet scarce. This work investigates miRNAs in an agronomically important legume, common bean (Phaseolus vulgaris). *A hybridization approach employing miRNA macroarrays - printed with oligonucleotides complementary to 68 known miRNAs - was used to detect miRNAs in the leaves, roots and nodules of control and nutrient-stressed (phosphorus, nitrogen, or iron deficiency; acidic pH; and manganese toxicity) common bean plants. *Thirty-three miRNAs were expressed in control plants and another five were only expressed under stress conditions. The miRNA expression ratios (stress:control) were evaluated using principal component and hierarchical cluster analyses. A group of miRNAs responded to nearly all stresses in the three organs analyzed. Other miRNAs showed organ-specific responses. Most of the nodule-responsive miRNAs showed up-regulation. miRNA blot expression analysis confirmed the macroarray results. Novel miRNA target genes were proposed for common bean and the expression of selected targets was evaluated by quantitative reverse transcriptase-polymerase chain reaction. *In addition to the detection of previously reported stress-responsive miRNAs, we discovered novel common bean stress-responsive miRNAs, for manganese toxicity. Our data provide a foundation for evaluating the individual roles of miRNAs in common bean.

  1. The role of nutrients in the biodegradation of 2,4,6-trinitrotoluene in liquid and soil.

    PubMed

    Muter, Olga; Potapova, Katrina; Limane, Baiba; Sproge, Kristine; Jakobsone, Ida; Cepurnieks, Guntis; Bartkevics, Vadims

    2012-05-15

    The widely used explosive 2,4,6-trinitrotoluene (TNT) has residues that are potentially explosive, toxic, and mutagenic. TNT and other explosives can be degraded by microorganisms; however, biostimulation is needed for process efficiency. To investigate the effectiveness of using biostimulation to degrade TNT, we added varying concentrations of a nutrient amendment consisting of inorganic salts, plant extracts, and molasses to soil and liquid media. For the inoculum we used a consortium of bacteria AM 06 that had exhibited the ability to degrade TNT and which had been previously isolated from explosives-contaminated soils. Phylogenetically, the clones clustered into seven different genera: Klebsiella, Raoultella, Serratia, Stenotrophomonas, Pseudoxanthomonas, Achromobacter and Pseudomonas. The addition of AM 06 consortium to a liquid environment along with 100% nutrient amendment decreased the amount of TNT (and its degradation products) by up to 90% after 14 days incubation. At the total amount of TNT was less than 100 mg/l, the concentration of TNT did not influence the amount of sugar consumed by the bacteria consortium. In soil media, the TNT degradation process was dependent on the concentration of nutrient amendment added. At higher initial concentrations of TNT (500 mg/kg), bioaugmentation (i.e., addition of bacteria inoculum) had a demonstrated effect, especially when nutrient concentrations of 50% and 100% were added to the soil. Findings of this study could further the understanding of the TNT biodegradation processes in water and soil and provide for optimization of the technological conditions for bioremediation.

  2. Impacts of Soil and Water Conservation Practices on Crop Yield, Run-off, Soil Loss and Nutrient Loss in Ethiopia: Review and Synthesis.

    PubMed

    Adimassu, Zenebe; Langan, Simon; Johnston, Robyn; Mekuria, Wolde; Amede, Tilahun

    2017-01-01

    Research results published regarding the impact of soil and water conservation practices in the highland areas of Ethiopia have been inconsistent and scattered. In this paper, a detailed review and synthesis is reported that was conducted to identify the impacts of soil and water conservation practices on crop yield, surface run-off, soil loss, nutrient loss, and the economic viability, as well as to discuss the implications for an integrated approach and ecosystem services. The review and synthesis showed that most physical soil and water conservation practices such as soil bunds and stone bunds were very effective in reducing run-off, soil erosion and nutrient depletion. Despite these positive impacts on these services, the impact of physical soil and water conservation practices on crop yield was negative mainly due to the reduction of effective cultivable area by soil/stone bunds. In contrast, most agronomic soil and water conservation practices increase crop yield and reduce run-off and soil losses. This implies that integrating physical soil and water conservation practices with agronomic soil and water conservation practices are essential to increase both provisioning and regulating ecosystem services. Additionally, effective use of unutilized land (the area occupied by bunds) by planting multipurpose grasses and trees on the bunds may offset the yield lost due to a reduction in planting area. If high value grasses and trees can be grown on this land, farmers can harvest fodder for animals or fuel wood, both in scarce supply in Ethiopia. Growing of these grasses and trees can also help the stability of the bunds and reduce maintenance cost. Economic feasibility analysis also showed that, soil and water conservation practices became economically more viable if physical and agronomic soil and water conservation practices are integrated.

  3. Biochar from sugarcane filtercake reduces soil CO2 emissions relative to raw residue and improves water retention and nutrient availability in a highly-weathered tropical soil.

    PubMed

    Eykelbosh, Angela Joy; Johnson, Mark S; Santos de Queiroz, Edmar; Dalmagro, Higo José; Guimarães Couto, Eduardo

    2014-01-01

    In Brazil, the degradation of nutrient-poor Ferralsols limits productivity and drives agricultural expansion into pristine areas. However, returning agricultural residues to the soil in a stabilized form may offer opportunities for maintaining or improving soil quality, even under conditions that typically promote carbon loss. We examined the use of biochar made from filtercake (a byproduct of sugarcane processing) on the physicochemical properties of a cultivated tropical soil. Filtercake was pyrolyzed at 575°C for 3 h yielding a biochar with increased surface area and porosity compared to the raw filtercake. Filtercake biochar was primarily composed of aromatic carbon, with some residual cellulose and hemicellulose. In a three-week laboratory incubation, CO2 effluxes from a highly weathered Ferralsol soil amended with 5% biochar (dry weight, d.w.) were roughly four-fold higher than the soil-only control, but 23-fold lower than CO2 effluxes from soil amended with 5% (d.w.) raw filtercake. We also applied vinasse, a carbon-rich liquid waste from bioethanol production typically utilized as a fertilizer on sugarcane soils, to filtercake- and biochar-amended soils. Total CO2 efflux from the biochar-amended soil in response to vinasse application was only 5% of the efflux when vinasse was applied to soil amended with raw filtercake. Furthermore, mixtures of 5 or 10% biochar (d.w.) in this highly weathered tropical soil significantly increased water retention within the plant-available range and also improved nutrient availability. Accordingly, application of sugarcane filtercake as biochar, with or without vinasse application, may better satisfy soil management objectives than filtercake applied to soils in its raw form, and may help to build soil carbon stocks in sugarcane-cultivating regions.

  4. Impacts of Soil and Water Conservation Practices on Crop Yield, Run-off, Soil Loss and Nutrient Loss in Ethiopia: Review and Synthesis

    NASA Astrophysics Data System (ADS)

    Adimassu, Zenebe; Langan, Simon; Johnston, Robyn; Mekuria, Wolde; Amede, Tilahun

    2017-01-01

    Research results published regarding the impact of soil and water conservation practices in the highland areas of Ethiopia have been inconsistent and scattered. In this paper, a detailed review and synthesis is reported that was conducted to identify the impacts of soil and water conservation practices on crop yield, surface run-off, soil loss, nutrient loss, and the economic viability, as well as to discuss the implications for an integrated approach and ecosystem services. The review and synthesis showed that most physical soil and water conservation practices such as soil bunds and stone bunds were very effective in reducing run-off, soil erosion and nutrient depletion. Despite these positive impacts on these services, the impact of physical soil and water conservation practices on crop yield was negative mainly due to the reduction of effective cultivable area by soil/stone bunds. In contrast, most agronomic soil and water conservation practices increase crop yield and reduce run-off and soil losses. This implies that integrating physical soil and water conservation practices with agronomic soil and water conservation practices are essential to increase both provisioning and regulating ecosystem services. Additionally, effective use of unutilized land (the area occupied by bunds) by planting multipurpose grasses and trees on the bunds may offset the yield lost due to a reduction in planting area. If high value grasses and trees can be grown on this land, farmers can harvest fodder for animals or fuel wood, both in scarce supply in Ethiopia. Growing of these grasses and trees can also help the stability of the bunds and reduce maintenance cost. Economic feasibility analysis also showed that, soil and water conservation practices became economically more viable if physical and agronomic soil and water conservation practices are integrated.

  5. Biochar from Sugarcane Filtercake Reduces Soil CO2 Emissions Relative to Raw Residue and Improves Water Retention and Nutrient Availability in a Highly-Weathered Tropical Soil

    PubMed Central

    Eykelbosh, Angela Joy; Johnson, Mark S.; Santos de Queiroz, Edmar; Dalmagro, Higo José; Guimarães Couto, Eduardo

    2014-01-01

    In Brazil, the degradation of nutrient-poor Ferralsols limits productivity and drives agricultural expansion into pristine areas. However, returning agricultural residues to the soil in a stabilized form may offer opportunities for maintaining or improving soil quality, even under conditions that typically promote carbon loss. We examined the use of biochar made from filtercake (a byproduct of sugarcane processing) on the physicochemical properties of a cultivated tropical soil. Filtercake was pyrolyzed at 575°C for 3 h yielding a biochar with increased surface area and porosity compared to the raw filtercake. Filtercake biochar was primarily composed of aromatic carbon, with some residual cellulose and hemicellulose. In a three-week laboratory incubation, CO2 effluxes from a highly weathered Ferralsol soil amended with 5% biochar (dry weight, d.w.) were roughly four-fold higher than the soil-only control, but 23-fold lower than CO2 effluxes from soil amended with 5% (d.w.) raw filtercake. We also applied vinasse, a carbon-rich liquid waste from bioethanol production typically utilized as a fertilizer on sugarcane soils, to filtercake- and biochar-amended soils. Total CO2 efflux from the biochar-amended soil in response to vinasse application was only 5% of the efflux when vinasse was applied to soil amended with raw filtercake. Furthermore, mixtures of 5 or 10% biochar (d.w.) in this highly weathered tropical soil significantly increased water retention within the plant-available range and also improved nutrient availability. Accordingly, application of sugarcane filtercake as biochar, with or without vinasse application, may better satisfy soil management objectives than filtercake applied to soils in its raw form, and may help to build soil carbon stocks in sugarcane-cultivating regions. PMID:24897522

  6. Stem, root, and older leaf N:P ratios are more responsive indicators of soil nutrient availability than new foliage.

    PubMed

    Schreeg, L A; Santiago, L S; Wright, S J; Turner, B L

    2014-08-01

    Foliar nitrogen to phosphorus (N:P) ratios are widely used to indicate soil nutrient availability and limitation, but the foliar ratios of woody plants have proven more complicated to interpret than ratios from whole biomass of herbaceous species. This may be related to tissues in woody species acting as nutrient reservoirs during active growth, allowing maintenance of optimal N:P ratios in recently produced, fully expanded leaves (i.e., "new" leaves, the most commonly sampled tissue). Here we address the hypothesis that N:P ratios of newly expanded leaves are less sensitive indicators of soil nutrient availability than are other tissue types in woody plants. Seedlings of five naturally established tree species were harvested from plots receiving two years of fertilizer treatments in a lowland tropical forest in the Republic of Panama. Nutrient concentrations were determined in new leaves, old leaves, stems, and roots. For stems and roots, N:P ratios increased after N addition and decreased after P addition, and trends were consistent across all five species. Older leaves also showed strong responses to N and P addition, and trends were consistent for four of five species. In comparison, overall N:P ratio responses in new leaves were more variable across species. These results indicate that the N:P ratios of stems, roots, and older leaves are more responsive indicators of soil nutrient availability than are those of new leaves. Testing the generality of this result could improve the use of tissue nutrient ratios as indices of soil nutrient availability in woody plants.

  7. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers.

  8. A novel P450-initiated biphasic process for sustainable biodegradation of benzo[a]pyrene in soil under nutrient-sufficient conditions by the white rot fungus Phanerochaete chrysosporium.

    PubMed

    Bhattacharya, Sukanta S; Syed, Khajamohiddin; Shann, Jodi; Yadav, Jagjit S

    2013-10-15

    High molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) such as benzo[a]pyrene (BaP) are resistant to biodegradation in soil. Conventionally, white rot fungus Phanerochaete chrysosporium has been investigated for HMW-PAH degradation in soil primarily using nutrient-deficient (ligninolytic) conditions, albeit with limited and non-sustainable biodegradation outcomes. In this study, we report development of an alternative novel biphasic process initiated under nutrient-sufficient (non-ligninolytic) culture conditions, by employing an advanced experimental design strategy. During the initial nutrient-sufficient non-ligninolytic phase (16 days), the process showed upregulation (3.6- and 22.3-fold, respectively) of two key PAH-oxidizing P450 monooxygenases pc2 (CYP63A2) and pah4 (CYP5136A3) and formation of typical P450-hydroxylated metabolite. This along with abrogation (84.9%) of BaP degradation activity in response to a P450-specific inhibitor implied key role of these monooxygenases. The subsequent phase triggered on continued incubation (to 25 days) switched the process from non-ligninolytic to ligninolytic resulting in a significantly higher net degradation (91.6% as against 67.4% in the control nutrient-limited set) of BaP with concomitant de novo ligninolytic enzyme expression making it a biphasic process yielding improved sustainable bioremediation of PAH-contaminated soil. To our knowledge this is the first report on development of such biphasic process for bioremediation application of a white rot fungus.

  9. Conservation tillage, optimal water and organic nutrient supply enhance soil microbial activities during wheat (Triticum Aestivum L.) cultivation

    PubMed Central

    Sharma, Pankaj; Singh, Geeta; Singh, Rana P.

    2011-01-01

    The field experiments were conducted on sandy loam soil at New Delhi, during 2007 and 2008 to investigate the effect of conservation tillage, irrigation regimes (sub-optimal, optimal and supra-optimal water regimes), and integrated nutrient management (INM) practices on soil biological parameters in wheat cultivation. The conservation tillage soils has shown significant (p<0.05) increase in soil respiration (81.1%), soil microbial biomass carbon (SMBC) (104%) and soil dehydrogenase (DH) (59.2%) compared to the conventional tillage soil. Optimum water supply (3-irrigations) enhanced soil respiration over sub-optimum and supra-optimum irrigations by 13.32% and 79% respectively. Soil dehydrogenase (DH) activity in optimum water regime has also increased by 23.33% and 8.18% respectively over the other two irrigation regimes. Similarly, SMBC has also increased by 12.14% and 27.17% respectively in soil with optimum water supply compared to that of sub-optimum and supra-optimum water regime fields. The maximum increase in soil microbial activities is found when sole organic source (50% Farm Yard Manure+25% biofertilizer+25% Green Manure) has been used in combination with the conservation tillage and the optimum water supply. Study demonstrated that microbial activity could be regulated by tillage, water and nitrogen management in the soil in a sustainable manner. PMID:24031665

  10. Effects of Wheat Straw Incorporation on the Availability of Soil Nutrients and Enzyme Activities in Semiarid Areas

    PubMed Central

    Wei, Ting; Zhang, Peng; Wang, Ke; Ding, Ruixia; Yang, Baoping; Nie, Junfeng; Jia, Zhikuan; Han, Qingfang

    2015-01-01

    Soil infertility is the main barrier to dryland agricultural production in China. To provide a basis for the establishment of a soil amelioration technical system for rainfed fields in the semiarid area of northwest China, we conducted a four—year (2007–2011) field experiment to determine the effects of wheat straw incorporation on the arid soil nutrient levels of cropland cultivated with winter wheat after different straw incorporation levels. Three wheat straw incorporation levels were tested (H: 9000 kg hm-2, M: 6000 kg hm-2, and L: 3000 kg hm-2) and no straw incorporation was used as the control (CK). The levels of soil nutrients, soil organic carbon (SOC), soil labile organic carbon (LOC), and enzyme activities were analyzed each year after the wheat harvest. After straw incorporation for four years, the results showed that variable straw amounts had different effects on the soil fertility indices, where treatment H had the greatest effect. Compared with CK, the average soil available N, available P, available K, SOC, and LOC levels were higher in the 0–40 cm soil layers after straw incorporation treatments, i.e., 9.1–30.5%, 9.8–69.5%, 10.3–27.3%, 0.7–23.4%, and 44.4–49.4% higher, respectively. On average, the urease, phosphatase, and invertase levels in the 0–40 cm soil layers were 24.4–31.3%, 9.9–36.4%, and 42.9–65.3% higher, respectively. Higher yields coupled with higher nutrient contents were achieved with H, M and L compared with CK, where these treatments increased the crop yields by 26.75%, 21.51%, and 7.15%, respectively. PMID:25880452

  11. Effect of trees on the reduction of nutrient concentrations in the soils of cultivated areas.

    PubMed

    Gikas, Georgios D; Tsihrintzis, Vassilios A; Sykas, Dimitrios

    2016-06-01

    The function of trees in reducing nutrient migration to groundwaters in cultivated areas, under Mediterranean climate conditions, is tested. Three cultivated fields were monitored for two cultivation periods. The common characteristic of the three fields was that on one side, they bordered with a poplar tree field. Four different crops were cultivated, and two cultivation periods were monitored. Based on the number of fields (i.e., three) and the cultivation periods (i.e., two), six different conditions (systems) were studied with four crops (i.e., sunflower, cotton, rapeseed, and corn). Soil samples were collected in all systems at the beginning, the middle, and the end of the cultivation period at various sampling sites (i.e., various distances from the tree row) and at various depths, and were analyzed in the laboratory for the determination of ΝΟ3-Ν and P-Olsen. In all systems, the greatest concentration of P-Olsen was measured in the surface layers (0-5, 10-15, and 30-35 cm) and was gradually decreased in the deeper layers (55-60 and 75-80 cm) indicating that P mobility is low. The ΝΟ3-Ν concentration in the deeper layers (55-60 and 75-80 cm) at all sampling sites was equal to or greater than that of the surface layers, indicating that ΝΟ3-Ν has high mobility in soils. At the sampling sites in the soil zone near the tree row, the ΝΟ3-Ν concentration in the deeper layers was lower than that of the surface, indicating that the tree root system takes up nutrients which otherwise would move toward the water table. There was also a reduction observed of the depth-averaged P-Olsen and ΝΟ3-Ν concentrations at the soil zone at a distance of 2.0-3.5 m from the tree row compared to locations more distant from the trees; this reduction ranged between 15 and 50 % and 36 and 54 %, respectively. The results indicate that planting of trees in cultivated fields can contribute to the reduction of nitrate pollution of groundwaters.

  12. Shrub canopies influence soil temperatures but not nutrient dynamics: An experimental test of tundra snow–shrub interactions

    PubMed Central

    Myers-Smith, Isla H; Hik, David S

    2013-01-01

    Shrubs are the largest plant life form in tundra ecosystems; therefore, any changes in the abundance of shrubs will feedback to influence biodiversity, ecosystem function, and climate. The snow–shrub hypothesis asserts that shrub canopies trap snow and insulate soils in winter, increasing the rates of nutrient cycling to create a positive feedback to shrub expansion. However, previous work has not been able to separate the abiotic from the biotic influences of shrub canopies. We conducted a 3-year factorial experiment to determine the influences of canopies on soil temperatures and nutrient cycling parameters by removing ∼0.5 m high willow (Salix spp.) and birch (Betula glandulosa) shrubs, creating artificial shrub canopies and comparing these manipulations to nearby open tundra and shrub patches. Soil temperatures were 4–5°C warmer in January, and 2°C cooler in July under shrub cover. Natural shrub plots had 14–33 cm more snow in January than adjacent open tundra plots. Snow cover and soil temperatures were similar in the manipulated plots when compared with the respective unmanipulated treatments, indicating that shrub canopy cover was a dominant factor influencing the soil thermal regime. Conversely, we found no strong evidence of increased soil decomposition, CO2 fluxes, or nitrate or ammonia adsorbtion under artificial shrub canopy treatments when compared with unmanipulated open tundra. Our results suggest that the abiotic influences of shrub canopy cover alone on nutrient dynamics are weaker than previously asserted. PMID:24198933

  13. Shrub canopies influence soil temperatures but not nutrient dynamics: An experimental test of tundra snow-shrub interactions.

    PubMed

    Myers-Smith, Isla H; Hik, David S

    2013-10-01

    Shrubs are the largest plant life form in tundra ecosystems; therefore, any changes in the abundance of shrubs will feedback to influence biodiversity, ecosystem function, and climate. The snow-shrub hypothesis asserts that shrub canopies trap snow and insulate soils in winter, increasing the rates of nutrient cycling to create a positive feedback to shrub expansion. However, previous work has not been able to separate the abiotic from the biotic influences of shrub canopies. We conducted a 3-year factorial experiment to determine the influences of canopies on soil temperatures and nutrient cycling parameters by removing ∼0.5 m high willow (Salix spp.) and birch (Betula glandulosa) shrubs, creating artificial shrub canopies and comparing these manipulations to nearby open tundra and shrub patches. Soil temperatures were 4-5°C warmer in January, and 2°C cooler in July under shrub cover. Natural shrub plots had 14-33 cm more snow in January than adjacent open tundra plots. Snow cover and soil temperatures were similar in the manipulated plots when compared with the respective unmanipulated treatments, indicating that shrub canopy cover was a dominant factor influencing the soil thermal regime. Conversely, we found no strong evidence of increased soil decomposition, CO2 fluxes, or nitrate or ammonia adsorbtion under artificial shrub canopy treatments when compared with unmanipulated open tundra. Our results suggest that the abiotic influences of shrub canopy cover alone on nutrient dynamics are weaker than previously asserted.

  14. Changes in liquid water alter nutrient bioavailability and gas diffusion in frozen antarctic soils contaminated with petroleum hydrocarbons.

    PubMed

    Harvey, Alexis Nadine; Snape, Ian; Siciliano, Steven Douglas

    2012-02-01

    Bioremediation has been used to remediate petroleum hydrocarbon (PHC)-contaminated sites in polar regions; however, limited knowledge exists in understanding how frozen conditions influence factors that regulate microbial activity. We hypothesized that increased liquid water (θ(liquid) ) would affect nutrient supply rates (NSR) and gas diffusion under frozen conditions. If true, management practices that increase θ(liquid) should also increase bioremediation in polar soils by reducing nutrient and oxygen limitations. Influence of θ(liquid) on NSR was determined using diesel-contaminated soil (0-8,000 mg kg(-1)) from Casey Station, Antarctica. The θ(liquid) was altered between 0.007 and 0.035 cm(3) cm(-3) by packing soil cores at different bulk densities. The nutrient supply rate of NH 4+ and NO 3-, as well as gas diffusion coefficient, D(s), were measured at two temperatures, 21°C and -5°C, to correct for bulk density effects. Freezing decreased NSR of both NH 4+ and NO 3-, with θ(liquid) linked to nitrate and ammonia NSR in frozen soil. Similarly for D(s), decreases due to freezing were much more pronounced in soils with low θ(liquid) compared to soils with higher θ(liquid) contents. Additional studies are needed to determine the relationship between degradation rates and θ(liquid) under frozen conditions.

  15. Nutrient availability affects pigment production but not growth in lichens of biological soil crusts

    USGS Publications Warehouse

    Bowker, M.A.; Koch, G.W.; Belnap, J.; Johnson, N.C.

    2008-01-01

    Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

  16. Soil inoculation with symbiotic microorganisms promotes plant growth and nutrient transporter genes expression in durum wheat

    PubMed Central

    Saia, Sergio; Rappa, Vito; Ruisi, Paolo; Abenavoli, Maria Rosa; Sunseri, Francesco; Giambalvo, Dario; Frenda, Alfonso S.; Martinelli, Federico

    2015-01-01

    In a field experiment conducted in a Mediterranean area of inner Sicily, durum wheat was inoculated with plant growth-promoting rhizobacteria (PGPR), with arbuscular mycorrhizal fungi (AMF), or with both to evaluate their effects on nutrient uptake, plant growth, and the expression of key transporter genes involved in nitrogen (N) and phosphorus (P) uptake. These biotic associations were studied under either low N availability (unfertilized plots) and supplying the soil with an easily mineralizable organic fertilizer. Regardless of N fertilization, at the tillering stage, inoculation with AMF alone or in combination with PGPR increased the aboveground biomass yield compared to the uninoculated control. Inoculation with PGPR enhanced the aboveground biomass yield compared to the control, but only when N fertilizer was added. At the heading stage, inoculation with all microorganisms increased the aboveground biomass and N. Inoculation with PGPR and AMF+PGPR resulted in significantly higher aboveground P compared to the control and inoculation with AMF only when organic N was applied. The role of microbe inoculation in N uptake was elucidated by the expression of nitrate transporter genes. NRT1.1, NRT2, and NAR2.2 were significantly upregulated by inoculation with AMF and AMF+PGPR in the absence of organic N. A significant down-regulation of the same genes was observed when organic N was added. The ammonium (NH4+) transporter genes AMT1.2 showed an expression pattern similar to that of the NO3- transporters. Finally, in the absence of organic N, the transcript abundance of P transporters Pht1 and PT2-1 was increased by inoculation with AMF+PGPR, and inoculation with AMF upregulated Pht2 compared to the uninoculated control. These results indicate the soil inoculation with AMF and PGPR (alone or in combination) as a valuable option for farmers to improve yield, nutrient uptake, and the sustainability of the agro-ecosystem. PMID:26483827

  17. Diversity enhances agricultural productivity via rhizosphere phosphorus facilitation on phosphorus-deficient soils

    PubMed Central

    Li, Long; Li, Shu-Min; Sun, Jian-Hao; Zhou, Li-Li; Bao, Xing-Guo; Zhang, Hong-Gang; Zhang, Fu-Suo

    2007-01-01

    Intercropping, which grows at least two crop species on the same pieces of land at the same time, can increase grain yields greatly. Legume–grass intercrops are known to overyield because of legume nitrogen fixation. However, many agricultural soils are deficient in phosphorus. Here we show that a new mechanism of overyielding, in which phosphorus mobilized by one crop species increases the growth of a second crop species grown in alternate rows, led to large yield increases on phosphorus-deficient soils. In 4 years of field experiments, maize (Zea mays L.) overyielded by 43% and faba bean (Vicia faba L.) overyielded by 26% when intercropped on a low-phosphorus but high-nitrogen soil. We found that overyielding of maize was attributable to below-ground interactions between faba bean and maize in another field experiment. Intercropping with faba bean improved maize grain yield significantly and above-ground biomass marginally significantly, compared with maize grown with wheat, at lower rates of P fertilizer application (<75 kg of P2O5 per hectare), and not significantly at high rate of P application (>112.5 kg of P2O5 per hectare). By using permeable and impermeable root barriers, we found that maize overyielding resulted from its uptake of phosphorus mobilized by the acidification of the rhizosphere via faba bean root release of organic acids and protons. Faba bean overyielded because its growth season and rooting depth differed from maize. The large increase in yields from intercropping on low-phosphorus soils is likely to be especially important on heavily weathered soils. PMID:17592130

  18. Advancing analysis of spatio-temporal variations of soil nutrients in the water level fluctuation zone of China's Three Gorges Reservoir using self-organizing map.

    PubMed

    Ye, Chen; Li, Siyue; Yang, Yuyi; Shu, Xiao; Zhang, Jiaquan; Zhang, Quanfa

    2015-01-01

    The ~350 km2 water level fluctuation zone (WLFZ) in the Three Gorges Reservoir (TGR) of China, situated at the intersection of terrestrial and aquatic ecosystems, experiences a great hydrological change with prolonged winter inundation. Soil samples were collected in 12 sites pre- (September 2008) and post submergence (June 2009) in the WLFZ and analyzed for soil nutrients. Self-organizing map (SOM) and statistical analysis including multi-way ANOVA, paired-T test, and stepwise least squares multiple regression were employed to determine the spatio-temporal variations of soil nutrients in relation to submergence, and their correlations with soil physical characteristics. Results showed significant spatial variability in nutrients along ~600 km long shoreline of the TGR before and after submergence. There were higher contents of organic matter, total nitrogen (TN), and nitrate (NO3-) in the lower reach and total phosphorus (TP) in the upper reach that were primarily due to the spatial variations in soil particle size composition and anthropogenic activities. Submergence enhanced soil available potassium (K), while significantly decreased soil N, possibly due to the alterations of soil particle size composition and increase in soil pH. In addition, SOM analysis determined important roles of soil pH value, bulk density, soil particle size (i.e., silt and sand) and nutrients (TP, TK, and AK) on the spatial and temporal variations in soil quality. Our results suggest that urban sewage and agricultural runoffs are primary pollutants that affect soil nutrients in the WLFZ of TGR.

  19. [Changes of plant community biomass and soil nutrients during the vegetation succession on abandoned cultivated land in desert steppe region].

    PubMed

    An, Hui; Yang, Xin-Guo; Liu, Bing-Ru; Li, Xue-Bin; He, Xiu-Zhen; Song, Nai-Ping

    2011-12-01

    By the method of substituting temporal serial with spatial serial, and taking five abandoned cultivated lands with different ages (1, 4, 9, 12, and 20 years) in desert steppe region as test objects, this paper studied the change characteristics of plant community biomass and soil nutrients during vegetation succession. With the increasing abandoned years, the plant community aboveground biomass on the abandoned lands increased after an initial decrease, whereas the total nitrogen, total phosphorus, organic carbon contents, and carbon density in 0-60 cm soil layer increased first, decreased then, and increased again, with the maximum values of soil total nitrogen and phosphorus contents appeared on the abandoned lands with the ages 4 and 20 years. During vegetation succession, the effects of soil total nitrogen and organic carbon on plant community biomass were greater than those of soil total phosphorus and soil bulk density.

  20. Effect of Fenton pre-oxidation on mobilization of nutrients and efficient subsequent bioremediation of crude oil-contaminated soil.

    PubMed

    Xu, Jinlan; Kong, Fanxing; Song, Shaohua; Cao, Qianqian; Huang, Tinglin; Cui, Yiwei

    2017-03-22

    Fenton pre-oxidation and a subsequent bioremediation phase of 80 days were used to investigate the importance of matching concentration of residual indigenous bacteria and nutrient levels on subsequent bioremediation of crude oil. Experiments were performed using either high (>10(7.7 ± 0.2) CFU/g soil) or low (<10(5.9 ± 0.1) CFU/g soil) concentrations of bacteria and three different nutrient levels: enough (C/N > 9.8), moderate (C/N:5-9.8), and lacking nutrient level (C/N < 5) conditions. Weak Fenton pre-oxidation (225 mM H2O2 and 2.9 mM Fe(2+)) resulted in highly matching between nutrient level and the population of residual indigenous bacteria. Up to 53% of total petroleum hydrocarbon (TPH) and 58% of main hydrocarbon (C15C25, during the first 10 days) were removed from the soil. Under matching conditions, the activity of indigenous bacteria and nutrient mobilization were enhanced, promoting the bioremediation of crude oil. In addition, the biodegradation of long chain molecules (C26C30) required a high level of NH4(+)-N.

  1. Integrated soil-crop system management: reducing environmental risk while increasing crop productivity and improving nutrient use efficiency in China.

    PubMed

    Zhang, Fusuo; Cui, Zhenling; Fan, Mingsheng; Zhang, Weifeng; Chen, Xinping; Jiang, Rongfeng

    2011-01-01

    During the past 47 yr (1961-2007), Chinese cereal production has increased by 3.2-fold, successfully feeding 22% of the global human population with only 9% of the world's arable land, but at high environmental cost and resource consumption. Worse, crop production has been stagnant since 1996 while the population and demand for food continue to rise. New advances for sustainability of agriculture and ecosystem services will be needed during the coming 50 yr to reduce environmental risk while increasing crop productivity and improving nutrient use efficiency. Here, we advocate and develop integrated soil-crop system management (ISSM). In this approach, the key points are (i) to take all possible soil quality improvement measures into consideration, (ii) to integrate the utilization of various nutrient resources and match nutrient supply to crop requirements, and (iii) to integrate soil and nutrient management with high-yielding cultivation systems. Recent field experiments have shed light on how ISSM can lead to significant increases in crop yields while increasing nutrient use efficiency and reducing environmental risk.

  2. Assessing the microbial activity of soil samples, its nutrient limitation and toxic effects of contaminants using a simple respiration test.

    PubMed

    Hollender, Juliane; Althoff, Katrin; Mundt, Matthias; Dott, Wolfgang

    2003-10-01

    Eight soil samples from five wells of a former gas plant site differing in the contamination with BTEX and PAHs as well as the nutrient content were investigated by soil respiration measurements. The basal, glucose as well as NH4+ and PO4(3-) induced cumulative oxygen consumption and carbon dioxide production in 72 and 120 h were determined and additionally the maximal turnover rates and the limitation quotients were calculated. Without additional carbon source only one of five investigated samples was clearly nutrient limited. After glucose supplementation four of seven investigated samples showed nutrient limitation that was in accordance with the available ammonium and phosphorous content. BTEX and PAHs did not exhibit an inhibiting effect on the respiration rate. In contrast, BTEX containing samples exhibited the highest oxygen consumption indicating biodegradation of the contaminants. The results show that oxygen consumption and carbon dioxide production as well as the kinetic of these processes are all informative parameters characterizing the whole microbial respiration potential and their nutrient limitation in soil samples. Therefore this fast respirometric method can be used for the decision if further detailed studies of the bioremediation are useful and if nutrient supplementation is recommended to enhance natural attenuation.

  3. The Potato Systems Planner: Integrating Cropping System Impacts on Crop Yield and Quality, Soil Biology, Nutrient Cycling, Diseases, and Economics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Finding and developing profitable cropping systems is a high priority for the potato industry. Consequently, an interdisciplinary team of ARS scientists from the New England Plant, Soil, & Water Laboratory evaluated 14 different rotations for their impacts on crop yield and quality, nutrient availa...

  4. Effects of geotextile landscape fabric on soil nutrient availability in an organic planting of ‘Marion’ trailing blackberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Geotextile landscape fabric, often referred to as weed mat, is becoming a popular option for weed control in many fruit crops, particularly for organic production. The present study was conducted in 2014 to evaluate the effects of landscape fabric relative to hand weeding on soil nutrient availabili...

  5. Soil erosion and nutrient runoff in corn silage production with kura clover living mulch and winter rye

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays L.) harvested for silage is a productive forage crop, but one that can exacerbate soil loss, surface water runoff, and nonpoint source nutrient pollution from agricultural fields. The objective of this research was to compare the effects of using Kura clover (Trifolium ambiguum M. Bie...

  6. Weed management, training, and irrigation practices for organic production of trailing blackberry: II. Soil and plant nutrient concentrations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic production of blackberries is increasing, but there is relatively little known about how production practices affect plant and soil nutrient status. The impact of cultivar (‘Black Diamond’ and ‘Marion’), weed management (weed mat, hand weeding, and no weeding), primocane training time (Augus...

  7. Nutrient and growth responses of Leersia oryzoides, rice cutgrass, to varying degrees of soil saturation and water nitrogen concentration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leersia oryzoides (rice cutgrass) is an obligate wetland plant common to agricultural ditches. The objective of this greenhouse study was to quantify the allocation of nutrients and biomass to different plant components exposed to various soil moisture and aqueous N input regimes. Plants in the con...

  8. NGEE Arctic Plant Traits: Soil Nutrient Availability, Kougarok Road Mile Marker 64, Seward Peninsula, Alaska, beginning 2016

    DOE Data Explorer

    Verity Salmon; Colleen Iversen; Amy Breen; Joanne Childs; Holly Vander Stel; Stan Wullschleger

    2017-03-09

    Soil nutrient availability at all vegetation plots was measured using anion and cation binding resins deployed to vegetation plots at the Kougarok hillslope site located at Kougarok Road Marker 64. Concentrations of ammonia, nitrate, and phosphate in resin extract solutions were determined in the lab.

  9. On-site assessment of extractable soil nutrients after long-term biosolids applications to perennial forage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate soil nutrient loading and depth distributions of extractable nitrogen (N), phosphorus (P), and potassium (K) after long-term, continuous annual surface-applications of anaerobically-digested Class B biosolids at a municipal recycling facility in central Te...

  10. [A long-term field trial on fertilization and on use of recycled nutrients in farming systems IV. Soil fertility changes].

    PubMed

    Zhang, Lu; Shen, Shanmin; Yu, Wantai

    2002-11-01

    The fertility changes of soil under different fertilization treatments of a twelve years field trial indicated that the application of compost recycled in a farming system with appropriate amount of fertilizer applied to balance the soil nutrient budget, could not only produce higher crop yields and less surplus of nutrients into environment, but also improved soil fertility with significant increase of soil organic carbon and nitrogen in cultivated layer. However, maintaine higher soil available phosphorus, it was not sufficient just to balance the budget of soil phosphorus, and more phosphorus fertilizer application was needed.

  11. Characterization of soybean β-expansin genes and their expression responses to symbiosis, nutrient deficiency, and hormone treatment.

    PubMed

    Li, Xinxin; Zhao, Jing; Walk, Thomas C; Liao, Hong

    2014-03-01

    Expansins are plant cell wall-loosening proteins encoded by a superfamily of genes including α-expansin, β-expansin, expansin-like A, and expansin-like B proteins. They play a variety of biological roles during plant growth and development. Expansin genes have been reported in many plant species, and results primarily from graminaceous members indicate that β-expansins are more abundant in monocots than in dicots. Soybean [Glycine max (L.) Merr] is an important legume crop. This work identified nine β-expansin gene family members in soybean (GmEXPBs) that were divided into two distinct classes based on phylogeny and gene structure, with divergence between the two groups occurring more in introns than in exons. A total of 887 hormone-responsive and environmental stress-related putative cis-elements from 188 families were found in the 2-kb upstream region of GmEXPBs. Variations in number and type of cis-elements associated with each gene indicate that the function of these genes is differentially regulated by these signals. Expression analysis confirmed that the family members were ubiquitously, yet differentially expressed in soybean. Responsiveness to nutrient deficiency stresses and regulation by auxin (indole-3-acetic acid) and cytokinin (6-benzylaminopurine) varied among GmEXPBs. In addition, most β-expansin genes were associated with symbiosis of soybean inoculated with Rhizobium or abuscular mycorrhizal fungi (AMF). Taken together, these results systematically investigate the characteristics of the entire GmEXPB family in soybean and comprise the first report analyzing the relationship of GmEXPBs with rhizobial or AMF symbiosis. This information is a valuable step in the process of understanding the expansin protein functions in soybean and opens avenues for continued researches.

  12. Soil-Transmitted Helminthiasis and Vitamin A Deficiency: Two Problems, One Policy.

    PubMed

    Strunz, Eric C; Suchdev, Parminder S; Addiss, David G

    2016-01-01

    Vitamin A deficiency (VAD) and soil-transmitted helminthiasis (STH) represent two widely prevalent and often overlapping global health problems. Approximately 75% of countries with moderate or severe VAD are coendemic for STH. We reviewed the literature on the complex relationship between STH and VAD. Treatment for STH significantly increases provitamin A (e.g., β-carotene) levels but is associated with minimal increases in preformed vitamin A (retinol). Interpretation of the data is complicated by variations in STH infection intensity and limitations of vitamin A biomarkers. Despite these challenges, increased coordination of STH and VAD interventions represents an important public health opportunity.

  13. A novel nanoparticle approach for imaging nutrient uptake by soil bacteria

    NASA Astrophysics Data System (ADS)

    O'Brien, S. L.; Whiteside, M. D.; Sholto-Douglas, D.; Antonopoulos, D. A.; Boyanov, M.; Durall, D. M.; Jones, M. D.; Lai, B.; O'Loughlin, E. J.; Kemner, K. M.

    2014-12-01

    The metabolic activities of soil microbes are the primary drivers of biogeochemical processes controlling the terrestrial carbon cycle, nutrient availability to plants, contaminant remediation, water quality, and other ecosystem services. However, we have a limited understanding of microbial metabolic processes such as nutrient uptake rates, substrate preferences, or how microbes and microbial metabolism are distributed throughout their habitat. Here we use a novel imaging technique with quantum dots (QDs, engineered semiconductor nanoparticles that produce size or composition-dependent fluorescence) to measure bacterial uptake of substrates of varying complexity. Cultures of two organisms differing in cell wall structure — Bacillus subtilis and Pseudomonas fluorescens — were grown in one of four ecologically relevant experimental conditions: nitrogen (N) limitation, phosphorus (P) limitation, N and P limitation, or no nutrient limitation. The cultures were then exposed to QDs with and without organic nutrients attached. X-ray fluorescence imaging was performed at 2ID-D at the Advanced Photon Source (APS) to determine the elemental distributions within both planktonic and surface-adhered (i.e, biofilms) cells. Uptake of unconjugated QDs was neglibible, and QDs conjugated to organic substrates varied depending on growth conditions and substrate, suggesting that they are a useful indicator of bacterial ecology. Cellular uptake was similar for the two bacterial species (2212 ± 273 nanoparticles per cm3 of cell volume for B. subtilis and 1682 ± 264 for P. fluorescens). On average, QD assimilation was six times greater when N or P was limiting, and cells took up about twice as much phosphoserine compared to other substrates, likely because it was the only compound providing both N and P. These results showed that regardless of their cell wall structure, bacteria can selectively take up quantifiable levels of QDs based on substrate and environmental conditions. APS

  14. Soil nutrients, land use history and species composition interact to influence tropical N2 fixation

    NASA Astrophysics Data System (ADS)

    Batterman, S. A.; Hall, J.; Van Breugel, M.; Hedin, L. O.

    2011-12-01

    Symbiotic di-nitrogen fixation plays an important role in terrestrial biogeochemical cycles as it can bring in large quantities of nitrogen into ecosystems and provide the nitrogen required for individual plant growth in nitrogen limited environments. Of particular interest is how fixation interacts with nitrogen and phosphorus cycles in heterogeneous tropical forests. Recent advances on this topic using plants grown in a shadehouse show that the interaction of nitrogen and phosphorus control fixation at the level of individual plants and that plants adjust nutrient acquisition strategies with some successes at overcoming nutrient limitation on biomass growth depending on nutrient availability and the strategy employed (Batterman et al. unpublished). Exactly how these results translate to biodiverse tropical forests with heterogeneous resource availabilities and a history of land use disturbances, however, remains largely unresolved. We surveyed fixation across a chronosequence of forest stands in Panama that were at various stages of recovery from the abandonment of cattle pasture. Stands ranged in age from new secondary regrowth to mature forest. We examined nine common species of putative N2 fixing trees and lianas for nodulation, tree size, and abundance for four stands each of four forest ages to determine if species differ in strategies and function. In addition, we measured light availability to each tree and total and bioavailable phosphorus and nitrogen for each stand to examine the interactions of fixation with these biogeochemical cycles. Results were scaled to estimate stand level fixation. We found unique patterns in fixation that contrasted with predictions based on evidence of how fixation interacts with land use and biogeochemical cycles in extra-tropical forests. Soil nutrients showed unexpected patterns in availability across the chronosequence and interacted with fixation. Finally, species displayed distinct differences in temporal patterns in

  15. Associations between soil bacterial community structure and nutrient cycling functions in long-term organic farm soils following cover crop and organic fertilizer amendment.

    PubMed

    Fernandez, Adria L; Sheaffer, Craig C; Wyse, Donald L; Staley, Christopher; Gould, Trevor J; Sadowsky, Michael J

    2016-10-01

    Agricultural management practices can produce changes in soil microbial populations whose functions are crucial to crop production and may be detectable using high-throughput sequencing of bacterial 16S rRNA. To apply sequencing-derived bacterial community structure data to on-farm decision-making will require a better understanding of the complex associations between soil microbial community structure and soil function. Here 16S rRNA sequencing was used to profile soil bacterial communities following application of cover crops and organic fertilizer treatments in certified organic field cropping systems. Amendment treatments were hairy vetch (Vicia villosa), winter rye (Secale cereale), oilseed radish (Raphanus sativus), buckwheat (Fagopyrum esculentum), beef manure, pelleted poultry manure, Sustane(®) 8-2-4, and a no-amendment control. Enzyme activities, net N mineralization, soil respiration, and soil physicochemical properties including nutrient levels, organic matter (OM) and pH were measured. Relationships between these functional and physicochemical parameters and soil bacterial community structure were assessed using multivariate methods including redundancy analysis, discriminant analysis, and Bayesian inference. Several cover crops and fertilizers affected soil functions including N-acetyl-β-d-glucosaminidase and β-glucosidase activity. Effects, however, were not consistent across locations and sampling timepoints. Correlations were observed among functional parameters and relative abundances of individual bacterial families and phyla. Bayesian analysis inferred no directional relationships between functional activities, bacterial families, and physicochemical parameters. Soil functional profiles were more strongly predicted by location than by treatment, and differences were largely explained by soil physicochemical parameters. Composition of soil bacterial communities was predictive of soil functional profiles. Differences in soil function were

  16. Plant nutrient acquisition strategies in tundra species: at which soil depth do species take up their nitrogen?

    NASA Astrophysics Data System (ADS)

    Limpens, Juul; Heijmans, Monique; Nauta, Ake; van Huissteden, Corine; van Rijssel, Sophie

    2016-04-01

    The Arctic is warming at unprecedented rates. Increased thawing of permafrost releases nutrients locked up in the previously frozen soils layers, which may initiate shifts in vegetation composition. The direction in which the vegetation shifts will co-determine whether Arctic warming is mitigated or accelerated, making understanding successional trajectories urgent. One of the key factors influencing the competitive relationships between plant species is their access to nutrients, in particularly nitrogen (N). We assessed the depth at which plant species took up N by performing a 15N tracer study, injecting 15(NH4)2SO4 at three depths (5, 15, 20 cm) into the soil in arctic tundra in north-eastern Siberia in July. In addition we explored plant nutrient acquisition strategy by analyzing natural abundances of 15N in leaves. We found that vascular plants took up 15N at all injection depths, irrespective of species, but also that species showed a clear preference for specific soil layers that coincided with their functional group (graminoids, dwarf shrubs, cryptogams). Graminoids took up most 15N at 20 cm depth nearest to the thaw front, with grasses showing a more pronounced preference than sedges. Dwarf shrubs took up most 15N at 5 cm depth, with deciduous shrubs displaying more preference than evergreens. Cryptogams did not take up any of the supplied 15N . The natural 15N abundances confirmed the pattern of nutrient acquisition from deeper soil layers in graminoids and from shallow soil layers in both deciduous and evergreen dwarf shrubs. Our results prove that graminoids and shrubs differ in their N uptake strategies, with graminoids profiting from nutrients released at the thaw front, whereas shrubs forage in the upper soil layers. The above implies that graminoids, grasses in particular, will have a competitive advantage over shrubs as the thaw front proceeds and/or superficial soil layers dry out. Our results suggest that the vertical distribution of nutrients

  17. Sapling leaf trait responses to light, tree height and soil nutrients for three conifer species of contrasting shade tolerance.

    PubMed

    Lilles, Erica B; Astrup, Rasmus; Lefrançois, Marie-Lou; David Coates, K

    2014-12-01

    We developed models to describe the responses of four commonly examined leaf traits (mass per area, weight, area and nitrogen (N) concentration) to gradients of light, soil nutrients and tree height in three conifer species of contrasting shade tolerance. Our observational dataset from the sub-boreal spruce forests of British Columbia included subalpine fir (Abies lasioscarpa [Hook.] Nutt; high shade tolerance), interior spruce (Picea glauca × Picea engelmannii [Moench] Voss; intermediate shade tolerance) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia; low shade tolerance) saplings from 0.18 to 4.87 m tall, in 8-98% of total incident light, from field sites with <17.6 kg ha(-1) to >46.8 kg ha(-1) total dissolved N. Leaf weights and areas showed strong positive responses to light and height, but little or no response to soil nutrients. Parameter estimates indicated that the shape of leaf weight and area responses to light corresponded with shade tolerance ranking for the three species; pine had the most linear response whereas spruce and fir had asymptotic responses. Leaf N concentration responded positively to soil nutrients, negatively to light and idiosyncratically to height. The negative effect of light was only apparent on sites of high soil nutrient availability, and parameter estimates for the shape of the negative response also corresponded to shade tolerance ranking (apine = -0.79, aspruce = -0.15, afir = -0.07). Of the traits we measured, leaf mass per area showed the least response to light, soil nutrient and height gradients. Although it is a common practice in comparisons across many species, characterizing these conifers by mean values of their leaf traits would miss important intraspecific variation across environmental and size gradients. In these forests, parameter estimates representing the intraspecific variability of leaf trait responses can be used to understand relative shade tolerances.

  18. Lianas always outperform tree seedlings regardless of soil nutrients: results from a long-term fertilization experiment.

    PubMed

    Pasquini, Sarah C; Wright, S Joseph; Santiago, Louis S

    2015-07-01

    Lianas are a prominent growth form in tropical forests, and there is compelling evidence that they are increasing in abundance throughout the Neotropics. While recent evidence shows that soil resources limit tree growth even in deep shade, the degree to which soil resources limit lianas in forest understories, where they coexist with trees for decades, remains unknown. Regardless, the physiological underpinnings of soil resource limitation in deeply shaded tropical habitats remain largely unexplored for either trees or lianas. Theory predicts that lianas should be more limited by soil resources than trees because they occupy the quick-return end of the "leaf economic spectrum," characterized by high rates of photosynthesis, high specific leaf area, short leaf life span, affinity to high-nutrient sites, and greater foliar nutrient concentrations. To address these issues, we asked whether soil resources (nitrogen, phosphorus, and potassium), alone or in combination, applied experimentally for more than a decade would cause significant changes in the morphology or physiology of tree and liana seedlings in a lowland tropical forest. We found evidence for the first time that phosphorus limits the photosynthetic performance of both trees and lianas in deeply shaded understory habitats. More importantly, lianas always showed significantly greater photosynthetic capacity, quenching, and saturating light levels compared to trees across all treatments. We found little evidence for nutrient x growth form interactions, indicating that lianas were not disproportionately favored in nutrient-rich habitats. Tree and liana seedlings differed markedly for six key morphological traits, demonstrating that architectural differences occurred very early in ontogeny prior to lianas finding a trellis (all seedlings were self-supporting). Overall, our results do not support nutrient loading as a mechanism of increasing liana abundance in the Neotropics. Rather, our finding that lianas

  19. Long-term changes in nutrient availability after prescribed fire management in a Mediterranean soil

    NASA Astrophysics Data System (ADS)

    Alcañiz, Meritxell; Outeiro, Luis; Francos, Marcos; Farguell, Joaquim; Úbeda, Xavier

    2016-04-01

    The study area is located in the Tivissa Ranges (NE Iberian Peninsula) and the slope is ~35%, at 615 m.a.s.l. The natural vegetation before prescribed fire was composed of the three stratums in which trees (1% of the plot) were Pinus halepensis, shrubs were Ulex parviflorus, Cistus albidus, Rosmarinus officinallis, Erica multiflora and Quercus coccifera (75% of the plot), and herbs (24%) manly composed of Brachypodium retusum. The firemen had two main forest management objectives with the prescribed fire that was carried out on April 2002: (1) to change the dominance from Ulex to Cistus which is less flammable specie, and which would (2) permit the livestock into this area. Nine years after the prescribed fire our study plot was burned again with a low severity fire to manage the accumulation of vegetation. The aim of this study is a) to see the evolution of nutrient availability in the soil during 13 years since the first prescribed fire, and b) to evaluate the use of prescribed fire as a forest management tool. We have five sampling moments: (1) before the first prescribed fire; (2) after; (3) one year after; (4) three years after and (5) thirteen years after. Within the study area was placed a sampling plot with a rectangular 4×18 m structure. The study was carried out with 30 unstructured soil samples which were air-dried and passed through a 2 mm sieve. After that, fine material was prepared to measure different chemicals parameters of soil studied: soil pH [1:2.5], electrical conductivity [1:2.5], potassium, calcium and magnesium. The results show that, while pH is stable during the period studied, electrical conductivity increased after the prescribed fire as it was expected. However, thirteen years after the first prescribed fire the value (167 μS/cm) was markedly lower than before the prescribed fire (326 μS/cm). Changes in nutrient availability depend on the cation valence. Divalent cations (calcium and magnesium) decreased just after the prescribed

  20. Controls on foliar nutrient and aluminium concentrations in a tropical tree flora: phylogeny, soil chemistry and interactions among elements.

    PubMed

    Metali, Faizah; Abu Salim, Kamariah; Tennakoon, Kushan; Burslem, David F R P

    2015-01-01

    Foliar elemental concentrations are predictors of life-history variation and contribute to spatial patterns in biogeochemical cycling. We examined the contributions of habitat association, local soil environment, and elemental interactions to variation in foliar elemental concentrations in tropical trees using methods that account for phylogeny. We sampled top-soils and leaves of 58 tropical trees in heath forest (HF) on nutrient-poor sand and mixed dipterocarp forest (MDF) on nutrient-rich clay soils. A phylogenetic generalized least squares method was used to determine how foliar nutrient and aluminium (Al) concentrations varied in response to habitat distribution, soil chemistry and other elemental concentrations. Foliar nitrogen (N) and Al concentrations were greater for specialists of MDF than for specialists of HF, while foliar calcium (Ca) concentrations showed the opposite trend. Foliar magnesium (Mg) concentrations were lower for generalists than for MDF specialists. Foliar element concentrations were correlated with fine-scale variation in soil chemistry in phylogenetically controlled analyses across species, but there was limited within-species plasticity in foliar elemental concentrations. Among Al accumulators, foliar Al concentration was positively associated with foliar Ca and Mg concentrations, and negatively associated with foliar phosphorus (P) concentrations. The Al-accumulation trait and relationships between foliar elemental and Al concentrations may contribute to species habitat partitioning and ecosystem-level differences in biogeochemical cycles.

  1. Leaf nutrient contents and morphology of invasive tamarisk in different soil conditions in the lower Virgin River

    NASA Astrophysics Data System (ADS)

    Imada, S.; Acharya, K.; Tateno, R.; Yamanaka, N.

    2012-12-01

    Invasive plants can alter ecosystem nitrogen (N) cycling. To increase our understanding of nutrient use strategy of invasive tamarisk (Tamarix spp.) on an arid riparian ecosystem, we examined leaf nutrient contents and morphology of Tamarix ramosissima and its relationship with soil properties in the lower Virgin River floodplain, Nevada, U.S. Leaves were collected in three different locations; near the river, near the stand edge (60-70 m from the river edge) and at 30-40 m from the river edge in the summer of 2011. Leaves were analyzed for carbon (C) and N contents, and specific leaf area (SLA). Soil samples at 10-20 cm depths and under the canopy were also collected for soil water, pH, electrical conductivity (EC) and inorganic nitrogen (NO3- and NH4+) analysis. Results suggested that tree size and SLA increased with decreasing distance from the river, whereas C isotope discrimination did not differ among the samples based on distance from the river. Nitrogen content per unit mass and N isotope discrimination (δ15N) were significantly higher in the trees near the river. Soil NO3- and total inorganic N had positive relationships with δ15N in leaves, which suggests that leaf δ15N may be influenced by N concentrations on the soil surface. Negative correlations were found between soil EC and leaf N contents, suggesting that high soil salinity may decrease Tamarix leaf N and thus limit tree growth.

  2. Environmental Controls on Multi-Scale Soil Nutrient Variability in the Tropics: the Importance of Land-Cover Change

    NASA Astrophysics Data System (ADS)

    Holmes, K. W.; Kyriakidis, P. C.; Chadwick, O. A.; Matricardi, E.; Soares, J. V.; Roberts, D. A.

    2003-12-01

    The natural controls on soil variability and the spatial scales at which correlation exists among soil and environmental variables are critical information for evaluating the effects of deforestation. We detect different spatial scales of variability in soil nutrient levels over a large region (hundreds of thousands of km2) in the Amazon, analyze correlations among soil properties at these different scales, and evaluate scale-specific relationships among soil properties and the factors potentially driving soil development. Statistical relationships among physical drivers of soil formation, namely geology, precipitation, terrain attributes, classified soil types, and land cover derived from remote sensing, were included to determine which factors are related to soil biogeochemistry at each spatial scale. Surface and subsurface soil profile data from a 3000 sample database collected in Rond“nia, Brazil, were used to investigate patterns in pH, phosphorus, nitrogen, organic carbon, effective cation exchange capacity, calcium, magnesium, potassium, aluminum, sand, and clay in this environment grading from closed canopy tropical forest to savanna. We focus on pH in this presentation for simplicity, because pH is the single most important soil characteristic for determining the chemical environment of higher plants and soil microbial activity. We determined four spatial scales which characterize integrated patterns of soil chemistry: less than 3 km; 3 to 10 km; 10 to 68 km; and from 68 to 550 km (extent of study area). Although the finest observable scale was fixed by the field sampling density, the coarser scales were determined from relationships in the data through coregionalization modeling, rather than being imposed by the researcher. Processes which affect soils over short distances, such as land cover and terrain attributes, were good predictors of fine scale spatial components of nutrients; processes which affect soils over very large distances, such as

  3. Physiological profiling of soil microbial communities in a Florida scrub-oak ecosystem: spatial distribution and nutrient limitations.

    PubMed

    Brown, Alisha L P; Garland, Jay L; Day, Frank P

    2009-01-01

    Rapid physiological profiling of heterotrophic microbial communities enables intensive analysis of the factors affecting activity in aerobic habitats, such as soil. Previous methods for performing such profiling were severely limited due to enrichment bias and inflexibility in incubation conditions. We tested a new physiological profiling approach based on a microtiter plate oxygen sensor system (Becton Dickinson Oxygen Biosensor System (BDOBS)), which allows for testing of lower substrate addition (i.e., lower enrichment potential) and manipulation of physiochemical assay conditions, such as pH and nutrients. Soil microbial communities associated with a scrub-oak forest ecosystem on Merritt Island Wildlife Refuge in central Florida, USA, were studied in order to evaluate microbial activity in a nutrient poor soil and to provide baseline data on the site for subsequent evaluation of the effects of elevated CO(2) on ecosystem function. The spatial variation in physiological activity amongst different habitats (litter, bulk soil, and rhizosphere) was examined as a function of adaptation to local resources (i.e., water soluble extracts of roots and leaf litter) and the degree of N and P limitation. All the communities were primarily N-limited, with a secondary P limitation, which was greater in the rhizosphere and bulk soil. The litter community showed greater overall oxygen consumption when exposed to litter extracts relative to the rhizosphere or soil, suggesting acclimation toward greater use of the mixed substrates in the extract. Root extracts were readily used by communities from all the habitats with no habitat specific acclimation observed. A priming effect was detected in all habitats; addition of glucose caused a significant increase in the use of soil organic carbon. Response to added glucose was only observed with N and P addition, suggesting that C may be lost to the groundwater from these porous soils because nutrient limitation prevents C immobilization.

  4. Pollution of intensively managed greenhouse soils by nutrients and heavy metals in the Yellow River Irrigation Region, Northwest China.

    PubMed

    Kong, Xiaole; Cao, Jing; Tang, Rangyun; Zhang, Shengqiang; Dong, Fang

    2014-11-01

    The present study aimed to assess the potential ecological risk of heavy metals and nutrient accumulation in polytunnel greenhouse soils in the Yellow River irrigation region (YRIR), Northwest China, and to identify the potential sources of these heavy metals using principal component analysis. Contents of available nitrogen (AN), phosphorus (AP), and potassium (AK) in the surface polytunnel greenhouse soils (0-20 cm) varied from 13.42 to 486.78, from 39.10 to 566.97, and from 21.64 to 1,156.40 mg kg(-1), respectively, as well as AP, soil organic matter (SOM) and AK contents tended to increase significantly at the 0-20- and 20-40-cm soil layers. Heavy metal accumulations occurred in the polytunnel greenhouse soils as compared to arable soils, especially at a depth of 20 cm where Cd, Zn and Cu contents were significantly higher than arable soil. Cd and As were found to be the two main polluting elements in the greenhouse soils because their contents exceeded the thresholds established for greenhouse vegetable production HJ333-2006 in China and the background of Gansu province. It has been shown that Cd, Cu, Pb and Zn at the 0-20-cm soil layer were derived mainly from agricultural production activities, whereas contents of Cr and Ni at the same soil layer were determined by 'natural' factors and As originated from natural sources, deposition and irrigation water.

  5. Use of plant residues for improving soil fertility, pod nutrients, root growth and pod weight of okra (Abelmoschus esculentum L).

    PubMed

    Moyin-Jesu, Emmanuel Ibukunoluwa

    2007-08-01

    The effect of wood ash, sawdust, ground cocoa husk, spent grain and rice bran upon root development, ash content, pod yield and nutrient status and soil fertility for okra (Abelmoschus esculentum L NHAe 47 variety) was studied. The five organic fertilizer treatments were compared to chemical fertilizer (400kg/ha/crop NPK 15-15-15) and unfertilized controls in four field experiments replicated four times in a randomized complete block design. The results showed that the application of 6tha(-1) of plant residues increased (P<0.05) the soil N, P, K, Ca, Mg, pH, and SOM; pod N, P, K, Ca, Mg and ash; root length; and pod yield of okra in all four experiments relative to the control treatment. For instance, spent grain treatment increased the okra pod yield by 99%, 33%, 50%, 49%, 65% and 67% compared to control, NPK, wood ash, cocoa husk, rice bran and sawdust treatments respectively. In the stepwise regression, out of the total R(2) value of 0.83 for the soil nutrients to the pod yield of okra; soil N accounted for 50% of the soil fertility improvement and yield of okra. Spent grain, wood ash and cocoa husk were the most effective in improving okra pod weight, pod nutrients, ash content, root length and soil fertility whereas the rice bran and sawdust were the least effective. This was because the spent grain, wood ash and cocoa husk had lower C/N ratio and higher nutrient composition than rice bran and sawdust, thus, the former enhanced an increase in pod nutrients, composition for better human dietary intake, increased the root length, pod weight of okra and improved soil fertility and plant nutrition crop. The significance of the increases in okra mineral nutrition concentration by plant residues is that consumers will consume more of these minerals in their meals and monetarily spend less for purchasing vitamins and mineral supplement drugs to meet health requirements. In addition, the increase in plant nutrition and soil fertility would help to reduce the high cost

  6. Interactions between spring temperatures and snow cover alter plant-soil nutrient feedbacks in moist acidic arctic tundra

    NASA Astrophysics Data System (ADS)

    Weintraub, M. N.; Steltzer, H.; Sullivan, P.; Darrouzet-Nardi, A.; Schimel, J.; Wallenstein, M. D.; Livensperger, C.; Segal, A. D.

    2012-12-01

    A significant spring warming trend has been observed across the arctic, resulting in higher spring temperatures and earlier snowmelt. These climate changes have the potential to alter arctic soil carbon (C) and nitrogen (N) dynamics because they can significantly influence both plant growth and decomposition during the growing season. These changes are of particular concern because arctic tundra soils contain large stores of C and may act as a significant CO2 source with warming. To determine how changes in the timing of snowmelt and higher spring temperatures affect plant growth and soil nutrient dynamics, we conducted a factorial accelerated snowmelt and warming experiment in a moist acidic tundra plant community in the Alaskan arctic. We measured changes plant phenology and growth, and soil nutrient dynamics in response to these manipulations to determine the implications of earlier snowmelt and warming. We hypothesized that accelerated snowmelt would allow plants to start growing earlier, resulting in earlier root growth and plant N uptake from these nutrient poor soils, potentially exacerbating N limitation to decomposer microorganisms and reducing their activities. Contrary to our predictions, we observed delayed and reduced root growth in response to accelerated snowmelt, without similar reductions in aboveground productivity. We also found that warming in combination with accelerated snowmelt alleviated the inhibition of root growth, suggesting that low air temperatures following snowmelt may have inhibited plant growth, as plants were unprotected from swings in air temperature without the insulating snowpack. Furthermore, we found that greater root growth was associated with elevated, not reduced, soil N availability, which was also opposite to our predictions. These results suggest that C-rich root exudates stimulate microbial N acquisition and can actually increase N availability even as roots and microbes are taking up more N. This implies that as long

  7. Utilization of ERTS data to detect plant diseases and nutrient deficiencies, soil types and moisture levels

    NASA Technical Reports Server (NTRS)

    Parks, W. L.; Sewell, J. I.; Hilty, J. W.; Rennie, J. C. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The separation of the Mississippi Delta from the Memphis Association (Loess) is clearly defined in ERTS-1 imagery covering west Tennessee and Mississippi.

  8. Utilization of ERTS data to detect plant diseases and nutrient deficiencies, soil types and moisture levels

    NASA Technical Reports Server (NTRS)

    Parks, W. L. (Principal Investigator); Sewell, J. I.; Hilty, J. W.; Rennie, J. C.

    1973-01-01

    The author has identified the following significant results. Findings demonstrate the feasibility of delineating major terrain features, land uses, and crop species through computerized analyses. Channel 6 appears to give the most information for making separations of this type. By enlarging satellite imagery and visually comparing this with high altitude aerial photographs, locating small terrain features and cropland areas on satellite imagery is greatly facilitated. Forest types are discernable on the 2402 imagery with a #25 filter: pine stands have dark tones, hardwood stands have light tones, and pine-hardwood have intermediate tones. No textural differences are evident on this type of imagery. However, on the 2424 imagery with #89B filter, textural differences are evident but tonal differences are absent. Areas of considerable texture are interpreted as stands of high volume while areas of suppressed texture are of low volume. The 2402 imagery with a #57 filter appears to have little information of importance in timber inventory.

  9. Nutrients in soil solution following selective logging of a humid tropical 'terra firme' forest north of Manaus, Brazil.

    PubMed

    Mello Ivo, W; Ferreira, S; Biot, Y; Ross, S

    1996-06-01

    Sustainable use of the Amazon forest for timber production is conditioned by the effect of logging on the system's nutrient cycling. This paper reports the results of a soil moisture and soil water chemistry monitoring campaign before and immediately after a selective logging which removed 35 m(3) wood/ha. Soil moisture was measured using tensiometers, and soil water chemistry using suction samplers in five disturbance classes: tractor tracks, clearing centres, clearing edges, forest edges and untouched forest. The results show that the soil under the tractor tracks and clearings contained more moisture than under the untouched forest. The suction samplers extracted substantially more nitrate, ammonium, calcium, magnesium and potassium from the clearing centres, the tractor tracks and the clearing edges than from the forest sites. The results are explained in terms of altered microbial activity, changes in crown interception and uptake by roots.

  10. Biochar can be used to capture essential nutrients from dairy wastewater and improve soil physico-chemical properties

    NASA Astrophysics Data System (ADS)

    Ghezzehei, T. A.; Sarkhot, D. V.; Berhe, A. A.

    2014-09-01

    Recently, the potential for biochar use to recapture excess nutrients from dairy wastewater has been a focus of a growing number of studies. It is suggested that biochar produced from locally available excess biomass can be important in reducing release of excess nutrient elements from agricultural runoff, improving soil productivity, and long-term carbon (C) sequestration. Here we present a review of a new approach that is showing promise for the use of biochar for nutrient capture. Using batch sorption experiments, it has been shown that biochar can adsorb up to 20-43% of ammonium and 19-65% of the phosphate in flushed dairy manure in 24 h. These results suggest a potential of biochar for recovering essential nutrients from dairy wastewater and improving soil fertility if the enriched biochar is returned to soil. Based on the sorption capacity of 2.86 and 0.23 mg ammonium and phosphate, respectively, per gram of biochar and 10-50% utilization of available excess biomass, in the state of California (US) alone, 11 440 to 57 200 tonnes of ammonium-N and 920-4600 tonnes of phosphate can be captured from dairy waste each year while at the same time disposing up to 8-40 million tons of excess biomass.

  11. Convergence of a specialized root trait in plants from nutrient-impoverished soils: phosphorus-acquisition strategy in a nonmycorrhizal cactus.

    PubMed

    Abrahão, A; Lambers, H; Sawaya, A C H F; Mazzafera, P; Oliveira, R S

    2014-10-01

    In old, phosphorus (P)-impoverished habitats, root specializations such as cluster roots efficiently mobilize and acquire P by releasing large amounts of carboxylates in the rhizosphere. These specialized roots are rarely mycorrhizal. We investigated whether Discocactus placentiformis (Cactaceae), a common species in nutrient-poor campos rupestres over white sands, operates in the same way as other root specializations. Discocactus placentiformis showed no mycorrhizal colonization, but exhibited a sand-binding root specialization with rhizosheath formation. We first provide circumstantial evidence for carboxylate exudation in field material, based on its very high shoot manganese (Mn) concentrations, and then firm evidence, based on exudate analysis. We identified predominantly oxalic acid, but also malic, citric, lactic, succinic, fumaric, and malonic acids. When grown in nutrient solution with P concentrations ranging from 0 to 100 μM, we observed an increase in total carboxylate exudation with decreasing P supply, showing that P deficiency stimulated carboxylate release. Additionally, we tested P solubilization by citric, malic and oxalic acids, and found that they solubilized P from the strongly P-sorbing soil in its native habitat, when the acids were added in combination and in relatively low concentrations. We conclude that the sand-binding root specialization in this nonmycorrhizal cactus functions similar to that of cluster roots, which efficiently enhance P acquisition in other habitats with very low P availability.

  12. Model of how plants sense zinc deficiency.

    PubMed

    Assunção, Ana G L; Persson, Daniel P; Husted, Søren; Schjørring, Jan K; Alexander, Ross D; Aarts, Mark G M

    2013-09-01

    Plants are capable of inducing a range of physico-chemical and microbial modifications of the rhizosphere which can mobilize mineral nutrients or prevent toxic elements from entering the roots. Understanding how plants sense and adapt to variations in nutrient availability is essential in order to develop plant-based solutions addressing nutrient-use-efficiency and adaptation to nutrient-limited or -toxic soils. Recently two transcription factors of the bZIP family (basic-region leucine zipper) have been identified in Arabidopsis and shown to be pivotal in the adaptation response to zinc deficiency. They represent not only the first regulators of zinc homeostasis identified in plants, but also a very promising starting-point that can provide new insights into the molecular basis of how plants sense and adapt to the stress of zinc deficiency. Considering the available information thus far we propose in this review a putative model of how plants sense zinc deficiency.

  13. Soil nutrient effects on oviposition preference, larval performance, and chemical defense of a specialist insect herbivore.

    PubMed

    Prudic, Kathleen L; Oliver, Jeffrey C; Bowers, M Deane

    2005-05-01

    This study examined the effects of increased leaf nitrogen in natural host-plants (Plantago spp.) on female oviposition preference, larval performance, and larval chemical defense of the butterfly Junonia coenia. Increased availability of soil nutrients caused the host-plant's foliar nitrogen to increase and its chemical defense to decrease. Larval performance did not correlate with increases in foliar nitrogen. Larval growth rate and survival were equivalent across host-plant treatments. However, larvae raised on fertilized host-plants showed concomitant decreases in chemical defense as compared to larvae reared on unfertilized host-plants. Since most butterfly larvae cannot move long distances during their first few instars and are forced to feed upon the plant on which they hatched, J. coenia larval chemical defense is determined, in large part, by female oviposition choice. Female butterflies preferred host-plants with high nitrogen over host-plants with low nitrogen; however, this preference was also mediated by plant chemical defense. Female butterflies preferred more chemically defended host-plants when foliar nitrogen was equivalent between host-plants. J. coenia larvae experience intense predation in the field, especially when larvae are not chemically well defended. Any qualitative or quantitative variation in plant allelochemical defense has fitness consequences on these larvae. Thus, these results indicate that females may be making sub-optimal oviposition decisions under a nutrient-enriched regime, when predators are present. Given the recent increase in fertilizer application and nitrogen deposition on the terrestrial landscape, these interactions between female preference, larval performance, and larval chemical defense may result in long-term changes in population dynamics and persistence of specialist insects.

  14. Responses of soil nutrient concentrations and stoichiometry to different human land uses in a subtropical tidal wetland

    PubMed Central

    Wang, W.; Sardans, J.; Zeng, C.; Zhong, C.; Li, Y.; Peñuelas, J.

    2015-01-01

    We studied the impacts of anthropogenic changes in land use on the stoichiometric imbalance of soil carbon (C), nitrogen (N), phosphorus (P) and potassium (K) in Phragmites australis wetlands in the Minjiang River estuary. We compared five areas with different land uses: P. australis wetland (control), grassland, a mudskipper breeding flat, pond aquaculture and rice cropland. Human activity has affected the elemental and stoichiometric compositions of soils through changes in land use. In general, soil C and N concentrations were lower and total soil K concentrations were higher at the sites under human land uses relative to the control site, and total soil P concentrations were generally not significantly different. The close relationship between total soil C and N concentrations in all cases, including fertilization with N, suggested that N was the most limiting nutrient in these wetlands. Lower soil N concentrations and similar soil P concentrations and higher soil K concentrations under human land-use activities suggest that human activity has increased the role of N limitation in these wetlands. Only grassland use increases soil N contents (only in the 0-10 cm of soil). Despite N fertilization, lower soil N concentrations were also observed in the rice cropland, indicating the difficulty of avoiding N limitation in these wetlands. The observed lower soil N:P ratio, together with higher soil P and K availabilities in rice croplands, is consistent with the tendency of human activity to change the competitive relationships of plants, in this case favoring species adapted to high rates of growth (low N:P ratio) and/or favoring plants with high demands for P and K. Both, soil C storage and respiration were higher in grasslands, likely due to the introduction of grasses, which led to a high density of plants, increased grazing activity and soil compaction. Soil C storage and respiration were lower under human land uses, except in the rice cropland, with respect to

  15. Rock Outcrops Redistribute Organic Carbon and Nutrients to Nearby Soil Patches in Three Karst Ecosystems in SW China.

    PubMed

    Wang, Dianjie; Shen, Youxin; Li, Yuhui; Huang, Jin

    2016-01-01

    Emergent rock outcrops are common in terrestrial ecosystems. However, little research has been conducted regarding their surface function in redistributing organic carbon and nutrient fluxes to soils nearby. Water that fell on and ran off 10 individual rock outcrops was collected in three 100 × 100 m plots within a rock desertification ecosystem, an anthropogenic forest ecosystem, and a secondary forest ecosystem between June 2013 and June 2014 in Shilin, SW China. The concentrations of total organic carbon (TOC), total nitrogen (N), total phosphorus (P), and potassium (K) in the water samples were determined during three seasons, and the total amounts received by and flowing out from the outcrops were calculated. In all three ecosystems, TOC and N, P, and K were found throughout the year in both the water received by and delivered to nearby soil patches. Their concentrations and amounts were generally greater in forested ecosystems than in the rock desertification ecosystem. When rock outcrops constituted a high percentage (≥ 30%) of the ground surface, the annual export of rock outcrop runoff contributed a large amount of organic carbon and N, P, and K nutrients to soil patches nearby by comparison to the amount soil patches received via atmospheric deposition. These contributions may increase the spatial heterogeneity of soil fertility within patches, as rock outcrops of different sizes, morphologies, and emergence ratios may surround each soil patch.

  16. Rock Outcrops Redistribute Organic Carbon and Nutrients to Nearby Soil Patches in Three Karst Ecosystems in SW China

    PubMed Central

    Wang, Dianjie; Shen, Youxin; Li, Yuhui; Huang, Jin

    2016-01-01

    Emergent rock outcrops are common in terrestrial ecosystems. However, little research has been conducted regarding their surface function in redistributing organic carbon and nutrient fluxes to soils nearby. Water that fell on and ran off 10 individual rock outcrops was collected in three 100 × 100 m plots within a rock desertification ecosystem, an anthropogenic forest ecosystem, and a secondary forest ecosystem between June 2013 and June 2014 in Shilin, SW China. The concentrations of total organic carbon (TOC), total nitrogen (N), total phosphorus (P), and potassium (K) in the water samples were determined during three seasons, and the total amounts received by and flowing out from the outcrops were calculated. In all three ecosystems, TOC and N, P, and K were found throughout the year in both the water received by and delivered to nearby soil patches. Their concentrations and amounts were generally greater in forested ecosystems than in the rock desertification ecosystem. When rock outcrops constituted a high percentage (≥ 30%) of the ground surface, the annual export of rock outcrop runoff contributed a large amount of organic carbon and N, P, and K nutrients to soil patches nearby by comparison to the amount soil patches received via atmospheric deposition. These contributions may increase the spatial heterogeneity of soil fertility within patches, as rock outcrops of different sizes, morphologies, and emergence ratios may surround each soil patch. PMID:27509199

  17. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil.

    PubMed

    Sutton, Nora B; Grotenhuis, Tim; Rijnaarts, Huub H M

    2014-02-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton's reagent and modified Fenton's reagent coupled with a subsequent bioremediation phase of 187d, both with and without nutrient amendment. Chemical oxidation mobilized SOM into the liquid phase, producing dissolved organic carbon (DOC) concentrations 8-16 times higher than the untreated field sample. Higher aqueous concentrations of nitrogen and phosphorous species were also observed following oxidation; NH4(+) increased 14-172 times. During the bioremediation phase, dissolved carbon and nutrient species were utilized for microbial growth-yielding DOC concentrations similar to field sample levels within 56d of incubation. In the absence of nutrient amendment, the highest microbial respiration rates were correlated with higher availability of nitrogen and phosphorus species mobilized by oxidation. Significant diesel degradation was only observed following nutrient amendment, implying that nutrients mobilized by chemical oxidation can increase microbial activity but are insufficient for bioremediation. While all bioremediation occurred in the first 28d of incubation in the biotic control microcosm with nutrient amendment, biodegradation continued throughout 187d of incubation following chemical oxidation, suggesting that chemical treatment also affects the desorption of organic contaminants from SOM. Overall, results indicate that biodegradation of DOC, as an alternative substrate to diesel, and biological utilization of mobilized nutrients have implications for the success of coupled ISCO and ISB treatments.

  18. Resistance and tolerance of Terminalia sericea trees to simulated herbivore damage under different soil nutrient and moisture conditions.

    PubMed

    Katjiua, Mutjinde L J; Ward, David

    2006-07-01

    Resource availability, degree of herbivore damage, genetic variability, and their interactions influence the allocation of investment by plants to resistance and tolerance traits. We evaluated the independent and interactive effects of soil nutrients and moisture, and simulated the effects of herbivore damage on condensed tannins (resistance) and growth/regrowth (tolerance) traits of Terminalia sericea, a deciduous tree in the Kalahari desert that constitutes a major component of livestock diet. We used a completely crossed randomized-block design experiment to examine the effects of nutrients, water availability, and herbivore damage on regrowth and resistance traits of T. sericea seedlings. Plant height, number of branches, internode length, leaf area, leaf mass for each seedling, combined weight of stems and twigs, and root mass were recorded. Condensed tannin concentrations were 22.5 and 21.5% higher under low nutrients and low soil moisture than under high nutrient and high water treatment levels. Tannin concentrations did not differ significantly between control and experimental seedlings 2 mo after simulated herbivore damage. Tannin concentrations correlated more strongly with growth traits under low- than under high-nutrient conditions. No trade-offs were detected among individual growth traits, nor between growth traits and condensed tannins. T. sericea appeared to invest more in both resistance and regrowth traits when grown under low-nutrient conditions. Investment in the resistance trait (condensed tannin) under high-nutrient conditions was minimal and, to a lesser degree, correlated with plant growth. These results suggest that T. sericea displays both resistance and tolerance strategies, and that the degree to which each is expressed is resource-dependent.

  19. Above- and belowground responses of Arctic tundra ecosystems to altered soil nutrients and mammalian herbivory.

    PubMed

    Gough, Laura; Moore, John C; Shaver, Gauis R; Simpson, Rodney T; Johnson, David R

    2012-07-01

    Theory and observation indicate that changes in the rate of primary production can alter the balance between the bottom-up influences of plants and resources and the top-down regulation of herbivores and predators on ecosystem structure and function. The exploitation ecosystem hypothesis (EEH) posited that as aboveground net primary productivity (ANPP) increases, the additional biomass should support higher trophic levels. We developed an extension of EEH to include the impacts of increases in ANPP on belowground consumers in a similar manner as aboveground, but indirectly through changes in the allocation of photosynthate to roots. We tested our predictions for plants aboveground and for phytophagous nematodes and their predators belowground in two common arctic tundra plant communities subjected to 11 years of increased soil nutrient availability and/or exclusion of mammalian herbivores. The less productive dry heath (DH) community met the predictions of EEH aboveground, with the greatest ANPP and plant biomass in the fertilized plots protected from herbivory. A palatable grass increased in fertilized plots while dwarf evergreen shrubs and lichens declined. Belowground, phytophagous nematodes also responded as predicted, achieving greater biomass in the higher ANPP plots, whereas predator biomass tended to be lower in those same plots (although not significantly). In the higher productivity moist acidic tussock (MAT) community, aboveground responses were quite different. Herbivores stimulated ANPP and biomass in both ambient and enriched soil nutrient plots; maximum ANPP occurred in fertilized plots exposed to herbivory. Fertilized plots became dominated by dwarf birch (a deciduous shrub) and cloudberry (a perennial forb); under ambient conditions these two species coexist with sedges, evergreen dwarf shrubs, and Sphagnum mosses. Phytophagous nematodes did not respond significantly to changes in ANPP, although predator biomass was greatest in control plots. The

  20. Enhanced growth of halophyte plants in biochar-amended coastal soil: roles of nutrient availability and rhizosphere microbial modulation.

    PubMed

    Zheng, Hao; Wang, Xiao; Chen, Lei; Wang, Zhenyu; Xia, Yang; Zhang, Yipeng; Wang, Hefang; Luo, Xianxiang; Xing, Baoshan

    2017-03-27

    Soil health is essential and irreplaceable for plant growth and global food production, which has been threatened by climate change and soil degradation. Degraded coastal soils are urgently required to reclaim using new sustainable technologies. Interest in applying biochar to improve soil health and promote crop yield has rapidly increased because of its multiple benefits. However, effects of biochar addition on the saline-sodic coastal soil health and halophyte growth were poorly understood. Response of two halophytes, Sesbania (Sesbania cannabina) and Seashore mallow (Kosteletzkya virginica), to the individual or co-application of biochar and inorganic fertilizer into a coastal soil was investigated using a 52-day pot experiment. The biochar alone or co-application stimulated the plant growth (germination, root development, biomass), primarily attributed to the enhanced nutrients availability from the biochar-improved soil health. Additionally, the promoted microbial activities and bacterial community shift towards the beneficial taxa (e.g., Pseudomonas and Bacillus) in the rhizosphere also contributed to the enhanced plant growth and biomass. Our findings showed the promising significance because biochar added at an optimal level (≤5%) could be a feasible option to reclaim the degraded coastal soil, enhance plant growth and production, and increase soil health and food security.

  1. Decoupling of soil nutrient cycles as a function of aridity in global drylands

    NASA Astrophysics Data System (ADS)

    Delgado-Baquerizo, Manuel; Maestre, Fernando T.; Gallardo, Antonio; Bowker, Matthew A.; Wallenstein, Matthew D.; Quero, Jose Luis; Ochoa, Victoria; Gozalo, Beatriz; García-Gómez, Miguel; Soliveres, Santiago; García-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Escolar, Cristina; Arredondo, Tulio; Barraza-Zepeda, Claudia; Bran, Donaldo; Carreira, José Antonio; Chaieb, Mohamed; Conceição, Abel A.; Derak, Mchich; Eldridge, David J.; Escudero, Adrián; Espinosa, Carlos I.; Gaitán, Juan; Gatica, M. Gabriel; Gómez-González, Susana; Guzman, Elizabeth; Gutiérrez, Julio R.; Florentino, Adriana; Hepper, Estela; Hernández, Rosa M.; Huber-Sannwald, Elisabeth; Jankju, Mohammad; Liu, Jushan; Mau, Rebecca L.; Miriti, Maria; Monerris, Jorge; Naseri, Kamal; Noumi, Zouhaier; Polo, Vicente; Prina, Aníbal; Pucheta, Eduardo; Ramírez, Elizabeth; Ramírez-Collantes, David A.; Romão, Roberto; Tighe, Matthew; Torres, Duilio; Torres-Díaz, Cristian; Ungar, Eugene D.; Val, James; Wamiti, Wanyoike; Wang, Deli; Zaady, Eli

    2013-10-01

    The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability. The increase in aridity predicted for the twenty-first century in many drylands worldwide may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.

  2. Decoupling of soil nutrient cycles as a function of aridity in global drylands.

    PubMed

    Delgado-Baquerizo, Manuel; Maestre, Fernando T; Gallardo, Antonio; Bowker, Matthew A; Wallenstein, Matthew D; Quero, Jose Luis; Ochoa, Victoria; Gozalo, Beatriz; García-Gómez, Miguel; Soliveres, Santiago; García-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Escolar, Cristina; Arredondo, Tulio; Barraza-Zepeda, Claudia; Bran, Donaldo; Carreira, José Antonio; Chaieb, Mohamed; Conceição, Abel A; Derak, Mchich; Eldridge, David J; Escudero, Adrián; Espinosa, Carlos I; Gaitán, Juan; Gatica, M Gabriel; Gómez-González, Susana; Guzman, Elizabeth; Gutiérrez, Julio R; Florentino, Adriana; Hepper, Estela; Hernández, Rosa M; Huber-Sannwald, Elisabeth; Jankju, Mohammad; Liu, Jushan; Mau, Rebecca L; Miriti, Maria; Monerris, Jorge; Naseri, Kamal; Noumi, Zouhaier; Polo, Vicente; Prina, Aníbal; Pucheta, Eduardo; Ramírez, Elizabeth; Ramírez-Collantes, David A; Romão, Roberto; Tighe, Matthew; Torres, Duilio; Torres-Díaz, Cristian; Ungar, Eugene D; Val, James; Wamiti, Wanyoike; Wang, Deli; Zaady, Eli

    2013-10-31

    The biogeochemical cycles of carbon (C), nitrogen (N) and phosphorus (P) are interlinked by primary production, respiration and decomposition in terrestrial ecosystems. It has been suggested that the C, N and P cycles could become uncoupled under rapid climate change because of the different degrees of control exerted on the supply of these elements by biological and geochemical processes. Climatic controls on biogeochemical cycles are particularly relevant in arid, semi-arid and dry sub-humid ecosystems (drylands) because their biological activity is mainly driven by water availability. The increase in aridity predicted for the twenty-first century in many drylands worldwide may therefore threaten the balance between these cycles, differentially affecting the availability of essential nutrients. Here we evaluate how aridity affects the balance between C, N and P in soils collected from 224 dryland sites from all continents except Antarctica. We find a negative effect of aridity on the concentration of soil organic C and total N, but a positive effect on the concentration of inorganic P. Aridity is negatively related to plant cover, which may favour the dominance of physical processes such as rock weathering, a major source of P to ecosystems, over biological processes that provide more C and N, such as litter decomposition. Our findings suggest that any predicted increase in aridity with climate change will probably reduce the concentrations of N and C in global drylands, but increase that of P. These changes would uncouple the C, N and P cycles in drylands and could negatively affect the provision of key services provided by these ecosystems.

  3. Evidence of soil nutrient availability as the proximate constraint on growth of treeline trees in northwest Alaska.

    PubMed

    Sullivan, Patrick F; Ellison, Sarah B Z; McNown, Robert W; Brownlee, Annalis H; Sveinbjörnsson, Bjartmar

    2015-03-01

    The position of the Arctic treeline, which is a key regulator of surface energy exchange and carbon cycling, is widely thought to be controlled by temperature. Here, we present evidence that soil nutrient availability, rather than temperature, may be the proximate control on growth of treeline trees at our study site in northwest Alaska. We examined constraints on growth and allocation of white spruce in three contrasting habitats. The habitats had similar aboveground climates, but soil temperature declined from the riverside terrace to the forest to the treeline. We identified six lines of evidence that conflict with the hypothesis of direct temperature control and/or point to the importance of soil nutrient availability. First, the magnitude of aboveground growth declined from the terrace to the forest to the treeline, along gradients of diminishing soil nitrogen (N) availability and needle N concentration. Second, peak rates of branch extension, main stem radial and fine-root growth were generally not coincident with seasonal air and soil temperature maxima. At the treeline, in particular, rates of aboveground and fine-root growth declined well before air and soil temperatures reached their seasonal peaks. Third, in contrast with the hypothesis of temperature-limited growth, growing season average net photosynthesis was positively related to the sum of normalized branch extension, main stem radial and fine-root growth across trees and sites. Fourth, needle nonstructural carbohydrate concentration was significantly higher on the terrace, where growth was greatest. Fifth, annual branch extension growth was positively related to snow depth, consistent with the hypothesis that deeper snow promotes microbial activity and greater soil nutrient availability. Finally, the tree ring record revealed a large growth increase during late 20th-century climate warming on the terrace, where soil N availability is relatively high. Meanwhile, trees in the forest and at the

  4. Linking the planting of cover crops to soil and water nutrient dynamics in Shatto Ditch Watershed, IN

    NASA Astrophysics Data System (ADS)

    Christopher, S. F.; Tank, J. L.; Hanrahan, B. R.; Mahl, U. H.; Huang, K.

    2013-12-01

    Tile drainage systems are common in the Midwest, and facilitate the transfer of excess inorganic nitrogen (N) and phosphorus (P) from agricultural soils to adjacent streams. These non-point sources contribute to elevated nutrient loads to tributaries in the Mississippi River Basin, which have been linked to widespread hypoxia and associated ecological and economic problems in the Gulf of Mexico. In agricultural areas dominated by row-crops, the planting of cover crops after the cash crop has been harvested offers a potential mechanism to reduce nutrient leaching from fields to tile drains in the off-season. In general, cover crops retain nutrients on fields and increase soil organic matter (SOM) content after they are harvested. The planting of cover crops also promotes immobilization of soil N and reduction in losses of dissolved P from soils due to reduced erosion, resulting in significantly less leaching to surface waters through tile drains. As part of a demonstration project in the Shatto Ditch Watershed, located in the Tippecanoe River Basin, IN, we are testing whether the planting of cover crops will influence soil nutrient and organic matter, and how cover crops alter the dynamics of nutrient leaching from tile drains. We have been sampling tile drain outflows on a twice-monthly sampling regime and have been measuring dissolved inorganic N and P concentrations in tile water since November 2012. During Spring 2013, tile drain nitrate concentrations sampled synoptically throughout the watershed ranged from 2.6 - 38.9 mg NO3- L -1 (mean = 17.2 +/- 1.6 mg NO3- L -1) with the lowest concentrations coming from fields planted in cover crops (range = 2.6 - 19.0 mg NO3- L -1, mean = 9.7 +/- 1.5 mg NO3- L -1). In contrast, soluble reactive phosphorus (SRP) concentrations were much lower in tile drain water and ranged from 7.5 - 182.7 μg L-1 (mean = 24.5 +/- 5.0 μg L-1 SRP) and preliminary data suggest that there were no differences between fields with and without

  5. Improvement of Arbuscular Mycorrhiza Development by Inoculation of Soil with Phosphate-Solubilizing Rhizobacteria To Improve Rock Phosphate Bioavailability ((sup32)P) and Nutrient Cycling

    PubMed Central

    Toro, M.; Azcon, R.; Barea, J.

    1997-01-01

    The interactive effect of phosphate-solubilizing bacteria and arbuscular mycorrhizal (AM) fungi on plant use of soil P sources of low bioavailability (endogenous or added as rock phosphate [RP] material) was evaluated by using soil microcosms which integrated (sup32)P isotopic dilution techniques. The microbial inocula consisted of the AM fungus Glomus intraradices and two phosphate-solubilizing rhizobacterial isolates: Enterobacter sp. and Bacillus subtilis. These rhizobacteria behaved as "mycorrhiza helper bacteria" promoting establishment of both the indigenous and the introduced AM endophytes despite a gradual decrease in bacterial population size, which dropped from 10(sup7) at planting to 10(sup3) CFU g(sup-1) of dry rhizosphere soil at harvest. Dual inoculation with G. intraradices and B. subtilis significantly increased biomass and N and P accumulation in plant tissues. Regardless of the rhizobacterium strain and of the addition of RP, AM plants displayed lower specific activity ((sup32)P/(sup31)P) than their comparable controls, suggesting that the plants used P sources not available in their absence. The inoculated rhizobacteria may have released phosphate ions ((sup31)P), either from the added RP or from the less-available indigenous P sources, which were effectively taken up by the external AM mycelium. Soluble Ca deficiency in the test soil may have benefited P solubilization. At least 75% of the P in dually inoculated plants derived from the added RP. It appears that these mycorrhizosphere interactions between bacterial and fungal plant associates contributed to the biogeochemical P cycling, thus promoting a sustainable nutrient supply to plants. PMID:16535730

  6. Nutrient depletion from rhizosphere solution by maize grown in soil with long-term compost amendment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improved understanding of rhizosphere chemistry will enhance our ability to model nutrient dynamics and on a broader scale, to develop effective management strategies for applied plant nutrients. With a controlled-climate study, we evaluated in situ changes in macro-nutrient concentrations in the rh...

  7. Seasonality, Rather than Nutrient Addition or Vegetation Types, Influenced Short-Term Temperature Sensitivity of Soil Organic Carbon Decomposition.

    PubMed

    Qian, Yu-Qi; He, Feng-Peng; Wang, Wei

    2016-01-01

    The response of microbial respiration from soil organic carbon (SOC) decomposition to environmental changes plays a key role in predicting future trends of atmospheric CO2 concentration. However, it remains uncertain whether there is a universal trend in the response of microbial respiration to increased temperature and nutrient addition among different vegetation types. In this study, soils were sampled in spring, summer, autumn and winter from five dominant vegetation types, including pine, larch and birch forest, shrubland, and grassland, in the Saihanba area of northern China. Soil samples from each season were incubated at 1, 10, and 20°C for 5 to 7 days. Nitrogen (N; 0.035 mM as NH4NO3) and phosphorus (P; 0.03 mM as P2O5) were added to soil samples, and the responses of soil microbial respiration to increased temperature and nutrient addition were determined. We found a universal trend that soil microbial respiration increased with increased temperature regardless of sampling season or vegetation type. The temperature sensitivity (indicated by Q10, the increase in respiration rate with a 10°C increase in temperature) of microbial respiration was higher in spring and autumn than in summer and winter, irrespective of vegetation type. The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio. Microbial respiration (or Q10) did not significantly respond to N or P addition. Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer.

  8. Seasonality, Rather than Nutrient Addition or Vegetation Types, Influenced Short-Term Temperature Sensitivity of Soil Organic Carbon Decomposition

    PubMed Central

    He, Feng-Peng; Wang, Wei

    2016-01-01

    The response of microbial respiration from soil organic carbon (SOC) decomposition to environmental changes plays a key role in predicting future trends of atmospheric CO2 concentration. However, it remains uncertain whether there is a universal trend in the response of microbial respiration to increased temperature and nutrient addition among different vegetation types. In this study, soils were sampled in spring, summer, autumn and winter from five dominant vegetation types, including pine, larch and birch forest, shrubland, and grassland, in the Saihanba area of northern China. Soil samples from each season were incubated at 1, 10, and 20°C for 5 to 7 days. Nitrogen (N; 0.035 mM as NH4NO3) and phosphorus (P; 0.03 mM as P2O5) were added to soil samples, and the responses of soil microbial respiration to increased temperature and nutrient addition were determined. We found a universal trend that soil microbial respiration increased with increased temperature regardless of sampling season or vegetation type. The temperature sensitivity (indicated by Q10, the increase in respiration rate with a 10°C increase in temperature) of microbial respiration was higher in spring and autumn than in summer and winter, irrespective of vegetation type. The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio. Microbial respiration (or Q10) did not significantly respond to N or P addition. Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer. PMID:27070782

  9. Glyphosate-based herbicides reduce the activity and reproduction of earthworms and lead to increased soil nutrient concentrations

    PubMed Central

    Gaupp-Berghausen, Mailin; Hofer, Martin; Rewald, Boris; Zaller, Johann G.

    2015-01-01

    Herbicide use is increasing worldwide both in agriculture and private gardens. However, our knowledge of potential side-effects on non-target soil organisms, even on such eminent ones as earthworms, is still very scarce. In a greenhouse experiment, we assessed the impact of the most widely used glyphosate-based herbicide Roundup on two earthworm species with different feeding strategies. We demonstrate, that the surface casting activity of vertically burrowing earthworms (Lumbricus terrestris) almost ceased three weeks after herbicide application, while the activity of soil dwelling earthworms (Aporrectodea caliginosa) was not affected. Reproduction of the soil dwellers was reduced by 56% within three months after herbicide application. Herbicide application led to increased soil concentrations of nitrate by 1592% and phosphate by 127%, pointing to potential risks for nutrient leaching into streams, lakes, or groundwater aquifers. These sizeable herbicide-induced impacts on agroecosystems are particularly worrisome because these herbicides have been globally used for decades. PMID:26243044

  10. Glyphosate-based herbicides reduce the activity and reproduction of earthworms and lead to increased soil nutrient concentrations.

    PubMed

    Gaupp-Berghausen, Mailin; Hofer, Martin; Rewald, Boris; Zaller, Johann G

    2015-08-05

    Herbicide use is increasing worldwide both in agriculture and private gardens. However, our knowledge of potential side-effects on non-target soil organisms, even on such eminent ones as earthworms, is still very scarce. In a greenhouse experiment, we assessed the impact of the most widely used glyphosate-based herbicide Roundup on two earthworm species with different feeding strategies. We demonstrate, that the surface casting activity of vertically burrowing earthworms (Lumbricus terrestris) almost ceased three weeks after herbicide application, while the activity of soil dwelling earthworms (Aporrectodea caliginosa) was not affected. Reproduction of the soil dwellers was reduced by 56% within three months after herbicide application. Herbicide application led to increased soil concentrations of nitrate by 1592% and phosphate by 127%, pointing to potential risks for nutrient leaching into streams, lakes, or groundwater aquifers. These sizeable herbicide-induced impacts on agroecosystems are particularly worrisome because these herbicides have been globally used for decades.

  11. Effect of sludge-amendment or nutrient addition on the biodegradation of the herbicide isoproturon in soil.

    PubMed

    Perrin-Ganier, C; Schiavon, F; Morel, J L; Schiavon, M

    2001-08-01

    Adding sludge to agricultural soil results in added organic matter, nutrients and metallic and/or organic pollutants. These components may modify the behaviour of pesticides in the soil. We monitored possible changes in the degradation of the herbicide isoproturon (production of CO2 and degradation products) in soil amended with sludge, heavy metals or nitrogen and phosphorus. The treated and control soils were incubated under controlled conditions for 60 days. The nitrogen and phosphorus had the greatest effect on isoproturon degradation, independent of the presence of pollutants. Mineralisation of the herbicide to CO2 was slow and seemed to be linked to a fast degradation and to the accumulation of a complex degradation product that was neither catabolized nor adsorbed, 4,4'-diisopropylazobenzene. This degradation pathway also produced smaller amounts of non-extractable residues. Sewage sludge had no significant effect on isoproturon degradation, despite a large increase of organic matter mineralisation (factor 2).

  12. Effects of nitrogen fertilization on soil nutrient concentration and phosphatase activity and forage nutrient uptake from a grazed pasture system.

    PubMed

    Dillard, Sandra Leanne; Wood, Charles Wesley; Wood, Brenda Hall; Feng, Yucheng; Owsley, Walter Frank; Muntifering, Russell Brian

    2015-05-01

    Over a 3-year period, the effect of differing N-application regimes on soil extractable-P concentration, soil phosphatase activity, and forage P uptake in a P-enriched grazed-pasture system was investigated. In the fall of each year, six 0.28-ha plots were overseeded with triticale ( × Triticosecale rimpaui Wittm.) and crimson clover (Trifolium incarnatum) into a tall fescue (Lolium arundinacea)/bermudagrass (Cynodon dactylon) sod and assigned to 1 of 3 N-fertilizer treatments (n = 2): 100% of N recommendation in a split application (100N), 50% in a single application (50N), and 0% of N recommendation (0N) for triticale. Cattle commenced grazing the following spring and grazed until May. In the summer, plots were overseeded with cowpea (Vigna unguiculata), fertilized at the same rates by reference to N recommendations for bermudagrass, and grazed by cattle until September. There were no effects of N fertilization on soil phosphatase activity, electrical conductivity, or concentrations of water-soluble P. Concentrations of extractable P decreased in plots receiving 50N, but increasing N fertilization to 100N resulted in no further reduction in extractable P. Forage biomass, foliar P concentrations, and forage P mass were not affected by N fertilization rates at the plant-community level, but responses were observed within individual forage species. Results are interpreted to mean that N fertilization at 50% of the agronomic recommendation for the grass component can increase forage P mass of specific forages and decrease soil extractable P, thus providing opportunity for decreasing P losses from grazed pasture.

  13. Effects of soil temperature on shoot and root growth and nutrient uptake of 5-year-old Norway spruce seedlings.

    PubMed

    Lahti, M; Aphalo, P J; Finér, L; Ryyppö, A; Lehto, T; Mannerkoski, H

    2005-01-01

    Soil temperature is a main factor limiting root growth in the boreal forest. To simulate the possible soil-warming effect of future climate change, 5-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were subjected to three simulated growing seasons in controlled environment rooms. The seedlings were acclimated to a soil temperature of 16 degrees C during the first (GS I) and third growing seasons (GS III), but were assigned to random soil-temperature treatments of 9, 13, 18 and 21 degrees C during the second growing season (GS II). In GS II, shoot diameter growth was lowest in the 21 degrees C treatment and root growth was lowest in the 9 degrees C treatment. In GS III, shoot height and root length growth improved in seedlings that had been kept at 9 degrees C during GS II, indicating compensatory growth in response to increased soil temperature. The temporary decrease in soil temperature had no long-lasting significant effect on seedling biomass or total nutrient uptake. At the end of GS III, fine roots of seedlings exposed to a soil temperature of 21 degrees C in GS II were distributed more evenly between the organic and mineral soil layers than roots of seedlings in the other treatments. During GS II and GS III, root growth started earlier than shoot growth, decreased during the rapid shoot elongation phase and increased again as shoot growth decreased.

  14. Impairment of Respiratory Chain under Nutrient Deficiency in Plants: Does it Play a Role in the Regulation of Iron and Sulfur Responsive Genes?

    PubMed

    Vigani, Gianpiero; Briat, Jean-François

    2015-01-01

    Plant production and plant product quality strongly depend on the availability of mineral nutrients. Among them, sulfur (S) and iron (Fe) play a central role, as they are needed for many proteins of the respiratory chain. Plant mitochondria play essential bioenergetic and biosynthetic functions as well as they have an important role in signaling processes into the cell. Here, by comparing several transcriptomic data sets from plants impaired in their respiratory function with the genes regulated under Fe or S deficiencies obtained from other data sets, nutrient-responsive genes potentially regulated by hypothetical mitochondrial retrograde signaling pathway are evidenced. It leads us to hypothesize that plant mitochondria could be, therefore, required for regulating the expression of key genes involved both in Fe and S metabolisms.

  15. Impairment of Respiratory Chain under Nutrient Deficiency in Plants: Does it Play a Role in the Regulation of Iron and Sulfur Responsive Genes?

    PubMed Central

    Vigani, Gianpiero; Briat, Jean-François

    2016-01-01

    Plant production and plant product quality strongly depend on the availability of mineral nutrients. Among them, sulfur (S) and iron (Fe) play a central role, as they are needed for many proteins of the respiratory chain. Plant mitochondria play essential bioenergetic and biosynthetic functions as well as they have an important role in signaling processes into the cell. Here, by comparing several transcriptomic data sets from plants impaired in their respiratory function with the genes regulated under Fe or S deficiencies obtained from other data sets, nutrient-responsive genes potentially regulated by hypothetical mitochondrial retrograde signaling pathway are evidenced. It leads us to hypothesize that plant mitochondria could be, therefore, required for regulating the expression of key genes involved both in Fe and S metabolisms. PMID:26779219

  16. Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition.

    PubMed

    Orwin, Kate H; Wardle, David A; Towns, David R; St John, Mark G; Bellingham, Peter J; Jones, Chris; Fitzgerald, Brian M; Parrish, Richard G; Lyver, Phil O'B

    2016-01-01

    Vertebrate consumers can be important drivers of the structure and functioning of ecosystems, including the soil and litter invertebrate communities that drive many ecosystem processes. Burrowing seabirds, as prevalent vertebrate consumers, have the potential to impact consumptive effects via adding marine nutrients to soil (i.e. resource subsidies) and non-consumptive effects via soil disturbance associated with excavating burrows (i.e. ecosystem engineering). However, the exact mechanisms by which they influence invertebrates are poorly understood. We examined how soil chemistry and plant and invertebrate communities changed across a gradient of seabird burrow density on two islands in northern New Zealand. Increasing seabird burrow density was associated with increased soil nutrient availability and changes in plant community structure and the abundance of nearly all the measured invertebrate groups. Increasing seabird densities had a negative effect on invertebrates that were strongly influenced by soil-surface litter, a positive effect on fungal-feeding invertebrates, and variable effects on invertebrate groups with diverse feeding strategies. Gastropoda and Araneae species richness and composition were also influenced by seabird activity. Generalized multilevel path analysis revealed that invertebrate responses were strongly driven by seabird engineering effects, via increased soil disturbance, reduced soil-surface litter, and changes in trophic interactions. Almost no significant effects of resource subsidies were detected. Our results show that seabirds, and in particular their non-consumptive effects, were significant drivers of invertebrate food web structure. Reductions in seabird populations, due to predation and human activity, may therefore have far-reaching consequences for the functioning of these ecosystems.

  17. Long-term Effects of Nutrient Addition and Phytoremediation on Diesel and Crude Oil Contaminated Soils in subarctic Alaska.

    PubMed

    Leewis, Mary-Cathrine; Reynolds, Charles M; Leigh, Mary Beth

    2013-12-01

    Phytoremediation is a potentially inexpensive method of detoxifying contaminated soils using plants and associated soil microorganisms. The remote locations and cold climate of Alaska provide unique challenges associated with phytoremediation such as finding effective plant species that can achieve successful site clean-up despite the extreme environmental conditions and with minimal site management. A long-term assessment of phytoremediation was performed which capitalized on a study established in Fairbanks in 1995. The original study sought to determine how the introduction of plants (Festuca rubra, Lolium multiflorum), nutrients (fertilizer), or their combination would affect degradation of petroleum hydrocarbon (TPH) contaminated soils (crude oil or diesel) over time. Within the year following initial treatments, the plots subjected to both planting and/or fertilization showed greater overall decreases in TPH concentrations in both the diesel and crude oil contaminated soils relative to untreated plots. We re-examined this field site after 15 years with no active site management to assess the long-term effects of phytoremediation on colonization by native and non-native plants, their rhizosphere microbial communities and on petroleum removal from soil. Native and non-native vegetation had extensively colonized the site, with more abundant vegetation found on the diesel contaminated soils than the more nutrient-poor, more coarse, and acidic crude oil contaminated soils. TPH concentrations achieved regulatory clean up levels in all treatment groups, with lower TPH concentrations correlating with higher amounts of woody vegetation (trees & shrubs). In addition, original treatment type has affected vegetation recruitment to each plot with woody vegetation and more native plants in unfertilized plots. Bacterial community structure also varies according to the originally applied treatments. This study suggests that initial treatment with native tree species in

  18. Long-term Effects of Nutrient Addition and Phytoremediation on Diesel and Crude Oil Contaminated Soils in subarctic Alaska

    PubMed Central

    Leewis, Mary-Cathrine; Reynolds, Charles M.; Leigh, Mary Beth

    2014-01-01

    Phytoremediation is a potentially inexpensive method of detoxifying contaminated soils using plants and associated soil microorganisms. The remote locations and cold climate of Alaska provide unique challenges associated with phytoremediation such as finding effective plant species that can achieve successful site clean-up despite the extreme environmental conditions and with minimal site management. A long-term assessment of phytoremediation was performed which capitalized on a study established in Fairbanks in 1995. The original study sought to determine how the introduction of plants (Festuca rubra, Lolium multiflorum), nutrients (fertilizer), or their combination would affect degradation of petroleum hydrocarbon (TPH) contaminated soils (crude oil or diesel) over time. Within the year following initial treatments, the plots subjected to both planting and/or fertilization showed greater overall decreases in TPH concentrations in both the diesel and crude oil contaminated soils relative to untreated plots. We re-examined this field site after 15 years with no active site management to assess the long-term effects of phytoremediation on colonization by native and non-native plants, their rhizosphere microbial communities and on petroleum removal from soil. Native and non-native vegetation had extensively colonized the site, with more abundant vegetation found on the diesel contaminated soils than the more nutrient-poor, more coarse, and acidic crude oil contaminated soils. TPH concentrations achieved regulatory clean up levels in all treatment groups, with lower TPH concentrations correlating with higher amounts of woody vegetation (trees & shrubs). In addition, original treatment type has affected vegetation recruitment to each plot with woody vegetation and more native plants in unfertilized plots. Bacterial community structure also varies according to the originally applied treatments. This study suggests that initial treatment with native tree species in

  19. [Nutrient Characteristics and Nitrogen Forms of Rhizosphere Soils Under Four Typical Plants in the Littoral Zone of TGR].

    PubMed

    Wang, Xiao-feng; Yuan, Xing-zhong; Liu, Hong; Zhang, Lei; Yu, Jian-jun; Yue, Jun-sheng

    2015-10-01

    The Three Gorges Reservoir (TGR), which is the largest water conservancy project ever built in tne world, produced a drawdown area of about 348.93 km2 because of water level control. The biological geochemical cycle of the soil in the drawdown zone has been changed as the result of long-term winter flooding and summer drought and vegetation covering. The loss of soil nitrogen in the drawdown zone poses a threat to the water environmental in TGR. Pengxi river, is an important anabranch, which has the largest drawdown area has been selected in the present study. The four typical vegetation, contained Cynodon dactylon, Cyperus rotundus, Anthium sibiricum and Zea mays L. as the control, were studied to measure nutrient characteristics and nitrogen forms of rhizosphere and non-rhizosphere soils in three distribution areas with different soil types (paddy soil, purple soil and fluvo-aquic soils). The variables measured included organic matter (OM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), hydrolysis N, available P and available K, pH, ion-exchangeable N (IEE-N), weak acid extractable N (CF-N) , iron-manganese oxides N (IMOF-N), organic matter sulfide N (OSF-N), added up four N forms for total transferable N (TF-N) and TN minus TF-N for non-transferable N (NTF-N). The results showed: (1) pH of rhizosphere soil was generally lower than that of non-rhizosphere soil under different vegetation in different type soils because the possible organic acid and H+ released form plant roots and cation absorption differences, and the OM, TP, TN and hydrolysis N of rhizosphere soil were generally higher than those of non-rhizosphere soil, and that the enrichment ratio (ER) of all the four nutrient indicators showed Cyperus rotundus > Cynodon dactylon > Zea mays L. > Anthium sibiricum. Available P showed enrichment in the rhizosphere of three natural vegetations but lose under corn, and available K, TK showed different ER in different conditions. (2) IEF-N CF

  20. Impacts of industrial waste resources on maize (Zea mays L.) growth, yield, nutrients uptake and soil properties.

    PubMed

    Singh, Satnam; Young, Li-Sen; Shen, Fo-Ting; Young, Chiu-Chung

    2014-10-01

    Discharging untreated highly acidic (pH<4.0), organic and nutrients rich monosodium glutamate wastewater (MW), and highly alkaline (pH>10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5±0.1) with PW and lime (treatments represented as MW+PW and MW+Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha(-1). Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear(-1) and 100-kernel weight were higher in MW+Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW+Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW+PW. The MW+PW and MW+Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances.

  1. Iron deficiency chlorosis in plants as related to Fe sources in soil

    NASA Astrophysics Data System (ADS)

    Díaz, I.; Delgado, A.; de Santiago, A.; del Campillo, M. C.; Torrent, J.

    2012-04-01

    Iron deficiency chlorosis (IDC) is a relevant agricultural problem in many areas of the World where calcareous soils are dominant. Although this problem has been traditionally ascribed to the pH-buffering effect of soil carbonates, the content and type of Fe oxides in soil contribute to explain Fe uptake by plants and the incidence of this problem. During the last two decades, it has been demonstrated Fe extraction with oxalate, related to the content of poorly crystalline Fe oxides, was well-correlated with the chlorophyll content of plants and thus with the incidence of IDC. This reveals the contribution of poorly crystalline Fe oxides in soil to Fe availability to plants in calcareous soils, previously shown in microcosm experiments using ferrihydrite as Fe source in the growing media. In order to supply additional information about the contribution of Fe sources in soil to explain the incidence of IDC and to perform accurate methods to predict it, a set of experiments involving different methods to extract soil Fe and plant cultivation in pots to correlate amounts of extracted Fe with the chlorophyll content of plants (measured using the SPAD chlorophyll meter) were performed. The first experiment involved 21 soils and white lupin cultivation, sequential Fe extraction in soil to study Fe forms, and single extractions (DTPA, rapid oxalate and non-buffered hydroxylamine). After that, a set of experiments in pot involving growing of grapevine rootstocks, chickpea, and sunflower were performed, although in this case only single extractions in soil were done. The Fe fraction more closely related to chlorophyll content in plants (r = 0.5, p < 0.05) was the citrate + ascorbate (CA) extraction, which was the fraction that releases most of the Fe related to poorly crystalline Fe oxides, thus revealing the key role of these compounds in Fe supply to plants. Fe extracted with CA was more correlated with chlorophyll content in plants that oxalate extractable Fe, probably

  2. Effect of Potato (Solanum tuberosum L.) Cropping Systems on Soil and Nutrient Losses Through Runoff in a Humic Nitisol, Kenya

    NASA Astrophysics Data System (ADS)

    Nyawade, Shadrack; Charles, Gachene; Karanja, Nancy; Elmar, Schulte-Geldermann

    2016-04-01

    Soil erosion has been identified as one of the major causes of soil productivity decline in the potato growing areas of East African Highlands. Potato establishes a protective soil cover only at about 45-60 days after planting and does not yield sufficient surface mulch upon harvest which leaves the soil bare at the critical times when rainfall intensities are usually high thus exposes soil to erosion. A field study was carried out using runoff plots during the short and long rainy seasons of 2014/15 respectively at the University of Nairobi Upper Kabete Farm, Kenya. The objectives were to assess the effect of soil surface roughness and potato cropping systems on soil loss and runoff, to determine the effect of erosion on nutrient enrichment ratio and to evaluate the soil organic matter fraction most susceptible to soil erosion. The treatments comprised of Bare Soil (T1); Potato + Garden Pea (Pisum sativa) (T2); Potato + Climbing Bean (Phaseolus vulgaris) (T3); Potato + Dolichos (Lablab purpureus) (T4) and Sole Potato (Solanum tuberosum L.) (T5). The amount of soil loss and runoff recorded in each event differed significantly between treatments (p<0.05) and were consistently highest in T1 and lowest in T4. Mean cumulative soil loss reduced by 6.4, 13.3 and 24.4 t ha-1from T2, T3 and T4 respectively compared to sole potato plots (T5), while mean cumulative runoff reduced by 8.5, 17.1 and 28.3 mm from T2, T3 and T4 respectively when compared with the sole potato plots (T5) indicating that T4 plots provided the most effective cover in reducing soil loss and runoff. Regression analyses revealed that both runoff and soil loss related significantly with surface roughness and percent cover (R2=0.83 and 0.73 respectively, p<0.05). Statistically significant linear dependence of runoff and soil loss on surface roughness and crop cover was found in T4 (p<0.05) indicating that this system was highly effective in minimizing soil loss and runoff. Enrichment ratio was on average

  3. [Soil microorganisms, nutrients and enzyme activity of Larix kaempferi plantation under different ages in mountainous region of eastern Liaoning Province, China].

    PubMed

    Niu, Xiao-yun; Sun, Xiao-mei; Chen, Dong-sheng; Zhang, Shou-gong

    2015-09-01

    We studied the community of soil microorganisms, enzyme activity and soil nutrients under 11-, 20-, 34-and 47-year-old Larix kaempferi plantations in mountainous region of eastern Liaoning Province to discuss the soil biological properties of L. kaempferi plantations of different stand ages and their relationships with soil nutrients. The results showed that the indexes reflecting soil micro-organisms, enzyme activity and soil nutrients of L. kaempferi plantations were the highest under the 11- or 47-year-old stand and the lowest in the 20- or 34-year-old stand. Soil productivity appeared in a decline trend with the increasing stand age, and the changes of soil microbial community structure and enzyme activity were responsive to soil degradation. The difference of fungi community was more noticeable than that of bacteria community among the plantations with different stand ages. The results of CCA showed soil nutrient and pH had no effect on seasonal difference of community structure, but had effects on community, structure among different stand ages. The total N, organic carbon, C/N, available nitrogen, exchangeable Mg2+ and pH had greater effects on bacteria community, while available P, total K and pH had greater effect on fungi community among different age forests. The main T-RFs of bacteria and fungi had higher correlation with N and P, and the fungi community had higher correlation with organic carbon and K than bacteria community. The microor-ganism community of the 11- and 47-year-old stands had greater correlation with soil nutrients and enzyme activity than that of 20- and 34-year-old stands. Consequently, soil organisms, in particular soil fungi, could be used to indicate soil degradation.

  4. Greenhouse gas and soil nutrient dynamics at Haliburton Forest: nitrogen and phosphorous amendments to soils to study the effects of high nitrogen deposition

    NASA Astrophysics Data System (ADS)

    Winsborough, C. L.; Basiliko, N.

    2011-12-01

    Many of Canada's forests are currently experiencing a major environmental disturbance in the form of atmospheric nitrogen (N) deposition from fossil fuel burning and agricultural practices. Nitrogen is a major nutrient required for plants and soil microorganisms and is normally in short supply relative to biological demands. However, when N is in excess various negative impacts result including nutrient leaching, increased nitrous oxide (N2O) emissions, and disturbances to carbon and methane (CH4) cycling. Introducing soil amendments might have the potential to mitigate the negative impacts of excess N in forest soils. Previous research at Haliburton Forest in southeastern Ontario, Canada has demonstrated that N is no longer a limiting nutrient for plants, but rather phosphorous (P), where the addition of P resulted in rapid increased growth in sugar maple trees. We characterized long term (>5 years) and more immediate/short-term effects of P additions and short-term effects of N and N+P additions to soils at Haliburton Forest on the exchange of greenhouse gases (CH4, N2O, CO2) and cycling of N and P to determine the extent of excess N impact and potential N saturation. Long-term effects of P addition demonstrated suppressed levels of CH4 uptake likely due to an N limitation of CH4 oxidizing bacteria. Decreased pools of N with P addition suggest that P additions alleviate P limitation and induce N uptake, however overall low inorganic N pools suggest that N saturation has not yet appeared. Immediate effects demonstrated increased N2O and CO2 efflux and suppressed CH4 uptake in N amended plots while P amended plots remained similar to control plots. 1- and 2-year post-application greenhouse gas and nutrient data will help to elucidate these findings.

  5. Groundwater Availability Alters Soil-plant Nutrient Cycling in a Stand of Invasive, N-fixing Phreatophytes

    NASA Astrophysics Data System (ADS)

    Dudley, B. D.; Miyazawa, Y.; Hughes, F.; Ostertag, R.; Kettwich, S. K.; MacKenzie, R.; Dulaiova, H.; Waters, C. A.; Bishop, J.; Giambelluca, T. W.

    2013-12-01

    N-fixing phreatophytic trees are common in arid and semi-arid regions worldwide, and can play significant roles in modifying hydrology and soil-plant nutrient cycling where they are present. In light of reductions in groundwater levels in many arid regions we estimated annual transpiration rates at a stand level, and alterations to C, N and P accretion in soils as a function of groundwater depth in a ca.120 year old stand of Prosopis pallida along an elevation gradient in coastal leeward Hawaii. We measured sapflow and stand level sapwood area to quantify transpiration, and calculated groundwater transpiration rates using P. pallida stem water δ18O values. By measuring soil resistivity, we were able to compare the volume of groundwater transpired by these trees to groundwater depth across the stand. We examined nutrient deposition and accretion in soils in lowland areas of the stand with accessible shallow groundwater, compared to upland areas with no groundwater access, as indicated by stem water δ18O values. Resistivity results suggested that groundwater was at a height close to sea level throughout the stand. Transpiration was around 1900 m3 ha-1 year-1 in the areas of the stand closest to the sea (where groundwater was at around 1-4 m below ground level) and decreased to around a tenth of that volume where groundwater was not accessible. Litterfall rates over the course of the year studied were 17 times greater at lowland sites, but this litterfall contributed ca. 24 times the N, and 35 times the P of upland sites. Thus, groundwater access contributed to the total mass of nitrogen and phosphorus deposited in the form of litter through higher litter quantity and quality. Total N content of soils was 4.7 times greater and inorganic N pools were eight times higher at lowland plots. These results suggest that groundwater depth can have strong effects on soil-plant nutrient cycling, so that reductions in the availability of shallow groundwater are likely to impact

  6. Modeling greenhouse gas emissions and nutrient transport in managed arable soils with a fully coupled hydrology-biogeochemical modeling system

    NASA Astrophysics Data System (ADS)

    Haas, Edwin; Klatt, Steffen; Kiese, Ralf; Butterbach-Bahl, Klaus; Kraft, Philipp; Breuer, Lutz

    2015-04-01

    The use of mineral nitrogen fertilizer sustains the global food production and therefore the livelihood of human kind. The rise in world population will put pressure on the global agricultural system to increase its productivity leading most likely to an intensification of mineral nitrogen fertilizer use. The fate of excess nitrogen and its distribution within landscapes is manifold. Process knowledge on the site scale has rapidly grown in recent years and models have been developed to simulate carbon and nitrogen cycling in managed ecosystems on the site scale. Despite first regional studies, the carbon and nitrogen cycling on the landscape or catchment scale is not fully understood. In this study we present a newly developed modelling approach by coupling the fully distributed hydrology model CMF (catchment modelling framework) to the process based regional ecosystem model LandscapeDNDC for the investigation of hydrological processes and carbon and nitrogen transport and cycling, with a focus on nutrient displacement and resulting greenhouse gas emissions in various virtual landscapes / catchment to demonstrate the capabilities of the modelling system. The modelling system was applied to simulate water and nutrient transport at the at the Yanting Agro-ecological Experimental Station of Purple Soil, Sichuan province, China. The catchment hosts cypress forests on the outer regions, arable fields on the sloping croplands cultivated with wheat-maize rotations and paddy rice fields in the lowland. The catchment consists of 300 polygons vertically stratified into 10 soil layers. Ecosystem states (soil water content and nutrients) and fluxes (evapotranspiration) are exchanged between the models at high temporal scales (hourly to daily) forming a 3-dimensional model application. The water flux and nutrients transport in the soil is modelled using a 3D Richards/Darcy approach for subsurface fluxes with a kinematic wave approach for surface water runoff and the

  7. Field-scale investigation of enhanced petroleum hydrocarbon biodegradation in the vadose zone combining soil venting as an oxygen source with moisture and nutrient addition. Appendices. Doctoral thesis

    SciTech Connect

    Miller, R.N.

    1990-01-01

    This document contains appendices regarding a reprint on a field scale investigation of enhanced petroleum hydrocarbon biodegradation in the vadose zone combining soil venting as a oxygen source with moisture and nutrient addition.

  8. Examining soil carbon uncertainty in a global model: response of microbial decomposition to temperature, moisture and nutrient limitation

    NASA Astrophysics Data System (ADS)

    Exbrayat, J.-F.; Pitman, A. J.; Zhang, Q.; Abramowitz, G.; Wang, Y.-P.

    2013-06-01

    Reliable projections of future climate require land-atmosphere carbon (C) fluxes to be represented realistically in Earth System Models. There are several sources of uncertainty in how carbon is parameterized in these models. First, while interactions between the C, nitrogen (N) and phosphorus (P) cycles have been implemented in some models, these lead to diverse changes in land-atmosphere fluxes. Second, while the parameterization of soil organic matter decomposition is similar between models, formulations of the control of the soil physical state on microbial activity vary widely. We address these sources uncertainty by implementing three soil moisture (SMRF) and three soil temperature (STRF) respiration functions in an Earth System Model that can be run with three degrees of biogeochemical nutrient limitation (C-only, C and N, and C and N and P). All 27 possible combinations of a SMRF with a STRF and a biogeochemical mode are equilibrated before transient historical (1850-2005) simulations are performed. As expected, implementing N and P limitation reduces the land carbon sink, transforming some regions from net sinks to net sources over the historical period (1850-2005). Differences in the soil C balance implied by the various SMRFs and STRFs also change the sign of some regional sinks. Further, although the absolute uncertainty in global carbon uptake is reduced, the uncertainty due to the SMRFs and STRFs grows relative to the inter-annual variability in net uptake when N and P limitations are added. We also demonstrate that the equilibrated soil C also depend on the shape of the SMRF and STRF. Equilibration using different STRFs and SMRFs and nutrient limitation generates a six-fold range of global soil C that largely mirrors the range in available (17) CMIP5 models. Simulating the historical change in soil carbon therefore critically depends on the choice of STRF, SMRF and nutrient limitation, as it controls the equilibrated state to which transient

  9. Long-term soil nutrient dynamics comparison under smallholding land and farmland policy in northeast of China.

    PubMed

    Ouyang, Wei; Wei, Xinfeng; Hao, Fanghua

    2013-04-15

    There are two kinds of land policies, the smallholding land policy (SLP) and the farmland policy (FLP) in China. The farmland nutrient dynamics under the two land policies were analysed with the soil system budget method. The averaged nitrogen (N) input of the SLP and the FLP over sixteen years increased about 23.9% and 33.3%, respectively and the phosphorus (P) input climbed about 39.1% and 42.3%, respectively. The statistical analysis showed that the land policies had significant impacts on N and P input from fertilizer and manure, but did not obviously affect the N input from seeds and biological N fixation. The efficiency percentage of N of the SLP and the FLP climbed about 54.5% and 59.4%, respectively, and the P efficiency improved by 52.7% and 82.6%, respectively. About the nutrient output, the F-test analysis indicated that the land polices had remarkable impacts on N output by crop uptake, ammonia volatilisation, denitrification, leaching and runoff, and P output by uptake, runoff, and leach. The balance showed that the absolute loss of N from land deceased about 43.6% and 46.0%, respectively, in the SLP and the FLP, and P discharge reduced about 34.2% and 75.2%, respectively. The F-test analysis of N and P efficiency and balance of between two polices both indicated that the FLP had significant impact on nutrient dynamic. With the Mitscherlich model, the correlations between nutrient input and crop uptake, usage efficiency and loss were analysed and showed that was a threshold value for the optimal nutrient input with the highest efficiency rate. For the optimal nutrient efficiency, the space for extra P addition was bigger than the N input. The FLP have more advantage than the SLP on the crop yield, nutrient efficiency and environmental discharge.

  10. Effects of grazing regimes on plant traits and soil nutrients in an alpine steppe, Northern Tibetan Plateau.

    PubMed

    Sun, Jian; Wang, Xiaodan; Cheng, Genwei; Wu, Jianbo; Hong, Jiangtao; Niu, Shuli

    2014-01-01

    Understanding the impact of grazing intensity on grassland production and soil fertility is of fundamental importance for grassland conservation and management. We thus compared three types of alpine steppe management by studying vegetation traits and soil properties in response to three levels of grazing pressure: permanent grazing (M1), seasonal grazing (M2), and grazing exclusion (M3) in the alpine steppe in Xainza County, Tibetan Plateau. The results showed that community biomass allocation did not support the isometric hypothesis under different grassland management types. Plants in M1 had less aboveground biomass but more belowground biomass in the top soil layer than those in M2 and M3, which was largely due to that root/shoot ratios of dominant plants in M1 were far greater than those in M2 and M3. The interramet distance and the tiller size of the dominant clonal plants were greater in M3 than in M1 and M2, while the resprouting from rhizome buds did not differ significantly among the three greezing regimes. Both soil bulk density and soil available nitrogen in M3 were greater than in M1 at the 15-30 cm soil depth (P = 0.05). Soil organic carbon and soil total nitrogen were greater in M3 than in M1 and M2 (P = 0.05). We conclude that the isometric hypothesis is not supported in this study and fencing is a helpful grassland management in terms of plant growth and soil nutrient retention in alpine steppe. The extreme cold, scarce precipitation and short growing period may be the causation of the unique plant and soil responses to different management regimes.

  11. Effects of Grazing Regimes on Plant Traits and Soil Nutrients in an Alpine Steppe, Northern Tibetan Plateau

    PubMed Central

    Sun, Jian; Wang, Xiaodan; Cheng, Genwei; Wu, Jianbo; Hong, Jiangtao; Niu, Shuli

    2014-01-01

    Understanding the impact of grazing intensity on grassland production and soil fertility is of fundamental importance for grassland conservation and management. We thus compared three types of alpine steppe management by studying vegetation traits and soil properties in response to three levels of grazing pressure: permanent grazing (M1), seasonal grazing (M2), and grazing exclusion (M3) in the alpine steppe in Xainza County, Tibetan Plateau. The results showed that community biomass allocation did not support the isometric hypothesis under different grassland management types. Plants in M1 had less aboveground biomass but more belowground biomass in the top soil layer than those in M2 and M3, which was largely due to that root/shoot ratios of dominant plants in M1 were far greater than those in M2 and M3. The interramet distance and the tiller size of the dominant clonal plants were greater in M3 than in M1 and M2, while the resprouting from rhizome buds did not differ significantly among the three greezing regimes. Both soil bulk density and soil available nitrogen in M3 were greater than in M1 at the 15–30 cm soil depth (P = 0.05). Soil organic carbon and soil total nitrogen were greater in M3 than in M1 and M2 (P = 0.05). We conclude that the isometric hypothesis is not supported in this study and fencing is a helpful grassland management in terms of plant growth and soil nutrient retention in alpine steppe. The extreme cold, scarce precipitation and short growing period may be the causation of the unique plant and soil responses to different management regimes. PMID:25268517

  12. Nutrients can enhance the abundance and expression of alkane hydroxylase CYP153 gene in the rhizosphere of ryegrass planted in hydrocarbon-polluted soil.

    PubMed

    Arslan, Muhammad; Afzal, Muhammad; Amin, Imran; Iqbal, Samina; Khan, Qaiser M

    2014-01-01

    Plant-bacteria partnership is a promising strategy for the remediation of soil and water polluted with hydrocarbons. However, the limitation of major nutrients (N, P and K) in soil affects the survival and metabolic activity of plant associated bacteria. The objective of this study was to explore the effects of nutrients on survival and metabolic activity of an alkane degrading rhizo-bacterium. Annual ryegrass (Lolium multiflorum) was grown in diesel-contaminated soil and inoculated with an alkane degrading bacterium, Pantoea sp. strain BTRH79, in greenhouse experiments. Two levels of nutrients were applied and plant growth, hydrocarbon removal, and gene abundance and expression were determined after 100 days of sowing of ryegrass. Results obtained from these experiments showed that the bacterial inoculation improved plant growth and hydrocarbon degradation and these were further enhanced by nutrients application. Maximum plant biomass production and hydrocarbon mineralization was observed by the combined use of inoculum and higher level of nutrients. The presence of nutrients in soil enhanced the colonization and metabolic activity of the inoculated bacterium in the rhizosphere. The abundance and expression of CYP153 gene in the rhizosphere of ryegrass was found to be directly associated with the level of applied nutrients. Enhanced hydrocarbon degradation was associated with the population of the inoculum bacterium, the abundance and expression of CYP153 gene in the rhizosphere of ryegrass. It is thus concluded that the combination between vegetation, inoculation with pollutant-degrading bacteria and nutrients amendment was an efficient approach to reduce hydrocarbon contamination.

  13. Effects of thinning, residue mastication, and prescribed fire on soil and nutrient budgets in a Sierra Nevada mixed-conifer forest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of thinning followed by residue mastication (THIN), prescribed fire (BURN), and thinning plus residue mastication plus burning (T+B) on nutrient budgets and resin-based (plant root simulator [PRS] probe) measurements of soil nutrient availability in a mixed-conifer forest were measured. ...

  14. Comparison of selected nutrients and bacteria from common contiguous soils inside and outside swine lagoon effluent spray fields after long-term use

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine (Sus scrofa domestica) lagoon effluent is a valuable fertilizer. In the Mid-South US it is applied to grass hay in spray-irrigated fields from April to September. Lagoon levels of nutrients and bacteria, and soil levels of nutrients, were known, but little was known of effluent bacterial level...

  15. Hydrological and nutrient fluxes in the soil-atmosphere interface in Brazilian semiarid

    NASA Astrophysics Data System (ADS)

    Leal, Karinne; Borma, Laura; Forti, Cristina

    2014-05-01

    Semiarids are water stress regions caused by the association of high potential evapotranspiration, high temperatures (in summer) and generally low rainfall. Although unfavorable climatic conditions, semiarid regions represent about 14% global population and has been suffering land transformation, such as replacement by pastures and croplands. Crescent demand for agricultural and forests products in Brazilian semiarid has taken Caatinga deforestations, typical vegetation of that area that covers about 10% of Brazilian territory, with consequences in hydrology and biogeochemistry. The effect of these disruptions are poorly understood. The aim of this research is to characterize the differences in transfers of water and nutrients, in soil-atmosphere interface, between a typical Caatinga vegetation and pasture. Two field campaigns were made to sample and measure the water from rainfall, throughfall, stemflow, runoff and soil water. The collections were conducted during the rainy season, extended from April to August in 2012 and 2013, in São João, a county in the semiarid region of Pernambuco State, in the northeast of Brazil. The samples are being analyzed in order to determine their major cations and anions concentrations, total dissolved carbon (TDC), total organic carbon (TOC), total nitrogen (TN), alkalinity and pH. The observed precipitation represented about 40% and 50% of the historical average precipitation, in 2012 and 2013, respectively. This observations highlight the severe drought experienced in the region, mainly in the first year of sampling. The throughfall represented about 35% of the rainfall in 2012, and about 25% in 2013. In semiarid vegetations the average throughfall is about 49%, with variation coefficient of ±32%, so the observed data are consistent with those reported in the literature. These observations suggests that in drier years the vegetation holds more moisture than in wetter years. However, these data must be correlated with others

  16. Soil and nutrient retention in winter-flooded ricefields with implications for watershed management

    USGS Publications Warehouse

    Manley, S.W.; Kaminski, R.M.; Rodrigue, P.B.; Dewey, J.C.; Schoenholtz, S.H.; Gerard, P.D.; Reinecke, K.J.

    2009-01-01

    The ability of water resources to support aquatic life and human needs depends, in part, on reducing nonpoint source pollution amid contemporary agricultural practices. Winter retention of shallow water on rice and other agricultural fields is an accepted management practice for wildlife conservation; however, soil and water conservation benefits are not well documented. We evaluated the ability of four post-harvest ricefield treatment combinations (stubble-flooded, stubble-open, disked-flooded and disked-open) to abate nonpoint source exports into watersheds of the Mississippi Alluvial Valley. Total suspended solid exports were 1,121 kg ha-1 (1,000 lb ac-1) from disked-open fields where rice stubble was disked after harvest and fields were allowed to drain, compared with 35 kg ha-1 (31 lb ac-1) from stubble-flooded fields where stubble was left standing after harvest and fields captured rainfall from November 1 to March 1. Estimates of total suspended solid exports from ricefields based on Landsat imagery and USDA crop data are 0.43 and 0.40 Mg km-2 day-1 in the Big Sunflower and L'Anguille watersheds, respectively. Estimated reductions in total suspended solid exports from ricefields into the Big Sunflower and L'Anguille water-sheds range from 26% to 64% under hypothetical scenarios in which 65% to 100% of the rice production area is managed to capture winter rainfall. Winter ricefield management reduced nonpoint source export by decreasing concentrations of solids and nutrients in, and reducing runoff volume from, ricefields in the Mississippi Alluvial Valley.

  17. [Effects of ground surface mulching in tea garden on soil water and nutrient dynamics and tea plant growth].

    PubMed

    Sun, Li-tao; Wang, Yu; Ding, Zhao-tang

    2011-09-01

    Taking a 2-year-old tea garden in Qingdao of Shandong Province as test object, this paper studied the effects of different mulching modes on the soil water and nutrient dynamics and tea plant growth. Four treatments were installed, i.e., no mulching (CK), straw mulching (T1), plastic film mulching (T2), and straw plus plastic film mulching (T3). Comparing with CK, mulching could keep the soil water content at a higher level, and enhance the water use efficiency. In treatments T1 and T3, the tea growth water use efficiency and yield water use efficiency increased by 43%-48% and 7%-13%, respectively, compared with CK. Also in treatments T1 and T3, the contents of soil organic matter, available-N, nitrate-N, and ammonium-N increased significantly, with the soil fertility improved, and the leaf nitrate-N content and nitrate reductase activity increased, which promoted the tea growth and yield (12%-13% higher than CK) and made the peak period of bud growth appeared earlier. Considering the tea growth and yield, water and nutrient use efficiency, environment safety and economic benefit, straw mulching could be an effective ground surface mulching mode for young tea garden.

  18. Variation in defence strategies in two species of the genus Beilschmiedia under differing soil nutrient and rainfall conditions.

    PubMed

    Simon, J; Miller, R E; Woodrow, I E

    2007-01-01

    The relationships between various leaf functional traits that are important in plant growth (e.g., specific leaf area) have been investigated in recent studies; however, research in this context on plants that are highly protected by chemical defences, particularly resource-demanding nitrogen-based defence, is lacking. We collected leaves from cyanogenic (N-defended) Beilschmiedia collina B. Hyland and acyanogenic (C-defended) Beilschmiedia tooram (F. M. Bailey) B. Hyland at high- and low-soil nutrient sites in two consecutive years that varied significantly in rainfall. We then measured the relationships between chemical defence and morphological and functional leaf traits under the different environmental conditions. We found that the two species differed significantly in their resource allocation to defence as well as leaf morphology and function. The N defended species had a higher leaf nitrogen concentration, whereas the C-defended species had higher amounts of C-based chemical defences (i.e., total phenolics and condensed tannins). The C-defended species also tended to have higher force to fracture and increased leaf toughness. In B. collina, cyanogenic glycoside concentration was higher with higher rainfall, but not with higher soil nutrients. Total phenolic concentration was higher at the high soil nutrient site in B. tooram, but lower in B. collina; however, with higher rainfall an increase was found in B. tooram, while phenolics decreased in B. collina. Condensed tannin concentration decreased in both species with rainfall and nutrient availability. We conclude that chemical defence is correlated with leaf functional traits and that variation in environmental resources affects this correlation.

  19. An inexpensive and simple method to demonstrate soil water and nutrient flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil quality, soil health, and soil sustainability are concepts which are being widely used but are difficult to define and illustrate especially to a non-technical audience in the field or classroom. The USDA-NRCS/ARS Soil Quality Test Kit, as well as other commercially-available kits, contains ma...

  20. Anaerobic soil disinfestation impact on nutrient dynamics in fresh-market tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD) is considered a promising sustainable alternative to chemical soil fumigation (CSF). Suitable for both organic and conventional growing systems. The soil amendment with organic material and its anaerobic decomposition cause a temporary variation of the soil redox...

  1. Phytosiderophore release by wheat genotypes differing in zinc deficiency tolerance grown with Zn-free nutrient solution as affected by salinity.

    PubMed

    Daneshbakhsh, Bahareh; Khoshgoftarmanesh, Amir Hossein; Shariatmadari, Hossein; Cakmak, Ismail

    2013-01-01

    There is limited information concerning the effect of salinity on phytosiderophores exudation from wheat roots. The aim of this hydroponic experiment was to investigate the effect of salinity on phytosiderophore release by roots of three bread wheat genotypes differing in Zn efficiency (Triticum aestivum L. cvs. Rushan, Kavir, and Cross) under Zn deficiency conditions. Wheat seedlings were transferred to Zn-free nutrient solutions and exposed to three salinity levels (0, 60, and 120 mM NaCl). The results indicated that Cross and Rushan genotypes exuded more phytosiderophore than did the Kavir genotype. Our findings suggest that the adaptive capacity of Zn-efficient 'Cross' and 'Rushan' wheat genotypes to Zn deficiency is due partly to the higher amounts of phytosiderophore release. Only 15 days of Zn deficiency stress was sufficient to distinguish between Zn-efficient (Rushan and Cross) and Zn-inefficient (Kavir) genotypes, with the former genotypes exuding more phytosiderophore than the latter. Higher phytosiderophore exudation under Zn deficiency conditions was accompanied by greater Fe transport from root to shoot. The maximum amount of phytosiderophore was exuded at the third week in 'Cross' and at the fourth week in 'Kavir' and 'Rushan'. For all three wheat genotypes, salinity stress resulted in higher amounts of phytosiderophore exuded by the roots. In general, for 'Kavir', the largest amount of phytosiderophore was exuded from the roots at the highest salinity level (120mM NaCl), while for 'Cross' and 'Rushan', no significant difference was found in phytosiderophore exudation between the 60 and 120 mM NaCl treatments. More investigation is needed to fully understand the physiology of elevated phytosiderophore release by Zn-deficient wheat plants under salinity conditions.

  2. Effect of subalpine canopy removal on snowpack, soil solution, and nutrient export, Fraser Experimental Forest, CO

    USGS Publications Warehouse

    Stottlemyer, R.; Troendle, C.A.

    1999-01-01

    proportionally greater than water flux. Increased subsurface flow accounted for most of the increase in non-limiting nutrient loss. For limiting nutrients, loss of plant uptake and increased shallow subsurface flow accounted for the greater loss. Seasonal ion concentration patterns in streamwater and subsurface flow were similar.Research on the effects of vegetation manipulation on snowpack, soil water, and streamwater chemistry and flux has been underway at the Fraser Experimental Forest (FEF), CO, since 1982. Greater than 95% of FEF snowmelt passes through watersheds as subsurface flow where soil processes significantly alter meltwater chemistry. To better understand the mechanisms accounting for annual variation in watershed streamwater ion concentration and flux with snowmelt, we studied subsurface water flow, its ion concentration, and flux in conterminous forested and clear cut plots. Repetitive patterns in subsurface flow and chemistry were apparent. Control plot subsurface flow chemistry had the highest ion concentrations in late winter and fall. When shallow subsurface flow occurred, its Ca2+, SO42-, and HCO3- concentrations were lower and K+ higher than deep flow. The percentage of Ca2+, NO3-, SO42-, and HCO3- flux in shallow depths was less and K+ slightly greater than the percentage of total flow. Canopy removal increased precipitation reaching the forest floor by about 40%, increased peak snowpack water equivalent (SWE) > 35%, increased the average snowpack Ca2+, NO3-, and NH4+ content, reduced the snowpack K+ content, and increased the runoff four-fold. Clear cutting doubled the percentage of subsurface flow at shallow depths, and increased K+ concentration in shallow subsurface flow and NO3- concentrations in both shallow and deep flow. The percentage change in total Ca2+, SO42-, and HCO3- flux in shallow depths was less than the change in water flux, while that of K+ and NO3- flux was greater. Relative to the control, in the clear cut the percentage of total Ca

  3. Acidification, heavy metal mobility and nutrient accumulation in the soil-plant system of a revegetated acid mine wasteland.

    PubMed

    Yang, Sheng-Xiang; Liao, Bin; Li, Jin-tian; Guo, Tao; Shu, Wen-Sheng

    2010-08-01

    A revegetation program was established at an extreme acidic and metal-toxic pyrite/copper mine wasteland in Guangdong Province, PR China using a combination of four native grass species and one non-native woody species. It was continued and monitored for 2 y. The emphasis was on acidification, metal mobility and nutrient accumulation in the soil-plant system. Our results showed the following: (i) the acid-forming potential of the mine soils decreased steadily with time, which might be due to plant root-induced changes inhibiting the oxidization of sulphide minerals; (ii) heavy metal extractability (diethylene-triamine-pentaacetic acid-extractable Pb and Zn) in the soils increased with time despite an increase in soil pH, which might be attributed to soil disturbance and plant rhizospheric processes, as well as a consequence of the enhanced metal accumulation in plants over time; and (iii) the vegetation cover increased rapidly with time, and plant development accelerated the accumulation of major nutrients (organic matter, total and ammonium-N, and available P and K). The 2-y field experiment demonstrates that direct seeding/planting of native plant species in combination with lime and manure amelioration is a practical approach to the initial establishment of a self-sustaining vegetation cover on this metalliferous and sulphide-bearing mine wasteland. However, heavy metal accumulation in the soil-plant system should be of great concern, and long-term monitoring of ecological risk must be an integral part of such a restoration scheme.

  4. Response of Soil Biogeochemistry to Freeze-thaw Cycles: Impacts on Greenhouse Gas Emission and Nutrient Fluxes

    NASA Astrophysics Data System (ADS)

    Rezanezhad, F.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2014-12-01

    Freeze-thaw is an abiotic stress applied to soils and is a natural process at medium to high latitudes. Freezing and thawing processes influence not only the physical properties of soil, but also the metabolic activity of soil microorganisms. Fungi and bacteria play a crucial role in soil organic matter degradation and the production of greenhouse gases (GHG) such as CO2, CH4 and N2O. Production and consumption of these atmospheric trace gases are the result of biological processes such as photosynthesis, aerobic respiration (CO2), methanogenesis, methanotrophy (CH4), nitrification and denitrification (N2O). To enhance our understanding of the effects of freeze-thaw cycles on soil biogeochemical transformations and fluxes, a highly instrumented soil column experiment was designed to realistically simulate freeze-thaw dynamics under controlled conditions. Pore waters collected periodically from different depths of the column and solid-phase analyses on core material obtained at the initial and end of the experiment highlighted striking geochemical cycling. CO2, CH4 and N2O production at different depths within the column were quantified from dissolved gas concentrations in pore water. Subsequent emissions from the soil surface were determined by direct measurement in the head space. Pulsed CO2 emission to the headspace was observed at the onset of thawing, however, the magnitude of the pulse decreased with each subsequent freeze-thaw cycle indicating depletion of a "freeze-thaw accessible" carbon pool. Pulsed CO2 emission was due to a combination of physical release of gases dissolved in porewater and entrapped below the frozen zone and changing microbial respiration in response to electron acceptor variability (O2, NO3-, SO42-). In this presentation, we focus on soil-specific physical, chemical, microbial factors (e.g. redox conditions, respiration, fermentation) and the mechanisms that drive GHG emission and nutrient cycling in soils under freeze-thaw cycles.

  5. D-galactose induces a mitochondrial complex I deficiency in mouse skeletal muscle: potential benefits of nutrient combination in ameliorating muscle impairment.

    PubMed

    Chang, Liao; Liu, Xin; Liu, Jing; Li, Hua; Yang, Yanshen; Liu, Jia; Guo, Zihao; Xiao, Ke; Zhang, Chen; Liu, Jiankang; Zhao-Wilson, Xi; Long, Jiangang

    2014-03-01

    Accumulating research has shown that chronic D-galactose (D-gal) exposure induces symptoms similar to natural aging in animals. Therefore, rodents chronically exposed to D-gal are increasingly used as a model for aging and delay-of-aging pharmacological research. Mitochondrial dysfunction is thought to play a vital role in aging and age-related diseases; however, whether mitochondrial dysfunction plays a significant role in mice exposed to D-gal remains unknown. In the present study, we investigated cognitive dysfunction, locomotor activity, and mitochondrial dysfunction involved in D-gal exposure in mice. We found that D-gal exposure (125 mg/kg/day, 8 weeks) resulted in a serious impairment in grip strength in mice, whereas spatial memory and locomotor coordination remained intact. Interestingly, muscular mitochondrial complex I deficiency occurred in the skeletal muscle of mice exposed to D-gal. Mitochondrial ultrastructure abnormality was implicated as a contributing factor in D-gal-induced muscular impairment. Moreover, three combinations (A, B, and C) of nutrients applied in this study effectively reversed D-gal-induced muscular impairment. Nutrient formulas B and C were especially effective in reversing complex I dysfunction in both skeletal muscle and heart muscle. These findings suggest the following: (1) chronic exposure to D-gal first results in specific muscular impairment in mice, rather than causing general, premature aging; (2) poor skeletal muscle strength induced by D-gal might be due to the mitochondrial dysfunction caused by complex I deficiency; and (3) the nutrient complexes applied in the study attenuated the skeletal muscle impairment, most likely by improving mitochondrial function.

  6. Cropping and tillage strategies to minimize off-site impacts of excess nutrients in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    If the conditions under which residue materials leach or sorb nutrients can be identified, it may be possible to adopt cropping and management practices that reduce nutrient delivery by overland flow. Conservation practices such as contouring, strip cropping, conservation tillage, terraces, and buff...

  7. A novel P450-initiated biphasic process for sustainable biodegradation of benzo[a]pyrene in soil under nutrient-sufficient conditions by the white rot fungus Phanerochaete chrysosporium

    PubMed Central

    Bhattacharya, Sukanta S.; Syed, Khajamohiddin; Shann, Jodi; Yadav, Jagjit S.

    2013-01-01

    High molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) such as benzo[a]pyrene (BaP) are resistant to biodegradation in soil. Conventionally, white rot fungus Phanerochaete chrysosporium has been investigated for HMW-PAH degradation in soil primarily using nutrient-deficient (ligninolytic) conditions, albeit with limited and non-sustainable biodegradation outcomes. In this study, we report development of an alternative novel biphasic process initiated under nutrient-sufficient (non-ligninolytic) culture conditions, by employing an advanced experimental design strategy. During the initial nutrient-sufficient non-ligninolytic phase (16 days), the process showed upregulation (3.6-and 22.3-fold, respectively) of two key PAH-oxidizing P450 monooxygenases pc2 (CYP63A2) and pah4 (CYP5136A3) and formation of typical P450-hydroxylated metabolite. This along with abrogation (84.9%) of BaP degradation activity in response to a P450-specific inhibitor implied key role of these monooxygenases. The subsequent phase triggered on continued incubation (to 25 days) switched the process from non-ligninolytic to ligninolytic resulting in a significantly higher net degradation (91.6% as against 67.4% in the control nutrient-limited set) of BaP with concomitant de novo ligninolytic enzyme expression making it a biphasic process yielding improved sustainable bioremediation of PAH-contaminated soil. To our knowledge this is the first report on development of such biphasic process for bioremediation application of a white rot fungus. PMID:24051002

  8. Correlation of soil organic carbon and nutrients (NPK) to soil mineralogy, texture, aggregation, and land use pattern.

    PubMed

    Adhikari, Gopi; Bhattacharyya, Krishna G

    2015-11-01

    This work investigates the correlations existing among soil organic carbon (C), nitrogen (N), phosphorous (P), potassium (K), and physicochemical properties like clay mineralogy, textural components, soil aggregation, and land use pattern. Seven different locations were chosen in the tropical rainforest climate region of Assam, India, for the work. The soil texture classifications were clay, sandy clay loam, and sandy loam with mixed clay mineralogy consisting of tectosilicates and phylosilicates. Two distinct compositions of total Fe/Al oxides≥11.5 and <10.8% were observed along with two distinct groups of water stable soil aggregates of mean weight diameter≈6.42 and ≤3.26 mm. The soil clay and sand had positive and negative contributions respectively to the soil organic carbon (SOC) protection, which was observed to be dependent on lesser sand content, higher silt+clay content, and the presence of higher percentages of total Fe/Al oxides. Soil clay mineralogy suggested that the mineral, chlorite, favored retention of higher SOC content in a particular site. Under similar climatic and mineralogical conditions, both natural and anthropogenic soil disturbances destabilized SOC protection through SOM mineralization and soil aggregate destabilization as indicated by SOC protective capacity studies. Urbanization resulting in soil compaction contributed to enhanced SOC level through increased contact between the occluded organic carbon and the soil mineralogical constituents.

  9. Landspreading MSW compost in Wisconsin: Effect on corn yield, nutrient and metal uptake, and soil nitrate-N

    SciTech Connect

    Wolkowski, R.P.

    1995-12-31

    Studies were conducted at several Wisconsin locations from 1991-1994 to determine the effect of municipal solid waste (MSW) compost on corn (Zea mays L.) growth, nutrient and metal uptake, and soil nitrate-N content. Composts of varying maturities were applied at rates ranging between 0 and 56 t/a (dry matter basis), depending on year and location. Commercial fertilizers were applied to separate plots to determine the extent of nutrient availability from the compost. All treatments were applied in the spring and incorporated prior to planting corn. Mature compost always increased growth and yield above the untreated control, but the highest yields were found where recommended fertilizer was applied. Immature compost suppressed growth and reduced yield. Compost generally increased the levels of plant nutrients in the whole-plant tissue and grain. While compost did increase the concentration of some metals in the whole-plant tissue, these levels were found to be within the range expected for corn. Compost did not affect metal concentration in the grain. Soil nitrate-N was higher throughout most of the growing season in treatments receiving recommended N fertilizer.

  10. Mycorrhiza and PGPB modulate maize biomass, nutrient uptake and metabolic pathways in maize grown in mining-impacted soil.

    PubMed

    Dhawi, Faten; Datta, Rupali; Ramakrishna, Wusirika

    2015-12-01

    Abiotic stress factors including poor nutrient content and heavy metal contamination in soil, can limit plant growth and productivity. The main goal of our study was to evaluate element uptake, biomass and metabolic responses in maize roots growing in mining-impacted soil with the combination of arbuscular mycorrhiza (My) and plant growth promoting bacteria (PGPB/B). Maize plants subjected to PGPB, My and combined treatments showed a significant increase in biomass and uptake of some elements in shoot and root. Metabolite analysis identified 110 compounds that were affected ≥2-fold compared to control, with 69 metabolites upregulated in the My group, 53 metabolites in the My+B group and 47 metabolites in B group. Pathway analysis showed that impact on glyoxylate and dicarboxylate metabolism was common between My and My+B groups, whereas PGPB group showed a unique effect on fatty acid biosynthesis with significant increase in palmitic acid and stearic acid. Differential regulation of some metabolites by mycorrhizal treatment correlated with root biomass while PGPB regulated metabolites correlated with biomass increase in shoot. Overall, the combination of rhizospheric microorganisms used in our study significantly increased maize nutrient uptake and growth relative to control. The changes in metabolic pathways identified during the symbiotic interaction will improve our understanding of mechanisms involved in rhizospheric interactions that are responsible for increased growth and nutrient uptake in crop plants.

  11. Effects of vegetation structure on soil carbon, nutrients and greenhouse gas exchange in a savannah ecosystem of Mount Kilimanjaro Region

    NASA Astrophysics Data System (ADS)

    Becker, J.

    2015-12-01

    The savannah biome is a hotspot for biodiversity and wildlife conservation in Africa and recently got in the focus of research on carbon sequestration. Savannah ecosystems are under strong pressure from climate and land-use change, especially around populous areas like the Mt. Kilimanjaro region. Savannah vegetation consists of grassland with isolated trees and is therefore characterized by high spatial variation of canopy cover, aboveground biomass and root structure. The canopy structure is a major regulator for soil ecological parameters and soil-atmospheric trace gas exchange (CO2, N2O, CH4) in water limited environments. The spatial distribution of these parameters and the connection between above and belowground processes are important to understand and predict ecosystem changes and estimate its vulnerability. Our objective was to determine spatial trends and changes of soil parameters and relate their variability to the vegetation structure. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca) in our research area. For each tree, we selected transects with nine sampling points of the same relative distances to the stem. At these each sampling point a soil core was taken and separated in 0-10 cm and 10-30 cm depth. We measured soil carbon (C) and nitrogen (N) storage, microbial biomass C and N, Natural δ13C, soil respiration, available nutrients, pH, cation exchange capacity (CEC) as well as root biomass and -density, soil temperature and soil water content. Concentrations and stocks of C and N fractions, CEC and K+ decreased up to 50% outside the crown covered area. Microbial C:N ratio and CO2 efflux was about 30% higher outside the crown. This indicates N limitation and low C use efficiency in soil outside the crown area. We conclude that the spatial structure of aboveground biomass in savanna ecosystems leads to a spatial variance in nutrient limitation. Therefore, the capability of a savanna ecosystem

  12. How do soil quality indicators (SOC and nutrients) change with long-term different crop residue management?

    NASA Astrophysics Data System (ADS)

    Spiegel, Heide; Lehtinen, Taru; Dersch, Georg; Baumgarten, Andreas

    2016-04-01

    Leaving the crop residues (cereal grain straw, maize stover, sugar beet leaves) on the field may enhance SOC and soil nutrient contents (e.g. P, K, Mg). In contrast, harvesting crop residues for livestock bedding or energy production are often connected with a loss of soil fertility (Lehtinen et al., 2014). We have evaluated the effects of different management of crop residues on selected soil parameters of the upper soil (0-25 cm) in two long-term field experiments in Austria focused on P-dynamics (Marchfeld, since 1982 and Alpenvorland, since 1986). In four P-fertilisation stages (0, 75, 150, 300 kg P2O5 ha-1y-1) all crop residues were incorporated in one treatment and all removed in the other one, respectively. The results show that the effects are different at the two investigated sites. At the site Marchfeld, a medium textured soil, on average SOC was significantly higher with the incorporation of crop residues (21.6 g kg-1) compared to the removal (19.9 g kg-1) after 32 years. In the long run, SOC levels could be maintained, if crop residues remained at the field, whereas the constant removal of crop residues resulted in a SOC decline. At the site Alpenvorland, SOC was only slightly higher with the incorporation of the crop residues after 28 years. In this case, in the long run, even with this management practice and, moreover, with the residue removal, SOC tended to decrease generally. At the Marchfeld, crop residue incorporation resulted in a significant increase of "plant available" phosphorus (P-CAL) only with very high P fertilization. However, "plant available" Mg (according to Schachtschabel) and potassium (K-CAL) were significantly higher in all P fertilisation stages compared to the residue removal treatments. At the site Alpenvorland, the soils are rich in silt and clay and with long-term incorporation of crop residues a significant increase only of „plant available" K of about 50% occurred. This indicates the necessity of taking into account the

  13. Reduction of soluble nitrogen and mobilization of plant nutrients in soils from U.S. northern Great Plains agroecosystems by phenolic compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenolic plant secondary metabolites actively participate in a broad range of important reactions that affect livestock, plants and soil. In soil, phenolic compounds can affect nutrient dynamics and mobility of metals but their role in northern Great Plains agroecosystems is largely unknown. We eval...

  14. Geostatistical approach for management of soil nutrients with special emphasis on different forms of potassium considering their spatial variation in intensive cropping system of West Bengal, India.

    PubMed

    Chatterjee, Sourov; Santra, Priyabrata; Majumdar, Kaushik; Ghosh, Debjani; Das, Indranil; Sanyal, S K

    2015-04-01

    A large part of precision agriculture research in the developing countries is devoted towards precision nutrient management aspects. This has led to better economics and efficiency of nutrient use with off-farm advantages of environmental security. The keystone of precision nutrient management is analysis and interpretation of spatial variability of soils by establishing management zones. In this study, spatial variability of major soil nutrient contents was evaluated in the Ghoragacha village of North 24 Parganas district of West Bengal, India. Surface soil samples from 100 locations, covering different cropping systems of the village, was collected from 0 to 15 cm depth using 100×100 m grid system and analyzed in the laboratory to determine organic carbon (OC), available nitrogen (N), phosphorus (P), and potassium (K) contents of the soil as well as its water-soluble K (KWS), exchangeable K (KEX), and non-exchangeable forms of K (KNEX). Geostatistical analyses were performed to determine the spatial variation structure of each nutrient content within the village, followed by the generation of surface maps through kriging. Four commonly used semivariogram models, i.e., spherical, exponential, Gaussian, and linear models were fitted to each soil property, and the best one was used to prepare surface maps through krigging. Spherical model was found the best for available N and P contents, while linear and exponential model was the best for OC and available K, and for KWS and KNEK, Gausian model was the best. Surface maps of nutrient contents showed that N content (129-195 kg ha(-1)) was the most limiting factor throughout the village, while P status was generally very high ( 10-678 kg ha(-1)) in the soils of the present village. Among the different soil K fractions, KWS registered the maximum variability (CV 75%), while the remaining soil K fractions showed moderate to high variation. Interestingly, KNEX content also showed high variability, which essentially

  15. Artificial recharge of groundwater through sprinkling infiltration: impacts on forest soil and the nutrient status and growth of Scots pine.

    PubMed

    Nöjd, Pekka; Lindroos, Antti-Jussi; Smolander, Aino; Derome, John; Lumme, Ilari; Helmisaari, Heljä-Sisko

    2009-05-01

    We studied the chemical changes in forest soil and the effects on Scots pine trees caused by continuous sprinkling infiltration over a period of two years, followed by a recovery period of two years. Infiltration increased the water input onto the forest soil by a factor of approximately 1000. After one year of infiltration, the pH of the organic layer had risen from about 4.0 to 6.7. The NH(4)-N concentration in the organic layer increased, most probably due to the NH(4) ions in the infiltration water, as the net N mineralization rate did not increase. Sprinkling infiltration initiated nitrification in the mineral soil. Macronutrient concentrations generally increased in the organic layer and mineral soil. An exception, however, was the concentration of extractable phosphorus, which decreased strongly during the infiltration period and did not show a recovery within two years. The NO(3)-N and K concentrations had reverted back to their initial level during the two-year recovery period, while the concentrations of Ca, Mg and NH(4)-N were still elevated. Nutrient concentrations in the pine needles increased on the infiltrated plots. However, the needle P concentration increased, despite the decrease in plant-available P in the soil. Despite the increase in the nutrient status, there were some visible signs of chlorosis in the current-year needles after two years of infiltration. The radial growth of the pines more than doubled on the infiltrated plots, which suggests that the very large increase in the water input onto the forest floor had no adverse effect on the functioning of the trees. However, a monitoring period of four years is not sufficient for detecting potential long term detrimental effects on forest trees.

  16. Anaemia and related nutrient deficiencies after Roux-en-Y gastric bypass surgery: a systematic review and meta-analysis

    PubMed Central

    Weng, Ting-Chia; Chang, Chia-Hsuin; Dong, Yaa-Hui; Chang, Yi-Cheng; Chuang, Lee-Ming

    2015-01-01

    Objective To obtain a pooled risk estimate on the long-term impact of anaemia and related nutritional deficiencies in patients receiving Roux-en-Y gastric bypass (RYGB) surgery. Design Systematic review and meta-analysis. Data sources MEDLINE, EMBASE and Cochrane databases were searched to identify English reports published before 16 May 2014. Eligibility criteria Articles with case numbers >100, follow-up period >12 months, and complete data from both before and after surgery were selected. Outcomes of interest were changes in baseline measurements of proportion of patients with anaemia, by haemoglobin, haematocrit, ferritin, iron, vitamin B12 and folate levels. Data collection and analysis Two reviewers independently reviewed data and selected six prospective and nine retrospective studies with a total of 5909 patients. A random effect model with inverse variance weighting was used to calculate summary estimates of outcomes at 6, 12, 24 and 36 months postoperatively. Results Proportion of patients with anaemia was 12.2% at baseline, which, respectively, increased to 20.9% and 25.9% at 12 and 24 months follow-up, consistent with decreases in haemoglobin and haematocrit levels. Although the serum iron level did not change substantially after surgery, the frequency of patients with ferritin deficiency increased from 7.9% at baseline to 13.4% and 23.0% at 12 and 24 months, respectively, postoperation. Vitamin B12 deficiency increased from 2.3% at baseline to 6.5% at 12 months after surgery in those subjects receiving RYGB. There was no obvious increase in folate deficiency. Conclusions RYGB surgery is associated with an increased risk of anaemia and deficiencies of iron and vitamin B12, but not folate. Ferritin is more sensitive when serum iron level is within normal range. PMID:26185175

  17. Nutrient cycling and soil biology in row crop systems under intensive tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent interest in management of the soil biological component to improve soil health requires a better understanding on how management practices (e.g., tillage) and environmental conditions influence soil organisms. Intensive tillage often results in reduced organic matter content in the surface so...

  18. Some Contributions of Resistant Compounds to Soil Organic Matter Formation and Nutrient Cycling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some biomolecules in soil organic matter (SOM) are intrinsically more resistant to microbial decomposition than are other SOM components. Their resistance can be altered by soil properties and by land management, which can affect the formation and stability of SOM and in turn soil processes. Selecte...

  19. An