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Sample records for acidic forest soils

  1. Influences of soil acidity on Streptomyces populations inhabiting forest soils.

    PubMed Central

    Hagedorn, C

    1976-01-01

    The Streptomyces populations inhabiting five acidic forest soils were examined. It was found that lowering the pH of a medium selective for streptomycetes (starch-casein agar) to the pH of the particular soil horizon being plated influenced both the total numbers and types of streptomycetes that were isolated from the soils examined in this study. On the acidified medium both the numbers of streptomycetes and the percentage of total bacteria on the plates represented by streptomycetes increased (as compared with the same medium with a pH of 7.2). These differences were greatest on the isolations from the most acid soils. The largest concentrations of streptomycetes were found in the surface horizon (0 to 15 cm) and the litter layer immediately over the surface mineral horizon. Acidity tolerance tests demonstrated that random samplings of isolates contained acidophilic, neutrophilic, and acidoduric strains, with the largest numbers of acidophiles being found on the acidified media from the most acid soils. There were no differences between overall utilization of selected carbohydrates among the isolates taken from either the neutral or acidic media, although a larger proportion of the acid media isolates produced acid from the carbohydrates. Evidence is presented which indicates that different types of streptomycetes were isolated on the acid media, and possible reasons for the presence of these acid-tolerant populations are discussed. PMID:10835

  2. Chemical evaluation of soil-solution in acid forest soils

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.

    1996-01-01

    Soil-solution chemistry is commonly studied in forests through the use of soil lysimeters.This approach is impractical for regional survey studies, however, because lysimeter installation and operation is expensive and time consuming. To address these problems, a new technique was developed to compare soil-solution chemistry among red spruce stands in New York, Vermont, New Hampshire, Maine. Soil solutions were expelled by positive air pressure from soil that had been placed in a sealed cylinder. Before the air pressure was applied, a solution chemically similar to throughfall was added to the soil to bring it to approximate field capacity. After the solution sample was expelled, the soil was removed from the cylinder and chemically analyzed. The method was tested with homogenized Oa and Bs horizon soils collected from a red spruce stand in the Adirondack Mountains of New York, a red spruce stand in east-central Vermont, and a mixed hardwood stand in the Catskill Mountains of New York. Reproducibility, effects of varying the reaction time between adding throughfall and expelling soil solution (5-65 minutes) and effects of varying the chemical composition of added throughfall, were evaluated. In general, results showed that (i) the method was reproducible (coefficients of variation were generally < 15%), (ii) variations in the length of reaction-time did not affect expelled solution concentrations, and (iii) adding and expelling solution did not cause detectable changes in soil exchange chemistry. Concentrations of expelled solutions varied with the concentrations of added throughfall; the lower the CEC, the more sensitive expelled solution concentrations were to the chemical concentrations of added throughfall. Addition of a tracer (NaBr) showed that the expelled solution was a mixture of added solution and solution that preexisted in the soil. Comparisons of expelled solution concentrations with concentrations of soil solutions collected by zero-tension and

  3. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  4. Soil water samplers in ion balance studies on acidic forest soils

    SciTech Connect

    Rasmussen, L.; Joergensen, P.; Kruse, S.

    1986-04-01

    During the last years an increasing consciousness has appeared of the injurious effects of acid rain on the forest ecosystems both in Europe and North America. At several localities ion balance studies have been implemented in order to evaluate the impact of the atmospheric deposition of acidic substances and heavy metals on the forest ecosystem. In many localities the leaching of material to the ground water or output from the ecosystem has to be determined by means of tensiometer measurements and soil water sampling. Many different soil water samplers are available on the market and they show useful applicability under the given circumstances. But in many cases soil water samples taken with different equipment give incommensurable results leading to differing explanations of the effects of acid precipitation on elements and their cycling in the ecosystem. The purpose of the present study is twofold. Firstly, the sorption characteristics of different types of soil water samplers are examined under acidic soil conditions both by installation in the field and by laboratory experiments. Secondly, a new method is introduced for current and constant soil water sampling under varying soil suctions in the unsaturated zone.

  5. Responses of soil buffering capacity to acid treatment in three typical subtropical forests.

    PubMed

    Jiang, Jun; Wang, Ying-Ping; Yu, Mengxiao; Li, Kun; Shao, Yijing; Yan, Junhua

    2016-09-01

    Elevated anthropogenic acid deposition can significantly affect forest ecosystem functioning by changing soil pH, nutrient balance, and chemical leaching and so on. These effects generally differ among different forests, and the dominant mechanisms for those observed responses often vary, depending on climate, soil conditions and vegetation types. Using soil monoliths (0-40cm) from pine forest (pioneer), coniferous and broadleaved mixed forest (transitional) and broadleaved forest (mature) in southern China, we conducted a leaching experiment with acid treatments at different pH levels (control: pH≈4.5; pH=3.5; pH=2.5). We found that pH3.5 treatment significantly reduced dissolved organic carbon (DOC) concentrations in leachate from the pioneer forest soil. pH2.5 treatment significantly increased concentrations of NO3(-), SO4(2-), Ca(2+), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the pioneer forest soil, and also concentrations of NO3(-), SO4(2-), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the transitional forest soil. All acid treatments had no significant effects on concentrations of these chemicals in leachate from the mature forest soil. The responses can be explained by the changes in soil pH, acid neutralizing capacity (ANC) and concentrations of Al and Fe. Our results showed that acid buffering capacity of the pioneer or transitional forest soil was lower than that of the mature forest soil. Therefore preserving mature forests in southern China is important for reducing the adverse impacts of high acid deposition on stream water quality at present and into the future. PMID:27185346

  6. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

  7. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  8. Effects of precipitation on soil acid phosphatase activity in three successional forests in southern China

    NASA Astrophysics Data System (ADS)

    Huang, W.; Liu, J.; Zhou, G.; Zhang, D.; Deng, Q.

    2011-07-01

    Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of organic P mineralization potential in soils. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment with precipitation treatments (no precipitation, natural precipitation and doubled precipitation) in three successional forests in southern China was carried out. The three forests include Masson pine forest (MPF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (MEBF). Results showed that driven by seasonality of precipitation, changes in soil acid phosphatase activities coincided with the seasonal climate pattern, with significantly higher values in the wet season than in the dry season. Soil acid phosphatase activities were closely linked to forest successional stages, with enhanced values in the later stages of forest succession. In the dry season, soil acid phosphatase activities in the three forests showed a rising trend with increasing precipitation treatments. In the wet season, soil acid phosphatase activity was depressed by no precipitation treatment in the three forests. However, doubled precipitation treatment exerted a significantly negative effect on it only in MEBF. These results indicate that the potential transformation rate of organic P might be more dependent on water in the dry season than in the wet season. A decrease in organic P turnover would occur in the three forests if there was a drought in a whole year in the future. More rainfall in the wet season would also be adverse to organic P turnover in MEBF due to its high soil moisture.

  9. Effects of acid precipitation on cation transport in New Hampshire forest soils. Technical completion report

    SciTech Connect

    Cronan, C.S.

    1981-07-01

    This report describes the results of our investigation of the effects of regional acid precipitation on forest soils and watershed biogeochemistry in New England. The report provides descriptions of the following research findings: (1) acid precipitation may cause increased aluminum mobilization and leaching from soils to sensitive aquatic systems; (2) acid deposition may shift the historic carbonic acid/organic acid leaching regime in forest soils to one dominated by atmospheric H/sub 2/SO/sub 4/; (3) acid precipitation may accelerate nutrient cation leaching from forest soils and may pose a particular threat to the potassium resources of northeastern forested ecosystems; (4) while acid rain may pass through some coniferous canopies without being neutralized, similar inputs of acid rainfall to hardwood canopies may be neutralized significantly by Bronsted base leaching and by leaf surface ion exchange mechanisms; and (5) progressive acid dissolution of soils in the laboratory may provide an important tool for predicting the patterns of aluminum leaching from soils exposed to acid deposition.

  10. [Effect of acid rain on mercury leaching from forest yellow soil in Jinyun Mountain].

    PubMed

    Li, Jing; Wei, Shiqiang; Yang, Xuechun

    2004-09-01

    Forest yellow soil and arable yellow soil in Jinyun Mountain were collected to study the effect of simulated acid rain(adjusted to pH 2.0, 3.0, 4.0 and 5.0) on the Hg leaching from soils by the methods of static extraction and dynamic leaching. The results showed that in forest yellow soils, surface accumulation of Hg occurred, and the accumulated Hg was easier to be leached out than that in arable yellow soil by acid rain. The amount of leached Hg was the largest at pH 4.0. To abate the risk of Hg pollution in water bodies by the Hg leaching from this forest soil, the Mountain should be closed, and timber-felling should be forbidden.

  11. Estimates of critical acid loads and exceedances for forest soils across the conterminous United States.

    PubMed

    McNulty, Steven G; Cohen, Erika C; Moore Myers, Jennifer A; Sullivan, Timothy J; Li, Harbin

    2007-10-01

    Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A pollutant load in excess of a critical acid load is termed exceedance. This study combined a simple mass balance equation with national-scale databases to estimate critical acid load and exceedance for forest soils at a 1-km(2) spatial resolution across the conterminous US. This study estimated that about 15% of US forest soils are in exceedance of their critical acid load by more than 250eqha(-1)yr(-1), including much of New England and West Virginia. Very few areas of exceedance were predicted in the western US.

  12. Estimates of critical acid loads and exceedances for forest soils across the conterminous United States.

    PubMed

    McNulty, Steven G; Cohen, Erika C; Moore Myers, Jennifer A; Sullivan, Timothy J; Li, Harbin

    2007-10-01

    Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A pollutant load in excess of a critical acid load is termed exceedance. This study combined a simple mass balance equation with national-scale databases to estimate critical acid load and exceedance for forest soils at a 1-km(2) spatial resolution across the conterminous US. This study estimated that about 15% of US forest soils are in exceedance of their critical acid load by more than 250eqha(-1)yr(-1), including much of New England and West Virginia. Very few areas of exceedance were predicted in the western US. PMID:17629382

  13. Effects of precipitation on soil acid phosphatase activity in three successional forests in Southern China

    NASA Astrophysics Data System (ADS)

    Huang, W.; Liu, J.; Zhou, G.; Zhang, D.; Deng, Q.

    2011-01-01

    Phosphorus (P) is often a limiting nutrient for plant growth in tropical and subtropical forests. Global climate change has led to alterations in precipitation in the recent years, which inevitably influences P cycling. Soil acid phosphatase plays a vital role in controlling P mineralization, and its activity reflects the capacity of P supply to ecosystems. In order to study the effects of precipitation on soil acid phosphatase activity, an experiment of precipitation treatments (no precipitation, natural precipitation and doubled precipitation) in three forests of early-, mid- and advanced-successional stages in Southern China was carried out. Results showed that driven by seasonality of precipitation, changes in soil acid phosphatase activities coincided with the seasonal climate pattern, with significantly higher values in the wet season than in the dry season. Soil acid phosphatase activities were closely linked to forest successional stages, with enhanced values in the later stages of forest succession. In the dry season, soil acid phosphatase activities in the three forests showed a rising trend with increasing precipitation treatments. In the wet season, no precipitation treatment depressed soil acid phosphatase activity, while doubled precipitation treatment exerted no positive effects on it, and even significantly lowered it in the advanced forest. These indicate the potential transformation rate of organic P might be more dependent on water in the dry season than in the wet season. The negative responses of soil acid phosphatase activity to precipitation suggest that P supply in subtropical ecosystems might be reduced if there was a drought in a whole year or more rainfall in the wet season in the future. NP, no precipitation; Control, natural precipitation; DP, double precipitation.

  14. P Limitation and Microbial Biogeochemistry in Acidic Forest Soils of the Northeastern United States

    NASA Astrophysics Data System (ADS)

    Smemo, K. A.; Deforest, J. L.; Burke, D. J.; Elliot, H. L.; Kluber, L. A.; Carrino-Kyker, S. R.

    2010-12-01

    In forest ecosystems with acidic soils, such as many hardwood forests of the Northeastern United States, net primary productivity should be limited by phosphorus (P) because P is biologically less available at pH < 5 and nitrogen (N) has become more abundant in response to anthropogenic inputs. However, previous studies have failed to demonstrate widespread P limitation in temperate forests that have naturally acidic soil or are exposed to chronic acid deposition; such findings are contrary to biogeochemical expectations. We hypothesize that many eastern forests possess an underlying P limitation not realized at the ecosystem level. Instead, shifts in the composition, structure and function of soil microbial communities compensate by acquiring more P from organic sources and P limitation is therefore not manifested at the aboveground (plant) level. To test this hypothesis, we manipulated soil pH and P availability in 72 20 x 40 m mature hardwood forest plots across northeastern (glaciated) and southeastern (unglaciated) Ohio beginning in late summer 2009. Ten months after treatment initiation, soil pH has increased from 4.5 to 5.5 and soil P has increased from 3 to ~25 mg P/kg soil on glaciated soils and from 0.5 to ~5 mg P/kg soil on unglaciated soils. To quantify treatment responses, we measured the activity of soil extracellular enzymes associated with liberation of P, N, and C from organic matter, as well as pools of N and N cycling processes. We saw no significant effects of our treatments on pools of available ammonium or nitrate, nor did we see effects on net N mineralization and net nitrification rates. However, glaciated soils had significantly greater nitrate pools and higher N cycling rates than older unglaciated soils. Nitrogen and C cycling enzymes in treatment plots were not significantly different than control plots, but N-acetylglucosaminidase activity (N acquisition) was significantly greater in the unglaciated soils and β-glucosidase and

  15. N{sub 2}O production pathways in the subtropical acid forest soils in China

    SciTech Connect

    Zhang Jinbo; Cai Zucong; Zhu Tongbin

    2011-07-15

    To date, N{sub 2}O production pathways are poorly understood in the humid subtropical and tropical forest soils. A {sup 15}N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N{sub 2}O production in four subtropical acid forest soils (pH<4.5) in China. The results showed that denitrification was the main source of N{sub 2}O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N{sub 2}O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N{sub 2}O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N{sub 2}O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N{sub 2}O product ratios from nitrification. The ratio of N{sub 2}O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: {yields} We studied N{sub 2}O production pathways in subtropical acid forest soil under aerobic conditions. {yields} Denitrification was the main source of N{sub 2}O production in subtropical acid forest soils. {yields} Heterotrophic nitrification accounted for 27.3%-41.8% of N{sub 2}O production. {yields} While, contribution of autotrophic nitrification to N{sub 2}O production was little. {yields} Ratios of N{sub 2}O-N emission from nitrification were higher than those in most previous references.

  16. Effects of simulated acid precipitation on decomposition and leaching of organic carbon in forest soils

    SciTech Connect

    Chang, F.H.; Alexander, M.

    1984-09-01

    Soil samples from three watersheds of New York State were treated with simulated rain at pH 3.5, 4.1, and 5.6 daily for 14 d, at 12 3-d intervals in three separate tests, or at 22 7-d intervals. Except for one system of treating the three forest soils, simulated acid rain reduced the amount of organic matter leached from samples of soil from which more than 0.05% of the organic carbon was leached during the exposure period. In the soil samples representing the exceptions, acid rain enhanced the leaching of organic matter. Samples from the organic layer of the treated samples of acid soil were taken at two equal depths, and the rates of organic matter decomposition in the two layers were studied. As compared with simulated rain at pH 5.6, simulated acid rain reduced the decomposition of organic matter in the three soils at both depths in three of the five tests and at both depths of two of the soils in the fourth test. In some instances, organic matter decomposition was enhanced by the simulated acid rain. Except for the sample of soil at the highest initial pH, carbon mineralization was inhibited in soils and treatments in which simulated acid rain reduced the amount of organic carbon leached, and it was stimulated in soils and treatments in which the quantity of organic carbon leached was increased by the simulated acid rain. 12 references, 3 figures, 8 tables.

  17. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    PubMed

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. PMID:26657252

  18. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    PubMed

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China.

  19. A conceptual framework: redefining forest soil's critical acid loads under a changing climate.

    PubMed

    McNulty, Steven G; Boggs, Johnny L

    2010-06-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

  20. A conceptual framework: redefining forest soil's critical acid loads under a changing climate.

    PubMed

    McNulty, Steven G; Boggs, Johnny L

    2010-06-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

  1. Crossing the pedogenetic threshold: Apparent phosphorus limitation by soil microorganisms in unglaciated acidic eastern hardwood forests

    NASA Astrophysics Data System (ADS)

    Deforest, J. L.; Smemo, K. A.; Burke, D. J.

    2010-12-01

    The availability of soil phosphorus (P) can significantly influence microbial community composition and the ecosystem-level processes they mediate. However, the threshold at which soil microorganisms become functionally P-limited is unclear because of soil acidity effect on P availability. We reason that acidic temperate hardwood forest ecosystems are, in fact, functionally P-limited, but compensation occur via soil microbial production of phosphatase enzymes. We tested this hypothesis in glaciated and unglaciated mature mixed-mesophytic forests in eastern Ohio where both soil pH and P availability had been experientially manipulated. We measured the activity of two P acquiring soil enzymes, phosphomonoesterase (PMono) and phosphodiesterase (PDi), to understand how soil acidity and available P influence microbial function. Our experimental treatments elevated ambient soil pH from below 4.5 to around 5.5 and increased readily available phosphate from 3 to ~25 mg P/kg on glaciated soils and from 0.5 to ~5 mg P/kg on unglaciated soils. The P treatment decreased the activity of PDi by 82% relative to the control on unglaciated soils, but we observed no P treatment effect on glaciated soils. A similar result was observed for PMono. Soil pH, alone, did not significantly influence enzyme activities. Results suggest that soil microorganisms are more likely to be P-limited in older unglaciated soils. However, dramatically higher phosphatase activity in response to very low P availability suggests that an underlying ecosystem P limitation can be ameliorated by soil microbial community dynamics. This mechanism may be more important for older, unglaciated soils that have already crossed a pedogenic threshold where P availability influences ecosystem and microbial function.

  2. Effects of simulated acid rain on glucose mineralization and some physicochemical properties of forest soils

    SciTech Connect

    Strayer, R.F.; Alexander, M.

    1981-10-01

    To study the effects of acid rain, samples of forest soils were exposed to a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm/hour, or to intermittent 1-hour applications of 5 cm of simulated acid rain three times per week for 7 weeks. The major effects of the simulated acid rain were localized at the top of the soil and included lower pH values and glucose mineralization rates, and higher exchangeable Al and total and exchange acidity. The acidity penetrated further in the more acid soils. The mineralization of /sup 14/C-glucose was measured at concentrations of 1.5-54 ..mu..g glucose/g of soil. Glucose mineralization in the test soils (pH values of 4.4-7.1) was inhibited by the continuous exposure to simulated acid rain at pH 3.2 but not a pH 4.1. The extent of inhibition depended on the soil and the initial glucose concentration. Exposure of one soil to 7 weeks of intermittent applications of simulated acid rain at pH 3.2 reduced the mineralization rate at the three glucose concentrations tested. These data suggest that acid rain may have a significant impact on microbial activity.

  3. Climate Change Impacts on Forest Soils Critical Acid Loads and Exceedances at a National Scale

    NASA Astrophysics Data System (ADS)

    McNulty, S. G.; Cohen, E.; Moore Myers, J.; Sun, G.; Caldwell, P.

    2011-12-01

    The Federal agencies of the United States (US) are currently developing guidelines for forest soil critical acid loads across the US. A critical acid load is defined as the amount of acid deposition (usually expressed on a annual basis) that an ecosystem can absorb. Traditionally, an ecosystem is considered to be at risk for health impairment when the critical acid load exceeds a level known to impair forest health. The excess over the critical acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical acid load applies to a single, long-term pollutant exposure. These guidelines are often used to establish regulations designed to maintain acidic deposition (e.g., nitrogen and sulfur) inputs below the level shown to exceed an ecosystem's critical acid load. The traditional definition for a critical acid load generally assume that the ecosystem is in a steady state condition (i.e. no major changes in the factors that regulate the ecosystems ability to absorb acids. Unfortunately, climate change is altering weather patterns and, thus, impacting the factors that regulate critical acid load limits. This paper explores which factors associated with establishing forest soil critical acid load limits will most likely be influenced by climate change, and how these changes might impact forest soil critical acid load limits across the US. Base cation weathering could increase with global warming, along with nitrogen uptake as a function of increased forest growth across New England. A moderate 20% increase in base cation weathering and nitrogen uptake would result in at least a 25% decrease in the amount of forest soil area that exceeded the critical acid load limit and at least a 50% decrease in the amount of high exceedance area across the US. While these results are encouraging, they do not account for other negative potential forest health risks associated with climate change such as elevated

  4. Effect of simulated acid rain on nitrification and nitrogen mineralization in forest soils

    SciTech Connect

    Strayer, R.F.; Lin, C.J.; Alexander, M.

    1981-01-01

    To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100cm of simulated acid rain (pH3.2-4.1) at 5 cm/hour or an intermittent 1.5-hour application of 1.2 cm of simulated acid rain twice weekly for 19 weeks. The upper 1.0- to 1.5-cm portions of soil from treated columns were used to determine the changes in inorganic N levels in the soil. Nitrification of added ammonium (NH4(+)) was inhibited following continuous exposure of soil to simulated acid rain of pH 4.1-3.2. The extent of the inhibition was directly related to the acidity of the simulated rain solutions. The production of inorganic N in the absence of added NH(+) was either stimulated or unaffected following continuous treatment of soils with pH 3.2 simulated acid rain. The addition of nitrapyrine, an inhibitor of autotrophic nitrification, caused a decrease in nitrification in water-treated soil but had little effect on nitrification in soil treated with pH 3.2 simulated acid rain.

  5. Interactions of aluminum with forest soils and vegetation: Implications for acid deposition

    SciTech Connect

    Maynard, A.A.

    1989-01-01

    Recent evidence suggests that an important ecological consequence of acidic deposition is increased aluminum mobilization. There is concern that increased aluminum activity may produce toxic effects in forested ecosystems. My studies were concerned with the behavior of pedogenic and added aluminum in soils derived from chemically different parent material. Soil aluminum was related to the aluminum content of the vegetation found growing in the soils. In addition, aluminum levels of forest litter was compared to levels determined 40 years ago. Field, greenhouse, and laboratory investigations were conducted in which the effects of aluminum concentration on germination and early growth was determined. Soils were then used in greenhouse and laboratory studies to establish patterns of soil and plant aluminum behavior with implications to acid deposition. Results show that the amount of aluminum extracted was related to the pH value of the extracting solution and to the chemical characteristics of the soil. Some acid rain solutions extracted measurable amounts of aluminum from selected primary minerals. Germination and early growth of Pinus radiata was controlled by levels of aluminum in the soil or in solution. Field studies indicated that most forest species were sensitive to rising levels of aluminum in the soil. In general, ferns and fern allies were less sensitive to very high levels of aluminum in the soil, continuing to grow when more advanced dicots have disappeared. Aluminum tissue levels of all species were related to the concentration of aluminum in the soil as was the reappearance of species. Aluminum levels in leaf litter have risen at least 50% in the last 40 years. These values were consistent over 3 years. The implications to acid deposition were discussed.

  6. Accumulation of different sulfur fractions in Chinese forest soil under acid deposition.

    PubMed

    Wang, Zhanyi; Zhang, Xiaoshan; Zhang, Yi; Wang, Zhangwei; Mulder, Jan

    2011-09-01

    Atmogenic sulfur (S) deposition loading by acid rain is one of the biggest environmental problems in China. It is important to know the accumulated S stored in soil, because eventually the size (and also the "desorption" rate) determines how rapidly the soil water pH responds to decrease in S deposition. The S fractions and the ratio of total carbon/total sulfur (C/S) of forest soil in 9 catchments were investigated by comparing soils at the rural and urban sites in China. The S fractions included water-soluble sulfate-S (SO(4)-S), adsorbed SO(4)-S, insoluble SO(4)-S and organic S. The ratio of C/S in soil at the rural site was significantly (p < 0.05) greater than that at the urban site. C/S of soil in the A horizon was significantly (p < 0.05) and negatively correlated with the wet S-deposition rate. The ratio of C/S presents a better indicator for atmogenic S loading. Organic S was the dominant form in soils at rural sites; contributing more than 69% of the total S in the uppermost 30 cm soil. Organic S and adsorbed SO(4)-S were the main forms of S in soil at urban sites. High contents of water-soluble SO(4)-S and adsorbed SO(4)-S were found in uppermost 30 cm soils at urban sites but not at rural sites. Decades of acid rain have caused accumulation of inorganic SO(4)-S in Chinese forest soil especially at the urban sites. The soil at urban sites had been firstly acidified, and the impacts on the forest ecosystem in these areas should be noticed.

  7. Element mobility and partitioning along a soil acidity gradient in central Ontario forests, Canada.

    PubMed

    Watmough, Shaun A

    2008-10-01

    The potential environmental risk posed by metals in forest soils is typically evaluated by modeling metal mobility using soil-solution partitioning coefficients (K(d)), although such information is generally restricted to a few well-studied metals. Soil-solution partitioning coefficients were determined for 17 mineral elements (Al, As, Be, Ba, Ca, Cr, Cu, Fe, Ga, K, Li, Mg, Rb, Sr, Tl, U and V) in A-horizon (0-5 cm) soil at 46 forested sites that border the Precambrian Shield in central Ontario, where soil pH(aq) varied from 3.9 to 8.1. Sites were dominated by mature sugar maple (Acer saccharum Marsh.), white birch (Betula papyrifera Marsh.), balsam fir (Abies balsamea (L.) Mill.) or white pine (Pinus strobus L.). Log K(d) values for all elements could be predicted by empirical linear regression with soil pH (r(2) = 0.17-0.77) independent of forest type, although this relationship was greatly affected by positive relationships between acid-extractable metal concentration and pH(aq) for 13 of the 17 elements. Elements that exhibited strong or moderate (r(2) > 0.29; p < 0.001) relationships with soil pH(aq) in soil water extracts include Al, Ba, Fe, Ga, K, Li, Rb, Tl, V (negative) and Ca (positive). Elemental partitioning in mineral soil was independent of forest type; tree species differed in their response to chemical differences in mineral soil. For example, Rb, Ba, and Sr concentrations in foliage of sugar maple and white birch significantly increased with increasing soil acidity, whereas Rb, Ba, and Sr concentrations in balsam fir and white pine foliage exhibited no response to soil pH(aq). While K(d) values can provide useful information on the potential mobility and bioavailability of mineral elements in forest soils, care must be used when interpreting the relative contribution of solid and aqueous phases to this relationship and the differing responses of vegetation in elemental cycling in forests must also be considered. PMID:18058024

  8. Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

    SciTech Connect

    Kuperman, R.G.

    1996-02-01

    Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

  9. Nitrogen saturation, soil acidification, and ecological effects in a subtropical pine forest on acid soil in southwest China

    NASA Astrophysics Data System (ADS)

    Huang, Yongmei; Kang, Ronghua; Mulder, Jan; Zhang, Ting; Duan, Lei

    2015-11-01

    Elevated anthropogenic nitrogen (N) deposition has caused nitrate (NO3-) leaching, an indication of N saturation, in several temperate and boreal forests across the Northern Hemisphere. So far, the occurrence of N saturation in subtropical forests and its effects on the chemistry of the typically highly weathered soils, forest growth, and biodiversity have received little attention. Here we investigated N saturation and the effects of chronically high N inputs on soil and vegetation in a typical, subtropical Masson pine (Pinus massoniana) forest at Tieshanping, southwest China. Seven years of N flux data obtained in ambient conditions and in response to field manipulation, including a doubling of N input either as ammonium nitrate (NH4NO3) or as sodium nitrate (NaNO3) solution, resulted in a unique set of N balance data. Our data showed extreme N saturation with near-quantitative leaching of NO3-, by far the dominant form of dissolved inorganic N in soil water. Even after 7 years, NH4+, added as NH4NO3, was nearly fully converted to NO3-, thus giving rise to a major acid input into the soil. Despite the large acid input, the decrease in soil pH was insignificant, due to pH buffering caused by Al3+ mobilization and enhanced SO42- adsorption. In response to the NH4NO3-induced increase in soil acidification and N availability, ground vegetation showed significant reduction of abundance and diversity, while Masson pine growth further declined. By contrast, addition of NaNO3 did not cause soil acidification. The comparison of NH4NO3 treatment and NaNO3 treatment indicated that pine growth decline was mainly attributed to acidification-induced nutrient imbalance, while the loss in abundance of major ground species was the combining effect of N saturation and acidification. Therefore, N emission control is of primary importance to curb further acidification and eutrophication of forest soils in much of subtropical south China.

  10. Effect of simulated acid rain on nitrification and nitrogen mineralization in forest soils

    SciTech Connect

    Strayer, R.F.; Lin, C.J.; Alexander, M.

    1981-10-01

    To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100 cm of simulated acid rain (pH 3.2-4.1) at 5 cm/hour or an intermittent 1.5-hour application of 1.2 cm of simulated acid rain twice weekly for 19 weeks. The upper 1.0- to 1.5-cm portions of soil from treated columns were used to determine the changes in inorganic N levels in the soil. Nitrification of added ammonium (NH/sub 4//sup +/) was inhibited following continuous exposure of soil to simulated acid rain of pH 4.1-3.2. The extent of the inhibition was directly related to the acidity of the simulated rain solutions. The production of inorganic N in the absence of added NH/sub 4//sup +/ was either stimulated or unaffected following continuous treatment of soils with pH 3.2 simulated acid rain. The addition of nitrapyrin (2-chloro-6-(trichloromethyl)pyridine), an inhibitor of autotrophic nitrification, caused a decrease in nitrification in water-treated soil but had little effect on nitrification in soil treated with pH 3.2 simulated acid rain. Intermittent applications of simulated acid rain (pH 3.5-4.1) for 19 weeks partially inhibited nitrate (NO/sub 3//sup -/) production in soil amended with NH/sub 4//sup +/ following the exposure period, but NO/sub 3//sup -/ production in unamended soil was either unaffected or stimulated.

  11. Abscisic acid in soil facilitates community succession in three forests in China.

    PubMed

    Zhao, Houben; Peng, Shaolin; Chen, Zhuoquan; Wu, Zhongmin; Zhou, Guangyi; Wang, Xu; Qiu, Zhijun

    2011-07-01

    Plants release secondary metabolites into the soil that change the chemical environment around them. Exogenous abscisic acid (ABA) is an important allelochemical whose role in successional trajectories has not been examined. We hypothesized that ABA can accumulate in the soil through successional processes and have an influence on forest dynamics. To this end, we investigated the distribution of ABA in forest communities from early to late successional stages and the response of dominant species to the gradient of ABA concentrations in three types of forests from northern to southern China. Concentrations of ABA in the soils of three forest types increased from early to late successional stages. Pioneer species' litters had the lowest ABA content, and their seed germination and seedling early growth were the most sensitive to the inhibitory effect of ABA. Mid- and late-successional species had a much higher ABA content in fallen leaves than pioneer species, and their seed germination and seedling early growth were inhibited by higher concentrations of ABA than pioneers. Late-successional species showed little response to the highest ABA concentration, possibly due to their large seed size. The results suggest that ABA accumulates in the soil as community succession proceeds. Sensitivity to ABA in the early stages, associated with other characteristics, may result in pioneer species losing their advantage in competition with late-successional species in an increasingly high ABA concentration environment, and being replaced by ABA-tolerant, late-successional species.

  12. [Relationships between soil moisture and needle-fall in Masson pine forests in acid rain region of Chongqing, Southwest China].

    PubMed

    Wang, Yi-Hao; Wang, Yan-Hui; Li, Zhen-Hua; Yu, Peng-Tao; Xiong, Wei; Hao, Jia; Duan, Jian

    2012-10-01

    From March 2009 to November 2011, an investigation was conducted on the spatiotemporal variation of soil moisture and its effects on the needle-fall in Masson pine (Pinus massoniana) forests in acid rain region of Chongqing, Southeast China, with the corresponding soil moisture thresholds determined. No matter the annual precipitation was abundant, normal or less than average, the seasonal variation of soil moisture in the forests could be obviously divided into four periods, i.e., sufficient (before May), descending (from June to July), drought (from August to September), and recovering (from October to November). With increasing soil depth, the soil moisture content increased after an initial decrease, but the difference of the soil moisture content among different soil layers decreased with decreasing annual precipitation. The amount of monthly needle-fall in the forests in growth season was significantly correlated with the water storage in root zone (0-60 cm soil layer), especially in the main root zone (20-50 cm soil layer). Soil field capacity (or capillary porosity) and 82% of field capacity (or 80% of capillary porosity) were the main soil moisture thresholds affecting the litter-fall. It was suggested that in acid rain region, Masson pine forest was easily to suffer from water deficit stress, especially in dry-summer period. The water deficit stress, together with already existed acid rain stress, would further threaten the health of the Masson forest.

  13. [Relationships between soil moisture and needle-fall in Masson pine forests in acid rain region of Chongqing, Southwest China].

    PubMed

    Wang, Yi-Hao; Wang, Yan-Hui; Li, Zhen-Hua; Yu, Peng-Tao; Xiong, Wei; Hao, Jia; Duan, Jian

    2012-10-01

    From March 2009 to November 2011, an investigation was conducted on the spatiotemporal variation of soil moisture and its effects on the needle-fall in Masson pine (Pinus massoniana) forests in acid rain region of Chongqing, Southeast China, with the corresponding soil moisture thresholds determined. No matter the annual precipitation was abundant, normal or less than average, the seasonal variation of soil moisture in the forests could be obviously divided into four periods, i.e., sufficient (before May), descending (from June to July), drought (from August to September), and recovering (from October to November). With increasing soil depth, the soil moisture content increased after an initial decrease, but the difference of the soil moisture content among different soil layers decreased with decreasing annual precipitation. The amount of monthly needle-fall in the forests in growth season was significantly correlated with the water storage in root zone (0-60 cm soil layer), especially in the main root zone (20-50 cm soil layer). Soil field capacity (or capillary porosity) and 82% of field capacity (or 80% of capillary porosity) were the main soil moisture thresholds affecting the litter-fall. It was suggested that in acid rain region, Masson pine forest was easily to suffer from water deficit stress, especially in dry-summer period. The water deficit stress, together with already existed acid rain stress, would further threaten the health of the Masson forest. PMID:23359920

  14. Effect of simulated acid precipitation on algal fixation of nitrogen and carbon dioxide in forest soils

    SciTech Connect

    Chang, F.H.; Alexander, M.

    1983-01-01

    Three forest soils from areas exposed to acid precipitation were incubated for 21 days in the light to enhance the development of indigenous algae. The rates of nitrogen fixation (acetylene reduction) in the light and dark were significantly less if the soils were treated with simulated rain at pH 3.5 than at pH 5.6. The inhibition increased with increasing amounts of simulated rain at pH 3.5. The fixation of CO/sub 2/ in the light was significantly less in the three soils following their exposure to simulated precipitation at pH 3.5 than to the same solutions at pH 5.6, and the extent of suppression rose with increasing amounts of synthetic rain. It is suggested that algae in terrestrial ecosystems may be especially susceptible to acid precipitation.

  15. Distribution and elevated soil pools of mercury in an acidic subtropical forest of southwestern China.

    PubMed

    Zhou, Jun; Wang, Zhangwei; Zhang, Xiaoshan; Chen, Jian

    2015-07-01

    Tieshanping catchment in southwest China was supposed to a large pool of atmospheric mercury. This work was aimed to examine THg (total mercury) concentrations, pools and influence factors in the acidic forest. THg concentrations were highly elevated in the study area, which was significantly depended on TOM (total organic matter) concentrations and altitudinal elevation, whereas negatively correlated with soil pH. The pools of mercury accumulated in soils were correlated strongly with the stocks of TOM and altitude, ranged from 5.9 to 32 mg m(-2) and averaged 14.5 mg m(-2), indicating that the acidic forest was a great sink of atmospheric mercury in southwest China. THg concentrations in stream waters decreased with altitude increasing and regression analyses showed that soil/air exchange flux would be increased with the decrease of altitude. Present results suggest that elevation increasing decreases THg losses as low THg concentrations in runoffs and volatilization from soils. PMID:25836382

  16. Effects of acid rain on mycorrhizal infection and N cycling in forest soils

    SciTech Connect

    Stroo, H.F.

    1986-01-01

    Increasing the acidity of simulated rain from pH 5.6 to 3.0 reduced the number of mycorrhizal roots on white pine seedlings by 20% after 16 weeks of exposure. Mycorrhizal infection of red oaks was 25% less at a rain pH of 3.5 than at pH 5.6. Simulated acid rain also caused increases in the N contents, net photosynthesis, and growth of seedlings, as well as decreases in root:shoot ratios and in the concentration of sucrose in the roots. To measure the effects of acid rain on N mineralization, nitrification, and total inorganic N, columns containing samples from the surface horizons of 12 forest soils were exposed to simulated rain at 3 times ambient deposition rates for 16 weeks. The effects on N mineralization varied between soils, with the greatest inhibitions being observed in soils with low organic matter contents. The apparent protection by organic matter was associated with an increase in short-term buffering capacity. The average amount of N mineralized after exposure was not significantly affected by rain pH. Similarly, nitrification was inhibited during exposure to simulated rain at pH 3.5, but was unaffected after exposure. Enrichments from an acid forest soil failed to show the presence of autotrophic nitrifiers, and the effects of temperature and selective inhibitors indicated that fungi were primarily responsible for nitrification in this soil. A fungus capable of heterotrophic nitrification at pH 4.0 was isolated and identified as Absidia cylindrospora Hagem.

  17. Actinobacterial community dominated by a distinct clade in acidic soil of a waterlogged deciduous forest.

    PubMed

    Kopecky, Jan; Kyselkova, Martina; Omelka, Marek; Cermak, Ladislav; Novotna, Jitka; Grundmann, Genevieve L; Moënne-Loccoz, Yvan; Sagova-Mareckova, Marketa

    2011-11-01

    Members of the Actinobacteria are among the most important litter decomposers in soil. The site of a waterlogged deciduous forest with acidic soil was explored for actinobacteria because seasonality of litter inputs, temperature, and precipitation provided contrasting environmental conditions, particularly variation of organic matter quantity and quality. We hypothesized that these factors, which are known to influence decomposition, were also likely to affect actinobacterial community composition. The relationship between the actinobacterial community, soil moisture and organic matter content was assessed in two soil horizons in the summer and winter seasons using a 16S rRNA taxonomic microarray and cloning-sequencing of 16S rRNA genes. Both approaches showed that the community differed significantly between horizons and seasons, paralleling the changes in soil moisture and organic matter content. The microarray analysis further indicated that the actinobacterial community of the upper horizon was characterized by high incidence of the genus Mycobacterium. In both horizons and seasons, the actinobacterial clone libraries were dominated (by 80%) by sequences of a separate clade sharing an ancestral node with Streptosporangineae. This relatedness is supported also by some common adaptations, for example, to soil acidity and periodic oxygen deprivation or dryness.

  18. Humic acids as proxies for assessing different Mediterranean forest soils signatures using solid-state CPMAS 13C NMR spectroscopy.

    PubMed

    Duarte, Regina M B O; Fernández-Getino, Ana P; Duarte, Armando C

    2013-06-01

    Humic acids (HAs) of four representative forest soils profiles from Central Spain (two with different vegetation - pine and oak - but same parent material - granitie, and two with same vegetation - holm oak - but different parent material - granite and limestone) were investigated by solid-state cross polarization with magic angle spinning (13)C nuclear magnetic resonance (NMR) spectroscopy. The objectives included the investigation of the impact of different forest properties on HA composition, assessing how the structural characteristics of the HA vary with soil depth, and evaluating the role of HA as surrogates for mapping the different forest soils signatures using structural data derived from (13)C NMR spectroscopy. On average, alkyl C is the dominant C constituent (38-48% of the total NMR peak area) in all HA samples, followed by aromatic (12-22%) and O-alkyl C (12-19%), and finally carboxyl C (7.0-10%). The NMR data also indicated that HA composition is likely to be differently affected by the soil physico-chemical properties and type of forest vegetation. The structural characteristics of the HA from soil under oak did not differ broadly downward in the profile, whereas soil HA under pine forest exhibits a somewhat higher recalcitrant nature as a consequence of a higher degree of decomposition. The soil HA from holm oak forests differed from the other two forest soils, exhibiting a progressive decomposition of the alkyl C structures with increasing depth, while the carbohydrate-like indicator (O-alkyl C) is apparently being protected from mineralization in the horizons below the ground level. Overall, these differences in soil HA NMR signatures are an important diagnostic tool for understanding the role of different soil environmental factors on the structural composition of HA from Mediterranean forest soils. PMID:23332874

  19. Humic acids as proxies for assessing different Mediterranean forest soils signatures using solid-state CPMAS 13C NMR spectroscopy.

    PubMed

    Duarte, Regina M B O; Fernández-Getino, Ana P; Duarte, Armando C

    2013-06-01

    Humic acids (HAs) of four representative forest soils profiles from Central Spain (two with different vegetation - pine and oak - but same parent material - granitie, and two with same vegetation - holm oak - but different parent material - granite and limestone) were investigated by solid-state cross polarization with magic angle spinning (13)C nuclear magnetic resonance (NMR) spectroscopy. The objectives included the investigation of the impact of different forest properties on HA composition, assessing how the structural characteristics of the HA vary with soil depth, and evaluating the role of HA as surrogates for mapping the different forest soils signatures using structural data derived from (13)C NMR spectroscopy. On average, alkyl C is the dominant C constituent (38-48% of the total NMR peak area) in all HA samples, followed by aromatic (12-22%) and O-alkyl C (12-19%), and finally carboxyl C (7.0-10%). The NMR data also indicated that HA composition is likely to be differently affected by the soil physico-chemical properties and type of forest vegetation. The structural characteristics of the HA from soil under oak did not differ broadly downward in the profile, whereas soil HA under pine forest exhibits a somewhat higher recalcitrant nature as a consequence of a higher degree of decomposition. The soil HA from holm oak forests differed from the other two forest soils, exhibiting a progressive decomposition of the alkyl C structures with increasing depth, while the carbohydrate-like indicator (O-alkyl C) is apparently being protected from mineralization in the horizons below the ground level. Overall, these differences in soil HA NMR signatures are an important diagnostic tool for understanding the role of different soil environmental factors on the structural composition of HA from Mediterranean forest soils.

  20. Comparative impacts of forest harvest and acid precipitation on soil and streamwater acidity.

    PubMed

    Hornbeck, J W

    1992-01-01

    Annual H+ budgets were calculated for a catchment with a 65-year-old spruce-fir forest, and for an adjacent catchment at three years after a whole-tree harvest. In the harvested catchment sinks for H+ due to weathering and mineralization reactions were 85% greater, and sources of H+ due to biomass uptake were 60% greater than in the undisturbed catchment. There was an overall net consumption of 550 eq H+ ha(-1) year(-1) at year 3 after harvest compared to a net generation of 520 eq H+ ha(-1) year(-1) for the 65-year-old forest. Soil pH increased by 0.2-0.4 units soon after harvest, but there was little change in pH of streamwater from the harvested watershed. The whole-tree harvest resulted in a total production of about 30,000 eq H+ ha(-1) due to biomass removal. In contrast, wet and dry deposition at rates measured in this study could add more than 50,000 eq H+ ha(-1) in the 65-year period before the next harvest. Reducing the intensity of harvest may lessen long-term impacts of these sources of H+ on acidification of soils and streams.

  1. [Effects of simulated nitrogen deposition on soil acid phosphomonoesterase activity and soil available phosphorus content in subtropical forests in Dinghushan Mountain].

    PubMed

    Li, Yin; Zeng, Shu-cai; Huang, Wen-juan

    2011-03-01

    An in situ field experiment was conducted to study the effects of simulated nitrogen (N) deposition on soil acid phosphomonoesterase activity (APA) and soil available phosphorous (AP) content in Pinus massoniana forest (PF), coniferous and broad-leaved mixed forest (MF), and monsoon evergreen broad-leaved forest (MEBF) in Dinghushan Mountain. In PF and MF, three treatments were installed, i.e., CK (0 kg N x hm(-2) x a(-1)), low N (50 kg N x hm(-2) x a(-1)), and medium N (100 kg N x hm(-2) x a(-1)); in MEBF, four treatments were installed, i.e., CK, low N, medium N, and high N (150 kg N x hm(-2) x a(-1)). The soil APA and soil AP content decreased with soil depth. The soil APA was the highest in MEBF, while the AP content had no significant difference in the three forests. The effects of N addition on soil APA differed with forest types. In MEBF, the APA was the highest (19.52 micromol x g(-1) x h(-1)) in low N treatment; while in PF and MF, the APA was the highest (12.74 and 11.02 micromol x g(-1) x h(-1), respectively) in medium N treatment. In the three forests, soil AP content was the highest in low N treatment, but had no significant differences among the N treatments. There was a significant positive correlation between soil APA and soil AP content.

  2. [Effects of simulated nitrogen deposition on soil acid phosphomonoesterase activity and soil available phosphorus content in subtropical forests in Dinghushan Mountain].

    PubMed

    Li, Yin; Zeng, Shu-cai; Huang, Wen-juan

    2011-03-01

    An in situ field experiment was conducted to study the effects of simulated nitrogen (N) deposition on soil acid phosphomonoesterase activity (APA) and soil available phosphorous (AP) content in Pinus massoniana forest (PF), coniferous and broad-leaved mixed forest (MF), and monsoon evergreen broad-leaved forest (MEBF) in Dinghushan Mountain. In PF and MF, three treatments were installed, i.e., CK (0 kg N x hm(-2) x a(-1)), low N (50 kg N x hm(-2) x a(-1)), and medium N (100 kg N x hm(-2) x a(-1)); in MEBF, four treatments were installed, i.e., CK, low N, medium N, and high N (150 kg N x hm(-2) x a(-1)). The soil APA and soil AP content decreased with soil depth. The soil APA was the highest in MEBF, while the AP content had no significant difference in the three forests. The effects of N addition on soil APA differed with forest types. In MEBF, the APA was the highest (19.52 micromol x g(-1) x h(-1)) in low N treatment; while in PF and MF, the APA was the highest (12.74 and 11.02 micromol x g(-1) x h(-1), respectively) in medium N treatment. In the three forests, soil AP content was the highest in low N treatment, but had no significant differences among the N treatments. There was a significant positive correlation between soil APA and soil AP content. PMID:21657017

  3. Temporal variations of low molecular mass organic acids during vegetation period in temperate forest soil affected by acidification

    NASA Astrophysics Data System (ADS)

    Tejnecky, V.; Drabek, O.; Bradová, M.; Němeček, K.; Šebek, O.; Zenáhlíková, J.; Boruvka, L.

    2011-12-01

    The Low Molecular Mass Organic Acids (LMMOA) are essential in processes affecting the soils and represent reactive fraction of dissolved organic carbon (DOC). LMMOA influence soil-chemistry behaviour, participate in transport of mineral nutrition and reduce potential toxicity of selected elements like Al. The aim of this research was to assess behaviour, amount and composition of LMMOA in forest soil under different vegetation cover. The researched area is located in the naturally acid Jizera Mountains (Czech Republic), which was further affected by acid deposition and improper forest management. Soil samples from organic F and H horizons, organo-mineral A horizon and spodic or cambic mineral B horizons were taken under beech and spruce stands monthly (from April to October). Both stands were located immediately next to each other. The collected soil samples were analyzed immediately in a "fresh" state. Contents of LMMOA in deionised water extract were determined by means of ion-exchange chromatography (ICS-1600, Dionex, USA) with suppressed conductivity and gradient elution of KOH mobile phase. The contents of LMMOAS were also determined in precipitation samples. In addition, other selected elements (Al, Fe, Ca, Na, Mg and K), Al speciation and main inorganic anions were determined in water extract and precipitation samples. The highest amounts of LMMOA (mainly lactic, acetic, formic, malic and oxalic acid) were observed in organic F and H horizons and measured amounts decreased with increasing soil profile depth. Higher contents were determined in soil under spruce forest than under beech forest. External inputs of LMMOA in a form of precipitation were assessed as less significant in comparison with the soil processes (e.g. soil biological activity, soil organic matter decomposition processes). LMMOA amounts were higher in spring and summer (from April to August), caused by increased biological activity, while lower amounts were observed during the autumn period

  4. Inter-laboratory variation in the chemical analysis of acidic forest soil reference samples from eastern North America

    USGS Publications Warehouse

    Ross, Donald S.; Bailiey, Scott W; Briggs, Russell D; Curry, Johanna; Fernandez, Ivan J.; Fredriksen, Guinevere; Goodale, Christine L.; Hazlett, Paul W.; Heine, Paul R; Johnson, Chris E.; Larson, John T; Lawrence, Gregory B.; Kolka, Randy K; Ouimet, Rock; Pare, D; Richter, Daniel D.; Shirmer, Charles D; Warby, Richard A.F.

    2015-01-01

    Long-term forest soil monitoring and research often requires a comparison of laboratory data generated at different times and in different laboratories. Quantifying the uncertainty associated with these analyses is necessary to assess temporal changes in soil properties. Forest soil chemical properties, and methods to measure these properties, often differ from agronomic and horticultural soils. Soil proficiency programs do not generally include forest soil samples that are highly acidic, high in extractable Al, low in extractable Ca and often high in carbon. To determine the uncertainty associated with specific analytical methods for forest soils, we collected and distributed samples from two soil horizons (Oa and Bs) to 15 laboratories in the eastern United States and Canada. Soil properties measured included total organic carbon and nitrogen, pH and exchangeable cations. Overall, results were consistent despite some differences in methodology. We calculated the median absolute deviation (MAD) for each measurement and considered the acceptable range to be the median 6 2.5 3 MAD. Variability among laboratories was usually as low as the typical variability within a laboratory. A few areas of concern include a lack of consistency in the measurement and expression of results on a dry weight basis, relatively high variability in the C/N ratio in the Bs horizon, challenges associated with determining exchangeable cations at concentrations near the lower reporting range of some laboratories and the operationally defined nature of aluminum extractability. Recommendations include a continuation of reference forest soil exchange programs to quantify the uncertainty associated with these analyses in conjunction with ongoing efforts to review and standardize laboratory methods.

  5. Thaumarchaeal ammonia oxidation in an acidic forest peat soil is not influenced by ammonium amendment.

    PubMed

    Stopnisek, Nejc; Gubry-Rangin, Cécile; Höfferle, Spela; Nicol, Graeme W; Mandic-Mulec, Ines; Prosser, James I

    2010-11-01

    Both bacteria and thaumarchaea contribute to ammonia oxidation, the first step in nitrification. The abundance of putative ammonia oxidizers is estimated by quantification of the functional gene amoA, which encodes ammonia monooxygenase subunit A. In soil, thaumarchaeal amoA genes often outnumber the equivalent bacterial genes. Ecophysiological studies indicate that thaumarchaeal ammonia oxidizers may have a selective advantage at low ammonia concentrations, with potential adaptation to soils in which mineralization is the major source of ammonia. To test this hypothesis, thaumarchaeal and bacterial ammonia oxidizers were investigated during nitrification in microcosms containing an organic, acidic forest peat soil (pH 4.1) with a low ammonium concentration but high potential for ammonia release during mineralization. Net nitrification rates were high but were not influenced by addition of ammonium. Bacterial amoA genes could not be detected, presumably because of low abundance of bacterial ammonia oxidizers. Phylogenetic analysis of thaumarchaeal 16S rRNA gene sequences indicated that dominant populations belonged to group 1.1c, 1.3, and "deep peat" lineages, while known amo-containing lineages (groups 1.1a and 1.1b) comprised only a small proportion of the total community. Growth of thaumarchaeal ammonia oxidizers was indicated by increased abundance of amoA genes during nitrification but was unaffected by addition of ammonium. Similarly, denaturing gradient gel electrophoresis analysis of amoA gene transcripts demonstrated small temporal changes in thaumarchaeal ammonia oxidizer communities but no effect of ammonium amendment. Thaumarchaea therefore appeared to dominate ammonia oxidation in this soil and oxidized ammonia arising from mineralization of organic matter rather than added inorganic nitrogen.

  6. Simultaneous inhibition of carbon and nitrogen mineralization in a forest soil by simulated acid precipitation

    SciTech Connect

    Klein, T.M.; Novick, N.J.; Kreitinger, J.P.; Alexander, M.

    1984-06-01

    One method to simulate the long-term exposure of soil to acid rain involves the addition of single doses of concentrated acid. The inhibition of carbon mineralization accompanied by a stimulation of nitrogen mineralization may result from this severe, unnatural treatment. The present study was designed to determine whether the inhibition of carbon mineralization and the accompanying enhanced nitrogen mineralization would occur when soils are treated with more dilute acid for long periods of time, as takes place in nature.

  7. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    PubMed

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems.

  8. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    PubMed

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems. PMID:20382410

  9. A short-term mineral amendment impacts the mineral weathering bacterial communities in an acidic forest soil.

    PubMed

    Lepleux, C; Uroz, S; Collignon, C; Churin, J-L; Turpault, M-P; Frey-Klett, P

    2013-09-01

    Mineral amendment (i.e. calcium, phosphorous, potassium and/or magnesium) is a management practice used in forestry to improve nutrient availability and recover soil fertility, especially in nutrient-poor forest ecosystems. However, whether this amendment can lead to modifications of the soil characteristics and an improvement in tree growth, and its impact on the soil bacterial communities, especially the mineral weathering bacterial communities, remains poorly documented. In this study, we investigated the short-term impact of a mineral amendment on the taxonomic and functional structure of the mineral weathering bacterial communities. To do this, a plantation of four-year old oak (Quercus petraea) trees amended with or without dolomite [CaMg(CO3)2] was established in the experimental forest site of Breuil-Chenue, which is characterized by an acidic soil and a low availability of calcium and magnesium. Three years after amendment, soil samples were used to isolate bacteria as well as to determine the soil characteristics and the metabolic potentials of these soil microbial communities. Based on a bioassay for quantifying the solubilisation of inorganic phosphorous, we demonstrate that the bacterial isolates coming from the non-amended bulk soil were significantly more efficient than those from the amended bulk soil. No difference was observed between the bacterial isolates coming from the amended and non-amended rhizospheres. Notably, the taxonomic analyses revealed a dominance of bacterial isolates belonging to the Burkholderia genus in both samples. Overall, our results suggest that the bioavailability of nutritive cations into soil impacts the distribution and the efficacy of mineral weathering bacterial communities coming from the soil but not those coming from the rhizosphere.

  10. Contributions of acid deposition and natural processes to cation leaching from forest soils: a review

    SciTech Connect

    Johnson, D.W.; Van Miegroet, H.; Cole, D.W.; Richter, D.D.

    1983-01-01

    Methods of quantifying the roles of atmospheric acid inputs and internal acid generation by carbonic, organic, and nitric acids are illustrated by reviewing data sets from several intensively studied sites in North America. Some of the sites (tropical, Costa Rica (La Selva); temperate deciduous, Tennessee (Walker Branch); and temperate coniferous, Washington (Thompson)) received acid precipitation whereas others (northern, southeast Alaska (Petersburg); and subalpine, Washington Cascades (Findley Lake)) did not. Natural leaching by carbonic acid dominated soil leaching in the tropical and temperate coniferous sites, nitric acid (caused by nitrification) dominated leaching in an N-fixing temperate deciduous site (red alder in Washington), and organic acids dominated surface soil leaching in the subalpine site and contributed to leaching of surface soils in several other sites. Only at the temperate deciduous sites in eastern Tennessee did atmospheric acid input play a major role in soil leaching. In no case, however, are the annual net losses of cations regarded as alarming as compared to soil exchangeable cation capital.

  11. Acid Precipitation and the Forest Ecosystem

    ERIC Educational Resources Information Center

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  12. Tree species affect cation exchange capacity (CEC) and cation binding properties of organic matter in acid forest soils.

    PubMed

    Gruba, Piotr; Mulder, Jan

    2015-04-01

    Soil organic matter (SOM) in forest soil is of major importance for cation binding and acid buffering, but its characteristics may differ among soils under different tree species. We investigated acidity, cation exchange properties and Al bonding to SOM in stands of Scots pine, pedunculate oak, Norway spruce, European beech and common hornbeam in southern Poland. The content of total carbon (Ct) was by far the major contributor to total cation exchange capacity (CECt) even in loamy soils and a strong relationship between Ct and CECt was found. The slope of the regression of CECt to Ct increased in the order hornbeam≈oakacid pH range was smallest for hornbeam and oak, and largest for spruce and pine soils. This was supported by the apparent dissociation constant (pKapp) values of SOM, which were largest in soils under oak. The maximum values of Al saturation were similar between the stands. However, maximum Al bonding to SOM occurred at higher pH values in soils under pine and spruce than under oak. Therefore, at any value in the acid pH range, the SOM in pine soil has less Al complexed and more adsorbed H+ than SOM from oak soils. Such differences in Al and H bonding are not only important for pH buffering and metal solubility controls, but also for stabilization of SOM via saturation of functional groups by Al and H.

  13. Tree species affect cation exchange capacity (CEC) and cation binding properties of organic matter in acid forest soils.

    PubMed

    Gruba, Piotr; Mulder, Jan

    2015-04-01

    Soil organic matter (SOM) in forest soil is of major importance for cation binding and acid buffering, but its characteristics may differ among soils under different tree species. We investigated acidity, cation exchange properties and Al bonding to SOM in stands of Scots pine, pedunculate oak, Norway spruce, European beech and common hornbeam in southern Poland. The content of total carbon (Ct) was by far the major contributor to total cation exchange capacity (CECt) even in loamy soils and a strong relationship between Ct and CECt was found. The slope of the regression of CECt to Ct increased in the order hornbeam≈oakacid pH range was smallest for hornbeam and oak, and largest for spruce and pine soils. This was supported by the apparent dissociation constant (pKapp) values of SOM, which were largest in soils under oak. The maximum values of Al saturation were similar between the stands. However, maximum Al bonding to SOM occurred at higher pH values in soils under pine and spruce than under oak. Therefore, at any value in the acid pH range, the SOM in pine soil has less Al complexed and more adsorbed H+ than SOM from oak soils. Such differences in Al and H bonding are not only important for pH buffering and metal solubility controls, but also for stabilization of SOM via saturation of functional groups by Al and H. PMID:25596350

  14. Co-occurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in subtropical acidic forest soils.

    PubMed

    Meng, Han; Wang, Yong-Feng; Chan, Ho-Wang; Wu, Ruo-Nan; Gu, Ji-Dong

    2016-09-01

    Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two new processes of recent discoveries linking the microbial nitrogen and carbon cycles. In this study, 16S ribosomal RNA (rRNA) gene of anammox bacteria and pmoA gene of n-damo bacteria were used to investigate their distribution and diversity in natural acidic and re-vegetated forest soils. The 16S rRNA gene sequences retrieved featured at least three species in two genera known anammox bacteria, namely Candidatus Brocadia anammoxidans, Candidatus Brocadia fulgida, and Candidatus Kuenenia stuttgartiensis while the pmoA gene amplified was affiliated with two species of known n-damo bacteria Candidatus Methylomirabilis oxyfera and a newly established Candidatus Methylomirabilis sp. According to the results, the diversity of anammox bacteria in natural forests was lower than in re-vegetated forests, but no significant difference was observed in n-damo community between them. Quantitative real-time PCR showed that both anammox and n-damo bacteria were more abundant in the lower layer (10-20 cm) than the surface layer (0-5 cm). The abundance of anammox bacteria varied from 2.21 × 10(5) to 3.90 × 10(6) gene copies per gram dry soil, and n-damo bacteria quantities were between 1.69 × 10(5) and 5.07 × 10(6) gene copies per gram dry soil in the two different layers. Both anammox and n-damo bacteria are reported for the first time to co-occur in acidic forest soil in this study, providing a more comprehensive information on more defined microbial processes contributing to C and N cycles in the ecosystems. PMID:27178181

  15. Early indications of soil recovery from acidic deposition in U.S. red spruce forests

    USGS Publications Warehouse

    Lawrence, Gregory B.; Shortle, Walter C.; David, Mark B.; Smith, Kevin T.; Warby, Richard A.F.; Lapenis, Andrei G.

    2012-01-01

    Forty to fifty percent decreases in acidic deposition through the 1980s and 1990s led to partial recovery of acidified surface waters in the northeastern United States; however, the limited number of studies that have assessed soil change found increased soil acidification during this period. From existing data, it's not clear whether soils continued to worsen in the 1990s or if recovery had begun. To evaluate possible changes in soils through the 1990s, soils in six red spruce (Picea rubens Sarg.) stands in New York, Vermont, New Hampshire, and Maine, first sampled in 1992 to 1993, were resampled in 2003 to 2004. The Oa-horizon pH increased (P 42−, which decreased the mobility of Al throughout the upper soil profile. Results indicate a nascent recovery driven largely by vegetation processes.

  16. Soil solution response to experimentally reduced acid deposition in a forest ecosystem

    SciTech Connect

    Alewell, C.; Matzner, E.; Bredemeier, M.; Blanch, K.

    1997-05-01

    In order to measure and predict reversibility of soil solution acidification under experimentally reduced acid input, a manipulation study with artificial {open_quote}preindustrial{close_quote} throughfall was established. A roof was installed underneath the canopy in a Norway Spruce stand of the German Soiling area. Water failing onto the roof was adjusted to clean rain concentrations before redistribution. Soil solutions were collected with suction cup lysimeters at various depths and were analyzed for major ions. The response of soil solution chemistry in the upper soil (10 cm depth) to a reduction of N, SO{sub 4}, and H input was rapid. While NO{sub 3} concentration in deeper soil layers reached input levels after 2 yr of treatment, SO{sub 4} concentration in the seepage water at 1 m depth remained high relative to the reduced input due to a release of formerly stored S from the soil. Aluminum concentration followed a similar pattern as the SO{sub 4} concentrations. The ion concentrations in soil leachate were predicted reasonably well using the MAGIC model with the measured SO{sub 4} sorption isotherms and the throughfall fluxes as model input Although the parameters of the Langmuir isotherm had no significant influence to the prediction of SO{sub 4} concentration in the upper soil layer, they were crucial for the prediction of SO{sub 4} dynamics in deeper soil layers. The model predicted that the reversibility of soil acidification at the Soiling area is delayed for decades due to the release of soil SO{sub 4}. 38 refs., 5 figs., 4 tabs.

  17. Effects of acid irrigation on carbon dioxide evolution, extractable nitrogen, phosphorus, and aluminum in a deciduous forest soil

    SciTech Connect

    Johnson, D.W.; Todd, D.E.

    1984-01-01

    A study was initiated to determine the effects of sulfuric and nitric acid irrigation on CO/sub 2/ evolution, and N, P, and Al availability in a deciduous forest soil. Irrigation with H/sub 2/O, H/sub 2/SO/sub 4/, or HNO/sub 3/ at 0.05 mol (p/sup +/) m/sup -2/ and 0.5 mol (p/sup +/) m/sup -2/ for 1 yr had no consistent effect on CO/sub 2/ evolution, soil NH/sub 4//sup +/, extractable P, or extractable Al in a deciduous forest soil under field conditions. Irrigation with HNO/sub 3/ caused temporary increases in soil NO/sub 3//sup -/, but irrigation with H/sub 2/SO/sub 4/ had no effect on soil NO/sub 3//sup -/. Nitrogen mineralization and nitrification by aerobic incubation were also unaffected by treatments. Seasonal variations in CO/sub 2/ evolution, NH/sub 4//sup +/, and extractable P were pronounced, with peaks in CO/sub 2/ evolution, NH/sub 4//sup +/, in June and a peak extractable P in August. 19 references, 2 tables.

  18. Effects of simulated acid rain on soil and soil solution chemistry in a monsoon evergreen broad-leaved forest in southern China.

    PubMed

    Qiu, Qingyan; Wu, Jianping; Liang, Guohua; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was <4.0. The effects of SAR on soil solution chemistry became increasingly apparent as the experiment proceeded (except for Na(+) and dissolved organic carbon (DOC)). The net exports of NO₃(-), SO₄(2-), Mg(2+), and Ca(2+) increased about 42-86% under pH 2.5 treatment as compared to CK. The Ca(2+) was sensitive to SAR, and the soil could release Ca(2+) through mineral weathering to mitigate soil acidification. The concentration of exchangeable Al(3+) in the soil increased with increasing the acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively.

  19. Effects of simulated acid rain on soil and soil solution chemistry in a monsoon evergreen broad-leaved forest in southern China.

    PubMed

    Qiu, Qingyan; Wu, Jianping; Liang, Guohua; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was <4.0. The effects of SAR on soil solution chemistry became increasingly apparent as the experiment proceeded (except for Na(+) and dissolved organic carbon (DOC)). The net exports of NO₃(-), SO₄(2-), Mg(2+), and Ca(2+) increased about 42-86% under pH 2.5 treatment as compared to CK. The Ca(2+) was sensitive to SAR, and the soil could release Ca(2+) through mineral weathering to mitigate soil acidification. The concentration of exchangeable Al(3+) in the soil increased with increasing the acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively. PMID:25893761

  20. Kinetics of aluminum and sulfate release from forest soil by mono- and diprotic aliphatic acids

    SciTech Connect

    Evans, A. Jr.; Zelazny, L.W. )

    1990-06-01

    A batch equilibration study evaluated the influence of naturally occurring low-molecular-weight mono- and diprotic aliphatic acids on the rate of Al and SO{sub 4}{sup 2{minus}} release in a Cecil soil (Typic Hapludult). The authors adjusted the pH of the organic acids (OAs) and of the soil suspension (3.8% w/w) to pH 4.0 and allowed them to equilibrate thermally before the experiment. After rapid addition of OAs to the soil suspension, they took solution samples at various time intervals and analyzed for Al, SO{sub 4}{sup 2{minus}}, and OA concentration. The initial concentration of OA in suspension was 1 {times} 10{sup {minus}5} mol liter{sup {minus}1}. Both Al and SO{sub 4}{sup 2{minus}} release followed pseudo-first-order kinetics, whereas OA adsorption obeyed simple first-order kinetics. The rate of Al release (k{sub 1}) was more rapid for the diprotic OA treatment (20.4 {times} 10{sup {minus}8} mol s{sup {minus}1}), as was SO{sub 4}{sup 2{minus}} release (1.63 {times} 10{sup {minus}8} mol s{sup {minus}1}), compared to the monoprotic OA treatment. The rate of Al release varied inversely with OA chain length and the distance between -COOH functional groups. The addition of substituent -OH groups between the -COOH groups further reduced K{sub 1}. A similar trend was observed for the rate of SO{sub 4}{sup 2{minus}} release (k{sub 1}) into solution. Monoprotic OAs were more rapidly adsorbed to the particle surfaces than were diprotic OAs. The authors postulate that removal of Al and SO{sub 4}{sup 2{minus}} from solution occurs via selective mineral precipitation.

  1. Estimating the buffer capacity of forest soils

    SciTech Connect

    Hornbeck, J.W.; Federer, C.A.

    1985-11-01

    The organic-matter content of New England soils is an index of buffer capacity, and can be measured to indicate how forest soils might respond to acid precipitation. Buffer capacity, as defined herein, is the milliequivalents of H/sup +/ or OH/sup -/ that must be added to a kilogram of soil to change its pH by one unit. As such, it is an index of how soil pH will respond to H/sup +/ in acid precipitation. At four locations in New England, the buffer capacity of organic and mineral horizons for well-drained forest soils under second-growth forests and in new and regrowing clearcuts was measured. The sites included a spruce-fir forest in central Maine, two northern hardwood forests in northern New Hampshire, and a central hardwood forest in southern Connecticut. Soil materials were titrated by adding known amounts of HCl or NaOH and measuring the pH after 24 hours. Details on methods were given in this paper. 1 table.

  2. Soil acidity reconstruction based on tree ring information of a dominant species Abies fabri in the subalpine forest ecosystems in southwest China.

    PubMed

    Chen, Lei; Wu, Fei-Hua; Liu, Ting-Wu; Chen, Juan; Li, Zhen-Ji; Pei, Zhen-Ming; Zheng, Hai-Lei

    2010-10-01

    To assess the suitability of dendrochemistry as an indicator of soil acidification, soil chemistry and tree ring information of Abies fabri were measured at two distinct sites (severe acid deposition site-Emei Mountain and clean site-Gongga Mountain) of the subalpine forest ecosystems of western Sichuan, southwest China. The actual soil acidity (pH) was significantly correlated with some of the recent xylem cation (Ca, Mg, Mn, Al, Sr and Ba) concentrations and their molar ratios. Xylem Ca/Mg and Ca/Mn of A. fabri were ultimately selected to reconstruct the historical changes of soil pH in Emei Mountain and Gongga Mountain, respectively. The validity of those rebuild was also verified to a certain extent. We conclude that xylem cation molar ratios of A. fabri were superior to the single cation concentrations in soil acidity rebuild at the study sites due to normalizing for concentration fluctuations.

  3. Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

    NASA Astrophysics Data System (ADS)

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2014-05-01

    Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

  4. Acid-base properties of water-soluble organic matter of forest soils, studied by the pK-spectroscopy method.

    PubMed

    Shamrikova, E V; Ryazanov, M A; Vanchikova, E V

    2006-11-01

    Using the potentiometric titration and pK spectroscopy method, acid-base properties of water-soluble organic matter of forest soils have been studied. Five acidic classes composed of different substances with pK(a) values around 3.6; 4.8; 6.7; 8.7 and 9.7 have been identified. Testing the properties of soluble soil fraction, it is to be taken into account that when it is isolated from non-soluble soil matter, some water-soluble substances remain in soil and do not pass into the solution. Most firmly adsorbed in soil are water-soluble components with pK(a) 9.6-9.8.

  5. Soil properties discriminating Araucaria forests with different disturbance levels.

    PubMed

    Bertini, Simone Cristina Braga; Azevedo, Lucas Carvalho Basilio; Stromberger, Mary E; Cardoso, Elke Jurandy Bran Nogueira

    2015-04-01

    Soil biological, chemical, and physical properties can be important for monitoring soil quality under one of the most spectacular vegetation formation on Atlantic Forest Biome, the Araucaria Forest. Our aim was to identify a set of soil variables capable of discriminating between disturbed, reforested, and native Araucaria forest soils such that these variables could be used to monitor forest recovery and maintenance. Soil samples were collected at dry and rainy season under the three forest types in two state parks at São Paulo State, Brazil. Soil biological, chemical, and physical properties were evaluated to verify their potential to differentiate the forest types, and discriminant analysis was performed to identify the variables that most contribute to the differentiation. Most of physical and chemical variables were sensitive to forest disturbance level, but few biological variables were significantly different when comparing native, reforested, and disturbed forests. Despite more than 20 years following reforestation, the reforested soils were chemically and biologically distinct from native and disturbed forest soils, mainly because of the greater acidity and Al3+ content of reforested soil. Disturbed soils, in contrast, were coarser in texture and contained greater concentrations of extractable P. Although biological properties are generally highly sensitive to disturbance and amelioration efforts, the most important soil variables to discriminate forest types in both seasons included Al3+, Mg2+, P, and sand, and only one microbial attribute: the NO2- oxidizers. Therefore, these five variables were the best candidates, of the variables we employed, for monitoring Araucaria forest disturbance and recovery.

  6. Long-term impact of acid resin waste deposits on soil quality of forest areas I. Contaminants and abiotic properties.

    PubMed

    Pérez-de-Mora, Alfredo; Madejón, Engracia; Cabrera, Francisco; Buegger, Franz; Fuss, Roland; Pritsch, Karin; Schloter, Michael

    2008-11-15

    Acid resins are residues characterised by elevated concentrations of hydrocarbons and trace elements, which were produced by mineral oil industries in Central Europe during the first half of the last century. Due to the lack of environmental legislation at that time, these wastes were dumped into excavated ponds in public areas without further protection. In this work, the long-term effects of such resin deposits on soil quality of two forest areas (Bayern, Germany) were assessed. We evaluated the distribution and accumulation of contaminants in the surroundings of the deposits, where the waste was disposed of about 60 years ago. General soil chemical properties such as pH, C, N and P content were also investigated. Chemical analysis of resin waste from the deposits revealed large amounts of potential contaminants such as hydrocarbons (93 g kg(-1)), As (63 mg kg(-1)), Cd (24 mg kg(-1)), Cu (1835 mg kg(-1)), Pb (8100 mg kg(-1)) and Zn (873 mg kg(-1)). Due to the location of the deposits on a hillside and the lack of adequate isolation, contaminants have been released downhill despite the solid nature of the waste. Five zones were investigated in each site: the deposit, three affected zones along the plume of contamination and a control zone. In affected zones, contaminants were 2 to 350 times higher than background levels depending on the site. In many cases, contaminants exceeded the German environmental guidelines for the soil-groundwater path and action levels based on extractable concentrations. Resin contamination yielded larger total C/total N ratios in affected zones, but no clear effect was observed on absolute C, N and P concentrations. In general, no major acidification effect was reported in affected zones.

  7. Microbial reduction of ferric iron oxyhydroxides as a way for remediation of grey forest soils heavily polluted with toxic metals by infiltration of acid mine drainage

    NASA Astrophysics Data System (ADS)

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2015-04-01

    The abandoned uranium mine Curilo is a permanent source of acid mine drainage (AMD) which steadily contaminated grey forest soils in the area. As a result, the soil pH was highly acidic and the concentration of copper, lead, arsenic, and uranium in the topsoil was higher than the relevant Maximum Admissible Concentration (MAC) for soils. The leaching test revealed that approximately half of each pollutant was presented as a reducible fraction as well as the ferric iron in horizon A was presented mainly as minerals with amorphous structure. So, the approach for remediation of the AMD-affected soils was based on the process of redoxolysis carried out by iron-reducing bacteria. Ferric iron hydroxides reduction and the heavy metals released into soil solutions was studied in the dependence on the source of organic (fresh or silage hay) which was used for growth and activity of soil microflora, initial soil pH (3.65; 4.2; and 5.1), and the ion content of irrigation solutions. The combination of limestone (2.0 g/ kg soil), silage addition (at rate of 45 g dry weight/ kg soil) in the beginning and reiterated at 6 month since the start of soil remediation, and periodical soil irrigation with slightly acidic solutions containing CaCl2 was sufficient the content of lead and arsenic in horizon A to be decreased to concentrations similar to the relevant MAC. The reducible, exchangeable, and carbonate mobile fractions were phases from which the pollutants was leached during the applied soil remediation. It determined the higher reduction of the pollutants bioavailability also as well as the process of ferric iron reduction was combined with neutralization of the soil acidity to pH (H2O) 6.2.

  8. Source and compositional changes of soil organic matter in an acidic forest soil - from top- to subsoil

    NASA Astrophysics Data System (ADS)

    Angst, Gerrit; John, Stephan; Rethemeyer, Janet; Kögel-Knabner, Ingrid; Mueller, Carsten W.

    2014-05-01

    Subsoils can significantly contribute to the terrestrial C pool. While processes of C turnover and storage in topsoils are generally well understood, little is known about subsoils. Our project, embedded within the DFG research group FOR 1806, aims to contribute to the knowledge about subsoil C by differentiating soil organic matter (SOM) in terms of its origin and its composition. In order to obtain a meaningful sample set we studied three soil ditches, 3.15 m in length and 2.15 m in depth, in a podzolic Cambisol under European beech (Fagus sylvatica L.) north of Hannover, Germany. In a to date unique sampling approach we took 64 soil samples in a regular vertical grid in each of the soil profiles, thus identifying possible gradients between top- and subsoil. The samples were subjected to a combined density and particle size fractionation to separate particulate organic matter (POM) from mineral compartments. We especially aimed at obtaining the combined fine silt and clay fraction which is thought to be most important in the long term stabilization of SOM. The chemical composition of the so obtained fractions and the bulk soil was revealed by C, N and 13C CPMAS NMR measurements. The source of OM in the soil was investigated by tracing the biopolymers cutin and suberin across the soil profile. Cutin occurs mainly in the cuticula of leaves while suberin mainly constitutes the endodermal cell walls of plant roots. In soils the two polymers can thus be used as proxies for above and belowground OM input respectively. To release the constituting monomers of the two biopolymers from the soil samples the latter were pretreated with organic solvents to extract free lipids. The soil residues were subsequently subjected to a base hydrolysis and the so obtained extracts were measured with GC/MS. The organic C contents of the bulk soil decrease significantly with depth in all transects from around 15 mg g-1 to 2 mg g-1. This is likely associated with the very high sand and

  9. Carbon Sequestration in Forest Soils

    NASA Astrophysics Data System (ADS)

    Lal, R.

    2006-05-01

    Carbon (C) sequestration in soils and forests is an important strategy of reducing the net increase in atmospheric CO2 concentration by fossil fuel combustion, deforestation, biomass burning, soil cultivation and accelerated erosion. Further, the so-called "missing or fugitive CO2" is also probably being absorbed in a terrestrial sink. Three of the 15 strategies proposed to stabilize atmospheric CO2 concentrations by 2054, with each one to sequester 1 Pg Cyr-1, include: (i) biofuel plantations for bioethanol production, (ii) reforestation, afforestation and establishment of new plantations, and (iii) conversion of plow tillage to no-till farming. Enhancing soil organic carbon (SOC) pool is an important component in each of these three options, but especially so in conversion of degraded/marginal agricultural soils to short rotation woody perennials, and establishment of plantations for biofuel, fiber and timber production. Depending upon the prior SOC loss because of the historic land used and management-induced soil degradation, the rate of soil C sequestration in forest soils may be 0 to 3 Mg C ha-1 yr-1. Tropical forest ecosystems cover 1.8 billion hectares and have a SOC sequestration potential of 200 to 500 Tg C yr-1 over 59 years. However, increasing production of forest biomass may not always increase the SOC pool. Factors limiting the rate of SOC sequestration include C: N ratio, soil availability of N and other essential nutrients, concentration of recalcitrant macro-molecules (e.g., lignin, suberin), soil properties (e.g., clay content and mineralogy, aggregation), soil drainage, and climate (mean annual precipitation and temperature). The SOC pool can be enhanced by adopting recommended methods of forest harvesting and site preparation to minimize the "Covington effect," improving soil drainage, alleviating soil compaction, growing species with a high NPP, and improving soil fertility including the availability of micro-nutrients. Soil fertility

  10. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    PubMed

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P < 0.05). The negative effects were correlated with the decrease in soil microbial biomass and fine root biomass due to soil acidification under the SAR. The temperature coefficients (Q10) of RT and its two components generally decreased with increasing levels of the SAR, but only the decrease of RT and RL was significant (P < 0.05). In addition, the contribution of RL to RT decreased significantly under the SAR, indicating that RL was more sensitive to the SAR than RS. In the context of elevated acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer. PMID:26755128

  11. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    PubMed

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P < 0.05). The negative effects were correlated with the decrease in soil microbial biomass and fine root biomass due to soil acidification under the SAR. The temperature coefficients (Q10) of RT and its two components generally decreased with increasing levels of the SAR, but only the decrease of RT and RL was significant (P < 0.05). In addition, the contribution of RL to RT decreased significantly under the SAR, indicating that RL was more sensitive to the SAR than RS. In the context of elevated acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer.

  12. Quantifying the role of forest soil and bedrock in the acid neutralization of surface water in steep hillslopes.

    PubMed

    Asano, Yuko; Uchida, Taro

    2005-02-01

    The role of soil and bedrock in acid neutralizing processes has been difficult to quantify because of hydrological and biogeochemical uncertainties. To quantify those roles, hydrochemical observations were conducted at two hydrologically well-defined, steep granitic hillslopes in the Tanakami Mountains of Japan. These paired hillslopes are similar except for their soils; Fudoji is leached of base cations (base saturation <6%), while Rachidani is covered with fresh soil (base saturation >30%), because the erosion rate is 100-1000 times greater. The results showed that (1) soil solution pH at the soil-bedrock interface at Fudoji (4.3) was significantly lower than that of Rachidani (5.5), (2) the hillslope discharge pH in both hillslopes was similar (6.7-6.8), and (3) at Fudoji, 60% of the base cations leaching from the hillslope were derived from bedrock, whereas only 20% were derived from bedrock in Rachidani. Further, previously published results showed that the stream pH could not be predicted from the acid deposition rate and soil base saturation status. These results demonstrate that bedrock plays an especially important role when the overlying soil has been leached of base cations. These results indicate that while the status of soil acidification is a first-order control on vulnerability to surface water acidification, in some cases such as at Fudoji, subsurface interaction with the bedrock determines the sensitivity of surface water to acidic deposition.

  13. Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S. and eastern Canada

    USGS Publications Warehouse

    Lawrence, Gregory B.; Hazlett, Paul W.; Fernandez, Ivan J.; Ouimet, Rock; Bailey, Scott W.; Shortle, Walter C.; Smith, Kevin T.; Antidormi, Michael

    2015-01-01

    Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been limited, and little is known regarding soil responses to ongoing acidic deposition decreases. In this study, resampling of soils in eastern Canada and the northeastern U.S. was done at 27 sites exposed to reductions in wet SO42– deposition of 5.7–76%, over intervals of 8–24 y. Decreases of exchangeable Al in the O horizon and increases in pH in the O and B horizons were seen at most sites. Among all sites, reductions in SO42– deposition were positively correlated with ratios (final sampling/initial sampling) of base saturation (P < 0.01) and negatively correlated with exchangeable Al ratios (P < 0.05) in the O horizon. However, base saturation in the B horizon decreased at one-third of the sites, with no increases. These results are unique in showing that the effects of acidic deposition on North American soils have begun to reverse.

  14. Declining Acidic Deposition Begins Reversal of Forest-Soil Acidification in the Northeastern U.S. and Eastern Canada.

    PubMed

    Lawrence, Gregory B; Hazlett, Paul W; Fernandez, Ivan J; Ouimet, Rock; Bailey, Scott W; Shortle, Walter C; Smith, Kevin T; Antidormi, Michael R

    2015-11-17

    Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been limited, and little is known regarding soil responses to ongoing acidic deposition decreases. In this study, resampling of soils in eastern Canada and the northeastern U.S. was done at 27 sites exposed to reductions in wet SO4(2-) deposition of 5.7-76%, over intervals of 8-24 y. Decreases of exchangeable Al in the O horizon and increases in pH in the O and B horizons were seen at most sites. Among all sites, reductions in SO4(2-) deposition were positively correlated with ratios (final sampling/initial sampling) of base saturation (P < 0.01) and negatively correlated with exchangeable Al ratios (P < 0.05) in the O horizon. However, base saturation in the B horizon decreased at one-third of the sites, with no increases. These results are unique in showing that the effects of acidic deposition on North American soils have begun to reverse.

  15. [Basidiomycetous laccase gene diversity in two subtropical forest soils].

    PubMed

    Chen, Xiang-bi; Su, Yi-rong; He, Xun-yang; Hu, Le-ning; Liang, Yue-ming; Feng, Shu-zhen; Ge, Yun-hui; Xiao, Wei

    2011-10-01

    As one of the key enzymes involved in lignin decomposition of forest litter, laccase plays an important role in the carbon cycling in forest ecosystem. By using TA cloning and sequencing, a comparative study was conducted on the basidiomycetous laccase gene diversity in the O horizon (litter layer) and A horizon (surface soil layer, 0-20 cm) in two subtropical forests (a primeval evergreen deciduous broadleaved mixed forest and an artificial masson pine forest). For the same soil horizons, the basidiomycetous laccase gene diversity and richness were higher in the primeval forest than in the masson pine forest; for the same forest ecosystems, the basidiomycetous laccase gene diversity and richness in the primeval forest were slightly higher in O horizon than in A horizon, but those in the masson pine forest were apparently lower in O horizon than in A horizon. The two forest soils had the same dominant laccase gene-containing basidiomycetous populations, and most of the populations had high similarity of amino acid sequence to Mycena sp. or Pleurotus sp. belonging to Agaricales. Comparing with the A horizon in primeval forest and the O horizon in masson pine forest, the O horizon in primeval forest and the A horizon in masson pine forest had a relatively uniform distribution of basidiomycetous populations. The nucleotide sequence similarity of basidiomycetous laccase gene between the O and A horizons in the masson pine forest was higher than that in the primeval forest. This study showed that vegetation and soil horizon had significant effects on the basidiomycetous laccase gene diversity and community structure, and the discrepancies in the substrate availability for basidiomycetes and in the soil pH induced by the vegetation and soil horizon could be the driving forces.

  16. [Soil carbon cycle of Pinus tabulaeformis forest in Huoditang forest region of Qinling Mountains].

    PubMed

    Kang, Bowen; Liu, Jianjun; Dang, Kunliang; Chen, Haibin

    2006-05-01

    With soil carbon cycle compartment model,this paper studied the carbon storage and flux of each carbon compartment of soil under Pinus tabulaeformis, a main forest type in the Huoditang forest region of Qinling Mountain. The results showed that the storage of soil organic carbon was 146.071 t x hm(-2), with 130.366 t x hm(-2) in mineral soil layer and 12.626 t x hm(-2) in litter layer. The storage was lower than the average value of forest soils in China and of oak Sharptooth forest soil in Huoditang, but higher than that of the soils under temperate coniferous forest and tropical forest. The annual carbon input into litter layer was 5.939 t x hm(-2), with 56.9% from above-ground litter and 43.1% from underground dead roots, while that into mineral soil layer via humic acid was 2. 034 t x hm(-2). The annual amount of carbon released from the respiration of P. zabulaeformis forest-soil system was 14. 012 t x hm(-2), with litter layer, mineral soil layer, dead root system, and live root system occupied 15.7%, 14.5%, 11.7% and 58.1%, respectively.

  17. Contributions of separate reactions to the acid-base buffering of soils in brook floodplains (Central Forest State Reserve)

    NASA Astrophysics Data System (ADS)

    Sokolova, T. A.; Tolpeshta, I. I.; Rusakova, E. S.

    2016-04-01

    The acid-base buffering of gleyic gray-humus soils developed in brook floodplains and undisturbed southern-taiga landscapes has been characterized by the continuous potentiometric titration of soil water suspensions. During the interaction with an acid, the major amount of protons (>80%) is consumed for the displacement of exchangeable bases and the dissolution of Ca oxalates. In the O and AY horizons, Mn compounds make the major contribution (2-15%) to the acid buffering. The buffer reactions with the participation of Al compounds make up from 0.5 to 1-2% of the total buffering capacity, and the protonation of the surface OH groups of kaolinite consumes 2-3% of the total buffering capacity. The deprotonation of OH groups on the surface of Fe hydroxides (9-43%), the deprotonation of OH groups on the surface of illite crystals (3-19%), and the dissolution of unidentified aluminosilicates (9-14%) are the most significant buffer reactions whose contributions have been quantified during the interaction with a base. The contribution of the deprotonation of OH groups on the surface of kaolinite particles is lower (1-5%) because of the small specific surface area of this mineral, and that of the dissolution of Fe compounds is insignificant. In the AY horizon, the acid and base buffering of soil in the rhizosphere is higher than beyond the rhizosphere because of the higher contents of organic matter and nonsilicate Fe and Al compounds.

  18. Acid rain and soil.

    PubMed

    vanLoon, G W

    1984-08-01

    A summary of important chemical properties of soil is given and the way in which acid rain may affect these properties is discussed. Acid rain may suppress microbiological decomposition and nitrification processes, thus influencing the nutrient status of soils. It has also been found that soil organic matter is less soluble in more acid solutions. Changed nutrient availability patterns are predicted in a low pH environment and enhanced leaching of essential elements from the soil exchange complex has been observed. Increased solubility of potentially toxic elements such as aluminium may also occur from soils which have been exposed to acidified rainfall.

  19. Acidification of forest soil in Russia: From 1893 to present

    USGS Publications Warehouse

    Lapenis, A.G.; Lawrence, G.B.; Andreev, A.A.; Bobrov, A.A.; Torn, M.S.; Harden, J.W.

    2004-01-01

    It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30-40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils developed on calcareous silt loam. In a chemical analysis comparing archived soils with modern soils collected from the same locations ???100 years later, we found varying degrees of forest-soil acidification in the taiga and forest steppe regions. Land-use history, increases in precipitation, and acidic deposition were contributing factors in acidification. The acidification of forest soil was documented through decreases in soil pH and changes in concentrations of exchangeable calcium and aluminum, which corresponded with changes in communities of soil microfauna. Although acidification was found at all three analyzed locations, the trends in soil chemistry were most pronounced where the highest loading of acidic deposition had taken place. Copyright 2004 by the American Geophysical Union.

  20. Acidification of forest soil in Russia: From 1893 to present

    SciTech Connect

    Lapenis, A.G.; Lawrence, G.B.; Andreev, A.A.; Bobrov, A.A.; Torn, M.S.; Harden, J.W.

    2003-01-02

    It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30-40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils developed on calcareous silt loam. In a chemical analysis comparing archived soils with modern soils collected from the same locations similar to 100 years later, we found varying degrees of forest-soil acidification in the taiga and forest steppe regions. Land-use history, increases in precipitation, and acidic deposition were contributing factors in acidification. The acidification of forest soil was documented through decreases in soil pH and changes in concentrations of exchangeable calcium and aluminum, which corresponded with changes in communities of soil microfauna. Although acidification was found at all three analyzed locations, the trends in soil chemistry were most pronounced where the highest loading of acidic deposition had taken place.

  1. Acid-base and copper-binding properties of three organic matter fractions isolated from a forest floor soil solution

    NASA Astrophysics Data System (ADS)

    van Schaik, Joris W. J.; Kleja, Dan B.; Gustafsson, Jon Petter

    2010-02-01

    Vast amounts of knowledge about the proton- and metal-binding properties of dissolved organic matter (DOM) in natural waters have been obtained in studies on isolated humic and fulvic (hydrophobic) acids. Although macromolecular hydrophilic acids normally make up about one-third of DOM, their proton- and metal-binding properties are poorly known. Here, we investigated the acid-base and Cu-binding properties of the hydrophobic (fulvic) acid fraction and two hydrophilic fractions isolated from a soil solution. Proton titrations revealed a higher total charge for the hydrophilic acid fractions than for the hydrophobic acid fraction. The most hydrophilic fraction appeared to be dominated by weak acid sites, as evidenced by increased slope of the curve of surface charge versus pH at pH values above 6. The titration curves were poorly predicted by both Stockholm Humic Model (SHM) and NICA-Donnan model calculations using generic parameter values, but could be modelled accurately after optimisation of the proton-binding parameters (pH ⩽ 9). Cu-binding isotherms for the three fractions were determined at pH values of 4, 6 and 9. With the optimised proton-binding parameters, the SHM model predictions for Cu binding improved, whereas the NICA-Donnan predictions deteriorated. After optimisation of Cu-binding parameters, both models described the experimental data satisfactorily. Iron(III) and aluminium competed strongly with Cu for binding sites at both pH 4 and pH 6. The SHM model predicted this competition reasonably well, but the NICA-Donnan model underestimated the effects significantly at pH 6. Overall, the Cu-binding behaviour of the two hydrophilic acid fractions was very similar to that of the hydrophobic acid fraction, despite the differences observed in proton-binding characteristics. These results show that for modelling purposes, it is essential to include the hydrophilic acid fraction in the pool of 'active' humic substances.

  2. Effect of the quantity and duration of application of simulated acid precipitation on nitrogen mineralization and nitrification in a forest soil

    SciTech Connect

    Klein, T.M.; Alexander, M.

    1986-01-01

    A study was conducted of the influence of the rate of application of simulated acid rain on N mineralization and nitrification in a forest soil. The rates were varied by applying different quantities of simulated rain for varying periods of time. The soil was exposed in the laboratory to simulated rain at pH 3.5, 4.1,, or 5.6 at rates equivalent to 1.5, 2.3, 4.6, 7.1 or 15 times the average rate of precipitation in the field and then mineralization of soil N or oxidation of added ammonium was determined. The rates of N mineralization were inhibited by precipitation at pH 3.5 or 4.1 when applied for 27-234 days at rates 1.5 times greater than that which occurs in nature. N mineralization was not affected by simulated rain at pH 3.5 or 4.1 in soils exposed for 156 days at 2.3 times the natural rate of precipitation, for 27 or 81 days at 4.6 times the natural rate, for 54 days at 7.1 times the natural rate, or for 234 day at 15 times the natural rate. (Copyright (c) 1986 by D. Reidel Publishing Company).

  3. Interactive effects of elevated CO2 and nitrogen deposition on fatty acid molecular and isotope composition of above- and belowground tree biomass and forest soil fractions.

    PubMed

    Griepentrog, Marco; Eglinton, Timothy I; Hagedorn, Frank; Schmidt, Michael W I; Wiesenberg, Guido L B

    2015-01-01

    Atmospheric carbon dioxide (CO2) and reactive nitrogen (N) concentrations have been increasing due to human activities and impact the global carbon (C) cycle by affecting plant photosynthesis and decomposition processes in soil. Large amounts of C are stored in plants and soils, but the mechanisms behind the stabilization of plant- and microbial-derived organic matter (OM) in soils are still under debate and it is not clear how N deposition affects soil OM dynamics. Here, we studied the effects of 4 years of elevated (13C-depleted) CO2 and N deposition in forest ecosystems established in open-top chambers on composition and turnover of fatty acids (FAs) in plants and soils. FAs served as biomarkers for plant- and microbial-derived OM in soil density fractions. We analyzed above- and belowground plant biomass of beech and spruce trees as well as soil density fractions for the total organic C and FA molecular and isotope (δ13C) composition. FAs did not accumulate relative to total organic C in fine mineral fractions, showing that FAs are not effectively stabilized by association with soil minerals. The δ13C values of FAs in plant biomass increased under high N deposition. However, the N effect was only apparent under elevated CO2 suggesting a N limitation of the system. In soil fractions, only isotope compositions of short-chain FAs (C16+18) were affected. Fractions of 'new' (experimental-derived) FAs were calculated using isotope depletion in elevated CO2 plots and decreased from free light to fine mineral fractions. 'New' FAs were higher in short-chain compared to long-chain FAs (C20-30), indicating a faster turnover of short-chain compared to long-chain FAs. Increased N deposition did not significantly affect the quantity of 'new' FAs in soil fractions, but showed a tendency of increased amounts of 'old' (pre-experimental) C suggesting that decomposition of 'old' C is retarded by high N inputs.

  4. The Effects of Acid Rain on Forest Nutrient Status

    NASA Astrophysics Data System (ADS)

    Johnson, Dale W.; Turner, John; Kelly, J. M.

    1982-06-01

    The effects of acidic atmospheric inputs on forest nutrient status must be assessed within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire, and fertilization. In all cases the anion associated with acid inputs must be mobile in the soil if leaching is to occur; immobilization of anions can effectively prevent cation leaching. Soil acidification will occur only if the often substantial buffering capacity of the soil in question is exceeded by acid inputs and if cation weathering from primary minerals is insufficient to offset cation losses by leaching. Such circumstances are rare but certainly could occur in theory, at least, given sufficiently large acid inputs on poorly buffered soils. Soils most sensitive to change are thought to be those of moderately acid pH and low cation exchange capacity. Neither very acid soils nor neutral, highly buffered soils are sensitive to acidification by acid rain. Given extremely high acid inputs, acid rain can cause temporary increases in nitrogen mineralization and nitritication as well as Al mobilization in soils. While temporary increases in N availability can cause increased forest growth in N-deficient forests, increased Al availability can cause toxic reactions in tree roots. Little is known about tree Al toxicity levels as yet, however. It must be emphasized that assessment of acid rain effects is a problem of quantification. Given sufficiently high inputs on sensitive sites, negative effects of acid rain must occur, as is true of inputs of any substance, including H2O. Acid rain inputs of sufficient magnitude to cause acute effects, such as growth increase due to N mobilization or growth decrease due to Al mobilization, are apparently very rare under ambient field conditions. Long-term effects on forest nutrient status can be either beneficial or adverse, depending on site nutrient status, silvicultural

  5. Characterization and evolution of dissolved organic matter in acidic forest soil and its impact on the mobility of major and trace elements (case of the Strengbach watershed)

    NASA Astrophysics Data System (ADS)

    Gangloff, Sophie; Stille, Peter; Pierret, Marie-Claire; Weber, Tiphaine; Chabaux, François

    2014-04-01

    Dissolved Organic Carbon (DOC) plays an important role in the behavior of major and trace elements in the soil and influences their transfer from soil to soil solution. The first objective of this study is to characterize different organic functional groups for the Water Extractable Organic Carbon (WEOC) fractions of a forest soil as well as their evolution with depth. The second objective is to clarify the influence of these organic functional groups on the migration of the trace elements in WEOC fractions compared to those in the soil solution obtained by lysimeter plates. All experiments have been performed on an acidic forest soil profile (five depths in the first meter) of the experimental spruce parcel in the Stengbach catchment. The Infra-red spectra of the freeze-dried WEOC fractions show a modification of the molecular structure with depth, i.e. a decrease of the polar compounds such as polysaccharides and an increase of the less polar hydro-carbon functional groups with a maximum value of the aromaticity at 30 cm depth. A Hierarchical Ascending Classification (HAC) of the evolution of Water Extractable Chemical Elements (WECE) with the evolution of the organic functional groups in the organic matter (OM) enriched soil compartments permits recognition of relationships between trace element behavior and the organic functional group variations. More specifically, Pb is preferentially bound to the carboxylic acid function of DOC mainly present in the upper soil compartment and rare earth elements (REE) show similar behavior to Fe, V and Cr with a good affinity to carboxy-phenolic and phenolic groups of DOC. The experimental results show that heavy REE compared to light REE are preferentially bound to the aromatic functional group. This different behavior fractionates the REE pattern of soil solutions at 30 cm depth due to the here observed aromaticity enrichment of DOC. These different affinities for the organic functional groups of the DOC explain some

  6. Nitrogen release from forest soils containing sulfide-bearing sediments

    NASA Astrophysics Data System (ADS)

    Maileena Nieminen, Tiina; Merilä, Päivi; Ukonmaanaho, Liisa

    2014-05-01

    Soils containing sediments dominated by metal sulfides cause high acidity and release of heavy metals, when excavated or drained, as the aeration of these sediments causes formation of sulfuric acid. Consequent leaching of acidity and heavy metals can kill tree seedlings and animals such as fish, contaminate water, and corrode concrete and steel. These types of soils are called acid sulfate soils. Their metamorphic equivalents, such as sulfide rich black shales, pose a very similar risk of acidity and metal release to the environment. Until today the main focus in treatment of the acid sulfate soils has been to prevent acidification and metal toxicity to agricultural crop plants, and only limited attention has been paid to the environmental threat caused by the release of acidity and heavy metals to the surrounding water courses. Even less attention is paid on release of major nutrients, such as nitrogen, although these sediments are extremely rich in carbon and nitrogen and present a potentially high microbiological activity. In Europe, the largest cover of acid sulfate soils is found in coastal lowlands of Finland. Estimates of acid sulfate soils in agricultural use range from 1 300 to 3 000 km2, but the area in other land use classes, such as managed peatland forests, is presumably larger. In Finland, 49 500 km2 of peatlands have been drained for forestry, and most of these peatland forests will be at the regeneration stage within 10 to 30 years. As ditch network maintenance is often a prerequisite for a successful establishment of the following tree generation, the effects of maintenance operations on the quality of drainage water should be under special control in peatlands underlain by sulfide-bearing sediments. Therefore, identification of risk areas and effective prevention of acidity and metal release during drain maintenance related soil excavating are great challenges for forestry on coastal lowlands of Finland. The organic and inorganic nitrogen

  7. Characterization and evolution of dissolved organic matter in acidic forest soil and its impact on the mobility of major and trace elements (case of the Strengbach watershed)

    NASA Astrophysics Data System (ADS)

    Gangloff, Sophie; Stille, Peter; Pierret, Marie-Claire; Weber, Tiphaine; Chabaux, François

    2014-04-01

    Dissolved Organic Carbon (DOC) plays an important role in the behavior of major and trace elements in the soil and influences their transfer from soil to soil solution. The first objective of this study is to characterize different organic functional groups for the Water Extractable Organic Carbon (WEOC) fractions of a forest soil as well as their evolution with depth. The second objective is to clarify the influence of these organic functional groups on the migration of the trace elements in WEOC fractions compared to those in the soil solution obtained by lysimeter plates. All experiments have been performed on an acidic forest soil profile (five depths in the first meter) of the experimental spruce parcel in the Stengbach catchment. The Infra-red spectra of the freeze-dried WEOC fractions show a modification of the molecular structure with depth, i.e. a decrease of the polar compounds such as polysaccharides and an increase of the less polar hydro-carbon functional groups with a maximum value of the aromaticity at 30 cm depth. A Hierarchical Ascending Classification (HAC) of the evolution of Water Extractable Chemical Elements (WECE) with the evolution of the organic functional groups in the organic matter (OM) enriched soil compartments permits recognition of relationships between trace element behavior and the organic functional group variations. More specifically, Pb is preferentially bound to the carboxylic acid function of DOC mainly present in the upper soil compartment and rare earth elements (REE) show similar behavior to Fe, V and Cr with a good affinity to carboxy-phenolic and phenolic groups of DOC. The experimental results show that heavy REE compared to light REE are preferentially bound to the aromatic functional group. This different behavior fractionates the REE pattern of soil solutions at 30 cm depth due to the here observed aromaticity enrichment of DOC. These different affinities for the organic functional groups of the DOC explain some

  8. Potential application of gasification to recycle food waste and rehabilitate acidic soil from secondary forests on degraded land in Southeast Asia.

    PubMed

    Yang, Zhanyu; Koh, Shun Kai; Ng, Wei Cheng; Lim, Reuben C J; Tan, Hugh T W; Tong, Yen Wah; Dai, Yanjun; Chong, Clive; Wang, Chi-Hwa

    2016-05-01

    Gasification is recognized as a green technology as it can harness energy from biomass in the form of syngas without causing severe environmental impacts, yet producing valuable solid residues that can be utilized in other applications. In this study, the feasibility of co-gasification of woody biomass and food waste in different proportions was investigated using a fixed-bed downdraft gasifier. Subsequently, the capability of biochar derived from gasification of woody biomass in the rehabilitation of soil from tropical secondary forests on degraded land (adinandra belukar) was also explored through a water spinach cultivation study using soil-biochar mixtures of different ratios. Gasification of a 60:40 wood waste-food waste mixture (w/w) produced syngas with the highest lower heating value (LHV) 5.29 MJ/m(3)-approximately 0.4-4.0% higher than gasification of 70:30 or 80:20 mixtures, or pure wood waste. Meanwhile, water spinach cultivated in a 2:1 soil-biochar mixture exhibited the best growth performance in terms of height (a 4-fold increment), weight (a 10-fold increment) and leaf surface area (a 5-fold increment) after 8 weeks of cultivation, owing to the high porosity, surface area, nutrient content and alkalinity of biochar. It is concluded that gasification may be an alternative technology to food waste disposal through co-gasification with woody biomass, and that gasification derived biochar is suitable for use as an amendment for the nutrient-poor, acidic soil of adinandra belukar.

  9. Potential application of gasification to recycle food waste and rehabilitate acidic soil from secondary forests on degraded land in Southeast Asia.

    PubMed

    Yang, Zhanyu; Koh, Shun Kai; Ng, Wei Cheng; Lim, Reuben C J; Tan, Hugh T W; Tong, Yen Wah; Dai, Yanjun; Chong, Clive; Wang, Chi-Hwa

    2016-05-01

    Gasification is recognized as a green technology as it can harness energy from biomass in the form of syngas without causing severe environmental impacts, yet producing valuable solid residues that can be utilized in other applications. In this study, the feasibility of co-gasification of woody biomass and food waste in different proportions was investigated using a fixed-bed downdraft gasifier. Subsequently, the capability of biochar derived from gasification of woody biomass in the rehabilitation of soil from tropical secondary forests on degraded land (adinandra belukar) was also explored through a water spinach cultivation study using soil-biochar mixtures of different ratios. Gasification of a 60:40 wood waste-food waste mixture (w/w) produced syngas with the highest lower heating value (LHV) 5.29 MJ/m(3)-approximately 0.4-4.0% higher than gasification of 70:30 or 80:20 mixtures, or pure wood waste. Meanwhile, water spinach cultivated in a 2:1 soil-biochar mixture exhibited the best growth performance in terms of height (a 4-fold increment), weight (a 10-fold increment) and leaf surface area (a 5-fold increment) after 8 weeks of cultivation, owing to the high porosity, surface area, nutrient content and alkalinity of biochar. It is concluded that gasification may be an alternative technology to food waste disposal through co-gasification with woody biomass, and that gasification derived biochar is suitable for use as an amendment for the nutrient-poor, acidic soil of adinandra belukar. PMID:26921564

  10. The effects of acid rain on forest nutrient status

    SciTech Connect

    Johnson, D.W.; Turner, J.; Kelly, J.M.

    1982-06-01

    The effects of acidic atmospheric inputs on forest nutrient status must be assessed within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire, and fertilization. Soil acidification will occur only if the often substantial buffering capacity of the soil in question is exceeded by acid inputs and if cation weathering from primary minerals is insufficient to offset cation losses by leaching. Such circumstances are rare but certainly could occur given sufficiently large acid inputs on poorly buffered soils. Soils most sensitive to change are thought to be those of moderately acid pH and low cation exchange capacity. Neither very acid soils nor neutral, highly buffered soils are sensitive to acidification by acid rain. Given extremely high acid inputs, acid rain can cause temporary increases in nitrogen mineralization and nitrification as well as Al mobilization in soils. While temporary increases in N availability can cause increased forest growth in N-deficient forests, increased Al availability can cause toxic reactions in tree roots. Given sufficiently high inputs on sensitive sites, negative effects of acid rain must occur, as is true of inputs of any substance, including H/sub 2/O. Acid rain inputs of sufficient magnitude to cause acute effects, such as growth increase due to N mobilization or growth decrease due to Al mobilization, are apparently very rare under ambient field conditions. Long-term effects on forest nutrient status can be either beneficial or adverse, depending on site nutrient status, silvicultural practices, and amount of atmospheric inputs. (JMT)

  11. Acid soil and acid rain, 2nd edition

    SciTech Connect

    Kennedy, I.R.

    1992-01-01

    This book examines the basic chemical processes involved in acidification in order to better assess their long-term effects on the status of soils, the health of plants and other living species that depend on them. It also discusses acidity, pH and protons their significance in bioenergetics and the consequent role of autotrophic organisms in acidifying ecosystems. This edition incorporates and integrates recent findings that render more explanations of the causes of the environmental impacts of acidity, especially in forests and lakes. Also explores current research into acid rain and soil in order to devise appropriate measures for their amelioration.

  12. Regulation of nitrification in upland forest soils

    SciTech Connect

    Donaldson, J.M.

    1987-01-01

    Forest soils often have low nitrate levels and are slow to produce NO/sub 3//sup -/-N when incubated in the laboratory or after site disturbance. Several hypotheses have been proposed to explain the patterns of nitrification that have been observed in forests ecosystems. These hypotheses suggest that nitrification is limited by low soil pH, NH/sub 4//sup +/-N availability, the presence of allelopathic inhibitors or low levels of other nutrients, such as phosphorus. In this study, experiments were designed to determine if nitrate production in forest soils is regulated by soil pH, NH/sub 4//sup +/ of allelopathic compounds. Three sites representing secondary succession in upland oak-hickory forests were sampled five times during a one-year period. Sampling dates coincided with important stages in the phenological development of the site vegetation. Soils were incubated for up to six weeks in the laboratory. This allowed accurate definition of the potential for nitrogen mineralization and nitrification. Results of laboratory incubation and field-treatment experiments indicate that HN/sub 4//sup +/-N availability is the main factor regulating NH/sub 4//sup +/-oxidizer populations and nitrification in the forest soils investigated. Ammonium is the substrate of nitrification.

  13. Changes in Forest Soil Properties in Different Successional Stages in Lower Tropical China

    PubMed Central

    Li, Yuelin; Yang, Fangfang; Ou, Yangxu; Zhang, Deqiang; Liu, Juxiu; Chu, Guowei; Zhang, Yaru; Otieno, Dennis; Zhou, Guoyi

    2013-01-01

    Background Natural forest succession often affects soil physical and chemical properties. Selected physical and chemical soil properties were studied in an old-growth forest across a forest successional series in Dinghushan Nature Reserve, Southern China. Methodology/Principal Findings The aim was to assess the effects of forest succession change on soil properties. Soil samples (0–20 cm depth) were collected from three forest types at different succession stages, namely pine (Pinus massoniana) forest (PMF), mixed pine and broadleaf forest (PBMF) and monsoon evergreen broadleaf forest (MEBF), representing early, middle and advanced successional stages respectively. The soil samples were analyzed for soil water storage (SWS), soil organic matter (SOM), soil microbial biomass carbon (SMBC), pH, NH4+-N, available potassium (K), available phosphorus (P) and microelements (available copper (Cu), available zinc (Zn), available iron (Fe) and available boron (B)) between 1999 and 2009. The results showed that SWS, SOM, SMBC, Cu, Zn, Fe and B concentrations were higher in the advanced successional stage (MEBF stage). Conversely, P and pH were lower in the MEBF but higher in the PMF (early successional stage). pH, NH4+-N, P and K declined while SOM, Zn, Cu, Fe and B increased with increasing forest age. Soil pH was lower than 4.5 in the three forest types, indicating that the surface soil was acidic, a stable trend in Dinghushan. Conclusion/Significance These findings demonstrated significant impacts of natural succession in an old-growth forest on the surface soil nutrient properties and organic matter. Changes in soil properties along the forest succession gradient may be a useful index for evaluating the successional stages of the subtropical forests. We caution that our inferences are drawn from a pseudo-replicated chronosequence, as true replicates were difficult to find. Further studies are needed to draw rigorous conclusions regarding on nutrient dynamics in

  14. Soil moisture in sessile oak forest gaps

    NASA Astrophysics Data System (ADS)

    Zagyvainé Kiss, Katalin Anita; Vastag, Viktor; Gribovszki, Zoltán; Kalicz, Péter

    2015-04-01

    By social demands are being promoted the aspects of the natural forest management. In forestry the concept of continuous forest has been an accepted principle also in Hungary since the last decades. The first step from even-aged stand to continuous forest can be the forest regeneration based on gap cutting, so small openings are formed in a forest due to forestry interventions. This new stand structure modifies the hydrological conditions for the regrowth. Without canopy and due to the decreasing amounts of forest litter the interception is less significant so higher amount of precipitation reaching the soil. This research focuses on soil moisture patterns caused by gaps. The spatio-temporal variability of soil water content is measured in gaps and in surrounding sessile oak (Quercus petraea) forest stand. Soil moisture was determined with manual soil moisture meter which use Time-Domain Reflectometry (TDR) technology. The three different sizes gaps (G1: 10m, G2: 20m, G3: 30m) was opened next to Sopron on the Dalos Hill in Hungary. First, it was determined that there is difference in soil moisture between forest stand and gaps. Second, it was defined that how the gap size influences the soil moisture content. To explore the short term variability of soil moisture, two 24-hour (in growing season) and a 48-hour (in dormant season) field campaign were also performed in case of the medium-sized G2 gap along two/four transects. Subdaily changes of soil moisture were performed. The measured soil moisture pattern was compared with the radiation pattern. It was found that the non-illuminated areas were wetter and in the dormant season the subdaily changes cease. According to our measurements, in the gap there is more available water than under the forest stand due to the less evaporation and interception loss. Acknowledgements: The research was supported by TÁMOP-4.2.2.A-11/1/KONV-2012-0004 and AGRARKLIMA.2 VKSZ_12-1-2013-0034.

  15. Forests and Soil Erosion across Europe

    NASA Astrophysics Data System (ADS)

    Bathurst, J. C.

    2012-04-01

    Land use and climate change threaten the ability of Europe's forests to provide a vital service in limiting soil erosion, e.g. from forest fires and landslides. However, our ability to define the threat and to propose mitigation measures suffers from two deficiencies concerning the forest/erosion interface: 1) While there have been a considerable number of field studies of the relationship between forest cover and erosion in different parts of Europe, the data sets are scattered among research groups and a range of literature outlets. There is no comprehensive overview of the forest/erosion interface at the European scale, essential for considering regional variations and investigating the effects of future changes in land use and climate. 2) Compared with forest/water studies, we have a poorer quantitative appreciation of forest/erosion interactions. In the forest/water area it is possible to make quantitative statements such as that a 20% change in forest cover across a river catchment is needed for the effect on annual water yield to be measurable or that a forested catchment in upland UK has an annual water yield around 15% lower than an otherwise comparable grassland catchment. Comparable statements are not yet possible for forest/erosion interactions and there are uncertainties in the mathematical representation of forest/erosion interactions which limit our ability to make predictions, for example of the impact of forest loss in a given area. This presentation therefore considers the next step in improving our predictive capability. It proposes the integration of existing research and data to construct the "big picture" across Europe, i.e. erosion rates and sediment yields associated with forest cover and its loss in a range of erosion regimes (e.g. post-forest fire erosion or post-logging landslides). This would provide a basis for generalizations at the European scale. However, such an overview would not form a predictive capability. Therefore it is also

  16. Shifts in soil testate amoeba communities associated with forest diversification.

    PubMed

    Bobrov, Anatoly A; Zaitsev, Andrei S; Wolters, Volkmar

    2015-05-01

    We studied changes of testate amoeba communities associated with the conversion of spruce monocultures into mixed beech-fir-spruce forests in the Southern Black Forest Mountains (Germany). In this region, forest conversion is characterized by a gradual development of beech undergrowth within thinned spruce tree stands leading to multiple age continuous cover forests with a diversified litter layer. Strong shifts in the abundance of testate amoeba observed in intermediate stages levelled off to monoculture conditions again after the final stage of the conversion process had been reached. The average number of species per conversion stage (i.e., local richness) did not respond strongly to forest conversion, but the total number of species (i.e., regional richness) was considerably higher in the initial stage than in the mixed forests, due to the large number of hygrophilous species inhabiting spruce monocultures. Functional diversity of the testate amoeba community, however, significantly increased during the conversion process. This shift was closely associated with improved C and N availability as well as higher niche diversity in the continuous cover stands. Lower soil acidity in these forests coincided with a higher relative abundance of eurytopic species. Our results suggest that testate amoeba communities are much more affected by physicochemical properties of the soil than directly by litter diversity.

  17. Exotic Earthworm Influence on Nitrogen Cycling in FACE Forest Soils

    NASA Astrophysics Data System (ADS)

    Top, S. M.; Filley, T. R.

    2010-12-01

    Exotic earthworm invasion in northern North American forests has the potential to significantly alter nitrogen and carbon cycling in forest soils, through litter layer losses, loss of organic horizon, and changes in fine root density. Earthworm influence on nitrogen cycling is currently being investigated in the free-air CO2 enrichment (FACE) sites at Rhinelander, WI. Because of the 13C depleted CO2 used in the FACE experiment and a 15N addition to the soil, this system affords an ideal opportunity to determine the impact of earthworm activity on soil organic matter dynamics by tracking the relative abundance and stable isotope compositions of biopolymers (amino acids, etc.) isolated in earthworms fecal pellets and soils. The 15N and 13C isotope composition of earthworm fecal matter from epigeic (litter and organic matter horizon dwelling) and endogeic (predominantly mineral soil dwelling) species highlighted their distinct role in litter, surface soil, and deeper soil movement through the soil. Specifically, endogeic fecal matter exhibited a lower uptake of FACE-derived C and a more enriched 15N signal. Nitrogen content of soil between the control and elevated CO2 treatments is not significantly different; however, elevated CO2 treatments exhibited relative depletion in both the soil and root 15N with respect to controls. The loss of 15N in the roots and the top 5 cm of the soil under elevated CO2, suggests that there is greater cycling power with increased below ground productivity and earthworm activity under elevated CO2, as higher abundances of earthworms exist in the elevated CO2 treatments. Amino acid extractions from the soil and fecal matter are ongoing and will help clarify the details regarding molecular nitrogen cycling.

  18. Urbanization in China drives soil acidification of Pinus massoniana forests

    PubMed Central

    Huang, Juan; Zhang, Wei; Mo, Jiangming; Wang, Shizhong; Liu, Juxiu; Chen, Hao

    2015-01-01

    Soil acidification instead of alkalization has become a new environmental issue caused by urbanization. However, it remains unclear the characters and main contributors of this acidification. We investigated the effects of an urbanization gradient on soil acidity of Pinus massoniana forests in Pearl River Delta, South China. The soil pH of pine forests at 20-cm depth had significantly positive linear correlations with the distance from the urban core of Guangzhou. Soil pH reduced by 0.44 unit at the 0–10 cm layer in urbanized areas compared to that in non-urbanized areas. Nitrogen deposition, mean annual temperature and mean annual precipitation were key factors influencing soil acidification based on a principal component analysis. Nitrogen deposition showed significant linear relationships with soil pH at the 0–10 cm (for ammonium N (-N), P < 0.05; for nitrate N (-N), P < 0.01) and 10–20 cm (for -N, P < 0.05) layers. However, there was no significant loss of exchangeable non-acidic cations along the urbanization gradient, instead their levels were higher in urban than in urban/suburban area at the 0–10 cm layer. Our results suggested N deposition particularly under the climate of high temperature and rainfall, greatly contributed to a significant soil acidification occurred in the urbanized environment. PMID:26400019

  19. Urbanization in China drives soil acidification of Pinus massoniana forests.

    PubMed

    Huang, Juan; Zhang, Wei; Mo, Jiangming; Wang, Shizhong; Liu, Juxiu; Chen, Hao

    2015-01-01

    Soil acidification instead of alkalization has become a new environmental issue caused by urbanization. However, it remains unclear the characters and main contributors of this acidification. We investigated the effects of an urbanization gradient on soil acidity of Pinus massoniana forests in Pearl River Delta, South China. The soil pH of pine forests at 20-cm depth had significantly positive linear correlations with the distance from the urban core of Guangzhou. Soil pH reduced by 0.44 unit at the 0-10 cm layer in urbanized areas compared to that in non-urbanized areas. Nitrogen deposition, mean annual temperature and mean annual precipitation were key factors influencing soil acidification based on a principal component analysis. Nitrogen deposition showed significant linear relationships with soil pH at the 0-10 cm (for ammonium N(NH4+(-N)), P < 0.05; for nitrate N(NO3-(-N)), P < 0.01) and 10-20 cm (for NO3-(-N), P < 0.05) layers. However, there was no significant loss of exchangeable non-acidic cations along the urbanization gradient, instead their levels were higher in urban than in urban/suburban area at the 0-10 cm layer. Our results suggested N deposition particularly under the climate of high temperature and rainfall, greatly contributed to a significant soil acidification occurred in the urbanized environment. PMID:26400019

  20. Urbanization in China drives soil acidification of Pinus massoniana forests

    NASA Astrophysics Data System (ADS)

    Huang, Juan; Zhang, Wei; Mo, Jiangming; Wang, Shizhong; Liu, Juxiu; Chen, Hao

    2015-09-01

    Soil acidification instead of alkalization has become a new environmental issue caused by urbanization. However, it remains unclear the characters and main contributors of this acidification. We investigated the effects of an urbanization gradient on soil acidity of Pinus massoniana forests in Pearl River Delta, South China. The soil pH of pine forests at 20-cm depth had significantly positive linear correlations with the distance from the urban core of Guangzhou. Soil pH reduced by 0.44 unit at the 0-10 cm layer in urbanized areas compared to that in non-urbanized areas. Nitrogen deposition, mean annual temperature and mean annual precipitation were key factors influencing soil acidification based on a principal component analysis. Nitrogen deposition showed significant linear relationships with soil pH at the 0-10 cm (for ammonium N (-N), P < 0.05 for nitrate N (-N), P < 0.01) and 10-20 cm (for -N, P < 0.05) layers. However, there was no significant loss of exchangeable non-acidic cations along the urbanization gradient, instead their levels were higher in urban than in urban/suburban area at the 0-10 cm layer. Our results suggested N deposition particularly under the climate of high temperature and rainfall, greatly contributed to a significant soil acidification occurred in the urbanized environment.

  1. Urbanization in China drives soil acidification of Pinus massoniana forests.

    PubMed

    Huang, Juan; Zhang, Wei; Mo, Jiangming; Wang, Shizhong; Liu, Juxiu; Chen, Hao

    2015-09-24

    Soil acidification instead of alkalization has become a new environmental issue caused by urbanization. However, it remains unclear the characters and main contributors of this acidification. We investigated the effects of an urbanization gradient on soil acidity of Pinus massoniana forests in Pearl River Delta, South China. The soil pH of pine forests at 20-cm depth had significantly positive linear correlations with the distance from the urban core of Guangzhou. Soil pH reduced by 0.44 unit at the 0-10 cm layer in urbanized areas compared to that in non-urbanized areas. Nitrogen deposition, mean annual temperature and mean annual precipitation were key factors influencing soil acidification based on a principal component analysis. Nitrogen deposition showed significant linear relationships with soil pH at the 0-10 cm (for ammonium N(NH4+(-N)), P < 0.05; for nitrate N(NO3-(-N)), P < 0.01) and 10-20 cm (for NO3-(-N), P < 0.05) layers. However, there was no significant loss of exchangeable non-acidic cations along the urbanization gradient, instead their levels were higher in urban than in urban/suburban area at the 0-10 cm layer. Our results suggested N deposition particularly under the climate of high temperature and rainfall, greatly contributed to a significant soil acidification occurred in the urbanized environment.

  2. Modeling soil response to acidic deposition in nonsulfate adsorbing soils

    SciTech Connect

    Bloom, P.R.; Grigal, D.F.

    1985-01-01

    A simple semiempirical model for the prediction of changes in soil pH and base saturation with acidic deposition was developed. In steady-state ecosystems acidic deposition results in losses of basic cations from exchange sites. In the model, depletion of exchangeable bases is calculated from the difference between input acidity and output of H/sup +/ and Al/sup 3 +/ in water percolating through the solum. A correction for the decrease in bicarbonate weathering is made but sulfate adsorption is not considered. Estimates including the effect of increased mineral weathering with decreased pH can be made if the natural weathering rate is known and if the order with respect to H/sup +/ is known for the rate expression for soil weathering. The model predicted laboratory data for the acidification of samples for three soil horizons. For a fourth horizon, that was formed in contact with bedrock and high in weatherable minerals, the model overestimated the effect of the acid. Model predictions using soil data showed a slow decrease in soil pH and base saturation until the pH region of Al buffering was attained and then a new steady-state was achieved. The pH and base saturation in the Al buffering region was similar to that found in very acid soils under forest vegetation.

  3. Dependence of soil respiration on soil temperature and soil moisture in successional forests in Southern China

    USGS Publications Warehouse

    Tang, X.-L.; Zhou, G.-Y.; Liu, S.-G.; Zhang, D.-Q.; Liu, S.-Z.; Li, J.; Zhou, C.-Y.

    2006-01-01

    The spatial and temporal variations in soil respiration and its relationship with biophysical factors in forests near the Tropic of Cancer remain highly uncertain. To contribute towards an improvement of actual estimates, soil respiration rates, soil temperature, and soil moisture were measured in three successional subtropical forests at the Dinghushan Nature Reserve (DNR) in southern China from March 2003 to February 2005. The overall objective of the present study was to analyze the temporal variations of soil respiration and its biophysical dependence in these forests. The relationships between biophysical factors and soil respiration rates were compared in successional forests to test the hypothesis that these forests responded similarly to biophysical factors. The seasonality of soil respiration coincided with the seasonal climate pattern, with high respiration rates in the hot humid season (April-September) and with low rates in the cool dry season (October-March). Soil respiration measured at these forests showed a clear increasing trend with the progressive succession. Annual mean (?? SD) soil respiration rate in the DNR forests was (9.0 ?? 4.6) Mg CO2-C/hm2per year, ranging from (6.1 ?? 3.2) Mg CO2-C/hm2per year in early successional forests to (10.7 ?? 4.9) Mg CO2-C/hm2 per year in advanced successional forests. Soil respiration was correlated with both soil temperature and moisture. The T/M model, where the two biophysical variables are driving factors, accounted for 74%-82% of soil respiration variation in DNR forests. Temperature sensitivity decreased along progressive succession stages, suggesting that advanced-successional forests have a good ability to adjust to temperature. In contrast, moisture increased with progressive succession processes. This increase is caused, in part, by abundant respirators in advanced-successional forest, where more soil moisture is needed to maintain their activities. ?? 2006 Institute of Botany, Chinese Academy of

  4. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  5. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  6. Soil production in forested landscapes (Invited)

    NASA Astrophysics Data System (ADS)

    Roering, J. J.; Booth, A. M.

    2009-12-01

    One of the most fundamental characteristics that defines landscapes is the presence or absence of a soil mantle. In actively eroding terrain, soil (and other natural resources that depend on it) persists only when the rate of soil production is not eclipsed by denudation. Despite successful efforts to empirically estimate long-term rates of soil production, little predictive capability exists as soil formation results from a complex interplay of biological, physical, and chemical processes. Here, we synthesize a suite of observations from the steep, forested Oregon Coast Range (OCR) and anlayze the role of trees in the conversion of bedrock to soil. Pit/mound topography on forest floors attests to the persistent, wholesale overturning of soil by tree root activity. Using airborne LiDAR data for our study site in the western Oregon Coast Range, we calculated how terrain roughness varies with spatial scale. At scales greater than 10m, the well-established ridge/valley structure of the landscape defines the topography; whereas for scales less than 7m, terrain roughness increases rapidly reflecting the stochastic nature of bioturbation associated with large, coniferous trees. Empirical estimates of soil production in the OCR by Heimsath et al (2001, ESPL) reveal that production rates decrease exponentially with depth and the decay constant is 2.68 (1/m). From dozens of soil pits in the OCR, we show that the density of trees roots declines exponentially with depth at a similar rate, 2.57 (1/m). In other words, rates of soil production appear to be well-correlated with root density. Bedrock is often excavated during tree turnover events and we documented that the volume of bedrock incorporated in overturned coniferous rootwads increases rapidly for tree diameters greater than 0.5m (which correponds to a 60-80 yr old Douglas fir tree in Western Oregon). Smaller (and thus younger) trees entrain negligible bedrock when overturned, suggesting that their root systems are

  7. Forest soil chemistry and terrain attributes in a Catskills watershed

    USGS Publications Warehouse

    Johnson, C.E.; Ruiz-Mendez, J. J.; Lawrence, G.B.

    2000-01-01

    Knowledge of soil chemistry is useful in assessing the sensitivity of forested areas to natural and anthropogenic disturbances, but characterizing large areas is expensive because of the large sample numbers required and the cost of soil chemical analyses. We collected and chemically analyzed soil samples from 72 sites within a 214-ha watershed in the Catskill Mountains of New York to evaluate factors that influence soil chemistry and whether terrain features could be used to predict soil chemical properties. Using geographic information system (GIS) techniques, we determined five terrain attributes at each sampling location: (i) slope, (ii) aspect, (iii) elevation, (iv) topographic index, and (v) flow accumulation. These attributes were ineffective in predicting the chemical properties of organic and mineral soil samples; together they explained only 4 to 25% of the variance in pH(w), effective cation-exchange capacity (CEC(e)), exchangeable bases, exchangeable acidity, total C, total N, and C/N ratio. Regressions among soil properties were much better; total C and pH(w) together explained 33 to 66% of the variation in exchangeable bases and CEC(e). Total C was positively correlated with N (r = 0.91 and 0.96 in Oa horizons and mineral soil, respectively), exchangeable bases (r = 0.65, 0.76), and CEC(e) (r = 0.54, 0.44), indicating the importance of organic matter to the chemistry of these acidic soils. The fraction of CEC(e) occupied by H explained 44% of the variation in pH(w). Soil chemical properties at this site vary on spatial scales finer than typical GIS analyses, resulting in relationships with poor predictive power. Thus, interrelationships among soil properties are more reliable for prediction.Knowledge of soil chemistry is useful in assessing the sensitivity of forested areas to natural and anthropogenic disturbances, but characterizing large areas is expensive because of the large sample numbers required and the cost of soil chemical analyses. We

  8. Phosphorus constrains accelerated nitrogen cycling in limed acidic forests

    NASA Astrophysics Data System (ADS)

    Deforest, J. L.; Shaw, A. N.; Kluber, L. A.; Burke, D. J.; Carrino-Kyker, S. R.; Smemo, K. A.

    2011-12-01

    Anthropogenic deposition can increase phosphorus (P) limitation by abiotic and biotic means. Soil acidification can remove P from available pools and nitrogen (N) deposition can increase the demand for P. We reason that chronic acidic deposition is promoting P limitation in acidic hardwood forests and thereby altering N cycling. The objectives of this study were to investigate the interactive influence of P availability and soil pH on N and P cycling and availability to determine if the response varies between two physiographic regions experiencing similar chronic acidic deposition. We addressed these objectives by experimentally manipulating soil pH, P, or both in strongly acidic glaciated and unglaciated hardwood forests in eastern Ohio, USA. Our results suggest complex interactions between P, soil pH, and the N cycle. Glaciated soils were found to be more N-saturated with nitrification rates 18 times greater than in unglaciated soils. Elevating pH, with or without added P, doubled nitrification rates in glaciated soils. For unglaciated soils, raising pH increased nitrification 10-fold, but increased nitrification only 5-fold in combination with P. This result suggests raising soil pH lowered the demand of soil N, or directly stimulated nitrifying activity, and that increasing P availability could limit N availability. To various degrees, readily available P was geochemically or biologically immobilized in all treatments, suggesting chronic P deficiency in these ecosystems. Phosphorus immobilization decreased as soil pH was elevated, but elevated P either had no effect (glaciated) or doubled P immobilization rates (unglaciated). These results suggest that raising soil pH reduces microbial P limitation for phosphate, whereas adding P appears to make phosphate scarcer. We suggest that P plays an important role in N transformations and cycling, but appears more important in unglaciated soils than in glaciated soils. Chronic soil acidification may have a greater

  9. Soil microbial community composition does not predominantly determine the variance of heterotrophic soil respiration across four subtropical forests.

    PubMed

    Wei, Hui; Xiao, Guoliang; Guenet, Bertrand; Janssens, Ivan A; Shen, Weijun

    2015-01-19

    To explore the importance of soil microbial community composition on explaining the difference in heterotrophic soil respiration (R(h)) across forests, a field investigation was conducted on Rh and soil physiochemical and microbial properties in four subtropical forests in southern China. We observed that Rh differed significantly among forests, being 2.48 ± 0.23, 2.31 ± 0.21, 1.83 ± 0.08 and 1.56 ± 0.15 μmol m(-2) s(-1) in the climax evergreen broadleaf forest (BF), the mixed conifer and broadleaf forest (CF), the conifer plantation (CP), and the native broadleaved species plantation (BP), respectively. Both linear mixed effect model and variance decomposition analysis indicated that soil microbial community composition derived from phospholipid fatty acids (PLFAs) was not the first-order explanatory variable for the R(h) variance across the forests, with the explanatory power being 15.7%. Contrastingly, vegetational attributes such as root biomass (22.6%) and soil substrate availability (18.6%) were more important for explaining the observed R(h) variance. Our results therefore suggest that vegetation attributes and soil carbon pool size, rather than soil microbial community composition, should be preferentially considered to understand the spatial R(h) variance across the subtropical forests in southern China.

  10. [Effects of forest type on soil organic matter, microbial biomass, and enzyme activities].

    PubMed

    Lu, Shun-bao; Zhou, Xiao-qi; Rui, Yi-chao; Chen, Cheng-rong; Xu, Zhi-hong; Guo, Xiao-min

    2011-10-01

    Taking the typical forest types Pinus elliottii var. elliotttii, Araucaria cunninghamii, and Agathis australis in southern Queensland of Australia as test objects, an investigation was made on the soil soluble organic carbon (SOC) and nitrogen (SON), microbial biomass C (MBC) and N (MBN), and enzyme activities, aimed to understand the effects of forest type on soil quality. In the three forests, soil SOC content was 552-1154 mg kg(-1), soil SON content was 20.11-57.32 mg kg(-1), soil MBC was 42-149 mg kg(-1), soil MBN was 7-35 mg kg(-1), soil chitinase (CAS) activity was 2.96-7.63 microg g(-1) h(-1), soil leucine aminopeptidase (LAP) activity was 0.18-0.46 microg g(-1) d(-1), soil acid phosphatase (ACP) activity was 16.5-29.6 microg g(-1) h(-1), soil alkaline phosphatase (AKP) activity was 0.79-3.42 microg g(-1) h(-1), and soil beta-glucosidase (BG) activity was 3.71-9.93 microg g(-1) h(-1). There was a significant correlation between soil MBC and MBN. Soil SOC content and soil CAS and LAP activities decreased in the order of P. elliottii > A. cunninghamii > A. australis, soil SON content decreased in the order of A. cunninghamii > A. australis > P. elliottii and was significantly higher in A. cunninghamii than in P. elliottii forest (P < 0.05), soil MBC and MBN and AKP activity decreased in the order of A. australis > P. elliottii > A. cunninghamii, and soil ACP and BG activities decreased in the order of P. elliottii > A. australis > A. cunninghamii. Among the test soil biochemical factors, soil MBC, MBN, SON, and LAP had greater effects on the soil quality under the test forest types. PMID:22263459

  11. [Soil active organic matter in broadleaved forest and Chinese fir plantation in subtropical region of China].

    PubMed

    Wang, Qing-Kui; Fan, Bing; Xu, Guang-Biao

    2009-07-01

    A comparative study was made on the soil active organic matter in a broadleaved forest and two Chinese fir (Cunninghamia lanceolata) plantations in subtropical region of China, aimed to understand the effects of forest conversion and continuous plantation on soil organic C and nutrient status. After the conversion from broadleaved forest to Chinese fir plantation, the contents of soil total organic C, humus C, humic acid, and fulvic acid decreased by 27.8%-52.1%, 32.2%-52.8%, 36.4%-59.0%, and 29.7%-50.0%, respectively. Continuous plantation also resulted in the decrease of soil organic C and humus contents. The contents of soil total organic C, humus C, humic acid, and fulvic acid in second generation of Chinese fir plantation were 9.0%-25.0%, 25.0%-38.0%, 28.6%-39.2% and 23.1%-36.4% lower than those in the first generation of Chinese fir plantation, respectively. More obvious effects were observed on the soil active organic matter. After the conversion from broadleaved forest to Chinese fir plantation, the maximum decrement of soil microbial biomass C and N and dissolved organic C and N was 61.8%, 38.2%, 43.3%, and 69.0%; while comparing with the first generation of Chinese fir plantation, the second generation of Chinese fir plantation had the maximum decrement of soil microbial biomass C and N and dissolved organic C and N being 34.7%, 29.3%, 30.4%, and 18.4%, respectively. Soil nutrient contents also decreased due to forest conversion and continuous plantation. In comparing with broadleaved forests, Chinese fir plantations had a decrease of soil N, P, and K contents being 15.7%-31.2%, 11.5%-49.3%, and 15.1%-33.8%, respectively. There were close relationships between soil nutrients and soil active organic matter fractions except cold water extractable organic N.

  12. [Effects of litters and tannin on forest soil inorganic nitrogen].

    PubMed

    Ma, Hong-Liang; Liu, Wei-Li; Gao, Ren; Yang, Yu-Sheng; Sun, Jie

    2011-01-01

    A laboratory incubation test was conducted to study the effects of litters and tannin on forest soil nitrate- and ammonium N. The addition of litters and tannic acid made the soil nitrate- and ammonium N decreased. With the addition of fir litter, the nitrate- and ammonium N contents in red soil decreased by 6.1%-25. 9% and 19.7%-68.6%, respectively, and the decrements in yellow-red soil were higher than those with the addition of bamboo litter, being significant for ammonium N. Compared with the control, the addition of tannin decreased the ammonium N content in yellow-red soil significantly, and there was a positive correlation between the concentration of added tannin and the decrement of soil ammonium N content. When the concentration of added tannin was high, the decrement of the ammonium N reached 31.9%-57.8%. With the addition of low concentration tannin, the soil nitrate N content decreased with time, and the decrement on the 84th day reached 4.5%. However, the addition of high concentration tannin increased the soil nitrate N content by 10.3%-18.5% in the first 7-28 days, but decreased it by 23.9% and 42.3% on the 56th and 85th day, respectively.

  13. Migration of (137)Cs, (90)Sr, and (239+240)Pu in Mediterranean forests: influence of bioavailability and association with organic acids in soil.

    PubMed

    Guillén, J; Baeza, A; Corbacho, J A; Muñoz-Muñoz, J G

    2015-06-01

    The understanding of downward migration of anthropogenic radionuclides in soil is a key factor in the assessment of their environmental behavior. There are several factors that can affect this process, such as the radionuclide source, their chemical form, soil and environmental characteristics, etc. Two Mediterranean pinewood ecosystems in Spain, which were affected mainly by global fallout, were selected to assess the migration of (137)Cs, (90)Sr, and (239+240)Pu. Using auxiliary modeling (diffusion-convection equation and compartmental model), it followed from field observations that the migration velocities of (90)Sr and (239+240)Pu were similar and higher than that of (137)Cs. The downward migration of radionuclides can be considered a consequence of their association with soil particles. A sequential speciation procedure also confirmed that (90)Sr was the most bioavailable radionuclide followed by (239+240)Pu and (137)Cs. Although this can explain the different velocity of (90)Sr and (137)Cs, bioavailability could not explain by itself the similar velocities of (239+240)Pu and (90)Sr. The presence of organic acids in the soil can also influence the migration of radionuclides attached to them, which decreased in the order: (239+240)Pu > (90)Sr > (137)Cs. Thus, the joint consideration of bioavailable and humic + fulvic acid fractions can explain the observed differences in the downward velocities. PMID:25827576

  14. Migration of (137)Cs, (90)Sr, and (239+240)Pu in Mediterranean forests: influence of bioavailability and association with organic acids in soil.

    PubMed

    Guillén, J; Baeza, A; Corbacho, J A; Muñoz-Muñoz, J G

    2015-06-01

    The understanding of downward migration of anthropogenic radionuclides in soil is a key factor in the assessment of their environmental behavior. There are several factors that can affect this process, such as the radionuclide source, their chemical form, soil and environmental characteristics, etc. Two Mediterranean pinewood ecosystems in Spain, which were affected mainly by global fallout, were selected to assess the migration of (137)Cs, (90)Sr, and (239+240)Pu. Using auxiliary modeling (diffusion-convection equation and compartmental model), it followed from field observations that the migration velocities of (90)Sr and (239+240)Pu were similar and higher than that of (137)Cs. The downward migration of radionuclides can be considered a consequence of their association with soil particles. A sequential speciation procedure also confirmed that (90)Sr was the most bioavailable radionuclide followed by (239+240)Pu and (137)Cs. Although this can explain the different velocity of (90)Sr and (137)Cs, bioavailability could not explain by itself the similar velocities of (239+240)Pu and (90)Sr. The presence of organic acids in the soil can also influence the migration of radionuclides attached to them, which decreased in the order: (239+240)Pu > (90)Sr > (137)Cs. Thus, the joint consideration of bioavailable and humic + fulvic acid fractions can explain the observed differences in the downward velocities.

  15. Acidic deposition, plant pests, and the fate of forest ecosystems.

    PubMed

    Gragnani, A; Gatto, M; Rinaldi, S

    1998-12-01

    We present and analyze a nonlinear dynamical system modelling forest-pests interactions and the way they are affected by acidic deposition. The model includes mechanisms of carbon and nitrogen exchange between soil and vegetation, biomass decomposition and microbial mineralization, and defoliation by pest grazers, which are partially controlled by avian or mammalian predators. Acidic deposition is assumed to directly damage vegetation, to decrease soil pH, which in turn damages roots and inhibits microbial activity, and to predispose trees to increased pest attack. All the model parameters are set to realistic values except the inflow of protons to soil and the predation mortality inflicted to the pest which are allowed to vary inside reasonable ranges. A numerical bifurcation analysis with respect to these two parameters is carried out. Five functioning modes are uncovered: (i) pest-free equilibrium; (ii) pest persisting at endemic equilibrium; (iii) forest-pest permanent oscillations; (iv) bistable behavior with the system converging either to pest-free equilibrium or endemic pest presence in accordance with initial conditions; (v) bistable behavior with convergence to endemic pest presence or permanent oscillations depending on initial conditions. Catastrophic bifurcations between the different behavior modes are possible, provided the abundance of predators is not too small. Numerical simulation shows that increasing acidic load can lead the forest to collapse in a short time period without important warning signals.

  16. Soil carbon stock and soil characteristics at Tasik Chini Forest Reserve, Pahang, Malaysia

    NASA Astrophysics Data System (ADS)

    Nur Aqlili Riana, R.; Sahibin A., R.

    2015-09-01

    This study was carried out to determine soil carbon stock and soil characteristic at Tasik Chini Forest Reserve (TCFR), Pahang. A total of 10 (20 m x 25 m) permanent sampling plot was selected randomly within the area of TCFR. Soil samples were taken from all subplots using dutch auger based on soil depth of 0-20cm, 20-40cm, 40-60cm. Soil parameters determined were size distribution, soil water content, bulk density, organic matter, organic carbon content, pH and electrical conductivity. All parameters were determined following their respective standard methods. Results obtained showed that the soil in TCFR was dominated by clay texture (40%), followed by sandy clay loam (30%), loam (20%). Silty clay, clay loam and sandy loam constitutes about 10% of the soil texture. Range of mean percentage of organic matter and bulk density are from 2.42±0.06% to 11.64±0.39% and 1.01 to 1.04 (gcm-ł), respectively. Soil pH are relatively very acidic and mean of electrical conductivity is low. Soil carbon content ranged from 0.83±0.03 to 1.87±0.41%. All soil parameter showed a decreasing trend with depth except electrical conductivity. ANOVA test of mean percentage of organic matter, soil water content, soil pH and electrical conductivity showed a significant difference between plot (p<0.05). However there are no significant difference of mean bulk density between plots (p>0.05). There are no significant difference in mean percentage of soil water content, organic matter and bulk density between three different depth (p>0.05). There were a significant difference on percentage of soil carbon organic between plots and depth. The mean of soil organic carbon stock in soil to a depth of 60 cm calculated was 35.50 t/ha.

  17. Diversity in soil fungi from undisturbed and disturbed Celtis tala and Scutia buxifolia forests in the eastern Buenos Aires province (Argentina).

    PubMed

    Cabello, Marta; Arambarri, Angélica

    2002-01-01

    The rhizospheric soil microfungi from a native forest (undisturbed and disturbed) were studied using soil dilution plate and soil washing methods. Fungi were isolated using slightly acid and alkaline culture media. 54 taxa were isolated: 49 from undisturbed forest soil and 37 from disturbed forest soil. Acremonium sp., Aspergillus ustus, Coemansia pectinata, Doratomyces stemonitis, Fusarium solani, F. oxysporum, Gliocladium roseum, Humicola fusco-atra, Mortierella sp., Penicillium lilacinum, Trichoderma harzianum, and T koningii, showed the highest frequency, in both, undisturbed and disturbed forests. In undisturbed soil forest the biodiversity index was 3.97 whereas in disturbed ones was 3.89.

  18. Priming effects in a subtropical forest soil

    NASA Astrophysics Data System (ADS)

    Li, Qianru; Sun, Yue; Xu, Xingliang

    2015-04-01

    Priming effects can accelerate decomposition of soil organic carbon (SOC) and thus have great potential to change SOC dynamics. Although temperature and addition of fresh substrates could affect the intensity and direction of priming, it remains unclear how their interactions affect priming. Therefore we conducted an incubation experiment using a subtropical forest soil. We incubated the soil for 10 days at two temperatures: 15oC and 25oC, with four treatments: CK (only adding water), G (13C-glucose addition), NT (13C-glucose and nitrate additions) and AM (13C-glucose and ammonium additions). The results showed that glucose addition significantly accelerated the decomposition of SOC in both temperatures, indicates that positive priming occurs in this subtropical soil. While negative priming was observed in soils with simultaneous additions of glucose and nitrogen addition, especially at 25oC. The effect of temperature on PE was not significant. This indicates that mining of nitrogen is a major mechanism responsible for priming in this subtropical soil and there is no strong interaction between temperature and substrate additions to induce priming.

  19. Forest soil carbon is threatened by intensive biomass harvesting

    NASA Astrophysics Data System (ADS)

    Achat, David L.; Fortin, Mathieu; Landmann, Guy; Ringeval, Bruno; Augusto, Laurent

    2015-11-01

    Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers’ decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventional biomass harvests preserved the SOC of forests, unlike intensive harvests where logging residues were harvested to produce fuelwood. Conventional harvests caused a decrease in carbon storage in the forest floor, but when the whole soil profile was taken into account, we found that this loss in the forest floor was compensated by an accumulation of SOC in deeper soil layers. Conversely, we found that intensive harvests led to SOC losses in all layers of forest soils. We assessed the potential impact of intensive harvests on the carbon budget, focusing on managed European forests. Estimated carbon losses from forest soils suggested that intensive biomass harvests could constitute an important source of carbon transfer from forests to the atmosphere (142-497 Tg-C), partly neutralizing the role of a carbon sink played by forest soils.

  20. Forest soil carbon is threatened by intensive biomass harvesting.

    PubMed

    Achat, David L; Fortin, Mathieu; Landmann, Guy; Ringeval, Bruno; Augusto, Laurent

    2015-01-01

    Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers' decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventional biomass harvests preserved the SOC of forests, unlike intensive harvests where logging residues were harvested to produce fuelwood. Conventional harvests caused a decrease in carbon storage in the forest floor, but when the whole soil profile was taken into account, we found that this loss in the forest floor was compensated by an accumulation of SOC in deeper soil layers. Conversely, we found that intensive harvests led to SOC losses in all layers of forest soils. We assessed the potential impact of intensive harvests on the carbon budget, focusing on managed European forests. Estimated carbon losses from forest soils suggested that intensive biomass harvests could constitute an important source of carbon transfer from forests to the atmosphere (142-497 Tg-C), partly neutralizing the role of a carbon sink played by forest soils. PMID:26530409

  1. Forest soil carbon is threatened by intensive biomass harvesting

    PubMed Central

    Achat, David L.; Fortin, Mathieu; Landmann, Guy; Ringeval, Bruno; Augusto, Laurent

    2015-01-01

    Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers’ decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventional biomass harvests preserved the SOC of forests, unlike intensive harvests where logging residues were harvested to produce fuelwood. Conventional harvests caused a decrease in carbon storage in the forest floor, but when the whole soil profile was taken into account, we found that this loss in the forest floor was compensated by an accumulation of SOC in deeper soil layers. Conversely, we found that intensive harvests led to SOC losses in all layers of forest soils. We assessed the potential impact of intensive harvests on the carbon budget, focusing on managed European forests. Estimated carbon losses from forest soils suggested that intensive biomass harvests could constitute an important source of carbon transfer from forests to the atmosphere (142–497 Tg-C), partly neutralizing the role of a carbon sink played by forest soils. PMID:26530409

  2. Dehydrogenase activity of forest soils depends on the assay used

    NASA Astrophysics Data System (ADS)

    Januszek, Kazimierz; Długa, Joanna; Socha, Jarosław

    2015-01-01

    Dehydrogenases are exclusively intracellular enzymes, which play an important role in the initial stages of oxidation of soil organic matter. One of the most frequently used methods to estimate dehydrogenase activity in soil is based on the use of triphenyltetrazolium chloride as an artificial electron acceptor. The purpose of this study was to compare the activity of dehydrogenases of forest soils with varied physicochemical properties using different triphenyltetrazolium chloride assays. The determination was carried out using the original procedure by Casida et al., a modification of the procedure which involves the use of Ca(OH)2 instead of CaCO3, the Thalmann method, and the assay by Casida et al. without addition of buffer or any salt. Soil dehydrogenase activity depended on the assay used. Dehydrogenase determined by the Casida et al. method without addition of buffer or any salt correlated with the pH values of soils. The autoclaved strongly acidic samples of control soils showed high concentrations of triphenylformazan, probably due to chemical reduction of triphenyltetrazolium chloride. There is, therefore, a need for a sterilization method other than autoclaving, ie a process that results in significant changes in soil properties, thus helping to increase the chemical reduction of triphenyltetrazolium chloride.

  3. [Vertical Distribution Characteristics of Typical Forest Soil Organic Nitrogen in Dawei Mountain].

    PubMed

    Ding, Xian-qing; Ma, Hui-jing; Zhu, Xiao-long; Chen, Shan; Hou, Hong-bo; Peng, Pei-qin

    2015-10-01

    To clarify altitudinal gradient of subtropical forest soil total nitrogen and organic nitrogen, soil samples were collected per 10 cm on soil profile (0-100 cm) in Dawei Mountain, researched the variation of soil organic nitrogen and correlation with soil physical and chemical properties. The results showed that: (1) Total nitrogen, acid hydrolysable organic nitrogen and soluble organic nitrogen decreased with the increase of depth, content of each component in mountain granite yellow-brown soils was much higher affected by altitude; (2) The average percentage of soil organic nitrogen to total nitrogen was 97.39% ± 1.17%, and soil acid hydrolysable organic nitrogen was 64.38% ± 10.68%, each component decreased with the increase of soil depth; (3) Soil soluble organic nitrogen content was 9.92- 23.45 mg x kg(-1), free amino acids (1.62 - 12.02 mg x kg(-1)) accounted for about 27.36% ± 9.95% of soluble organic nitrogen; (4) Soil acid hydrolysable organic nitrogen and soluble organic nitrogen were significantly positively correlated with total nitrogen, total soluble nitrogen and inorganic nitrogen (P < 0.05), were highly significantly correlated with soil bulk density, organic carbon, and total phosphorus (P < 0.01). Organic nitrogen was the main body of soil nitrogen in typical subtropical forest, each component showed a downward trend increase with soil depth affected by altitude and soil physical and chemical properties. There was a close conversion relationship between soil organic nitrogen and other nitrogen forms, the characteristics of soil organic nitrogen will have profound impact on nitrogen cycling of forest ecological system. PMID:26841616

  4. [Vertical Distribution Characteristics of Typical Forest Soil Organic Nitrogen in Dawei Mountain].

    PubMed

    Ding, Xian-qing; Ma, Hui-jing; Zhu, Xiao-long; Chen, Shan; Hou, Hong-bo; Peng, Pei-qin

    2015-10-01

    To clarify altitudinal gradient of subtropical forest soil total nitrogen and organic nitrogen, soil samples were collected per 10 cm on soil profile (0-100 cm) in Dawei Mountain, researched the variation of soil organic nitrogen and correlation with soil physical and chemical properties. The results showed that: (1) Total nitrogen, acid hydrolysable organic nitrogen and soluble organic nitrogen decreased with the increase of depth, content of each component in mountain granite yellow-brown soils was much higher affected by altitude; (2) The average percentage of soil organic nitrogen to total nitrogen was 97.39% ± 1.17%, and soil acid hydrolysable organic nitrogen was 64.38% ± 10.68%, each component decreased with the increase of soil depth; (3) Soil soluble organic nitrogen content was 9.92- 23.45 mg x kg(-1), free amino acids (1.62 - 12.02 mg x kg(-1)) accounted for about 27.36% ± 9.95% of soluble organic nitrogen; (4) Soil acid hydrolysable organic nitrogen and soluble organic nitrogen were significantly positively correlated with total nitrogen, total soluble nitrogen and inorganic nitrogen (P < 0.05), were highly significantly correlated with soil bulk density, organic carbon, and total phosphorus (P < 0.01). Organic nitrogen was the main body of soil nitrogen in typical subtropical forest, each component showed a downward trend increase with soil depth affected by altitude and soil physical and chemical properties. There was a close conversion relationship between soil organic nitrogen and other nitrogen forms, the characteristics of soil organic nitrogen will have profound impact on nitrogen cycling of forest ecological system.

  5. Air Pollution, Acid Rain, and the Future of Forests. Worldwatch Paper 58.

    ERIC Educational Resources Information Center

    Postel, Sandra

    This book traces centuries of human use and abuse of forest ecosystems by discussing past decades of intense burning, grazing, and timber cutting that added to the natural acidification of the soil. Air pollutants and acids generated by industrial activities worldwide are also considered. Many forests in Europe and North America now receive as…

  6. Soil nitrogen gas emissions increase considerably in warmer forest soils

    NASA Astrophysics Data System (ADS)

    Kitzler, Barbara; Schindlbacher, Andreas; Jandl, Robert; Zechmeister-Boltenstern, Sophie

    2015-04-01

    Climate change will likely modify ecosystem properties and processes and therefore impact nitrogen (N) dynamics of forest soils. To elucidate the effect of warming and drought conditions on the nitrogen gas emissions we measured N2O and NO fluxes from the soil warming experiment Achenkirch, a spruce-fir-beech forest soil in the North Tyrolean limestone Alps in Austria. The uppermost layer of the soil was warmed (4°C) by heating cables during the snow-free seasons. Roofs were installed during 25 days in July/August 2008 and 2009 to simulate drought conditions. Gas sampling was conducted biweekly with static chambers (N2O). Gas concentrations were detected by GC. Nitric oxide fluxes were measured by an automatic dynamic chamber system on an hourly basis. In our study the emissions of N2O were increased by up to 73 % at warmed plots, and we observed a temporary increase following first rain. However N2O emissions of the drought affected plots remained depressed for more than two months after roof removal. Nitric oxide fluxes were increased considerably during dry periods and under warmer conditions.

  7. [Soil microbial functional diversity of different altitude Pinus koraiensis forests].

    PubMed

    Han, Dong-xue; Wang, Ning; Wang, Nan-nan; Sun, Xue; Feng, Fu-juan

    2015-12-01

    In order to comprehensively understand the soil microbial carbon utilization characteristics of Pinus koraiensis forests, we took the topsoil (0-5 cm and 5-10 cm) along the 700-1100 m altitude in Changbai Mountains and analyzed the vertical distributed characteristics and variation of microbial functional diversity along the elevation gradient by Biolog microplate method. The results showed that there were significant differences in functional diversity of microbial communities at different elevations. AWCD increased with the extension of incubation time and AWCD at the same soil depth gradually decreased along with increasing altitude; Shannon, Simpson and McIntosh diversity index also showed the same trend with AWCD and three different diversity indices were significantly different along the elevation gradient; Species diversity and functional diversity showed the same variation. The utilization intensities of six categories carbon sources had differences while amino acids were constantly the most dominant carbon source. Principal component analysis (PCA) identified that soil microbial carbon utilization at different altitudes had obvious spatial differentiation, as reflected in the use of carbohydrates, amino acids and carboxylic acids. In addition, the cluster of the microbial diversity indexes and AWCD values of different altitudes showed that the composition of vegetation had a significant impact on soil microbial composition and functional activity. PMID:27112001

  8. [Soil microbial functional diversity of different altitude Pinus koraiensis forests].

    PubMed

    Han, Dong-xue; Wang, Ning; Wang, Nan-nan; Sun, Xue; Feng, Fu-juan

    2015-12-01

    In order to comprehensively understand the soil microbial carbon utilization characteristics of Pinus koraiensis forests, we took the topsoil (0-5 cm and 5-10 cm) along the 700-1100 m altitude in Changbai Mountains and analyzed the vertical distributed characteristics and variation of microbial functional diversity along the elevation gradient by Biolog microplate method. The results showed that there were significant differences in functional diversity of microbial communities at different elevations. AWCD increased with the extension of incubation time and AWCD at the same soil depth gradually decreased along with increasing altitude; Shannon, Simpson and McIntosh diversity index also showed the same trend with AWCD and three different diversity indices were significantly different along the elevation gradient; Species diversity and functional diversity showed the same variation. The utilization intensities of six categories carbon sources had differences while amino acids were constantly the most dominant carbon source. Principal component analysis (PCA) identified that soil microbial carbon utilization at different altitudes had obvious spatial differentiation, as reflected in the use of carbohydrates, amino acids and carboxylic acids. In addition, the cluster of the microbial diversity indexes and AWCD values of different altitudes showed that the composition of vegetation had a significant impact on soil microbial composition and functional activity.

  9. Soil organic matter degradability in four Japanese forest soils

    NASA Astrophysics Data System (ADS)

    Moriya, K.; Koarashi, J.; Atarashi-Andoh, M.; Moriizumi, J.; Yamazawa, H.; Ishizuka, S.

    2011-12-01

    Soil organic carbon (SOC) is the largest carbon reservoir in terrestrial ecosystems, and CO2 emission derived from SOC decomposition is considered to strongly influence atmospheric CO2 concentration. Therefore, it is important to understand what factors control the process of SOC decomposition. We studied the temperature sensitivity of SOC decomposition in forest surface soils by an incubation experiment at two temperatures. Soil samples were collected from the top 20 cm of mineral soils at four forest sites in Japan: AP (Appi: 40°00'N, 140°56'E), US (Ushiku: 35°57'N, 140°10'E), OG (Ogawa: 36°56'N, 140°35'E), and HO (Hitsujigaoka: 43°59'N, 141°23'E). The soil samples were sieved with a 4 mm-mesh and remaining roots in the samples were carefully removed by hand. Approximately a 75 g dry weight equivalent of the sample was adjusted to 50% of water holding capacity and put into a 1 L jar. Triplicate jars were enclosed after flushing their headspaces with CO2-free air and incubated at temperatures of 10°C and 20°C, respectively. We periodically collected 1 mL of headspace gas from the jars to measure CO2 concentration using a gas chromatograph. When the CO2 concentration in each jar reached 1.5% in volume, the headspace gas in the jar was collected to measure carbon isotope ratio of the CO2, and then the headspace of the jar was re-flushed and continued to incubate. The SOC decomposition rate at 20°C was consistently higher than that at 10°C, the order of which was AP ≤ US ≤ OG < HO. This order did not correspond to the orders of both mean annual temperature at the sites (AP < HO < OG < US), and total organic carbon content per dry soil weight (HO < US < AP < OG). Our result suggests that field temperature does not exert predominant control over SOC degradability in Japanese forest surface soils. Q10 values obtained for the AP, US, and OG soils was initially approximately 3 and increased up to 4 after one month of incubation. The increase in Q10 value

  10. Chemical features of soils in a natural forest of West Hungary

    NASA Astrophysics Data System (ADS)

    Hofmann, Eszter; Bidló, András

    2015-04-01

    The present research focuses on the chemical results of soils formed on miocene carbonate rocks in a natural forest of West Hungary. Soil profiles derived from the Szárhalom Forest, located near the Lake Fertő, next to the city of Sopron. Six soil profiles were opened and analysed in this area. In the field the following physical parameters were evaluated from the soil profiles: transition, structure, compactness, roots, skeletal percent, colour, physical assortment, concretion and soil defect. Laboratory analysis involved the measurement of acidity, particle distribution, carbonated lime content, humus content, ammonium lactate-acetic acid soluble phosphorus- and potassium content, potassium chloride soluble calcium- and magnesium content, ethylene-diamine-tetraacetic-acid (EDTA) and diethylene-triamine-pentaacetic-acid (DTPA) soluble copper-, iron-, manganese- and zinc contents. These soils formed under a hornbeam-oak forest climate mainly and under a beech forest climate diffusely. The location and climate of the sites forms a basis of the comparison of the soils with similar base rock. The formation of the acidic and humus-rich upper layer of the soil profiles is influenced by the mineral composition and the weathering of the rocks. X-ray diffraction (Philips P W3710/PW1050 type X-ray diffractometer), thermoanalytical measurements (Mettler Toledo TGA/DSC 1 type thermogravimeter) and ICP-OES (Thermo Scientific iCAP 7000 Series) were also carried out to determine the mineral composition of the soils and the content of heavy metals. The soil samples were collected with both traditional and undisturbed (using the Kubiena box) sampling methods to enable further micromorphological investigations as well. The research is supported by the "Agroclimate-2" (VKSZ_12-1-2013-0034) joint EU-national research project. Key words: Natural forest, Miocene limestone, Mineral composition, Thermal analysis, Micromorphology

  11. Nitrogen and phosphorus resorption in a neotropical rain forest of a nutrient-rich soil.

    PubMed

    Martínez-Sánchez, José Luis

    2005-01-01

    In tropical forests with nutrient-rich soil tree's nutrient resorption from senesced leaves has not always been observed to be low. Perhaps this lack of consistence is partly owing to the nutrient resorption methods used. The aim of the study was to analyse N and P resorption proficiency from tropical rain forest trees in a nutrient-rich soil. It was hypothesised that trees would exhibit low nutrient resorption in a nutrient-rich soil. The soil concentrations of total N and extractable P, among other physical and chemical characteristics, were analysed in 30 samples in the soil surface (10 cm) of three undisturbed forest plots at 'Estaci6n de Biologia Los Tuxtlas' on the east coast of Mexico (18 degrees 34' - 18 degrees 36' N, 95 degrees 04' - 95 degrees 09' W). N and P resorption proficiency were determined from senescing leaves in 11 dominant tree species. Nitrogen was analysed by microkjeldahl digestion with sulphuric acid and distilled with boric acid, and phosphorus was analysed by digestion with nitric acid and perchloric acid. Soil was rich in total N (0.50%, n = 30) and extractable P (4.11 microg g(-1) n = 30). As expected, trees showed incomplete N (1.13%, n = 11) and P (0.11%, n = 1) resorption. With a more accurate method of nutrient resorption assessment, it is possible to prove that a forest community with a nutrient-rich soil can have low levels of N and P resorption.

  12. Quantification of soil respiration in forest ecosystems across China

    NASA Astrophysics Data System (ADS)

    Song, Xinzhang; Peng, Changhui; Zhao, Zhengyong; Zhang, Zhiting; Guo, Baohua; Wang, Weifeng; Jiang, Hong; Zhu, Qiuan

    2014-09-01

    We collected 139 estimates of the annual forest soil CO2 flux and 173 estimates of the Q10 value (the temperature sensitivity) assembled from 90 published studies across Chinese forest ecosystems. We analyzed the annual soil respiration (Rs) rates and the temperature sensitivities of seven forest ecosystems, including evergreen broadleaf forests (EBF), deciduous broadleaf forests (DBF), broadleaf and needleleaf mixed forests (BNMF), evergreen needleleaf forests (ENF), deciduous needleleaf forests (DNF), bamboo forests (BF) and shrubs (SF). The results showed that the mean annual Rs rate was 33.65 t CO2 ha-1 year-1 across Chinese forest ecosystems. Rs rates were significantly different (P < 0.001) among the seven forest types, and were significantly and positively influenced by mean annual temperature (MAT), mean annual precipitation (MAP), and actual evapotranspiration (AET); but negatively affected by latitude and elevation. The mean Q10 value of 1.28 was lower than the world average (1.4-2.0). The Q10 values derived from the soil temperature at a depth of 5 cm varied among forest ecosystems by an average of 2.46 and significantly decreased with the MAT but increased with elevation and latitude. Moreover, our results suggested that an artificial neural network (ANN) model can effectively predict Rs across Chinese forest ecosystems. This study contributes to better understanding of Rs across Chinese forest ecosystems and their possible responses to global warming.

  13. Comparison of Al speciation and other soil characteristics between meadow, young forest and old forest stands.

    PubMed

    Dlouhá, Sárka; Borůvka, Lubos; Pavlů, Lenka; Tejnecký, Václav; Drábek, Ondrej

    2009-11-01

    The aim of this paper is to describe the influence of spruce (Picea abies) afforestation on soil chemical properties, especially on soil acidity and aluminium (Al) mobilization and speciation in soil. For our study we used a unique set of three adjacent plots, including a meadow and two spruce forest stands of different age, in otherwise comparable conditions. The plots were located in the region of Giant Mountains, north-eastern Czech Republic. In general, pH values decreased and Al concentrations increased significantly after afforestation. Speciation of KCl-extractable and water-soluble Al in soil samples was done by means of HPLC/IC method. The concentrations of Al(X)(1+) and Al(Y)(2+) forms (in both extracts) are higher in humic and organically enriched (Bhs) horizons. The highest concentration of Al(3+) in both extracts is in the B horizons of old forest. Generally, in all studied stands majority of Al in aqueous extract is in the Al(X)(1+) form, which indicates that a large amount of mobile Al is bound in organic complexes. It suggests that actual toxicity is rather low. On the other hand, we have proved that majority of KCl-extractable Al exists in Al(3+) form. Thus we can conclude that disturbance of existing equilibrium may cause massive release of highly toxic Al(3+) from soil sorption complex to the soil solution, and consequently it can endanger the whole ecosystem. Moreover, continuous soil acidification accelerated by anthropogenic factors leading to Al mobilization represents a chemical time bomb. PMID:19748129

  14. Long-term changes in soil pH across major forest ecosystems in China

    NASA Astrophysics Data System (ADS)

    Yang, Yuanhe; Li, Pin; He, Honglin; Zhao, Xia; Datta, Arindam; Ma, Wenhong; Zhang, Ying; Liu, Xuejun; Han, Wenxuan; Wilson, Maxwell C.; Fang, Jingyun

    2015-02-01

    Atmospheric acidic deposition has been a major environmental problem since the industrial revolution. However, our understanding of the effect of acidic deposition on soil pH is inconclusive. Here we examined temporal variations in topsoil pH and their relationships with atmospheric sulfur and nitrogen deposition across China's forests from the 1980s to the 2000s. To accomplish this goal, we conducted artificial neural network simulations using historical soil inventory data from the 1980s and a data set synthesized from literature published after 2000. Our results indicated that significant decreases in soil pH occurred in broadleaved forests, while minor changes were observed in coniferous and mixed coniferous and broadleaved forests. The magnitude of soil pH change was negatively correlated with atmospheric sulfur and nitrogen deposition. This relationship highlights the need for stringent measures that reduce sulfur and nitrogen emissions so as to maintain ecosystem structure and function.

  15. Pyrogenic Carbon in forest soils across climate and soil property gradients in Switzerland

    NASA Astrophysics Data System (ADS)

    Reisser, Moritz; González Domínguez, Beatriz R.; Hagedorn, Frank; Abiven, Samuel

    2016-04-01

    Soil organic carbon (SOC) is an important measure for soil quality. Usually a high organic matter content in soils is favourable for most ecosystems. As a very stable component, pyrogenic organic carbon (PyC) can be of major interest to investigate to potential of organic matter, to persist very long in soils. Recent studies have shown, that the mean residence time of organic matter is not only due to its intrinsic chemical nature, but also to a variety of abiotic and biotic variables set by the ecosystem. Especially for PyC it is unclear, whether its content is related to fire regime, soil properties or other climatic conditions. In this study we wanted to investigate, how climatic and soil-related conditions are influencing the persistence of PyC in soils. Therefore we used a sample set from Swiss forest soil (n = 54), which was designed for the purpose of having most differing climatic conditions (aridity and temperature) and a large range of soil properties (pH between 3.4 and 7.6; clay content between 4.7 % and 60 %). The soils were sampled in the first 20 cm of the mineral horizon on a representative plot area of 40 x 40 m. The soils were sieved to 2 mm and dried prior to the analysis. We used the benzene polycarboxylic acids (BPCA) molecular marker method to quantify and characterize PyC in these soil samples. Despite the large span in environmental conditions, we observed rather small differences in the contribution of PyC to SOC between warmer and colder, as well as between wetter and dryer soils. The PyC content in SOC lies well in range with a global average for forest soils estimated in other studies. Stocks of PyC vary more than the content, because of the large range of SOC contents in the samples. The influence of other parameters like soil properties is still under investigation. Qualitative investigation of the BPCAs showed that the degree of condensation, defined by the relative amount of B6CA in the total BPCA, was higher in warmer soils. This

  16. Forest harvesting reduces the soil metagenomic potential for biomass decomposition.

    PubMed

    Cardenas, Erick; Kranabetter, J M; Hope, Graeme; Maas, Kendra R; Hallam, Steven; Mohn, William W

    2015-11-01

    Soil is the key resource that must be managed to ensure sustainable forest productivity. Soil microbial communities mediate numerous essential ecosystem functions, and recent studies show that forest harvesting alters soil community composition. From a long-term soil productivity study site in a temperate coniferous forest in British Columbia, 21 forest soil shotgun metagenomes were generated, totaling 187 Gb. A method to analyze unassembled metagenome reads from the complex community was optimized and validated. The subsequent metagenome analysis revealed that, 12 years after forest harvesting, there were 16% and 8% reductions in relative abundances of biomass decomposition genes in the organic and mineral soil layers, respectively. Organic and mineral soil layers differed markedly in genetic potential for biomass degradation, with the organic layer having greater potential and being more strongly affected by harvesting. Gene families were disproportionately affected, and we identified 41 gene families consistently affected by harvesting, including families involved in lignin, cellulose, hemicellulose and pectin degradation. The results strongly suggest that harvesting profoundly altered below-ground cycling of carbon and other nutrients at this site, with potentially important consequences for forest regeneration. Thus, it is important to determine whether these changes foreshadow long-term changes in forest productivity or resilience and whether these changes are broadly characteristic of harvested forests. PMID:25909978

  17. Development of soil hydraulic soil properties below ancient forest, planted forest and grassland

    NASA Astrophysics Data System (ADS)

    Archer, Nicole; Otten, Wilfred; Schmidt, Sonja; Bengough, Glyn; Bonell, Mike; Shah, Nadeem

    2014-05-01

    A number of serious flood events in recent years have focused attention on flood prevention and mitigation and modelling work suggests that climate change will lead to an increase in the intensity and frequency of flood events in many areas. To understand how soil hydraulic characteristics develops in relation to facilitating the infiltration and storage of storm rainfall, a hypothetical pedogensis sequence was first developed and then tested by investigating a grassland site and four Scots pine (Pinus sylvestris) forests of different ages in the Scottish Highlands. These sites are: grassland, six and 45 year-old Scots pine plantations, remnant 300 year old individual Scots pines and a 4000 year old Caledonian Forest. The soil characteristics measured were: field saturated hydraulic conductivity (Kfs) using a constant head well permeameter, root numbers and proportion were estimated from soil pits and soil cores were taken for three different soil depths (0.06 - 0.10, 0.16 - 0.20 and 0.26 to 0.40m) for laboratory measurements to estimate organic matter, soil water release curves, macro-pores, and X - ray tomography measured pore connectivity and soil pore structure. It was observed that cutting down of the plantation increased organic matter because of the increase of dead biomass and decreased pore connectivity, which resulted in reduced hydraulic conductivity during the early years of re-afforestation. Where older trees were left, after cutting and removing younger trees; the range of OM, hydraulic conductivity, pore connectivity, and macropores remained similar to and older Scots pine plantation (45 years old). The undisturbed Ancient Caledonian remnant forest (approximately 4000 years old) was observed to have remarkably heterogeneous soil characteristics, providing extreme values of Kfs (12 to 4992 mm hr-1), OM, and macropores. Such ranges of soil characteristics were considered to be the optimum to reduce local flooding, because the soil matrix could

  18. Changes in fungal communities along a boreal forest soil fertility gradient.

    PubMed

    Sterkenburg, Erica; Bahr, Adam; Brandström Durling, Mikael; Clemmensen, Karina E; Lindahl, Björn D

    2015-09-01

    Boreal forests harbour diverse fungal communities with decisive roles in decomposition and plant nutrition. Although changes in boreal plant communities along gradients in soil acidity and nitrogen (N) availability are well described, less is known about how fungal taxonomic and functional groups respond to soil fertility factors. We analysed fungal communities in humus and litter from 25 Swedish old-growth forests, ranging from N-rich Picea abies stands to acidic and N-poor Pinus sylvestris stands. 454-pyrosequencing of ITS2 amplicons was used to analyse community composition, and biomass was estimated by ergosterol analysis. Fungal community composition was significantly related to soil fertility at the levels of species, genera/orders and functional groups. Ascomycetes dominated in less fertile forests, whereas basidiomycetes increased in abundance in more fertile forests, both in litter and humus. The relative abundance of mycorrhizal fungi in the humus layer remained high even in the most fertile soils. Tolerance to acidity and nitrogen deficiency seems to be of greater importance than plant carbon (C) allocation patterns in determining responses of fungal communities to soil fertility, in old-growth boreal forests. PMID:25952659

  19. Changes in fungal communities along a boreal forest soil fertility gradient.

    PubMed

    Sterkenburg, Erica; Bahr, Adam; Brandström Durling, Mikael; Clemmensen, Karina E; Lindahl, Björn D

    2015-09-01

    Boreal forests harbour diverse fungal communities with decisive roles in decomposition and plant nutrition. Although changes in boreal plant communities along gradients in soil acidity and nitrogen (N) availability are well described, less is known about how fungal taxonomic and functional groups respond to soil fertility factors. We analysed fungal communities in humus and litter from 25 Swedish old-growth forests, ranging from N-rich Picea abies stands to acidic and N-poor Pinus sylvestris stands. 454-pyrosequencing of ITS2 amplicons was used to analyse community composition, and biomass was estimated by ergosterol analysis. Fungal community composition was significantly related to soil fertility at the levels of species, genera/orders and functional groups. Ascomycetes dominated in less fertile forests, whereas basidiomycetes increased in abundance in more fertile forests, both in litter and humus. The relative abundance of mycorrhizal fungi in the humus layer remained high even in the most fertile soils. Tolerance to acidity and nitrogen deficiency seems to be of greater importance than plant carbon (C) allocation patterns in determining responses of fungal communities to soil fertility, in old-growth boreal forests.

  20. Soil Changes Induced by Rubber and Tea Plantation Establishment: Comparison with Tropical Rain Forest Soil in Xishuangbanna, SW China

    NASA Astrophysics Data System (ADS)

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH4 +-N and NO3 --N. However, soil IN pools were dominated by NH4 +-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH4 +-N concentration and decreases NO3 --N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH4 +-N and NO3 --N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH4 +-N and NO3 --N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH4 +-N were measured at the upper slopes of all sites, but NO3 --N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH4 +-N and NO3 --N concentrations. Options for improved soil management in plantations are discussed.

  1. Soil changes induced by rubber and tea plantation establishment: comparison with tropical rain forest soil in Xishuangbanna, SW China.

    PubMed

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH(4) (+)-N and NO(3) (-)-N. However, soil IN pools were dominated by NH(4) (+)-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH(4) (+)-N concentration and decreases NO(3) (-)-N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH(4) (+)-N and NO(3) (-)-N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH(4) (+)-N and NO(3) (-)-N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH(4) (+)-N were measured at the upper slopes of all sites, but NO(3) (-)-N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH(4) (+)-N and NO(3) (-)-N concentrations. Options for improved soil management in plantations are discussed.

  2. Soil changes induced by rubber and tea plantation establishment: comparison with tropical rain forest soil in Xishuangbanna, SW China.

    PubMed

    Li, Hongmei; Ma, Youxin; Liu, Wenjie; Liu, Wenjun

    2012-11-01

    Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10 cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH(4) (+)-N and NO(3) (-)-N. However, soil IN pools were dominated by NH(4) (+)-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH(4) (+)-N concentration and decreases NO(3) (-)-N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH(4) (+)-N and NO(3) (-)-N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH(4) (+)-N and NO(3) (-)-N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH(4) (+)-N were measured at the upper slopes of all sites, but NO(3) (-)-N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH(4) (+)-N and NO(3) (-)-N concentrations. Options for improved soil management in plantations are discussed. PMID:22986585

  3. Leaf and soil nitrogen and phosphorus availability in a neotropical rain forest of nutrient-rich soil.

    PubMed

    Martínez-Sánchez, José Luis

    2006-06-01

    The nitrogen and phosphorus supply in a lowland rain forest with a nutrient-rich soil was investigated by means of the leaf N/P quotient. It was hypothesised a high N and P supply to the forest ecosystem with a N and P rich soil. Total N and extractable P were determined in the surface (10 cm) soil of three plots of the forest. Total N was analysed by the Kjeldahl method, and P was extracted with HCI and NH4F. The leaf N/P quotient was evaluated from the senesced leaves of 11 dominant tree species from the mature forest. Samples of 5 g of freshly fallen leaves were collected from three trees of each species. Nitrogen was analysed by microkjeldahl digestion with sulphuric acid and distilled with boric acid, and phosphorus was analysed by digestion with nitric acid and perchloric acid, and determined by photometry. Concentrations of total N (0.50%, n = 30) and extractable P (4.11 microg g(-1), n = 30) in the soil were high. As expected, P supply was sufficient, but contrary to expected, N supply was low (N/P = 11.8, n = 11).

  4. Degradation of forest soils near an industrial zone

    NASA Astrophysics Data System (ADS)

    Pavlů, Lenka; Drábek, Ondřej; Borůvka, Luboš

    2014-05-01

    Forest soils near industrial zones could be endangered by acid deposition and by contamination by potentially toxic elements (PTEs). The Silesian Beskids represents a feasible example of these two types of forest soils damage. Soils of this area are strongly acid. The surface enrichment by several studied PTEs (Cd, Cu, Pb, Zn) reflects anthropogenic contamination. Moreover, acid character of soils enables presence of dangerous forms of Al. Two forms of all these PTEs were evaluated; potentially mobilized and mobile - the most danger form. Negligible amounts of Cu, Pb, and Al3+ are found in the mobile form. These elements represent just a potential risk for the system. The mobile forms of Cd, Zn, and Mn account for approximately 30 % of potentially mobilized forms in organic horizons. In the mineral horizon, Cd and Zn represent only about 20 % and Mn less than 10 % of potentially mobilized forms. These elements could pose a problem to ecosystem vitality. Cadmium is phytotoxic in small concentrations and its content in mobilized form approaches the critical load. For this reason, Cd could be considered as the most dangerous element in the studied area. While the distribution of mobile Cd is control by cation exchange capacity and hydrolytic acidity in the mineral horizon, stabilization of Cd in potentially mobilized form in organic horizons is enhanced by organic matter quality. A limiting nutrient could be P. Phosphorus plays an important role in the immobilization of toxic Al forms by creation of stable complexes as it was proven by a factor analysis in the H horizon. Negative aspect of this fact is decrease of bioavailability of P for plants. With regard to decreasing emissions, it is important to focus on the stabilization of PTEs deposited into the soil in the past. It is necessary to keep a relatively high quality of organic matter (connected to high CEC), higher pH, and higher nutrient content. This state could be temporarily achieved by the chemical

  5. Effects of Forest Gaps on Soil Properties in Castanopsis kawakamii Nature Forest.

    PubMed

    He, Zhongsheng; Liu, Jinfu; Su, Songjin; Zheng, Shiqun; Xu, Daowei; Wu, Zeyan; Hong, Wei; Wang, James Li-Ming

    2015-01-01

    The aim of this study is to analyze the effects of forest gaps on the variations of soil properties in Castanopsis kawakamii natural forest. Soil physical and chemical properties in various sizes and development stages were studied in C. kawakamii natural forest gaps. The results showed that forest gaps in various sizes and development stages could improve soil pore space structure and water characteristics, which may effectively promote the water absorbing capacity for plant root growth and play an important role in forest regeneration. Soil pore space structure and water characteristics in small gaps showed more obvious improvements, followed by the medium and large gaps. Soil pore space structure and water characteristics in the later development stage of forest gaps demonstrated more obvious improvements, followed by the early and medium development stages. The contents of hydrolysable N and available K in various sizes and development stages of forest gaps were higher than those of non-gaps, whereas the contents of total N, total P, available P, organic matter, and organic carbon were lower. The contents of total N, hydrolysable N, available K, organic matter, and organic carbon in medium gaps were higher than those of large and small gaps. The disturbance of forest gaps could improve the soils' physical and chemical properties and increase the population species' richness, which would provide an ecological basis for the species coexistence in C. kawakamii natural forest.

  6. Resistance and resilience of forest soils in the Limestone Alps

    NASA Astrophysics Data System (ADS)

    Katzensteiner, K.; Darabant, A.; Gratzer, G.

    2009-04-01

    During the last decades a dramatic increase in frequency and extent of forest disturbances, in particular of bark beetle infestations after windthrows, can be observed in Austria. In protective forests of the montane and subalpine vegetation zone, forest recovery can take several decades - a period of altered micro-climatic conditions and nutrient cycles. Soils on calcareous bedrock are considered to be particularly vulnerable under these conditions. Erosion and disintegration of ecto-organic layers of folic Histosols (Tangel) and lithic and rendzic Leptosols will lead to a loss of soil functions. In a pilot study on resilience of protective forests, soil development along chronosequences of windthrows has been surveyed in three climatically different test regions. Multivariate statistics uncover the relation between micro-topography, time since disturbance, and vegetation status on the one hand and morphological characteristics, carbon and nitrogen stocks of soils on the other hand. Factors affecting resistance and resilience of soils on calcareous bedrock are discussed.

  7. Soil Organic Matter in Forest Ecosystems of the Forest-tundra zone of Central Siberia

    NASA Astrophysics Data System (ADS)

    Mukhortova, Liudmila

    2010-05-01

    Our study was conducted on 17 forest sample plots in the forest-tundra zone of Central Siberia, Krasnoyarsk region, Russia. They were covered by larch/feather moss/shrub and larch/grass forest types growing on cryozems and podburs (Cryosols). The investigation was aimed at estimating soil organic matter storage and structure in forest ecosystems growing along the northern tree line. Such ecosystems have low rates of exchange processes and biological productivity. Estimating soil carbon in these forest types is important for a deeper understanding of their role in biogeochemical cycles and forecasting consequences of climate changes. Soil organic matter was divided into pools by biodegradation resistance level and, hence, different roles of these pools in biological cycles. The soil organic matter was divided into an easily mineralizable (LMOM) fraction, which includes labile (insoluble) (LOM) and mobile (soluble) (MOM) organic compounds, and a stable organic matter fraction that is humus substances bound with soil matrix. The forest-tundra soil carbon was found to total 30.9 to 125.9 tons/ha. Plant residues were the main part of the soil easily mineralizable organic matter and contained from 13.3 to 62.4% of this carbon. Plant residue carbon was mainly allocated on the soil surface, in the forest litter. Plant residues in the soil (dead roots + other "mortmass") were calculated to contribute 10-30% of the plant residues carbon, or 2.5-15.1% of the total soil carbon. Soil surface and in-soil dead plant material included 60-95% of heavily decomposed residues that made up a forest litter fermentation subhorizon and an "other mortmass" fraction of the root detritus. Mobile organic matter (substances dissolved in water and 0.1N NaOH) of plant residues was found to allocate 15-25% of carbon. In soil humus, MOM contribution ranged 14 to 64%. Easily mineralizable organic matter carbon appeared to generally dominate forest-tundra soil carbon pool. It was measured to

  8. Soil Quality of Restinga Forest: Organic Matter and Aluminum Saturation

    NASA Astrophysics Data System (ADS)

    Rodrigues Almeida Filho, Jasse; Casagrande, José Carlos; Martins Bonilha, Rodolfo; Soares, Marcio Roberto; Silva, Luiz Gabriel; Colato, Alexandre

    2013-04-01

    The restinga vegetation (sand coastal plain vegetation) consists of a mosaic of plant communities, which are defined by the characteristics of the substrates, resulting from the type and age of the depositional processes. This mosaic complex of vegetation types comprises restinga forest in advanced (high restinga) and medium regeneration stages (low restinga), each with particular differentiating vegetation characteristics. Of all ecosystems of the Atlantic Forest, restinga is the most fragile and susceptible to anthropic disturbances. The purpose of this study was evaluating the organic matter and aluminum saturation effects on soil quality index (SQI). Two locations were studied: State Park of the Serra do Mar, Picinguaba, in the city of Ubatuba (23°20' e 23°22' S / 44°48' e 44°52' W), and State Park of Cardoso Island in the city of Cananéia (25°03'05" e 25°18'18" S / 47°53'48" e 48° 05'42" W). The soil samples were collect at a depth of 0-10 cm, where concentrate 70% of vegetation root system. Was studied an additive model to evaluate soil quality index. The shallow root system development occurs due to low calcium levels, whose disability limits their development, but also can reflect on delay, restriction or even in the failure of the development vegetation. The organic matter is kept in the soil restinga ecosystem by high acidity, which reduces the decomposition of soil organic matter, which is very poor in nutrients. The base saturation, less than 10, was low due to low amounts of Na, K, Ca and Mg, indicating low nutritional reserve into the soil, due to very high rainfall and sandy texture, resulting in high saturation values for aluminum. Considering the critical threshold to 3% organic matter and for aluminum saturation to 40%, the IQS ranged from 0.95 to 0.1 as increased aluminum saturation and decreased the soil organic matter, indicating the main limitation to the growth of plants in this type of soil, when deforested.

  9. Biogeographic Distribution Patterns of Bacteria in Typical Chinese Forest Soils

    PubMed Central

    Xia, Zongwei; Bai, Edith; Wang, Qingkui; Gao, Decai; Zhou, Jidong; Jiang, Ping; Wu, Jiabing

    2016-01-01

    Microbes are widely distributed in soils and play a very important role in nutrient cycling and ecosystem services. To understand the biogeographic distribution of forest soil bacteria, we collected 115 soil samples in typical forest ecosystems across eastern China to investigate their bacterial community compositions using Illumina MiSeq high throughput sequencing based on 16S rRNA. We obtained 4,667,656 sequences totally and more than 70% of these sequences were classified into five dominant groups, i.e., Actinobacteria, Acidobacteria, Alphaproteobacteria, Verrucomicrobia, and Planctomycetes (relative abundance >5%). The bacterial diversity showed a parabola shape along latitude and the maximum diversity appeared at latitudes between 33.50°N and 40°N, an area characterized by warm-temperate zones and moderate temperature, neutral soil pH and high substrate availability (soil C and N) from dominant deciduous broad-leaved forests. Pairwise dissimilarity matrix in bacterial community composition showed that bacterial community structure had regional similarity and the latitude of 30°N could be used as the dividing line between southern and northern forest soils. Soil properties and climate conditions (MAT and MAP) greatly accounted for the differences in the soil bacterial structure. Among all soil parameters determined, soil pH predominantly affected the diversity and composition of the bacterial community, and soil pH = 5 probably could be used as a threshold below which soil bacterial diversity might decline and soil bacterial community structure might change significantly. Moreover, soil exchangeable cations, especially Ca2+ (ECa2+) and some other soil variables were also closely related to bacterial community structure. The selected environmental variables (21.11%) explained more of the bacterial community variation than geographic distance (15.88%), indicating that the edaphic properties and environmental factors played a more important role than geographic

  10. Biogeographic Distribution Patterns of Bacteria in Typical Chinese Forest Soils.

    PubMed

    Xia, Zongwei; Bai, Edith; Wang, Qingkui; Gao, Decai; Zhou, Jidong; Jiang, Ping; Wu, Jiabing

    2016-01-01

    Microbes are widely distributed in soils and play a very important role in nutrient cycling and ecosystem services. To understand the biogeographic distribution of forest soil bacteria, we collected 115 soil samples in typical forest ecosystems across eastern China to investigate their bacterial community compositions using Illumina MiSeq high throughput sequencing based on 16S rRNA. We obtained 4,667,656 sequences totally and more than 70% of these sequences were classified into five dominant groups, i.e., Actinobacteria, Acidobacteria, Alphaproteobacteria, Verrucomicrobia, and Planctomycetes (relative abundance >5%). The bacterial diversity showed a parabola shape along latitude and the maximum diversity appeared at latitudes between 33.50°N and 40°N, an area characterized by warm-temperate zones and moderate temperature, neutral soil pH and high substrate availability (soil C and N) from dominant deciduous broad-leaved forests. Pairwise dissimilarity matrix in bacterial community composition showed that bacterial community structure had regional similarity and the latitude of 30°N could be used as the dividing line between southern and northern forest soils. Soil properties and climate conditions (MAT and MAP) greatly accounted for the differences in the soil bacterial structure. Among all soil parameters determined, soil pH predominantly affected the diversity and composition of the bacterial community, and soil pH = 5 probably could be used as a threshold below which soil bacterial diversity might decline and soil bacterial community structure might change significantly. Moreover, soil exchangeable cations, especially Ca(2+) (ECa(2+)) and some other soil variables were also closely related to bacterial community structure. The selected environmental variables (21.11%) explained more of the bacterial community variation than geographic distance (15.88%), indicating that the edaphic properties and environmental factors played a more important role than

  11. Biogeographic Distribution Patterns of Bacteria in Typical Chinese Forest Soils.

    PubMed

    Xia, Zongwei; Bai, Edith; Wang, Qingkui; Gao, Decai; Zhou, Jidong; Jiang, Ping; Wu, Jiabing

    2016-01-01

    Microbes are widely distributed in soils and play a very important role in nutrient cycling and ecosystem services. To understand the biogeographic distribution of forest soil bacteria, we collected 115 soil samples in typical forest ecosystems across eastern China to investigate their bacterial community compositions using Illumina MiSeq high throughput sequencing based on 16S rRNA. We obtained 4,667,656 sequences totally and more than 70% of these sequences were classified into five dominant groups, i.e., Actinobacteria, Acidobacteria, Alphaproteobacteria, Verrucomicrobia, and Planctomycetes (relative abundance >5%). The bacterial diversity showed a parabola shape along latitude and the maximum diversity appeared at latitudes between 33.50°N and 40°N, an area characterized by warm-temperate zones and moderate temperature, neutral soil pH and high substrate availability (soil C and N) from dominant deciduous broad-leaved forests. Pairwise dissimilarity matrix in bacterial community composition showed that bacterial community structure had regional similarity and the latitude of 30°N could be used as the dividing line between southern and northern forest soils. Soil properties and climate conditions (MAT and MAP) greatly accounted for the differences in the soil bacterial structure. Among all soil parameters determined, soil pH predominantly affected the diversity and composition of the bacterial community, and soil pH = 5 probably could be used as a threshold below which soil bacterial diversity might decline and soil bacterial community structure might change significantly. Moreover, soil exchangeable cations, especially Ca(2+) (ECa(2+)) and some other soil variables were also closely related to bacterial community structure. The selected environmental variables (21.11%) explained more of the bacterial community variation than geographic distance (15.88%), indicating that the edaphic properties and environmental factors played a more important role than

  12. The occurrence of yeasts in the forest soils.

    PubMed

    Sláviková, E; Vadkertiová, R

    2000-01-01

    One hundred and eighty one yeast strains were isolated from 180 soil samples collected in three types of forest. The samples were taken during one year. The yeast species found were similar in spite of distinct forest types. Cryptococcus laurentii, Cystofilobasidium capitatum, Leucosporidium scottii, Rhodotorula aurantiaca, and Trichosporon cutaneum were the predominant species in both deciduous and coniferous forests. The number of yeasts ranged from 1.5 x 10(3) to 1.1 x 10(4) CFU/g soil. We found that yeasts occurred unevenly in soils during the year. The lowest number of yeasts was ascertained in December and the highest one in May.

  13. Changes in faunal and vegetation communities along a soil calcium gradient in northern hardwood forests

    USGS Publications Warehouse

    Beier, Colin M.; Woods, Anne M.; Hotopp, Kenneth P.; Gibbs, James P.; Mitchell, Myron J.; Dovciak, Martin; Leopold, Donald J.; Lawrence, Gregory B.; Page, Blair D.

    2012-01-01

    Depletion of Ca from forest soils due to acidic deposition has had potentially pervasive effects on forest communities, but these impacts remain largely unknown. Because snails, salamanders, and plants play essential roles in the Ca cycle of northern hardwood forests, we hypothesized that their community diversity, abundance, and structure would vary with differences in biotic Ca availability. To test this hypothesis, we sampled 12 upland hardwood forests representing a soil Ca gradient in the Adirondack Mountains, New York (USA), where chronic deposition has resulted in acidified soils but where areas of well-buffered soils remain Ca rich due to parent materials. Along the gradient of increasing soil [Ca2+], we observed increasing trends in snail community richness and abundance, live biomass of redback salamanders (Plethodon cinereus (Green, 1818)), and canopy tree basal area. Salamander communities were dominated by mountain dusky salamanders (Desmognathus ochrophaeus Cope, 1859) at Ca-poor sites and changed continuously along the Ca gradient to become dominated by redback salamanders at the Ca-rich sites. Several known calciphilic species of snails and plants were found only at the highest-Ca sites. Our results indicated that Ca availability, which is shaped by geology and acidic deposition inputs, influences northern hardwood forest ecosystems at multiple trophic levels, although the underlying mechanisms require further study.

  14. Effects of Forest Gaps on Soil Properties in Castanopsis kawakamii Nature Forest

    PubMed Central

    He, Zhongsheng; Liu, Jinfu; Su, Songjin; Zheng, Shiqun; Xu, Daowei; Wu, Zeyan; Hong, Wei; Wang, James Li-Ming

    2015-01-01

    The aim of this study is to analyze the effects of forest gaps on the variations of soil properties in Castanopsis kawakamii natural forest. Soil physical and chemical properties in various sizes and development stages were studied in C. kawakamii natural forest gaps. The results showed that forest gaps in various sizes and development stages could improve soil pore space structure and water characteristics, which may effectively promote the water absorbing capacity for plant root growth and play an important role in forest regeneration. Soil pore space structure and water characteristics in small gaps showed more obvious improvements, followed by the medium and large gaps. Soil pore space structure and water characteristics in the later development stage of forest gaps demonstrated more obvious improvements, followed by the early and medium development stages. The contents of hydrolysable N and available K in various sizes and development stages of forest gaps were higher than those of non-gaps, whereas the contents of total N, total P, available P, organic matter, and organic carbon were lower. The contents of total N, hydrolysable N, available K, organic matter, and organic carbon in medium gaps were higher than those of large and small gaps. The disturbance of forest gaps could improve the soils’ physical and chemical properties and increase the population species’ richness, which would provide an ecological basis for the species coexistence in C. kawakamii natural forest. PMID:26496710

  15. Variation in pH optima of hydrolytic enzyme activities in tropical rain forest soils.

    PubMed

    Turner, Benjamin L

    2010-10-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

  16. Variation in pH Optima of Hydrolytic Enzyme Activities in Tropical Rain Forest Soils

    PubMed Central

    Turner, Benjamin L.

    2010-01-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates. PMID:20709838

  17. Management Impacts on Forest Floor and Soil Organic Carbon in Northern Temperate Forests of the US

    PubMed Central

    2011-01-01

    Background The role of forests in the global carbon cycle has been the subject of a great deal of research recently, but the impact of management practices on forest soil dynamics at the stand level has received less attention. This study used six forest management experimental sites in five northern states of the US to investigate the effects of silvicultural treatments (light thinning, heavy thinning, and clearcutting) on forest floor and soil carbon pools. Results No overall trend was found between forest floor carbon stocks in stands subjected to partial or complete harvest treatments. A few sites had larger stocks in control plots, although estimates were often highly variable. Forest floor carbon pools did show a trend of increasing values from southern to northern sites. Surface soil (0-5 cm) organic carbon content and concentration were similar between treated and untreated plots. Overall soil carbon (0-20 cm) pool size was not significantly different from control values in sites treated with partial or complete harvests. No geographic trends were evident for any of the soil properties examined. Conclusions Results indicate that it is unlikely that mineral soil carbon stocks are adversely affected by typical management practices as applied in northern hardwood forests in the US; however, the findings suggest that the forest floor carbon pool may be susceptible to loss. PMID:22206625

  18. Soil micronutrients at the plot scale under agricultural and forest soil uses

    NASA Astrophysics Data System (ADS)

    da Silva Días, Rosane; Vidal Vázquez, Eva; dos Santos Batista Bonini, Carolina; Marasca, Indiamara; Paz-Ferreiro, Jorge

    2013-04-01

    Land use practices affect soil properties and nutrient supply. Very limited data are available on the heavy metal extractability in northwest Spain. The aim of this study is to analyze long-term effects of land use on the supply, variability and spatial distribution of soil nutrients, which was undertaken by comparison of a forest and a cultivated stand, rich in organic matter content. The study was carried out in an acid, rich in organic matter soil developed over sediments at the province of Lugo, northwestern of Spain. Adjacent plots with were marked on regular square grids with 2-m spacing. Fe, Mn, Zn and Cu were extracted both by Mehlich-3 and DTPA solutions and determined by ICP-MS. General soil chemical and physical properties were routinely analyzed. In arable land microelement concentration ranges were as follows: Fe (100 and 135 mg/Kg), Mn (7.6 and 21.5 mg/Kg), Zn (0.6 and 3.7 mg/Kg), Cu (0.2 and 0.7 mg/Kg). In forest land, these ranges were: Fe (62 and 309 mg/Kg), Mn (0.2 and 2.1 mg/Kg), Zn (0.2 and 2.9 mg/Kg), Cu (0.1 and 0.2 mg/Kg), Microelement concentrations extracted both with DTPA and Mehlich-3 were higher in the cultivated than in the forest stand, being Fe-DTPA the exception. Coefficients of variation were higher for the microelement content of the soil under forest. Principal component analysis was performed to evaluate associations between extractable microelements and general physico-chemical properties. At the study scale, nutrient management is the main factor affecting the agricultural site, whereas soil-plant interactions are probably driving the higher variation within the forest site. Patterns of spatial variability of the study nutrients at the small plot scale were assessed by geostatistical techniques. Results are discussed in the frame of organic matter decline with conventional tillage and sustainable land use.

  19. Stemflow acid neutralization capacity in a broadleaved deciduous forest: the role of edge effects.

    PubMed

    Shiklomanov, Alexey N; Levia, Delphis F

    2014-10-01

    Atmospheric deposition is an important pathway for moisture, nutrient, and pollutant exchange among the atmosphere, forest, and soils. Previous work has shown the importance of proximity to the forest edge to chemical fluxes in throughfall, but far less research has considered stemflow. This study examined the difference in acid neutralization capacity (ANC) of stemflow of nineteen Liriodendron tulipifera L. (yellow poplar) trees between the forest edge and interior in a rural area of northeastern Maryland. We measured ANC directly via potentiometric titration. Stemflow from trees at the forest edge was found to have significantly higher and more variable pH and ANC than in the forest interior (p < 0.01). No mathematical trend between ANC and distance to the forest edge was observed, indicating the importance of individual tree characteristics in stemflow production and chemistry. These results reaffirm the importance of stemflow for acid neutralization by deciduous tree species.

  20. Stemflow acid neutralization capacity in a broadleaved deciduous forest: the role of edge effects.

    PubMed

    Shiklomanov, Alexey N; Levia, Delphis F

    2014-10-01

    Atmospheric deposition is an important pathway for moisture, nutrient, and pollutant exchange among the atmosphere, forest, and soils. Previous work has shown the importance of proximity to the forest edge to chemical fluxes in throughfall, but far less research has considered stemflow. This study examined the difference in acid neutralization capacity (ANC) of stemflow of nineteen Liriodendron tulipifera L. (yellow poplar) trees between the forest edge and interior in a rural area of northeastern Maryland. We measured ANC directly via potentiometric titration. Stemflow from trees at the forest edge was found to have significantly higher and more variable pH and ANC than in the forest interior (p < 0.01). No mathematical trend between ANC and distance to the forest edge was observed, indicating the importance of individual tree characteristics in stemflow production and chemistry. These results reaffirm the importance of stemflow for acid neutralization by deciduous tree species. PMID:25005886

  1. 1997 Canadian acid rain assessment. Volume 4: The effects on Canada`s forests

    SciTech Connect

    Hall, P.

    1997-12-31

    This report reviews the state of acid rain assessment related to Canadian forests as it has progressed since the last assessment carried out in 1990. The assessment also highlights key policy issues and the uncertainties associated with addressing them. Sections of the report cover the following: Acid rain and current forest decline in coastal birch, sugar maple, and high elevation forests; the effects of acid rain on tree physiology and soil chemistry; results of forest health monitoring in national, North American, Ontario, and Quebec networks; the critical loads or levels of acid deposition, with reference to case studies; and international involvement in acid rain research and abatement. Finally, research and information needs are identified.

  2. Comparison of vegetation patterns and soil nutrient relations in an oak-pine forest and a mixed deciduous forest on Long Island, New York

    SciTech Connect

    Peterson, S.C.; Curtis, P.S.

    1980-11-01

    An analysis of soil nutrient relations in two forest communities on Long Island, NY, yielded a correlation between the fertility of the top-soil and vegetational composition. The oak-pine forest soils at Brookhaven National Laboratory contain lower average concentrations of NH/sub 3/, Ca, K, and organic matter than the mixed deciduous forest soils in the Stony Brook area. The pH of the topsoil is also more acidic at Brookhaven. The observed differences between localities are greater than within-locality differences between the two soil series tested (Plymouth and Riverhead), which are common to both localities. Nutrient concentrations in the subsoil are not consistently correlated with either locality or soil series, although organic matter and NH/sub 3/ show significantly higher concentrations at Stony Brook. Supporting data on density and basal area of trees and coverage of shrubs and herbs also reveals significant variation between the two forest communities. An ordination of the vegetation data shows higher similarity within than between localities, while no obvious pattern of within-locality variation due to soil series treatments is apparent. These data support the hypothesis that fertility gradients may influence forest community composition and structure. This hypothesis is discussed with reference to vegetation-soil interactions and other factors, such as frequency of burning, which may direct the future development of the Brookhaven oak-pine forest.

  3. Understanding the prairie-forest transitional zone in northern Minnesota through variations in soil chemistry

    NASA Astrophysics Data System (ADS)

    Kasmerchak, C. S.; Mason, J. A.

    2015-12-01

    Boundaries between soil types are not discrete, but instead there are transitional zones that exhibit characteristics of soil types that they border. The prairie-forest transitional zone is seen throughout North America and Eurasia. Prairie soils (Mollisols) and deciduous forest soils (Alfisols) demonstrate interesting contrasts in morphology. Understanding variations in chemical properties is key to understanding nutrient cycling and retention, ecosystem development, and furthering the field of soil geography. Research sites are located in northern Minnesota's eastern forest, western prairie, and the transitional forested zone between. Evidence of clay translocation is a key indicator of Alfisol development. The double layer theory suggests chemical factors allowing clays to be dispersed/flocculated are ionic strength of the solution, relative abundance of Na+ and di- or trivalent cations, and pH (Sposito, 1984; van Olphen, 1977). In initial stages of soil formation exchangeable bases (Na+, K+, Ca++, and Mg++) occupy 100% of clay exchange sites, but as soil develops are these replaced by acidity ions (H+ and Al3+) and base saturation decreases. The relationship between exchangeable cations and clay dispersion is understood in lower horizons where Ca++ and Mg++ are abundant, and clay is flocculated, but this is not well understood in upper horizons. However it is suggested that clay dispersion can occur in upper horizons of pH values between 7 and 5 (van Breeman and Buurman, 2002). CEC values are expected to be much higher in soils where clay is flocculated and base ion concentration is high. Preliminary analyses supports that differences in these chemical factors are key indicators of varying rates of soil development, and explain geographic distribution of soils in this region. Through further lab work and data analysis, the relative importance of these chemical properties will come to light and the drivers prairie-forest soil transition will be better understood.

  4. Microflora of soils under pine forests area affected by gradation of leaf-eating insects.

    PubMed

    Stremińska, Marta A; Błaszczyk, Mieczysław; Sierpińska, Alicja; Kolk, Andrzej

    2002-01-01

    Soils of pine forests in the Bytnica Forestry District, Poland, are poor in nutrients readily accessible to plants. The excessively acidic reaction of the soils, typical for soils under pine forests, unfavourably affects the growth of microorganisms whose numbers are lower than in soils under deciduous and mixed forests. In the pine forests of the studied forestry there were outbreaks of a defoliating insect - pine beauty moth (Panolis flammea L.), which resulted in over 60% defoliation of the trees. The studies were carried out on the area of tree stands subjected to gradation by leaf-eating insects (sprayed and not sprayed) and healthy stand of the same age class (age 60 to 70 years). The studies revealed increased number of soil microorganisms in samples taken from the area affected by pine beauty moth gradation in the case of both unsprayed areas and those sprayed with the pesticide. The occurrence in these soils of larger numbers of ammonifying and denitrifying bacteria points to the presence of conditions favouring the growth of heterotrophic organisms. Changes in the number of actinomycetes and fungi in soils under tree stands subjected to gradation by insects, compared to healthy stands, can be a consequence of a change of environmental conditions (e.g. % content of organic carbon). Soils under defoliated tree stands show higher biochemical activity related to nitrogen cycling in the pine forest ecosystem. This leads to higher availability of organic nitrogen for conversion to inorganic forms of nitrogen, which are utilised by trees. Further changes occurring in soils under forest stands affected by gradation by leaf-eating insects would allow to gain knowledge on the ecological consequences of the use of insecticides in the protection of pine stands against harmful insects, with particular stress on those situations in which pine stands not threatened by complete defoliation are sprayed.

  5. Role of forest soils in the national greenhouse gas inventory

    NASA Astrophysics Data System (ADS)

    Jandl, R.

    2012-12-01

    In Austria the forests are a key category of the GHG budget. The role of forest soils as a sink or source of carbon has so far not been fully assessed and as a default position a stable soil carbon pool was reported. A combination from a modeling exercise and a field survey allowed the scrutinization of this assumption. The field data represent a repeated soil inventory after 20 years. Due to the spatial heterogeneity of chemical soil properties no clear conclusion of the temporal change of soil carbon was made. The data set from the field survey was used for the validation of a modeling exercise. We used the model Yasso07 that is well suited for the available site information in Austria. The measured and the simulated soil carbon change had an acceptable fit. The modeling exercise suggested a statistically insignificant loss of soil carbon during a committment period of the Kyoto Protocol. The standing biomass of the forest is still a carbon sink. Owing to the large forest area this insignificant soil carbon loss strongly reduces the carbon sink strength of the entire forest.

  6. Stemflow Acid Neutralization Capacity in a Broadleaved Deciduous Forest: The Role of Edge Effects

    NASA Astrophysics Data System (ADS)

    Levia, D. F., Jr.; Shiklomanov, A.

    2014-12-01

    The fragmentation of forests is occurring at an accelerated rate in parts of the United States. Forest fragmentation creates edge habitat that affects the biogeochemistry of forests. Atmospheric deposition is known to increase at the forest edge in comparison to the forest interior. Past research has demonstrated the critical role of edge effects on throughfall chemistry but no known work has examined the relationship between stemflow chemistry and edge effects. To fill this data gap, we quantified the stemflow acid neutralization capacity (ANC) of nineteen Liriodendron tulipifera L. (yellow poplar) trees between forest edge and interior locations in the Piedmont of the mid-Atlantic USA. ANC was measured directly by potentiometric titration. Both stemflow pH and ANC were higher for L. tulipifera trees on the forest edge as opposed to those in interior locations (p < 0.01), although marked variability was observed among individual trees. It is critical to note that the ANC of stemflow of edge trees is almost certainly contextual, depending on geographic locality. This is to say that stemflow from edge trees may neutralize acid inputs in some locations (as in our case) but lead to enhanced acidification of aqueous inputs to forest soils in other locales where the dry deposition of acid anions is high. The experimental results have ramifications for forest management schema seeking to increase or decrease the extent of edge habitat in forest fragments.

  7. FOREST SOIL CARBON SEQUESTRATION: ACCOUNTING FOR THIS VITAL ECOSYSTEM SERVICE

    EPA Science Inventory

    Forests play a crucial role in supplying many goods and services that society depends upon on a daily basis including water supply, production of oxygen, soil protection, building materials, wildlife habitat and recreation. Forests also provide a significant amount of carbon seq...

  8. Phosphorus runoff from Coastal Plain forest soil in Louisiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although not a common practice, poultry litter (PL) may be used for forest fertilization. Despite usually low soil phosphorus (P) and runoff under forest, repeated or high rates of PL application may cause appreciable P loss. Phosphorus in natural runoff under loblolly pine (Pinus taeda L.) fertiliz...

  9. Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions.

    PubMed

    Hengl, Tomislav; Heuvelink, Gerard B M; Kempen, Bas; Leenaars, Johan G B; Walsh, Markus G; Shepherd, Keith D; Sila, Andrew; MacMillan, Robert A; Mendes de Jesus, Jorge; Tamene, Lulseged; Tondoh, Jérôme E

    2015-01-01

    80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008-2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management--organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15-75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological

  10. Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions.

    PubMed

    Hengl, Tomislav; Heuvelink, Gerard B M; Kempen, Bas; Leenaars, Johan G B; Walsh, Markus G; Shepherd, Keith D; Sila, Andrew; MacMillan, Robert A; Mendes de Jesus, Jorge; Tamene, Lulseged; Tondoh, Jérôme E

    2015-01-01

    80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008-2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management--organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15-75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological

  11. Mapping Soil Properties of Africa at 250 m Resolution: Random Forests Significantly Improve Current Predictions

    PubMed Central

    Hengl, Tomislav; Heuvelink, Gerard B. M.; Kempen, Bas; Leenaars, Johan G. B.; Walsh, Markus G.; Shepherd, Keith D.; Sila, Andrew; MacMillan, Robert A.; Mendes de Jesus, Jorge; Tamene, Lulseged; Tondoh, Jérôme E.

    2015-01-01

    80% of arable land in Africa has low soil fertility and suffers from physical soil problems. Additionally, significant amounts of nutrients are lost every year due to unsustainable soil management practices. This is partially the result of insufficient use of soil management knowledge. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. Over the period 2008–2014, the AfSIS project compiled two point data sets: the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site database. These data sets contain over 28 thousand sampling locations and represent the most comprehensive soil sample data sets of the African continent to date. Utilizing these point data sets in combination with a large number of covariates, we have generated a series of spatial predictions of soil properties relevant to the agricultural management—organic carbon, pH, sand, silt and clay fractions, bulk density, cation-exchange capacity, total nitrogen, exchangeable acidity, Al content and exchangeable bases (Ca, K, Mg, Na). We specifically investigate differences between two predictive approaches: random forests and linear regression. Results of 5-fold cross-validation demonstrate that the random forests algorithm consistently outperforms the linear regression algorithm, with average decreases of 15–75% in Root Mean Squared Error (RMSE) across soil properties and depths. Fitting and running random forests models takes an order of magnitude more time and the modelling success is sensitive to artifacts in the input data, but as long as quality-controlled point data are provided, an increase in soil mapping accuracy can be expected. Results also indicate that globally predicted soil classes (USDA Soil Taxonomy, especially Alfisols and Mollisols) help improve continental scale soil property mapping, and are among the most important predictors. This indicates a promising potential for transferring pedological

  12. Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests

    SciTech Connect

    Cusack, Daniela F.; Silver, Whendee; Torn, Margaret S.; Burton, Sarah D.; Firestone, Mary

    2011-03-01

    Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types.

  13. Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests.

    PubMed

    Cusack, Daniela F; Silver, Whendee L; Torn, Margaret S; Burton, Sarah D; Firestone, Mary K

    2011-03-01

    Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types.

  14. Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests.

    PubMed

    Cusack, Daniela F; Silver, Whendee L; Torn, Margaret S; Burton, Sarah D; Firestone, Mary K

    2011-03-01

    Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types. PMID:21608471

  15. Forest productivity decline caused by successional paludification of boreal soils.

    PubMed

    Simard, Martin; Lecomte, Nicolas; Bergeron, Yves; Bernier, Pierre Y; Paré, David

    2007-09-01

    Long-term forest productivity decline in boreal forests has been extensively studied in the last decades, yet its causes are still unclear. Soil conditions associated with soil organic matter accumulation are thought to be responsible for site productivity decline. The objectives of this study were to determine if paludification of boreal soils resulted in reduced forest productivity, and to identify changes in the physical and chemical properties of soils associated with reduction in productivity. We used a chronosequence of 23 black spruce stands ranging in postfire age from 50 to 2350 years and calculated three different stand productivity indices, including site index. We assessed changes in forest productivity with time using two complementary approaches: (1) by comparing productivity among the chronosequence stands and (2) by comparing the productivity of successive cohorts of trees within the same stands to determine the influence of time independently of other site factors. Charcoal stratigraphy indicates that the forest stands differ in their fire history and originated either from high- or low-severity soil burns. Both chronosequence and cohort approaches demonstrate declines in black spruce productivity of 50-80% with increased paludification, particularly during the first centuries after fire. Paludification alters bryophyte abundance and succession, increases soil moisture, reduces soil temperature and nutrient availability, and alters the vertical distribution of roots. Low-severity soil burns significantly accelerate rates of paludification and productivity decline compared with high-severity fires and ultimately reduce nutrient content in black spruce needles. The two combined approaches indicate that paludification can be driven by forest succession only, independently of site factors such as position on slope. This successional paludification contrasts with edaphic paludification, where topography and drainage primarily control the extent and rate

  16. Windthrows increase soil carbon stocks in a Central Amazon forest

    NASA Astrophysics Data System (ADS)

    dos Santos, L. T.; Magnabosco Marra, D.; Trumbore, S.; Camargo, P. B.; Chambers, J. Q.; Negrón-Juárez, R. I.; Lima, A. J. N.; Ribeiro, G. H. P. M.; dos Santos, J.; Higuchi, N.

    2015-12-01

    Windthrows change forest structure and species composition in Central Amazon forests. However, the effects of widespread tree mortality associated with wind-disturbances on soil properties have not yet been described. In this study, we investigated short-term effects (seven years after disturbance) of a windthrow event on soil carbon stocks and concentrations in a Central Amazon terra firme forest. The soil carbon stock (averaged over a 0-30 cm depth profile) in disturbed plots (61.4 ± 4.18 Mg ha-1, mean ± standard error) was marginally higher (p = 0.009) than that from undisturbed plots (47.7 ± 6.95 Mg ha-1). The soil organic carbon concentration in disturbed plots (2.0 ± 0.08 %) was significantly higher (p < 0.001) than that from undisturbed plots (1.36 ± 0.12 %). Moreover, soil carbon stocks were positively correlated with soil clay content (r = 0.575 and p = 0.019) and with tree mortality intensity (r = 0.493 and p = 0.045). Our results indicate that large inputs of plant litter associated with large windthrow events cause a short-term increase in soil carbon content, and the degree of increase is related to soil clay content and tree mortality intensity. Higher nutrient availability in soils from large canopy gaps created by wind disturbance may increase vegetation resilience and favor forest recovery.

  17. [Community diversity of soil arthropods in forest-steppe ecotone].

    PubMed

    Zhu, Xin-yu; Gao, Bao-ji; Bi, Hua-ming; Wang, Wen-xun; Yuan, Sheng-liang; Hu, Yun-chuan

    2007-11-01

    An investigation on the community diversity of soil arthropods in the forest-steppe ecotone of north Hebei Province was conducted. A total of 10 420 individuals of soil arthropods were collected, which belonged to 25 groups, 6 classes and 24 orders. Acarina and Collembola were the dominant orders, and there were 8 groups of frequent orders and 15 groups of rare orders. The diversity index (H'), DG index, and evenness of soil arthropod community were relatively higher in forest zone, but lower in meadow-steppe zone. Soil pH had a higher degree of interconnection with the numbers of soil arthropod groups, while soil temperature and moisture content had a higher degree of interconnection with the numbers of soil arthropod individuals.

  18. Assessment of soil calcium status in red spruce forests in the northeastern United States

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.; Bailey, S.W.; Shortle, W.C.

    1997-01-01

    Long-term changes in concentrations of available Ca in soils of red spruce forests have been documented, but remaining questions about the magnitude and regional extent of these changes have precluded an assessment of the current and future status of soil Ca. To address this problem, soil samples were collected in 1992-93 from 12 sites in New York, Vermont, New Hampshire, and Maine to provide additional data necessary to synthesize all available research results on soil Ca in red spruce forests. Sites were chosen to encompass the range of environmental conditions experienced by red spruce. Concentrations of exchangeable Ca ranged from 2.13 to 21.6 cmol(c) kg-1 in the Oa horizon, and from 0.11 to 0.68 cmol(c) kg-1 in the upper 10 cm of the B horizon. These measurements expanded the range of exchangeable Ca reported in the literature for both horizons in northeastern red spruce forests. Exchangeable Ca was the largest Ca fraction in the forest floor at most sites (92% of acid-extractable Ca), but mineral Ca was the largest fraction at the three sites that also had the highest mineral-matter concentrations. The primary factor causing variability in Ca concentrations among sites was the mineralogy of parent material, but exchangeable concentrations in the B horizon of all sites were probably reduced by acidic deposition. Because the majority of Ca in the forest floor is in a readily leachable form, and Ca inputs to the forest floor from the mineral soil and atmospheric deposition have been decreasing in recent decades, the previously documented decreases in Ca concentrations in the forest floor over previous decades may extend into the future.

  19. Microbial functional diversity in a mediterranean forest soil: impact of soil nitrogen availability

    NASA Astrophysics Data System (ADS)

    Dalmonech, D.; Lagomarsino, A.; Moscatelli, M. C.

    2009-04-01

    Beneficial or negative effects of N deposition on forest soil are strongly linked to the activity of microbial biomass and enzyme activities because they regulate soil quality and functioning due to their involvement in organic matter dynamics, nutrient cycling and decomposition processes. Moreover, because the ability of an ecosystem to withstand serious disturbances may depend in part on the microbial component of the system, by characterizing microbial functional diversity we may be able to better understand and manipulate ecosystem processes. Changes in the biodiversity of the soil microbial community are likely to be important in relation to maintenance of soil ecosystem function because the microbial communities influence the potential of soils for enzyme-mediated substrate catalysis. Objective of this study was to evaluate how soil N availability affected microbial functional diversity in a 4 months laboratory experiment. The incubation experiment was carried out with an organo-mineral soil collected in a Quercus cerris forest at the Roccarespampani site (Central Italy, Viterbo). All samples were incubated at 28°C and were kept to a water content between 55 and 65% of the water holding capacity. Different amount of N (NH4NO3) were added as solution once a week in order to mimic the N wet deposition and to let microbial community deal with a slow increase in time of inorganic N content. The amount of nutrient solutions was chosen depending on the average soil-water loss due to evaporation in one week. The total amount of N-NH4NO3 was chosen to be comparable with the range of N depositions currently reported in European forests, i.e. between 1 and 75 kg N ha-1 y-1. The total amount added at the end of incubation varied from 0, 10, 25, 50 and 75 kg N ha-1. Distilled water was added in the control soil in order to provide the same amount of solution as the treated soils. In order to discriminate the effect of N, the NH4NO3 solutions were adjusted to soil pH and

  20. Long-term forest soil warming alters microbial communities in temperate forest soils

    PubMed Central

    DeAngelis, Kristen M.; Pold, Grace; Topçuoğlu, Begüm D.; van Diepen, Linda T. A.; Varney, Rebecca M.; Blanchard, Jeffrey L.; Melillo, Jerry; Frey, Serita D.

    2015-01-01

    Soil microbes are major drivers of soil carbon cycling, yet we lack an understanding of how climate warming will affect microbial communities. Three ongoing field studies at the Harvard Forest Long-term Ecological Research (LTER) site (Petersham, MA) have warmed soils 5°C above ambient temperatures for 5, 8, and 20 years. We used this chronosequence to test the hypothesis that soil microbial communities have changed in response to chronic warming. Bacterial community composition was studied using Illumina sequencing of the 16S ribosomal RNA gene, and bacterial and fungal abundance were assessed using quantitative PCR. Only the 20-year warmed site exhibited significant change in bacterial community structure in the organic soil horizon, with no significant changes in the mineral soil. The dominant taxa, abundant at 0.1% or greater, represented 0.3% of the richness but nearly 50% of the observations (sequences). Individual members of the Actinobacteria, Alphaproteobacteria and Acidobacteria showed strong warming responses, with one Actinomycete decreasing from 4.5 to 1% relative abundance with warming. Ribosomal RNA copy number can obfuscate community profiles, but is also correlated with maximum growth rate or trophic strategy among bacteria. Ribosomal RNA copy number correction did not affect community profiles, but rRNA copy number was significantly decreased in warming plots compared to controls. Increased bacterial evenness, shifting beta diversity, decreased fungal abundance and increased abundance of bacteria with low rRNA operon copy number, including Alphaproteobacteria and Acidobacteria, together suggest that more or alternative niche space is being created over the course of long-term warming. PMID:25762989

  1. Long-term forest soil warming alters microbial communities in temperate forest soils.

    PubMed

    DeAngelis, Kristen M; Pold, Grace; Topçuoğlu, Begüm D; van Diepen, Linda T A; Varney, Rebecca M; Blanchard, Jeffrey L; Melillo, Jerry; Frey, Serita D

    2015-01-01

    Soil microbes are major drivers of soil carbon cycling, yet we lack an understanding of how climate warming will affect microbial communities. Three ongoing field studies at the Harvard Forest Long-term Ecological Research (LTER) site (Petersham, MA) have warmed soils 5°C above ambient temperatures for 5, 8, and 20 years. We used this chronosequence to test the hypothesis that soil microbial communities have changed in response to chronic warming. Bacterial community composition was studied using Illumina sequencing of the 16S ribosomal RNA gene, and bacterial and fungal abundance were assessed using quantitative PCR. Only the 20-year warmed site exhibited significant change in bacterial community structure in the organic soil horizon, with no significant changes in the mineral soil. The dominant taxa, abundant at 0.1% or greater, represented 0.3% of the richness but nearly 50% of the observations (sequences). Individual members of the Actinobacteria, Alphaproteobacteria and Acidobacteria showed strong warming responses, with one Actinomycete decreasing from 4.5 to 1% relative abundance with warming. Ribosomal RNA copy number can obfuscate community profiles, but is also correlated with maximum growth rate or trophic strategy among bacteria. Ribosomal RNA copy number correction did not affect community profiles, but rRNA copy number was significantly decreased in warming plots compared to controls. Increased bacterial evenness, shifting beta diversity, decreased fungal abundance and increased abundance of bacteria with low rRNA operon copy number, including Alphaproteobacteria and Acidobacteria, together suggest that more or alternative niche space is being created over the course of long-term warming.

  2. Soil phosphorus and the ecology of lowland tropical forests

    NASA Astrophysics Data System (ADS)

    Turner, Ben

    2016-04-01

    In this presentation I will explore the extent to which phosphorus influences the productivity, diversity, and distribution of plant species in tropical forests. I will highlight the range of soils that occur in tropical forests and will argue that pedogenesis and associated phosphorus depletion is a primary driver of forest diversity over long timescales. I will draw on data from a regional-scale network of forest dynamics plots in Panama to show that tree species distributions are determined predominantly as a function of dry season intensity and soil phosphorus availability, and will suggest potential mechanistic explanations for this pattern in relation to phosphorus acquisition. Finally, I will present observational and experimental evidence from Panama to show how phosphorus, nitrogen, and potassium, limit plant productivity and microbial communities on strongly-weathered soils in the lowland tropics.

  3. Effects of soil water repellency on microbial community structure and functions in Mediterranean pine forests

    NASA Astrophysics Data System (ADS)

    Lozano, Elena; Grayston, Sue J.; Mataix-Solera, Jorge; Arcenegui, Victoria; Jimenez-Pinilla, Patricia; Mataix-Beneyto, Jorge

    2015-04-01

    Soil water repellency (SWR) is a property commonly observed in forest areas showing wettable and water repellent patches with high spatial variability. SWR can greatly influence the hydrology and the ecology of forest soils. The capacity of soil microorganisms to degrade different organic compounds depends upon species composition, so this may affect changes in SWR on the microsite scale (such as the presence of soil water repellent patches; Mülleret al., 2010). In the Mediterranean forest context, SWR has been found to be related to microbial community composition. The accumulation of different hydrophobic compounds might be causing the shifts in microbial community structure (Lozano et al., 2014). In this study we investigated the effects of SWR persistence on soil microbial community structure and enzyme activity under Pinus halepensis forest in three different sites: Petrer, Gorga and Jávea (Alicante, E Spain). Soil samples were classified into three different water repellency classes (wettable, slight or strongly water repellent samples) depending on the SWR persistence. The soil microbial community was determined through phospholipid fatty acids (PLFAs). Enzyme activities chosen for this study were cellulase, β-glucosidase and N-acetyl-β-glucosaminide (NAG). The relationships between microbiological community structure and some soil properties such as pH, Glomalin Related Soil Protein, soil organic matter content and soil respiration were also studied. Redundancy analyses and decomposition of the variances were performed to clarify how microbial community composition and enzyme activities are affected by SWR and soil properties. The effect of SWR on microbial community composition differed between locations. This effect was clearer in the Petrer site. Enzyme activity varied considerably depending on SWR persistence. The highest activities were found in slightly SWR samples and the lowest mostly in the strongly water repellent ones. These preliminary

  4. [Soil microbial community structure of two types of forests in the mid-subtropics of China].

    PubMed

    Han, Shi-zhong; Gao, Ren; Li, Ai-ping; Ma, Hong-liang; Yin, Yun-feng; Si, You-tao; Chen, Shi-dong; Zheng, Qun-rui

    2015-07-01

    Soil microbial community structures were analyzed by biomarker method of phospholipid fatty acid (PLFA) for a natural forest dominated by Castanopsis fabri (CF) and an adjacent plantation of Cunninghamia lanceolata (CL) in the mid-subtropics of China. The results showed that the amounts of total PLFAs, bacterial PLFAs, fungal PLFAs, gram-positive bacterial PLFAs and gramnegative bacterial PLFAs in the 0-10 cm soil layer were higher than in the 10-20 cm soil layer, and each type of PLFAs in CF were higher than in CL. In either soil layer of the two forest types, the contents of bacterial PLFAs were significantly higher than those of fungal PLFAs. In the two forests, the contents of bacterial PLFAs accounted for 44%-52% of total PLFAs, while the contents of fungal PLFAs just accounted for 6%-8%, indicating the bacteria were dominant in the soils of the two vegetation types. Principal component analysis showed that the influence of vegetation types was greater than soil depth on the microbial community structures. Correlation analysis showed that gram-negative bacterial PLFAs, gram-positive bacterial PLFAs and bacterial PLFAs were significantly negatively correlated with pH, positively with water content, and the PLFAs of main soil microorganism groups were significantly positively correlated with soil total nitrogen, organic carbon, C/N and ammonium.

  5. Characterization of soil microarthropod communities in Italian beech forest

    NASA Astrophysics Data System (ADS)

    Conti, F. D.; Menta, C.; Piovesan, G.

    2009-04-01

    The contribution of soil organisms to ecosystem functions such as decomposition, nutrient recycling and the maintenance of physico-chemical properties is well recognised, as is the fact that soil fauna plays an important role in the formation and stabilisation of soil structure. The diversity of soil fauna includes a quarter of described living species, the majority of which are insects and arachnids. Soil fauna plays an essential role in forests and agro-ecosystems by maintaining their functionality and productivity. The aim of this study is to evaluate the biodiversity of soil microarthropods communities in different Italian beech forest. Particular attention is paid to the role of fossorial microarthropods in the maintenance of soil structure and in the organic matter movements. Three beech forests are studied, two located in the North and one in the Centre of Italy. Microarthropods are extracted from litter and soil with a Berlese-Tullgren funnel, identified to order level (class level for myriapods) and counted using a microscope. Relative order abundance and biodiversity are expressed using the Shannon-Weaver diversity index (H) and evenness index (J). Soil biological quality is expressed using the QBS-ar index and Acari/Collembola ratio. The results show a richness of microarthropods: several orders, till 19 different groups, are determined and identified. Acari and collembola are the main represented taxa and, especially in litter samples, pseudoscorpions, different specimens of diplopods (or millipedes) and chilopods (centipedes) are found. Thus the presence in particular of diplopods offers the possibility of studying fossorial microarthropods functions in detail. Furthermore, both in soil and in litter samples, adapted groups are recognized, such as pauropods, symphyla, proturans and diplurans, with specific morphological characteristics that these species suited to soil habitat. Therefore they attest a good level of soil quality and high natural value

  6. Soil warming affects soil organic matter chemistry of all density fractions of a mountain forest soil

    NASA Astrophysics Data System (ADS)

    Schnecker, Jörg; Wanek, Wolfgang; Borken, Werner; Schindlbacher, Andreas

    2016-04-01

    Rising temperatures enhance microbial decomposition of soil organic matter (SOM) and increase thereby the soil CO2 efflux. Elevated microbial activity might differently affect distinct SOM pools, depending on their stability and accessibility. Soil fractions derived from density fractionation have been suggested to represent SOM pools with different turnover times and stability against microbial decomposition. We here investigated the chemical and isotopic composition of bulk soil and three different density fractions of forest soils from a long term warming experiment in the Austrian Alps. At the time of sampling the soils in this experiment had been warmed during the snow-free period for 8 consecutive years. During that time no thermal adaptation of the microbial community could be identified and CO2 release from the soil continued to be elevated by the warming treatment. Our results which included organic C content, total N content, δ13C, δ 14C, δ 15N and the chemical composition, identified by pyrolysis-GC/MS, showed no significant differences in bulk soil between warming treatment and control. The differences in the three individual fractions (free particulate organic matter, occluded particulate organic matter and mineral associated organic matter) were mostly small and the direction of warming induced change was variable with fraction and sampling depth. We did however find statistically significant effects of warming in all density fractions from 0-10 cm depth, 10-20 cm depth or both. Our results also including significant changes in the supposedly more stable mineral associated organic matter fraction where δ 13C values decreased at both sampling depths and the relative proportion of N-bearing compounds decreased at a sampling depth of 10-20 cm. All the observed changes can be attributed to an interplay of enhanced microbial decomposition of SOM and increased root litter input. This study suggests that soil warming destabilizes all density fractions of

  7. Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Quideau, S. A.; Swallow, M. J. B.; Prescott, C. E.; Grayston, S. J.; Oh, S.-W.

    2013-04-01

    Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability, and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.

  8. Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Quideau, S. A.; Swallow, M. J. B.; Prescott, C. E.; Grayston, S. J.; Oh, S.-W.

    2013-08-01

    Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems, covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of Northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.

  9. Soil warming, carbon–nitrogen interactions, and forest carbon budgets

    PubMed Central

    Melillo, Jerry M.; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

    2011-01-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon–nitrogen interactions in atmosphere–ocean–land earth system models to accurately simulate land feedbacks to the climate system. PMID:21606374

  10. Soil warming, carbon-nitrogen interactions, and forest carbon budgets.

    PubMed

    Melillo, Jerry M; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

    2011-06-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon-nitrogen interactions in atmosphere-ocean-land earth system models to accurately simulate land feedbacks to the climate system.

  11. Exchangeable Cations in the Soils of Quercus Dominated Forests in Northeastern Austria

    NASA Astrophysics Data System (ADS)

    Yan, Shuai; Bruckman, Viktor J.; Glatzel, Gerhard

    2010-05-01

    In northeastern Austria there is a growing interest in increased utilisation of forest biomass for energy. This study focuses on soil properties and nutrient pool characteristics in deciduous forests in order to provide advice for forest management. We (i) quantified selected exchangeable cations in the soils of our study area and (ii) identified the effects of stand age, soil type, soil depth and soil pH on exchangeable cations and cation exchange capacity (CEC). Nine permanent Quercus petraea dominated plots on sandy, clayey cambisols and calcic chernozem were selected for our study. From each plot 18 soil samples were collected in a systematic grid by means of a soil corer with 70 mm diameter to a maximum depth of 60 cm. Soil pH, exchangeable mineral elements K, Ca, Mg, Na, Mn, Al, and Fe were determined in five geometric soil horizons. Statistical analysis showed that (i) forest age did not influence the exchangeable K content of the sandy soils; (ii) the exchangeable K content decreased with increasing stand age in clayey cambisols; (iii) exchangeable K, Na and Mg were higher in calcic chernozems and clayey cambisols (iv) exchangeable Fe was significantly higher in sandy forest soils except in the 60-80 years old stand; (v) exchangeable Fe was below detection limit in calcic chernozem soils. A comparison of exchangeable cations revealed that (i) Ca is the key element of base cations (ii) the content of base cations is strongly significantly higher in calcic chernozem soils (iii) calcic chernozem soils have the highest CEC. CEC ranged from 38 to 190 μmol/g in the entire research area. Base cations, acid cations and CEC differ with soil depth as followed (i) in sandy and clayey cambisols, CEC had a minimum in 20 cm depth and then increased with soil depth to 50 cm; (ii) CEC decreased steadily with soil depth in calcic chernozems. As expected, CEC is significantly positively correlated (Pearson correlation coefficient 0.661, P<0.01) with the pH of the soil. The

  12. Relationship between basal soil respiration rate, tree stand and soil characteristics in boreal forests.

    PubMed

    Vanhala, P; Tamminen, P; Fritze, H

    2005-02-01

    Soil respiration is considered to represent the overall microbial activity reflecting mineralisation of organic matter in soil. It is the most commonly used biological variable in soil studies. In long-term monitoring of forested areas, there is a need for reference values for soil microbiological variables in different forest ecosystems. In this study we describe the relationship between soil respiration rate, tree stand and humus chemical characteristics of boreal coniferous forests stands. Soil respiration rate was higher in pine dominated than in spruce dominated study sites when the result was calculated on dry matter bases. However, when calculated on area bases, the result was opposite and no difference was found when the soil respiration rate was calculated on organic carbon bases. Irrespective of the main tree species, the soil respiration rate was equal in different development classes but not equal in soil fertility classes, i.e. within forest site types based on differences in ground vegetation. Respiration rates were clearly higher in mesic sites when calculated on dry matter, C(org) or area bases. However, soil respiration rate did not correlate with soil chemical variables indicating site fertility. Soil respiration rate on dry matter basis was at a lower level in the south and on more fertile sites, and on the other hand at a higher level in older stands and on sites with a thicker organic layer. PMID:15736877

  13. Interactive effects of litter quality and soil mineralogy on temperate forest soil carbon response to temperature

    NASA Astrophysics Data System (ADS)

    Rasmussen, C.; Horwath, W.; Southard, R.

    2007-12-01

    Temperate forest soil organic carbon (C) represents a significant pool of terrestrial C that may be released to the atmosphere as CO2 with predicted climate change. To address feedbacks between climate change and terrestrial C turnover, we quantified forest soil C response to litter quality and temperature change as a function of soil parent material. We collected soils from three conifer forest-types dominated by ponderosa pine (PP), white fir (WF), and red fir (RF) from each of three parent materials, granite (GR), basalt (BS), and andesite (AN) in the Sierra Nevada of California. AN soils were dominated by short-range-order (SRO) minerals, GR soils by crystalline minerals, and BS soils by a mix of crystalline and SRO minerals. Field soils were incubated in the laboratory at their mean annual soil temperature (MAST), with addition of native 13C-labeled litter. Further, we incubated WF and RF soils at PP MAST with 13C-labeled PP litter; and RF soils at WF MAST with 13C-labeled WF litter to simulate a migration of MAST and vegetation type up-elevation in response to predicted climate warming. Results indicated that total CO2 and percent of CO2 derived from soil C varied significantly across forest-types, following the pattern of GR>BS>AN. Regression analyses indicated significant control of C mineralization and soil C priming by litter quality and SRO minerals. Addition of litter derived water-soluble compounds enabled priming of recalcitrant soil C in soils with high SRO mineral content, whereas water-soluble litter components did little to promote priming of extant soil C in soils of low SRO mineral content. Results further indicated a 10-300% increase in WF and RF forest-type soil C mineralization under climate change conditions that varied substantially between parent materials. Soils derived from andesite exhibited minimal change; whereas granite and basalt derived soils lost large amounts of soil C under climate change conditions. This study corroborates the

  14. Root and arbuscular mycorrhizal mycelial interactions with soil microorganisms in lowland tropical forest.

    PubMed

    Nottingham, Andrew T; Turner, Benjamin L; Winter, Klaus; Chamberlain, Paul M; Stott, Andrew; Tanner, Edmund V J

    2013-07-01

    Tropical forests have high rates of soil carbon cycling, but little information is available on how roots, arbuscular mycorrhizal fungi (AMF), and free-living microorganisms interact and influence organic matter mineralization in these ecosystems. We used mesh ingrowth cores and isotopic tracers in phospholipid fatty acid biomarkers to investigate the effects of roots and AMF mycelia on (1) microbial community composition, microbial carbon utilization, and hydrolytic enzyme activities for large, potted tropical trees and (2) enzyme activities and litter mass loss in a lowland tropical forest. Under the tropical tree, plant-derived carbon was incorporated predominantly into bacterial groups in both rhizosphere and AMF-only soils. Gram-positive bacteria incorporated additional soil-derived carbon in rhizosphere soils, which also contained the highest microbial biomass. For hydrolytic enzymes, β-glucosidase and N-acetyl β-glucosaminidase activities were highest in rhizosphere soils, while phosphomonoesterase activity was highest in AMF-only soil. In the forest, leaf litter mass loss was increased by the presence of roots, but not by the presence of AMF mycelia only. Root-microbial interactions influenced organic matter cycling, with evidence for rhizosphere priming and accelerated leaf litter decomposition in the presence of roots. Although AMF mycelia alone did not stimulate organic matter mineralization, they were a conduit of carbon to other soil microorganisms. PMID:23406337

  15. Experimental warming effects on the microbial community of a temperate mountain forest soil.

    PubMed

    Schindlbacher, A; Rodler, A; Kuffner, M; Kitzler, B; Sessitsch, A; Zechmeister-Boltenstern, S

    2011-07-01

    Soil microbial communities mediate the decomposition of soil organic matter (SOM). The amount of carbon (C) that is respired leaves the soil as CO(2) (soil respiration) and causes one of the greatest fluxes in the global carbon cycle. How soil microbial communities will respond to global warming, however, is not well understood. To elucidate the effect of warming on the microbial community we analyzed soil from the soil warming experiment Achenkirch, Austria. Soil of a mature spruce forest was warmed by 4 °C during snow-free seasons since 2004. Repeated soil sampling from control and warmed plots took place from 2008 until 2010. We monitored microbial biomass C and nitrogen (N). Microbial community composition was assessed by phospholipid fatty acid analysis (PLFA) and by quantitative real time polymerase chain reaction (qPCR) of ribosomal RNA genes. Microbial metabolic activity was estimated by soil respiration to biomass ratios and RNA to DNA ratios. Soil warming did not affect microbial biomass, nor did warming affect the abundances of most microbial groups. Warming significantly enhanced microbial metabolic activity in terms of soil respiration per amount of microbial biomass C. Microbial stress biomarkers were elevated in warmed plots. In summary, the 4 °C increase in soil temperature during the snow-free season had no influence on microbial community composition and biomass but strongly increased microbial metabolic activity and hence reduced carbon use efficiency.

  16. Soil organic matter regulates molybdenum storage and mobility in forests

    USGS Publications Warehouse

    Marks, Jade A; Perakis, Steven; King, Elizabeth K; Pett-Ridge, Julie

    2015-01-01

    The trace element molybdenum (Mo) is essential to a suite of nitrogen (N) cycling processes in ecosystems, but there is limited information on its distribution within soils and relationship to plant and bedrock pools. We examined soil, bedrock, and plant Mo variation across 24 forests spanning wide soil pH gradients on both basaltic and sedimentary lithologies in the Oregon Coast Range. We found that the oxidizable organic fraction of surface mineral soil accounted for an average of 33 %of bulk soil Mo across all sites, followed by 1.4 % associated with reducible Fe, Al, and Mn-oxides, and 1.4 % in exchangeable ion form. Exchangeable Mo was greatest at low pH, and its positive correlation with soil carbon (C) suggests organic matter as the source of readily exchangeable Mo. Molybdenum accumulation integrated over soil profiles to 1 m depth (τMoNb) increased with soil C, indicating that soil organic matter regulates long-term Mo retention and loss from soil. Foliar Mo concentrations displayed no relationship with bulk soil Mo, and were not correlated with organic horizon Mo or soil extractable Mo, suggesting active plant regulation of Mo uptake and/or poor fidelity of extractable pools to bioavailability. We estimate from precipitation sampling that atmospheric deposition supplies, on average, over 10 times more Mo annually than does litterfall to soil. In contrast, bedrock lithology had negligible effects on foliar and soil Mo concentrations and on Mo distribution among soil fractions. We conclude that atmospheric inputs may be a significant source of Mo to forest ecosystems, and that strong Mo retention by soil organic matter limits ecosystem Mo loss via dissolution and leaching pathways.

  17. A new mechanism for calcium loss in forest-floor soils

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.; Shortle, W.C.

    1995-01-01

    CALCIUM is the fifth most abundant element in trees, and is an essential component for wood formation and the maintenance of cell walls. Depletion of Ca from the rooting zone can result in acidification of soil1 and surface water2 and possibly growth decline and dieback of red spruce3,4. During the past six decades, concentrations of root-available Ca (exchangeable and acid-ex tract able forms) in forest-floor soils have decreased in the northeastern United States5,6. Both net forest growth and acid deposition have been put forth as mechanisms that can account for this Ca depletion5,6. Here, however, we present data collected in red spruce forests in the northeastern United States that are inconsistent with either of these mechanisms. We propose that aluminium, mobilized in the mineral soil by acid deposition, is transported into the forest floor in a reactive form that reduces storage of Ca, and thus its availability for root uptake. This results in potential stress to trees and, by increasing the demand for Ca, also decreases neutralization of drainage waters, thereby leading to acidification of lakes and streams.

  18. Soils of pine-birch forests on high Pleistocene terraces in the Selenga delta region

    NASA Astrophysics Data System (ADS)

    Gyninova, A. B.; Tursina, T. V.; Balsanova, L. D.; Gyninova, B. D.; Inozemtsev, S. A.

    2010-06-01

    The soils of pine-birch forests on Pleistocene lake-river terraces in the Selenga delta region were studied. These soils are characterized by their weak differentiation into genetic horizons, pale or light brown color, and the weak structure of their mineral horizons. The high base saturation, weakly acid or close to neutral reaction, and homogeneous bulk chemical composition evidence the absence of the eluvial-illuvial differentiation of the soil profiles. The humus is of the fulvate-humate type. Among the humic acids, the brown acids predominate; the content of black humic acids is slightly lower and that of the nonhydrolyzable residue is elevated. In the mineral horizons, the clay and iron-clay autochthonous formations on the primary mineral grains point to the weakly pronounced process of metamorphism. In the Bm horizon, the formation of crystallized iron compounds in the form of films and fine iron segregations is observed.

  19. [Soil microbial biomass in Larix gmelinii forests along a latitudinal gradient during spring soil thawing].

    PubMed

    Ding, Shuang; Wang, Chuan-kuan

    2009-09-01

    The 8-year-old Larix gmelinii forests were transplanted from four sites (Tahe, Songling, Sunwu, and Dailing) comprising a latitudinal gradient across the distribution range of L. gmelinii in Northeastern China, and the soil microbial biomass carbon (Cmic) and nitrogen (Nmic) in spring soil thawing period were measured after 3-year transplanting. Under the similar soil substrates and the same climate conditions, the mean values of soil Cmic and Nmic in the L. gmelinii forests transplanted from the four sites differed significantly, being decreased with increasing latitude and soil depth. The Cmic for Tahe, Songling, Sunwu, and Dailing averaged 554.63, 826.41, 874.81, and 1246.18 mg x kg(-1), and the Nmic averaged 70.63, 96.78, 79.76, and 119.66 mg x kg(-1), respectively. The Cmic and Nmic peaked before soil thawing, declined rapidly at the early stage of soil thawing, and had less change and maintained at a lower level during the period of soil freezing-thawing. By the end of soil thawing, the Cmic for lower latitudinal soils (i.e., Dailing and Sunwu) recovered faster. Soil temperature and moisture content during spring soil thawing affected the temporal patterns of Cmic and Nmic significantly, but the affecting degree depended on the stages of soil thawing. The Cmic and Nmic were negatively correlated to the soil temperature at the early stage of soil thawing, and exponentially related to the soil moisture content during the whole soil thawing period.

  20. Forest Management Type Influences Diversity and Community Composition of Soil Fungi across Temperate Forest Ecosystems

    PubMed Central

    Goldmann, Kezia; Schöning, Ingo; Buscot, François; Wubet, Tesfaye

    2015-01-01

    Fungal communities have been shown to be highly sensitive toward shifts in plant diversity and species composition in forest ecosystems. However, little is known about the impact of forest management on fungal diversity and community composition of geographically separated sites. This study examined the effects of four different forest management types on soil fungal communities. These forest management types include age class forests of young managed beech (Fagus sylvatica L.), with beech stands age of approximately 30 years, age class beech stands with an age of approximately 70 years, unmanaged beech stands, and coniferous stands dominated by either pine (Pinus sylvestris L.) or spruce (Picea abies Karst.) which are located in three study sites across Germany. Soil were sampled from 48 study plots and we employed fungal ITS rDNA pyrotag sequencing to assess the soil fungal diversity and community structure. We found that forest management type significantly affects the Shannon diversity of soil fungi and a significant interaction effect of study site and forest management on the fungal operational taxonomic units richness. Consequently distinct fungal communities were detected in the three study sites and within the four forest management types, which were mainly related to the main tree species. Further analysis of the contribution of soil properties revealed that C/N ratio being the most important factor in all the three study sites whereas soil pH was significantly related to the fungal community in two study sites. Functional assignment of the fungal communities indicated that 38% of the observed communities were Ectomycorrhizal fungi (ECM) and their distribution is significantly influenced by the forest management. Soil pH and C/N ratio were found to be the main drivers of the ECM fungal community composition. Additional fungal community similarity analysis revealed the presence of study site and management type specific ECM genera. This study extends our

  1. Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

    PubMed

    Chen, Jing; Li, Wei; Gao, Fang

    2010-10-01

    The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development.

  2. Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

    PubMed

    Chen, Jing; Li, Wei; Gao, Fang

    2010-10-01

    The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development. PMID:20859590

  3. pH as a Driver for Ammonia-Oxidizing Archaea in Forest Soils.

    PubMed

    Stempfhuber, Barbara; Engel, Marion; Fischer, Doreen; Neskovic-Prit, Ganna; Wubet, Tesfaye; Schöning, Ingo; Gubry-Rangin, Cécile; Kublik, Susanne; Schloter-Hai, Brigitte; Rattei, Thomas; Welzl, Gerhard; Nicol, Graeme W; Schrumpf, Marion; Buscot, Francois; Prosser, James I; Schloter, Michael

    2015-05-01

    In this study, we investigated the impact of soil pH on the diversity and abundance of archaeal ammonia oxidizers in 27 different forest soils across Germany. DNA was extracted from topsoil samples, the amoA gene, encoding ammonia monooxygenase, was amplified; and the amplicons were sequenced using a 454-based pyrosequencing approach. As expected, the ratio of archaeal (AOA) to bacterial (AOB) ammonia oxidizers' amoA genes increased sharply with decreasing soil pH. The diversity of AOA differed significantly between sites with ultra-acidic soil pH (<3.5) and sites with higher pH values. The major OTUs from soil samples with low pH could be detected at each site with a soil pH <3.5 but not at sites with pH >4.5, regardless of geographic position and vegetation. These OTUs could be related to the Nitrosotalea group 1.1 and the Nitrososphaera subcluster 7.2, respectively, and showed significant similarities to OTUs described from other acidic environments. Conversely, none of the major OTUs typical of sites with a soil pH >4.6 could be found in the ultra- and extreme acidic soils. Based on a comparison with the amoA gene sequence data from a previous study performed on agricultural soils, we could clearly show that the development of AOA communities in soils with ultra-acidic pH (<3.5) is mainly triggered by soil pH and is not influenced significantly by the type of land use, the soil type, or the geographic position of the site, which was observed for sites with acido-neutral soil pH.

  4. Gaseous mercury fluxes from forest soils in response to forest harvesting intensity: a field manipulation experiment.

    PubMed

    Mazur, M; Mitchell, C P J; Eckley, C S; Eggert, S L; Kolka, R K; Sebestyen, S D; Swain, E B

    2014-10-15

    Forest harvesting leads to changes in soil moisture, temperature and incident solar radiation, all strong environmental drivers of soil-air mercury (Hg) fluxes. Whether different forest harvesting practices significantly alter Hg fluxes from forest soils is unknown. We conducted a field-scale experiment in a northern Minnesota deciduous forest wherein gaseous Hg emissions from the forest floor were monitored after two forest harvesting prescriptions, a traditional clear-cut and a clearcut followed by biomass harvest, and compared to an un-harvested reference plot. Gaseous Hg emissions were measured in quadruplicate at four different times between March and November 2012 using Teflon dynamic flux chambers. We also applied enriched Hg isotope tracers and separately monitored their emission in triplicate at the same times as ambient measurements. Clearcut followed by biomass harvesting increased ambient Hg emissions the most. While significant intra-site spatial variability was observed, Hg emissions from the biomass harvested plot (180 ± 170 ng m(-2)d(-1)) were significantly greater than both the traditional clearcut plot (-40 ± 60 ng m(-2)d(-1)) and the un-harvested reference plot (-180 ± 115 ng m(-2)d(-1)) during July. This difference was likely a result of enhanced Hg(2+) photoreduction due to canopy removal and less shading from downed woody debris in the biomass harvested plot. Gaseous Hg emissions from more recently deposited Hg, as presumably representative of isotope tracer measurements, were not significantly influenced by harvesting. Most of the Hg tracer applied to the forest floor became sequestered within the ground vegetation and debris, leaf litter, and soil. We observed a dramatic lessening of tracer Hg emissions to near detection levels within 6 months. As post-clearcutting residues are increasingly used as a fuel or fiber resource, our observations suggest that gaseous Hg emissions from forest soils will increase, although it is not yet clear for

  5. Gaseous mercury fluxes from forest soils in response to forest harvesting intensity: a field manipulation experiment.

    PubMed

    Mazur, M; Mitchell, C P J; Eckley, C S; Eggert, S L; Kolka, R K; Sebestyen, S D; Swain, E B

    2014-10-15

    Forest harvesting leads to changes in soil moisture, temperature and incident solar radiation, all strong environmental drivers of soil-air mercury (Hg) fluxes. Whether different forest harvesting practices significantly alter Hg fluxes from forest soils is unknown. We conducted a field-scale experiment in a northern Minnesota deciduous forest wherein gaseous Hg emissions from the forest floor were monitored after two forest harvesting prescriptions, a traditional clear-cut and a clearcut followed by biomass harvest, and compared to an un-harvested reference plot. Gaseous Hg emissions were measured in quadruplicate at four different times between March and November 2012 using Teflon dynamic flux chambers. We also applied enriched Hg isotope tracers and separately monitored their emission in triplicate at the same times as ambient measurements. Clearcut followed by biomass harvesting increased ambient Hg emissions the most. While significant intra-site spatial variability was observed, Hg emissions from the biomass harvested plot (180 ± 170 ng m(-2)d(-1)) were significantly greater than both the traditional clearcut plot (-40 ± 60 ng m(-2)d(-1)) and the un-harvested reference plot (-180 ± 115 ng m(-2)d(-1)) during July. This difference was likely a result of enhanced Hg(2+) photoreduction due to canopy removal and less shading from downed woody debris in the biomass harvested plot. Gaseous Hg emissions from more recently deposited Hg, as presumably representative of isotope tracer measurements, were not significantly influenced by harvesting. Most of the Hg tracer applied to the forest floor became sequestered within the ground vegetation and debris, leaf litter, and soil. We observed a dramatic lessening of tracer Hg emissions to near detection levels within 6 months. As post-clearcutting residues are increasingly used as a fuel or fiber resource, our observations suggest that gaseous Hg emissions from forest soils will increase, although it is not yet clear for

  6. Soil Respiration of Three Mangrove Forests on Sanibel Island, Florida

    NASA Astrophysics Data System (ADS)

    Cartwright, F.; Bovard, B. D.

    2011-12-01

    Carbon cycling studies conducted in mangrove forests have typically focused on aboveground processes. Our understanding of carbon storage in these systems is therefore limited by the lack information on belowground processes such as fine root production and soil respiration. To our knowledge there exist no studies investigating temporal patterns in and environmental controls on soil respiration in multiple types of mangrove ecosystems concurrently. This study is part of a larger study on carbon storage in three mangrove forests on Sanibel Island, Florida. Here we report on eight months of soil respiration data within these forests that will ultimately be incorporated into an annual carbon budget for each habitat type. Soil respiration was monitored in the following three mangrove habitat types: a fringe mangrove forest dominated by Rhizophora mangle, a basin mangrove forest dominated by Avicennia germinans, and a higher elevation forest comprised of a mix of Avicennia germinans and Laguncularia racemosa, and non-woody salt marsh species. Beginning in June of 2010, we measured soil emissions of carbon dioxide at 5 random locations within three-100 m2 plots within each habitat type. Sampling was performed at monthly intervals and conducted over the course of three days. For each day, one plot from each habitat type was measured. In addition to soil respiration, soil temperature, salinity and gravimetric moisture content were also measured. Our data indicate the Black mangrove forest, dominated by Avicennia germinans, experiences the highest rates of soil respiration with a mean rate of 4.61 ± 0.60 μmol CO2 m-2 s-1. The mixed mangrove and salt marsh habitat has the lowest soil carbon emission rates with a mean of 2.78 ± 0.40 μmol CO2 m-2 s-1. Soil carbon effluxes appear to peak in the early part of the wet season around May to June and are lower and relatively constant the remainder of the year. Our data also suggest there are important but brief periods where

  7. Relating microbial community structure to functioning in forest soil organic carbon transformation and turnover

    PubMed Central

    You, Yeming; Wang, Juan; Huang, Xueman; Tang, Zuoxin; Liu, Shirong; Sun, Osbert J

    2014-01-01

    Forest soils store vast amounts of terrestrial carbon, but we are still limited in mechanistic understanding on how soil organic carbon (SOC) stabilization or turnover is controlled by biotic and abiotic factors in forest ecosystems. We used phospholipid fatty acids (PLFAs) as biomarker to study soil microbial community structure and measured activities of five extracellular enzymes involved in the degradation of cellulose (i.e., β-1,4-glucosidase and cellobiohydrolase), chitin (i.e., β-1,4-N-acetylglucosaminidase), and lignin (i.e., phenol oxidase and peroxidase) as indicators of soil microbial functioning in carbon transformation or turnover across varying biotic and abiotic conditions in a typical temperate forest ecosystem in central China. Redundancy analysis (RDA) was performed to determine the interrelationship between individual PFLAs and biotic and abiotic site factors as well as the linkage between soil microbial structure and function. Path analysis was further conducted to examine the controls of site factors on soil microbial community structure and the regulatory pathway of changes in SOC relating to microbial community structure and function. We found that soil microbial community structure is strongly influenced by water, temperature, SOC, fine root mass, clay content, and C/N ratio in soils and that the relative abundance of Gram-negative bacteria, saprophytic fungi, and actinomycetes explained most of the variations in the specific activities of soil enzymes involved in SOC transformation or turnover. The abundance of soil bacterial communities is strongly linked with the extracellular enzymes involved in carbon transformation, whereas the abundance of saprophytic fungi is associated with activities of extracellular enzymes driving carbon oxidation. Findings in this study demonstrate the complex interactions and linkage among plant traits, microenvironment, and soil physiochemical properties in affecting SOC via microbial regulations. PMID

  8. [Effects of Different Altitudes on Soil Microbial PLFA and Enzyme Activity in Two Kinds of Forests].

    PubMed

    Zeng, Qing-ping; He, Bing-hui; Mao, Qiao-zhi; Wu, Yao-peng; Huang, Qi; Li, Yuan

    2015-12-01

    The soil microbial community is an important part in soil ecosystem, and it is sensitive to the ecological environment. Phospholipid-derived fatty acids ( PLFA ) analysis was used to examine variations in soil microbial community diversity and its influencing factors. The results showed that: there existed 48 PLFAs that were significant in the soil samples from six altitudes. The PLFAs of six altitudes with the highest contents were i16:0, 10Me17:0, 10Me18:0 TBSA. The citrus forest exhibited richer soil PLFAs distribution both in type and amount than those in masson pine. The microbial activity and functional diversity of masson pine were increased with increasing altitudes, and citrus forest gradually decreased, the PLFA content of different microbial groups in each altitude were significantly different. The richness index, Shannon-Wiener index and Pielou evenness index of masson pine in low elevation were holistically higher than those in high elevation. However, the highest richness index of citrus forest was in low altitude, the highest Shannon-Wiener index and Pielou evenness index were in high altitude. The PLFAs content of different microbial groups were closely correlated to the soil enzyme activities and environmental factors. The PLFAs of bacteria, actinomycetes, G⁻ (Gram- positive), G⁺ (Gram-negative) were positively correlated with Ure(urease) , Ive(invertase) , CAT( catalase activity) and forest type, the PLFAs of fungi was significantly correlated with Ure, Ive, CAT, the PLFAs of bacteria, fungi, actinomycetes, G⁻ , G⁺ were significantly negatively or less correlated with elevation. Ure, Ive, CAT, forest type and elevation are the pivotal factors controlling the soil microbial biomass and activities.

  9. [Effects of Different Altitudes on Soil Microbial PLFA and Enzyme Activity in Two Kinds of Forests].

    PubMed

    Zeng, Qing-ping; He, Bing-hui; Mao, Qiao-zhi; Wu, Yao-peng; Huang, Qi; Li, Yuan

    2015-12-01

    The soil microbial community is an important part in soil ecosystem, and it is sensitive to the ecological environment. Phospholipid-derived fatty acids ( PLFA ) analysis was used to examine variations in soil microbial community diversity and its influencing factors. The results showed that: there existed 48 PLFAs that were significant in the soil samples from six altitudes. The PLFAs of six altitudes with the highest contents were i16:0, 10Me17:0, 10Me18:0 TBSA. The citrus forest exhibited richer soil PLFAs distribution both in type and amount than those in masson pine. The microbial activity and functional diversity of masson pine were increased with increasing altitudes, and citrus forest gradually decreased, the PLFA content of different microbial groups in each altitude were significantly different. The richness index, Shannon-Wiener index and Pielou evenness index of masson pine in low elevation were holistically higher than those in high elevation. However, the highest richness index of citrus forest was in low altitude, the highest Shannon-Wiener index and Pielou evenness index were in high altitude. The PLFAs content of different microbial groups were closely correlated to the soil enzyme activities and environmental factors. The PLFAs of bacteria, actinomycetes, G⁻ (Gram- positive), G⁺ (Gram-negative) were positively correlated with Ure(urease) , Ive(invertase) , CAT( catalase activity) and forest type, the PLFAs of fungi was significantly correlated with Ure, Ive, CAT, the PLFAs of bacteria, fungi, actinomycetes, G⁻ , G⁺ were significantly negatively or less correlated with elevation. Ure, Ive, CAT, forest type and elevation are the pivotal factors controlling the soil microbial biomass and activities. PMID:27012007

  10. Soil humus composition - comparison between mountain grasslands and forest lands with different land-use intensity

    NASA Astrophysics Data System (ADS)

    Naydenova, Lora; Zhiyanski, Miglena; Leifeld, Jens; Filcheva, Ekaterina

    2015-04-01

    Soil humus is a dynamic characteristic greatly vulnerable to land use and climate and with important feedbacks to the atmospheric green house gas balance and the rate of climate change. The increased demand for accurate soil carbon stocks assessments and predictions of its changes as a result of land use/cover and climate change has triggered large-scale and long-term measurements of soil organic matter specifics. We studied the soil humus composition in four mountain grasslands, differentiated according to the land-use sub-type and land-use intensity and four forest lands. Two pastures - with intensive (Pi) and extensive grazing (Pe) and two meadows- managed (Mm) and unmanaged (Mu) were objects of present study. Two spruce plantations (Picea abies Karst), and two natural beech forests (Fagus sylvatica L.) - control, unmanaged for the both (Su and Bu) and with 10 % cutting intensity (Sc and Bc). Humus composition was analyzed following the methodology of Kononova-Belchikova. The aggressive and mobile fulvic acids predominated in all of the investigated plots, except Pe and Bu. Humic acids are "free" and bonded with R3O3 and no Ca-bonded humic acids were established under the grasslands, but in the soils under the two beech forest we observed Ca-bonded humic acids in small quantities. The values of total org. C and C-extracted by 0.1 N NaOH was similar in most of studied horizons. Our results showed that the highest total carbon content was localized in the organic-mineral soil horizon and decreased toward deeper soil. The highest total carbon content estimated at 14.04 % was determined in A-horizon of soil in pasture with extensive grazing, for the grasslands. The higher grazing disturbance in Pi leads to increase root biomass in patch areas and in inter-patch upper soil related with decrease of soil humus content. We supposed that the reduced amount of litter input with increased recalcitrance to decomposition provoked the reduction of organic carbon content and

  11. Windthrows increase soil carbon stocks in a central Amazon forest

    NASA Astrophysics Data System (ADS)

    dos Santos, Leandro T.; Magnabosco Marra, Daniel; Trumbore, Susan; de Camargo, Plínio B.; Negrón-Juárez, Robinson I.; Lima, Adriano J. N.; Ribeiro, Gabriel H. P. M.; dos Santos, Joaquim; Higuchi, Niro

    2016-03-01

    Windthrows change forest structure and species composition in central Amazon forests. However, the effects of widespread tree mortality associated with wind disturbances on soil properties have not yet been described in this vast region. We investigated short-term effects (7 years after disturbance) of widespread tree mortality caused by a squall line event from mid-January of 2005 on soil carbon stocks and concentrations in a central Amazon terra firme forest. The soil carbon stock (averaged over a 0-30 cm depth profile) in disturbed plots (61.4 ± 8.2 Mg ha-1, mean ±95 % confidence interval) was marginally higher (p = 0.09) than that from undisturbed plots (47.7 ± 13.6 Mg ha-1). The soil organic carbon concentration in disturbed plots (2.0 ± 0.17 %) was significantly higher (p < 0.001) than that from undisturbed plots (1.36 ± 0.24 %). Moreover, soil carbon stocks were positively correlated with soil clay content (r2 = 0.332, r = 0.575 and p = 0.019) and with tree mortality intensity (r2 = 0.257, r = 0.506 and p = 0.045). Our results indicate that large inputs of plant litter associated with large windthrow events cause a short-term increase in soil carbon content, and the degree of increase is related to soil clay content and tree mortality intensity. The higher carbon content and potentially higher nutrient availability in soils from areas recovering from windthrows may favor forest regrowth and increase vegetation resilience.

  12. Spatial variability of soils in a seasonally dry tropical forest

    NASA Astrophysics Data System (ADS)

    Pulla, Sandeep; Riotte, Jean; Suresh, Hebbalalu; Dattaraja, Handanakere; Sukumar, Raman

    2016-04-01

    Soil structures communities of plants and soil organisms in tropical forests. Understanding the controls of soil spatial variability can therefore potentially inform efforts towards forest restoration. We studied the relationship between soils and lithology, topography, vegetation and fire in a seasonally dry tropical forest in southern India. We extensively sampled soil (available nutrients, Al, pH, and moisture), rocks, relief, woody vegetation, and spatial variation in fire burn frequency in a permanent 50-ha plot. Lower elevation soils tended to be less moist and were depleted in several nutrients and clay. The availability of several nutrients was, in turn, linked to whole-rock chemical composition differences since some lithologies were associated with higher elevations, while the others tended to dominate lower elevations. We suggest that local-scale topography in this region has been shaped by the spatial distribution of lithologies, which differ in their susceptibility to weathering. Nitrogen availability was uncorrelated with the presence of trees belonging to Fabaceae, a family associated with N-fixing species. No effect of burning on soil parameters could be discerned at this scale.

  13. Mycorrhizal Response to Experimental pH and P Manipulation in Acidic Hardwood Forests

    PubMed Central

    Kluber, Laurel A.; Carrino-Kyker, Sarah R.; Coyle, Kaitlin P.; DeForest, Jared L.; Hewins, Charlotte R.; Shaw, Alanna N.; Smemo, Kurt A.; Burke, David J.

    2012-01-01

    Many temperate forests of the Northeastern United States and Europe have received significant anthropogenic acid and nitrogen (N) deposition over the last century. Although temperate hardwood forests are generally thought to be N-limited, anthropogenic deposition increases the possibility of phosphorus (P) limiting productivity in these forest ecosystems. Moreover, inorganic P availability is largely controlled by soil pH and biogeochemical theory suggests that forests with acidic soils (i.e., forest ecosystems overcome an underlying P limitation by accessing mineral and organic P sources that are otherwise unavailable for direct plant uptake. We examined arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) communities and soil microbial activity in an ecosystem-level experiment where soil pH and P availability were manipulated in mixed deciduous forests across eastern Ohio, USA. One year after treatment initiation, AM root biomass was positively correlated with the most available P pool, resin P, while AM colonization was negatively correlated. In total, 15,876 EcM root tips were identified and assigned to 26 genera and 219 operational taxonomic units (97% similarity). Ectomycorrhizal richness and root tip abundance were negatively correlated with the moderately available P pools, while the relative percent of tips colonized by Ascomycetes was positively correlated with soil pH. Canonical correspondence analysis revealed regional, but not treatment, differences in AM communities, while EcM communities had both treatment and regional differences. Our findings highlight the complex interactions between mycorrhizae and the soil environment and further underscore the fact that mycorrhizal communities do not merely

  14. Mycorrhizal response to experimental pH and P manipulation in acidic hardwood forests.

    PubMed

    Kluber, Laurel A; Carrino-Kyker, Sarah R; Coyle, Kaitlin P; DeForest, Jared L; Hewins, Charlotte R; Shaw, Alanna N; Smemo, Kurt A; Burke, David J

    2012-01-01

    Many temperate forests of the Northeastern United States and Europe have received significant anthropogenic acid and nitrogen (N) deposition over the last century. Although temperate hardwood forests are generally thought to be N-limited, anthropogenic deposition increases the possibility of phosphorus (P) limiting productivity in these forest ecosystems. Moreover, inorganic P availability is largely controlled by soil pH and biogeochemical theory suggests that forests with acidic soils (i.e., forest ecosystems overcome an underlying P limitation by accessing mineral and organic P sources that are otherwise unavailable for direct plant uptake. We examined arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) communities and soil microbial activity in an ecosystem-level experiment where soil pH and P availability were manipulated in mixed deciduous forests across eastern Ohio, USA. One year after treatment initiation, AM root biomass was positively correlated with the most available P pool, resin P, while AM colonization was negatively correlated. In total, 15,876 EcM root tips were identified and assigned to 26 genera and 219 operational taxonomic units (97% similarity). Ectomycorrhizal richness and root tip abundance were negatively correlated with the moderately available P pools, while the relative percent of tips colonized by Ascomycetes was positively correlated with soil pH. Canonical correspondence analysis revealed regional, but not treatment, differences in AM communities, while EcM communities had both treatment and regional differences. Our findings highlight the complex interactions between mycorrhizae and the soil environment and further underscore the fact that mycorrhizal communities do not merely

  15. Mycorrhizal response to experimental pH and P manipulation in acidic hardwood forests.

    PubMed

    Kluber, Laurel A; Carrino-Kyker, Sarah R; Coyle, Kaitlin P; DeForest, Jared L; Hewins, Charlotte R; Shaw, Alanna N; Smemo, Kurt A; Burke, David J

    2012-01-01

    Many temperate forests of the Northeastern United States and Europe have received significant anthropogenic acid and nitrogen (N) deposition over the last century. Although temperate hardwood forests are generally thought to be N-limited, anthropogenic deposition increases the possibility of phosphorus (P) limiting productivity in these forest ecosystems. Moreover, inorganic P availability is largely controlled by soil pH and biogeochemical theory suggests that forests with acidic soils (i.e., forest ecosystems overcome an underlying P limitation by accessing mineral and organic P sources that are otherwise unavailable for direct plant uptake. We examined arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) communities and soil microbial activity in an ecosystem-level experiment where soil pH and P availability were manipulated in mixed deciduous forests across eastern Ohio, USA. One year after treatment initiation, AM root biomass was positively correlated with the most available P pool, resin P, while AM colonization was negatively correlated. In total, 15,876 EcM root tips were identified and assigned to 26 genera and 219 operational taxonomic units (97% similarity). Ectomycorrhizal richness and root tip abundance were negatively correlated with the moderately available P pools, while the relative percent of tips colonized by Ascomycetes was positively correlated with soil pH. Canonical correspondence analysis revealed regional, but not treatment, differences in AM communities, while EcM communities had both treatment and regional differences. Our findings highlight the complex interactions between mycorrhizae and the soil environment and further underscore the fact that mycorrhizal communities do not merely

  16. Changing Boreal Fire Regimes: Impacts on Permafrost Soils and Forest Succession in Siberian Larch Forests

    NASA Astrophysics Data System (ADS)

    Alexander, H. D.; Mack, M. C.; Natali, S.; Loranty, M. M.; Davydov, S. P.; Zimov, N.

    2014-12-01

    Fire activity has increased across the boreal forest biome in conjuction with climate warming and drying. Because these forests contain a large proportion of global terrestrial carbon (C) stocks, there has been great interest in understanding feedbacks between a changing fire regime and climate warming. An important mechanism by which increased fire activity may alter boreal C balance is by consuming the soil organic layer (SOL). Fire removal of the SOL may alter germination microsites and tree recruitment, thereby altering forest successional trajectories and C accumulation and storage. In permafrost soils, loss of the insulating SOL can increase soil temperature and active layer depth, impacting growth and survival conditions for both soil microbes and vegetation. To assess fire severity effects on permafrost soils and tree recruitment, we conducted plot-level experimental burns in July 2012 in a larch forest near Cherskii, Siberia. We achieved four burn severity treatments based on residual SOL depths: control, low (> 8 cm), moderate (5-8 cm), and high severity (2-5 cm). For two growing seasons post-fire, we measured thaw depth, soil moisture, and soil temperature. We sowed larch seeds in fall 2012 and 2013 and quantified seedling establishment and vegetation re-growth for two growing seasons. Immediately post-fire, thaw depth increased rapidly with increasing fire severity, and this trend has persisted for two years. In 2013 and 2014, thaw depth was ~ 40 cm deeper in high severity plots compared to controls, likely due to lower summer soil insulation, higher black char cover, and higher surface soil temperatures. We observed little to no larch recruitment in unburned and low severity plots, but new seedling density was ~5 seedlings m-2 in moderate and high severity plots, which had low cover of other vegetation types and high soil moisture. Findings suggest that increased fire severity may increase larch recruitment and provide favorable soil conditions for

  17. Redistribution and Destabilization of Forest Soil Carbon by Earthworm Invasion

    NASA Astrophysics Data System (ADS)

    Swanston, C. W.; Torn, M. S.; Allen, L.; Lilleskov, E. A.; Maggi, F.

    2008-12-01

    Soils of temperate forests in the northern Great Lakes region have developed in the absence of earthworms, which were largely eradicated during the last ice age. European earthworms, such as Lumbricus terrestris, are spreading and their effect on forest soil C has not been widely studied. We examined soils along a chronosequence of worm activity (wormosequence) ranging from no apparent activity (Low) to high activity over several decades (High). In the soil profile, including organic horizons, there was only a small loss (4%) of C with high worm activity. There was a 71% decrease in the Oe and no remaining Oa in the High site. Conversely, the mineral soil contained 25% more C in the High site, with most of that in the top 20 cm. We densimetrically separated the mineral soil into primarily organic free light fraction (FLF) and occluded light fraction (OLF), a mineral-associated intermediate fraction (IF), and a mineral-associated dense fraction (DF). We measured fraction mass, C, nitrogen, and 14C content. In comparison to Low sites, each depth of High worm soil had less FLF C and more IF C. With worms, more C was stored in aggregates in the upper soil but less in the lower soil. The presence of worms had a very large effect on the 14C content of soil organic matter, with shifts of > 60 per mil in several fractions presumably due to a combination of vertical redistribution and more rapid transfer into and out of some fractions. For example, from the Low to High sites OLF 14C increased 100 per mil at 0-10 cm depth, while DF 14C decreased 80 per mil at 20-50 cm. The effect of worms on C cycling can be explored using a multi-pool, multi-depth model that treats 14C as a conservative (i.e., stable) tracer. Our results suggest that worms play a major role in redistributing soil C in these forest soils by pathways that differ with depth: the upper soil loses FLF C and incorporates organic horizon C into OLF and IF, whereas in the lower depths FLF is lost and the previously

  18. Land use, forest density, soil mapping, erosion, drainage, salinity limitations

    NASA Technical Reports Server (NTRS)

    Yassoglou, N. J. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The results of analyses show that it is possible to obtain information of practical significance as follows: (1) A quick and accurate estimate of the proper use of the valuable land can be made on the basis of temporal and spectral characteristics of the land features. (2) A rather accurate delineation of the major forest formations in the test areas was achieved on the basis of spatial and spectral characteristics of the studied areas. The forest stands were separated into two density classes; dense forest, and broken forest. On the basis of ERTS-1 data and the existing ground truth information a rather accurate mapping of the major vegetational forms of the mountain ranges can be made. (3) Major soil formations are mapable from ERTS-1 data: recent alluvial soils; soil on quarternary deposits; severely eroded soil and lithosol; and wet soils. (4) An estimation of cost benefits cannot be made accurately at this stage of the investigation. However, a rough estimate of the ratio of the cost for obtaining the same amount information from ERTS-1 data and from conventional operations would be approximately 1:6 to 1:10, in favor of the ERTS-1.

  19. The impact of vegetation on humus formation and morphology of brown forest soils in coastal areas of the southeastern part of Russian far east

    NASA Astrophysics Data System (ADS)

    Pshenichnikov, B. F.; Pshenichnikova, N. F.

    2015-04-01

    Specific features of brown forest soils (burozems, Cambisols) in coastal areas of the southeastern part of Russian Far East are discussed. It is shown that the color of the illuvial horizons in these soils depends on the character of vegetation; it is reddish brown under oak forests and dark gray under herb-shrub and post-pyrogenic communities. These soils combine the features shaped by the humus-accumulative and humus-illuvial processes. In the soils under oak forests, the humate-fulvate type of humus predominates; in the soils under herb-shrub and post-pyrogenic communities, the fulvate-humate humus is formed. The dynamics of humus and its separate fractions in the soil profiles control the morphochromatic differentiation of brown forest soils under different vegetation communities. In the soils under oak forests, the maximum precipitation of the aggressive fraction of fulvic acids (fraction FA-1a) in the illuvial-humus horizons coincides with the maximum concentration of oxalate-extractable iron oxides; these substances ensure the reddish brown color of the illuvial horizons in these soils. In the brown forest soils under herb-shrub and post-pyrogenic communities, the illuvial horizon is the zone of accumulation of not only the aggressive fraction of fulvic acids but also the second (Ca-bound) fractions of fulvic and humic acids ensuring the dark gray color of this horizon.

  20. Continuous Monitoring of Soil Respiration in Black Spruce Forest Soils, Interior Alaska

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Kim, S.; Kim, W.

    2009-12-01

    This research was carried out to estimate the continuous monitoring of soil respiration using automatic chamber system that was equipped with a control system, a compressor, and seven chambers (50 cm diameter, 30 cm high) set in sphagnum moss, feather moss, lichen, and tussock in black spruce forest soils, interior Alaska during growing season of 2008. The average daily soil respirations were 0.050±0.012 (standard deviation, CV 23%), 0.022±0.020 (91%), 0.082±0.035 (43%), and 0.027±0.010 mgCO2/m2/s (37%) in lichens, sphagnum moss, tussock and feather moss on black spruce forest soils with light chamber made by transparent material. The temporal variation of soil respiration in different vegetation types on black spruce forest soils during the growing season of 2008 is shown in Figure 1. The accumulative daily soil respiration was 5.2, 9.5, 2.3, and 2.8 mgCO2/m2/s in lichen, tussock, sphagnum moss, and feather moss of black spruce forest ground during the growing periods of 103 days, 2008 (Figure 2). Therefore, averaged regional soil respiration rate is 0.19±0.18 and 0.12±0.08 kgC/m2/(growing season) of 2007 and 2008 in black spruce forest soils, interior Alaska. The winter soil respiration was 0.049±0.013 gC/m2/(winter season), corresponding from 21±7% to 29±13% of the annual CO2 emitted from black spruce forest soils, interior Alaska.

  1. Rapid Shifts in Soil and Forest Floor Microbial Communities with Changes in Vegetation during Secondary Tropical Forest Succession

    NASA Astrophysics Data System (ADS)

    Smith, A.; Marin-Spiotta, E.; Balser, T. C.

    2012-12-01

    Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. In order to predict how disturbance affects belowground carbon storage, it is important to understand how the forest floor and soil microbial community respond to changes in land cover, and the consequences on SOM formation and stabilization. We are measuring microbial functional diversity and activity across a long-term successional chronosequence of secondary forests regrowing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Here we report intra- and interannual data on soil and litter microbial community composition (via phospholipid fatty acid analysis, PLFA) and microbial activity (via extracellular enzyme activity) from active pastures, secondary forests aged 20, 30, 40, 70, and 90-years, and primary forests. Microbial community composition and extracellular enzyme activity differed significantly by season in these wet subtropical ecosystems, even though differences in mean monthly precipitation between the middle of the dry season (January) and the wet season (July) is only 30mm. Despite seasonal differences, there was a persistent strong effect of land cover type and forest successional stage, or age, on overall microbial community PLFA structure. Using principal component analysis, we found differences in microbial community structure among active pastures, early, and late successional forests. The separation of soil microbes into early and late successional communities parallels the clustering of tree composition data. While the successional patterns held across seasons, the importance of different microbial groups driving these patterns differed seasonally. Biomarkers for gram-positive and actinobacteria (i15:0 and 16:0 10Me) were associated with early (20, 30 & 40 year old) secondary forests in the dry season. These younger forest communities were identified by the biomarker for

  2. Mapping organic carbon stocks of Swiss forest soil

    NASA Astrophysics Data System (ADS)

    Nussbaum, M.; Papritz, A.; Baltensweiler, A.; Walthert, L.

    2012-04-01

    Carbon (C) sequestration into forest sinks offsets greenhouse gas emissions under the Kyoto protocol. Therefore, quantifying C stocks and fluxes in forest ecosystems is of interest for reporting greenhouse gas emissions. In Switzerland, the National Forest Inventory offers comprehensive data to quantify the above ground forest biomass and its change in time. Estimating stocks of soil organic C (SOC) in forests is more difficult because of its high spatial variability. To date the greenhouse gas inventory relies only on sparse data and regionally differentiated predictions of SOC stocks in forest soils are currently not possible. Recently, more soil data and new explanatory variables for statistical modeling like high resolution elevation data and satellite images became available. Based on data from 1'033 sites, we modeled SOC stocks to a depth of 1 m including the organic layer for the Swiss forested area. We used a novel robust restricted maximum likelihood method to fit a linear regression model with spatially correlated errors to the C stock data. For the regression analysis we used a broad range of covariates derived from climate data (precipitation, temperature, radiation), two elevation models (resolutions 25 and 2 m) and spectral variables representing vegetation. Furthermore, the main cartographic categories of an overview soil map were used to broadly represent the parent material. The numerous covariates, that partly correlated strongly, were reduced to a first subset using LASSO (Least Absolute Shrinkage and Selection Operator). This subset of covariates was then further reduced based on cross validation of the robustly fitted spatial model. The levels of categorical covariates were partly aggregated during this process and interactions between covariates were explored to account for nonlinear dependence of C stocks on the covariates. Using the final model, robust kriging prediction and error maps were computed with a resolution of one hectare.

  3. Designer, acidic biochar influences calcareous soil characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 degrees celsius) and steam activation to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0, 1, 2, and 10 percent (by weight) to an eroded Portneuf soil (coarse-silty,...

  4. Short-term effects of forest disturbances on soil nematode communities in European mountain spruce forests.

    PubMed

    Čerevková, A; Renčo, M; Cagáň, L

    2013-09-01

    The nematode communities in spruce forests were compared with the short-term effects of forest damage, caused by windstorm, wildfire and management practices of forest soils. Soil samples were collected in June and October from 2006 to 2008 in four different sites: (1) forest unaffected by the wind (REF); (2) storm-felled forest with salvaged timber (EXT); (3) modified forest affected by timber salvage (wood removal) and forest fire (FIR); and (4) storm-felled forest where timber had been left unsalvaged (NEX). Nematode analysis showed that the dominant species in all four investigated sites were Acrobeloides nanus and Eudorylaimus silvaticus. An increase of A. nanus (35% of the total nematode abundance) in the first year in the FIR site led to the highest total abundance of nematodes compared with other sites, where nematode abundance reached the same level in the third year. In the FIR site bacterial feeders appeared to be the most representative trophic group, although in the second and third year, after disturbance, the abundance of this trophic group gradually decreased. In the NEX site, the number of nematode species, population densities and Maturity Index were similar to that recorded for the FIR site. In EXT and NEX sites, the other dominant species was the plant parasitic nematode Paratylenchus microdorus. Analyses of nematodes extracted from different forest soil samples showed that the highest number of species and diversity index for species (H'spp) were in the REF site. Differences between the nematode fauna in REF and other localities were clearly depicted by cluster analysis. The greatest Structure Index and Enrichment Index values were also in REF. In the EXT site, the number of nematode species, their abundance, H'spp and Maturity Index were not significantly different from those recorded in the reference site.

  5. Changes in Soil Nitrogen Storage and Dynamics in Response to Forest Management in Southeastern Pine Forest

    NASA Astrophysics Data System (ADS)

    Boutton, T. W.; Foote, J. A.; Scott, D. A.

    2013-12-01

    Forest harvesting increases radiation reaching the soil surface, decreases transpiration and rainfall interception, and increases the amount of precipitation reaching and infiltrating into the soil. The magnitude of these impacts varies with intensity of tree harvest method, but generally results in warmer, moister soils that favor microbial activity and accelerate N cycling processes that can result in leaching and gaseous N losses from the ecosystem. More intense forest harvest (i.e., removal of increasing amounts of aboveground biomass) results in greater N losses, potentially limiting the productivity and sustainability of future rotations. This study determined the impact of forest harvest intensity, soil compaction, and their interaction on N-cycling in a loblolly pine (Pinus taeda L.) forest 15-years following treatment. We quantified N and δ15N in litter, root, and soil compartments at the Long Term Soil Productivity Experiment in Crockett National Forest in eastern Texas. Treatment plots of 0.4 ha were established in 1997 and consisted of three harvest methods (bole only, whole tree, and whole tree + forest floor removal) in factorial combination with three levels of soil compaction (none, intermediate, and severe); all treatment combinations were replicated (n=3). Sampling was conducted quarterly from March 2011 through March 2012. Litter N pool sizes were reduced significantly by increasing harvest intensity and varied significantly through time. Litter N was highest in the bole only treatment (10-13 g N m-2) and lowest in the whole tree+forest floor removal treatment (9-10 g N m-2). Soil total N storage in the 0-10-cm increment was also reduced significantly by increasing harvest intensity and was highest in the bole only treatment (74-99 g N m-2) and lowest in the whole tree+forest floor removal treatment (61-83 g N m-2). Tree harvest methods had no effect on the total root N pool (fine + coarse roots) in the upper 10 cm of the soil profile; however

  6. A Study of Effects of Acid Deposition on Pine Forest Ecosystem in Southwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Li, F.; Lv, Z.; Song, W.; Yang, S.

    2013-12-01

    We used a long-term soil acidification model (LTSAM) and a terrestrial biogeochemical model (CENTURY) coupled to simulate the effects of acid deposition on pine forest ecosystem in southwestern China, based on indoor experiment results of aluminum toxicity to individual plant growth. The results of indoor aluminum experiments show that high aluminum concentration may restrict the plant growth and the acidic condition may aggravate it. The behavior of restriction of plant growth includes decreases of pine seedling biomass, root elongation and the sorption of soil cations (e.g. Ca2+, Mg2+, Na+ and K+). The model simulation results about soil chemistry show that, as acid deposition increases more, the pH value decreases faster, the soil aluminum ion concentration increase more rapidly, and the nutrition ions in soil solution decrease more quickly. The increased acid deposition also has negative impacts on the forest ecosystem according to the biogeochemical model simulation, for example, decreases of vegetation biomass, net primary productivity (NPP) and net CO2 uptake. Furthermore, the decrease of plant biomass will result in the decrease of the soil organic carbon content for the limited decomposition material supply.

  7. Preliminary assessment of soil erosion impact during forest restoration process

    NASA Astrophysics Data System (ADS)

    Lai, Yen-Jen; Chang, Cheng-Sheng; Tsao, Tsung-Ming; Wey, Tsong-Huei; Chiang, Po-Neng; Wang, Ya-Nan

    2014-05-01

    Taiwan has a fragile geology and steep terrain. The 921 earthquake, Typhoon Toraji, Typhoon Morakot, and the exploitation and use of the woodland by local residents have severely damaged the landscape and posed more severe challenges to the montane ecosystem. A land conservation project has been implemented by the Experimental Forest of National Taiwan University which reclaimed approximately 1,500 hectares of leased woodland from 2008 to 2010, primarily used to grow bamboo, tea trees, betel nut, fruit, and vegetable and about 1,298 hectares have been reforested. The process of forest restoration involves clear cutting, soil preparation and a six-year weeding and tending period which may affect the amount of soil erosion dramatically. This study tried to assess the impact of forest restoration from the perspective of soil erosion through leased-land recovery periods and would like to benefit the practical implementation of reforestation in the future. A new plantation reforested in the early 2013 and a nearby 29-year-old mature forest were chosen as experimental and comparison sites. A self-designed weir was set up in a small watershed of each site for the runoff and sediment yield observation. According to the observed results from May to August 2013, a raining season in Taiwan, the runoff and erosion would not as high as we expected, because the in-situ soil texture of both sites is sandy loam to sandy with high percentage of coarse fragment which increased the infiltration. There were around 200 kg to 250 kg of wet sand/soil yielded in mature forest during the hit of Typhoon Soulik while the rest of the time only suspended material be yielded at both sites. To further investigate the influence of the six-year weeding and tending period, long term observations are needed for a more completed assessment of soil erosion impact.

  8. Basal area growth of sugar maple in relation to acid deposition, stand health, and soil nutrients.

    PubMed

    Duchesne, Louis; Ouimet, Rock; Houle, Daniel

    2002-01-01

    Previous studies have shown in noncalcareous soils that acid deposition may have increased soil leaching of basic cations above the input rate from soil weathering and atmospheric depositions. This phenomenon may have increased soil acidity levels, and, as a consequence, may have reduced the availability of these essential nutrients for forest growth. Fourteen plots of the Forest Ecosystem Research and Monitoring Network in Québec were used to examine the relation between post-industrial growth trends of sugar maple (Acer saccharum Marsh.) and acid deposition (N and S), stand decline rate, and soil exchangeable nutrient concentrations. Atmospheric N and S deposition and soil exchangeable acidity were positively associated with stand decline rate, and negatively with the average tree basal area increment trend. The growth rate reduction reached on average 17% in declining stands compared with healthy ones. The results showed a significant sugar maple growth rate reduction since 1960 on acid soils. The appearance of the forest decline phenomenon in Québec can be attributed, at least partially, to soil acidification and acid deposition levels.

  9. Impact of anthropogenic induced nitrogen input and liming on phosphorous leaching in forest soils

    NASA Astrophysics Data System (ADS)

    Holzmann, Stefan; Puhlmann, Heike; Wilpert, Klaus

    2016-04-01

    Introduction: Phosphorous (P) is essential for sustainable forest growth, yet the impact of anthropogenic impacts on P leaching losses from forest soils are hardly known. Methods: We conducted an irrigation experiment with 128 mesocosms of 7.4 cm diameter containing 20 cm mineral soil plus the organic layer from three forest sites representing a gradient of resin extractable P of the A-horizon. On each site we selected a Fagus sylvatica and a Picea abies managed subsite. Half of the cylinders where planted with seedlings of the respective species to access the plant impact. We simulated ambient rain (AR), anthropogenic nitrogen input (NI) of 100 kg/ha/a and forest liming (FL) with a dolomite input of 0.3 Mg/ha/a. Soil solution was extracted from the organic layer and at 20 cm depth. We collected the soil solution over a period of 13.5 months and analyzed it separated by 5 periods. The soil solution was analyzed for total phosphorous (TP) by measuring the molybdane reactive phosphorous after acid digestion. To analyze the multivariate dataset we applied random forest modelling and used partial (co-)dependency plots to interpret the results. Results: The TP content of the soil solution from the organic horizon was approximately ten times higher than the soil solution content of the mineral soil. The NI treatment did increase the TP content on all sites. The increase was more pronounced in the organic layer than in the mineral layer. The FL treatment lead to a slight increase of TP in the organic layer while we could observe a slight decrease in the mineral horizon. Both the organic layer and the mineral horizon showed a seasonal cycle with the exception of one Picea abies subsite which displayed a constant increase in TP in the organic layer. The seasonal cycle of the organic horizon had a minimum during the period of April to July, while the minimum at the mineral horizon was during November to January. Conclusion: TP in the soil solution is highest in the organic

  10. Role of Possible Soil toxicity in Die back of Montane Forests in Sri Lanka.

    NASA Astrophysics Data System (ADS)

    Ranasinghe, P. N.; Fernando, R.; Wimalasena, R. N.; Ekanayake, S. P.

    2008-12-01

    Rapid dying back of Tropical Upper Montane Rain forests of Sri Lanka which are considered as "Biodiversity Hotspots" is a nationally as well as globally important environmental issue. Although various hypotheses were tested during recent past, nothing could be proved except the possible involvement of soil toxicity due to excess levels of certain elements. This study investigated the extractable soil trace and major element levels in 3 pilot plots situated in dieback and healthy forests. Based on the results, Al, Mn, Fe and Pb concentrations in 30 individuals of 08 most susceptible plant species at different dieback stages and in soils in the immediate vicinity in Hakgala Strict Nature Reserve of Sri Lanka were determined in order to recognize the contribution of these element in forest die back. Collected Plant leaves were analyzed for total element levels and soils were analyzed for the extractable element levels. This study reveals the presence of high DTPA extractable Pb (0.6 - 2.4 ppm), Mn (1.7-57.2ppm), Fe (48.1- 372.1ppm) and KCl extractable Al (0.7-390.8 ppm) in soils. The most important observation was the presence of high accumulations of Pb (2.2-36.3 ppm) and Al (18.9 - 20047.6 ppm) in plant leaves which are high above the normal range. Acidic conditions in soils (pH 4.2-5.6) may increase Al+3 from Al bearing feldspar rich soils. Increased soil acidity due to lowering the pH of precipitation by air pollution may also contribute in dissolution of toxic Al+3. Extractable Soil Pb levels are higher on wind exposed slope areas. Increased Pb levels in soils on slope areas, differences between total and extractable soil Pb levels, amounts of washable Pb on leaves before and after the banning of Pb containing gasoline usage and comparisons of Pb levels in plants with known Pb polluted areas of the country prove that air pollution could be the main Pb source in this montane forests soils. Although no direct relationship could be recognized between element levels

  11. Modeling the contribution of soil fauna to litter decomposition influenced by acidic deposition

    SciTech Connect

    Cai, B.; Loucks, O.L; Kuperman, R. Argonne National Lab., IL )

    1993-06-01

    The effect of acidic deposition on soil pH and therefore on soil invertebrates and litter decomposition is being investigated in oak-hickory forests across a three-state, midwest, pollution gradient. The role of soil invertebrates has been assessed previously through the use of feeding, assimilation and respiratory rates. These energetic parameters depend strongly on the form of the allometric equations which have been improved here by incorporating uncertainties in body and population size. Results show that changes in reproduction and turnover dynamics of soil invertebrates (particularly of earthworms) due to acid-induced changes in soil pH explains observed patterns in litter depth.

  12. Actinomadura rayongensis sp. nov., isolated from peat swamp forest soil.

    PubMed

    Phongsopitanun, Wongsakorn; Tanasupawat, Somboon; Suwanborirux, Khanit; Ohkuma, Moriya; Kudo, Takuji

    2015-03-01

    A novel actinomycete strain RY35-68(T), isolated from a peat swamp forest soil sample in Rayong Province, Thailand, was characterized using a polyphasic approach. The strain belonged to the genus Actinomadura based on morphological and chemotaxonomic characteristics. Cell-wall analysis revealed the presence of meso-diaminopimelic acid and N-acetylmuramic acid in the peptidoglycan layer. The diagnostic sugar in whole-cell hydrolysates was identified as madurose. The predominant menaquinones were MK-9(H6), MK-9(H8) and MK-9(H4). The major cellular fatty acids were C16 : 0 and iso-C16 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The genomic DNA G+C content was 73.7 mol%. On the basis of 16S rRNA gene sequence similarity analysis, strain RY35-68(T) was closely related to the species Actinomadura atramentaria JCM 6250(T) (97.5 %). The value of DNA-DNA relatedness between strain RY35-68(T) and A. atramentaria JCM 6250(T) was 37.6-42.6 %. On the basis of its phenotypic characteristics and these results mentioned, this strain could be distinguished from the closely related type strain and represents a novel species of the genus Actinomadura, for which the name Actinomadura rayongensis sp. nov. (type strain RY35-68(T) = JCM 19830(T) = TISTR 2211(T) = PCU 332(T)) is proposed.

  13. Soil Diversity Along a Forest Profile Using PCR-DGGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forest ecosystems are complex and involve diverse relationships between its biotic and abiotic components. As implementation of fire for restoration and conservation practices has increased, a vital need for quantitative metrics of the effects of fire on the ecosystem as a whole, including soil qua...

  14. Calculation and mapping of critical loads of sulphur and nitrogen for forest soils in Galicia (NW Spain).

    PubMed

    Rodríguez-Lado, L; Macías, F

    2006-08-01

    Calculations of critical loads of acidity within Europe have shown Galicia to be one of the regions in Spain with the highest risk of soil acidification by deposition of atmospheric pollutants. We used the simple mass balance method (SMB) to derive critical loads of sulphur and nitrogen for forest soils in Galicia using available site-specific information. Exceedance of acidic deposition was calculated using the deposition levels of N and S registered in 2001. Most forest ecosystems analysed can support acid loads of more than 2000 eq N ha(-1) year(-1). The lowest critical loads of acidity (1483 eq ha(-1) year(-1)) occurred in coniferous forest stands growing on shallow soils developed on slates, in the interior zone. The highest critical load values (9386 eq ha(-1) year(-1)) were observed in coniferous stands in zones with elevated precipitation rates, in the littoral area. The critical load for acidity was exceeded in 5% of the forest soils. Such exceedances were mainly caused by deposition of nitrogen compounds. The contribution of sulphur deposition to acid exceedance was important in the surroundings of the city of A Coruña. Analysis of rainfall bulk composition revealed that N deposition in Galicia was mainly due to ammonium emissions, probably derived from agricultural and cattle breeding activities.

  15. Spatial variability of the dehydrogenase activity in forest soils

    NASA Astrophysics Data System (ADS)

    Błońska, Ewa; Lasota, Jarosław

    2014-05-01

    The aim of this study was to assess the spatial variability of the dehydrogenase activity (DH) in forest soils using geostatistics. We have studied variability soil dehydrogenase and their relationship with variability of some physic-chemical properties. Two study areas (A and B) were set up in southern Poland in the Zlotoryja Forest District. Study areas were covered by different types of vegetation (A- broadleaf forest with beech, ash and sycamore), B- coniferous forest with Norway spruce). The soils were classified as Dystric Cambisols (WRB 2006). The samples for laboratory testing were collected from 49 places on each areas. 15 cm of surface horizon of soil were taken (with previously removed litter). Dehydrogenase activity was marked with Lenhard's method according to the Casida procedure. Soil pH, nitrogen (N) and soil organic carbon (C) content (by LECO CNS 2000 carbon analyzer) was marked. C/N ratio was calculated. Particle size composition was determined using laser diffraction. Statistical analysis were performed using STATISTICA 10 software. Geostatistical analysis and mapping were done by application of GS 9+ (Gamma Design) and Surfer 11 (Golden Software). The activity of DH ranged between 5,02 and 71,20 mg TPP• kg-1 •24 h-1 on the A area and between 0,94 and 16,47 mg TPP• kg-1 •24 h-1. Differences in spatial variability of the analised features were noted. The variability of dehydrogenase activity on the A study area was described by an exponential model, whereas on the B study area the spatial correlation has not been noted. The relationship of dehydrogenase activity with the remaining parameters of soil was noted only in the case of A study area. The variability of organic carbon content on the A and B study areas were described by an exponential model. The variability of nitrogen content on both areas were described by an spherical model.

  16. The variations of aluminium species in mountainous forest soils and its implications to soil acidification.

    PubMed

    Bradová, Monika; Tejnecký, Václav; Borůvka, Luboš; Němeček, Karel; Ash, Christopher; Šebek, Ondřej; Svoboda, Miroslav; Zenáhlíková, Jitka; Drábek, Ondřej

    2015-11-01

    Aluminium (Al) speciation is a characteristic that can be used as a tool for describing the soil acidification process. The question that was answered is how tree species (beech vs spruce) and type of soil horizon affect Al speciation. Our hypotesis is that spruce and beech forest vegetation are able to modify the chemical characteristics of organic horizon, hence the content of Al species. Moreover, these characteristics are seasonally dependent. To answer these questions, a detailed chromatographic speciation of Al in forest soils under contrasting tree species was performed. The Jizera Mountains area (Czech Republic) was chosen as a representative mountainous soil ecosystem. A basic forestry survey was performed on the investigated area. Soil and precipitation samples (throughfall, stemflow) were collected under both beech and spruce stands at monthly intervals from April to November during the years 2008-2011. Total aluminium content and Al speciation, pH, and dissolved organic carbon were determined in aqueous soil extracts and in precipitation samples. We found that the most important factors affecting the chemistry of soils, hence content of the Al species, are soil horizons and vegetation cover. pH strongly affects the amount of Al species under both forests. Fermentation (F) and humified (H) organic horizons contain a higher content of water extractable Al and Al(3+) compared to organo-mineral (A) and mineral horizons (B). With increasing soil profile depth, the amount of water extractable Al, Al(3+) and moisture decreases. The prevailing water-extractable species of Al in all studied soils and profiles under both spruce and beech forests were organically bound monovalent Al species. Distinct seasonal variations in organic and mineral soil horizons were found under both spruce and beech forests. Maximum concentrations of water-extractable Al and Al(3+) were determined in the summer, and the lowest in spring.

  17. The variations of aluminium species in mountainous forest soils and its implications to soil acidification.

    PubMed

    Bradová, Monika; Tejnecký, Václav; Borůvka, Luboš; Němeček, Karel; Ash, Christopher; Šebek, Ondřej; Svoboda, Miroslav; Zenáhlíková, Jitka; Drábek, Ondřej

    2015-11-01

    Aluminium (Al) speciation is a characteristic that can be used as a tool for describing the soil acidification process. The question that was answered is how tree species (beech vs spruce) and type of soil horizon affect Al speciation. Our hypotesis is that spruce and beech forest vegetation are able to modify the chemical characteristics of organic horizon, hence the content of Al species. Moreover, these characteristics are seasonally dependent. To answer these questions, a detailed chromatographic speciation of Al in forest soils under contrasting tree species was performed. The Jizera Mountains area (Czech Republic) was chosen as a representative mountainous soil ecosystem. A basic forestry survey was performed on the investigated area. Soil and precipitation samples (throughfall, stemflow) were collected under both beech and spruce stands at monthly intervals from April to November during the years 2008-2011. Total aluminium content and Al speciation, pH, and dissolved organic carbon were determined in aqueous soil extracts and in precipitation samples. We found that the most important factors affecting the chemistry of soils, hence content of the Al species, are soil horizons and vegetation cover. pH strongly affects the amount of Al species under both forests. Fermentation (F) and humified (H) organic horizons contain a higher content of water extractable Al and Al(3+) compared to organo-mineral (A) and mineral horizons (B). With increasing soil profile depth, the amount of water extractable Al, Al(3+) and moisture decreases. The prevailing water-extractable species of Al in all studied soils and profiles under both spruce and beech forests were organically bound monovalent Al species. Distinct seasonal variations in organic and mineral soil horizons were found under both spruce and beech forests. Maximum concentrations of water-extractable Al and Al(3+) were determined in the summer, and the lowest in spring. PMID:26084557

  18. Dinghuibacter silviterrae gen. nov., sp. nov., isolated from forest soil.

    PubMed

    Lv, Ying-Ying; Wang, Jia; Chen, Mei-Hong; You, Jia; Qiu, Li-Hong

    2016-04-01

    A novel Gram-stain negative, non-motile, rod-shaped, aerobic bacterial strain, designated DHOA34T, was isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, China. Comparative 16S rRNA gene sequence analysis showed that it exhibited highest similarity with Flavisolibacter ginsengiterrae Gsoil 492T and Flavitalea populi HY-50RT, at 90.89 and 90.83%, respectively. In the neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, DHOA34T formed an independent lineage within the family Chitinophagaceae but was distinct from all recognized species and genera of the family. The major cellular fatty acids of DHOA34T included iso-C15:0, anteiso-C15:0, iso-C17:0 3-OH and summed feature 3 (C16:1ω6c and/or C16:1ω7c). The DNA G+C content was 51.6 mol% and the predominant quinone was menaquinone 7 (MK-7). Flexirubin pigments were produced. The phenotypic, chemotaxonomic and phylogenetic data demonstrate consistently that strain DHOA34T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Dinghuibacter silviterrae gen. nov., sp. nov. is proposed. The type strain of Dinghuibacter silviterrae is DHOA34T (=CGMCC 1.15023T=KCTC 42632T). PMID:26828023

  19. Sewage sludge fertiliser use: implications for soil and plant copper evolution in forest and agronomic soils.

    PubMed

    Ferreiro-Domínguez, Nuria; Rigueiro-Rodríguez, Antonio; Mosquera-Losada, M Rosa

    2012-05-01

    Fertilisation with sewage sludge may lead to crop toxicity and environmental degradation. This study aims to evaluate the effects of two types of soils (forest and agronomic), two types of vegetation (unsown (coming from soil seed bank) and sown), and two types of fertilisation (sludge fertilisation and mineral fertilisation, with a no fertiliser control) in afforested and treeless swards and in sown and unsown forestlands on the total and available Cu concentration in soil, the leaching of this element and the Cu levels in plant. The experimental design was completely randomised with nine treatments and three replicates. Fertilisation with sewage sludge increased the concentration of Cu in soil and plant, but the soil values never exceeded the maximum set by Spanish regulations. Sewage sludge inputs increased both the total and Mehlich 3 Cu concentrations in agronomic soils and the Cu levels in plant developed in agronomic and forest soils, with this effect pronounced in the unsown swards of forest soils. Therefore, the use of high quality sewage sludge as fertiliser may improve the global productivity of forest, agronomic and silvopastoral systems without creating environmental hazards. PMID:22425275

  20. Quantifying soil and critical zone variability in a forested catchment through digital soil mapping

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying catchment scale soil property variation yields insights into critical zone evolution and function. The objective of this study was to quantify and predict the spatial distribution of soil properties within a high elevation forested catchment in southern AZ, USA using a combined set of di...

  1. Distribution of black carbon in ponderosa pine forest floor and soils following the High Park wildfire

    NASA Astrophysics Data System (ADS)

    Boot, C. M.; Haddix, M.; Paustian, K.; Cotrufo, M. F.

    2015-05-01

    Biomass burning produces black carbon (BC), effectively transferring a fraction of the biomass C from an actively cycling pool to a passive C pool, which may be stored in the soil. Yet the timescales and mechanisms for incorporation of BC into the soil profile are not well understood. The High Park fire (HPF), which occurred in northwestern Colorado in the summer of 2012, provided an opportunity to study the effects of both fire severity and geomorphology on properties of carbon (C), nitrogen (N) and BC in the Cache La Poudre River drainage. We sampled montane ponderosa pine forest floor (litter plus O-horizon) and soils at 0-5 and 5-15 cm depth 4 months post-fire in order to examine the effects of slope and burn severity on %C, C stocks, %N and BC. We used the benzene polycarboxylic acid (BPCA) method for quantifying BC. With regard to slope, we found that steeper slopes had higher C : N than shallow slopes but that there was no difference in BPCA-C content or stocks. BC content was greatest in the forest floor at burned sites (19 g BPCA-C kg-1 C), while BC stocks were greatest in the 5-15 cm subsurface soils (23 g BPCA-C m-2). At the time of sampling, unburned and burned soils had equivalent BC content, indicating none of the BC deposited on the land surface post-fire had been incorporated into either the 0-5 or 5-15 cm soil layers. The ratio of B6CA : total BPCAs, an index of the degree of aromatic C condensation, suggested that BC in the 5-15 cm soil layer may have been formed at higher temperatures or experienced selective degradation relative to the forest floor and 0-5 cm soils. Total BC soil stocks were relatively low compared to other fire-prone grassland and boreal forest systems, indicating most of the BC produced in this system is likely lost, either through erosion events, degradation or translocation to deeper soils. Future work examining mechanisms for BC losses from forest soils will be required for understanding the role BC plays in the global

  2. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream-flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid-forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Streamwater pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by calcium, magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southeast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site.

  3. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Stream water pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southwast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site. 10 references, 2 tables.

  4. Does drought alter hydrological functions in forest soils?

    NASA Astrophysics Data System (ADS)

    Gimbel, Katharina; Puhlmann, Heike; Weiler, Markus

    2014-05-01

    Climate change will probably alter precipitation patterns across central Europe, and (summer) droughts are expected to be more frequent and severe in future. Droughts may modify soil properties, such as the pore volume distribution, soil aggregation, water repellency and rooting patterns. These changes in soil properties affect the hydrological functioning of the soil like water retention, infiltration and percolation and thereby the site conditions for plants. The aim of this research is to investigate the effect of droughts on the hydrological functioning of forest soils. We conducted rainfall-reduction experiments in three woodlands (nine investigation sites) across Germany. We established adaptive roofing systems which allow a flexible reduction of the precipitation between 15 % and 65 % of the incoming precipitation depending on the actual precipitation. The impact of the imposed droughts on the soil properties was assessed by repeated analyses of soil aggregation, hydrophobicity and pore volume distribution. Hydrological functioning of the soil was assessed by means of repeated dye tracer sprinkling experiments. Comparing dye tracer images of 2011 with images taken after two years of imposed drought, we found a general shift in infiltration processes depending on the soil type. Sandy soils showed a shift from front-like infiltration towards a more fingered and scattered infiltration. Soils rich in clay tend to develop unstained (= not wetted) areas in the top layer, which might hint to evolving hydrophobicity. This was confirmed by field and laboratory hydrophobicity tests. Further, the same profiles were showing signs of lower permeability in the bottom layers. Similar to hydrophobicity, we want to link the results of soil aggregation and pore volume distribution to the changes in the infiltration pattern. Our study shows that changes in precipitation pattern can severely affect forest soil properties and their hydrological functions. The results of this

  5. A slight recovery of soils from Acid Rain over the last three decades is not reflected in the macro nutrition of beech (Fagus sylvatica) at 97 forest stands of the Vienna Woods.

    PubMed

    Berger, Torsten W; Türtscher, Selina; Berger, Pétra; Lindebner, Leopold

    2016-09-01

    Rigorous studies of recovery from soil acidification are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area at different soil depths) and foliar chemistry from three decades ago. It was hypothesized that declining acidic deposition is reflected in soil and foliar chemistry. Top soil pH within the stemflow area increased significantly by 0.6 units in both H2O and KCl extracts from 1984 to 2012. Exchangeable Ca and Mg increased markedly in the stemflow area and to a lower extent in the top soil of the between trees area. Trends of declining base cations in the lower top soil were probably caused by mobilization of organic S and associated leaching with high amounts of sulfate. Contents of C, N and S decreased markedly in the stemflow area from 1984 to 2012, suggesting that mineralization rates of organic matter increased due to more favorable soil conditions. It is concluded that the top soil will continue to recover from acidic deposition. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed. The beech trees of the Vienna Woods showed no sign of recovery from acidification although S deposition levels decreased. Release of historic S even increased foliar S contents. Base cation levels in the foliage declined but are still adequate for beech trees. Increasing N/nutrient ratios over time were considered not the result of marginally higher N foliar contents in 2012 but of diminishing nutrient uptake due to the decrease in ion concentration in soil solution. The mean foliar N/P ratio already increased to the alarming value of 31. Further nutritional imbalances will predispose trees to vitality loss.

  6. A slight recovery of soils from Acid Rain over the last three decades is not reflected in the macro nutrition of beech (Fagus sylvatica) at 97 forest stands of the Vienna Woods.

    PubMed

    Berger, Torsten W; Türtscher, Selina; Berger, Pétra; Lindebner, Leopold

    2016-09-01

    Rigorous studies of recovery from soil acidification are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area at different soil depths) and foliar chemistry from three decades ago. It was hypothesized that declining acidic deposition is reflected in soil and foliar chemistry. Top soil pH within the stemflow area increased significantly by 0.6 units in both H2O and KCl extracts from 1984 to 2012. Exchangeable Ca and Mg increased markedly in the stemflow area and to a lower extent in the top soil of the between trees area. Trends of declining base cations in the lower top soil were probably caused by mobilization of organic S and associated leaching with high amounts of sulfate. Contents of C, N and S decreased markedly in the stemflow area from 1984 to 2012, suggesting that mineralization rates of organic matter increased due to more favorable soil conditions. It is concluded that the top soil will continue to recover from acidic deposition. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed. The beech trees of the Vienna Woods showed no sign of recovery from acidification although S deposition levels decreased. Release of historic S even increased foliar S contents. Base cation levels in the foliage declined but are still adequate for beech trees. Increasing N/nutrient ratios over time were considered not the result of marginally higher N foliar contents in 2012 but of diminishing nutrient uptake due to the decrease in ion concentration in soil solution. The mean foliar N/P ratio already increased to the alarming value of 31. Further nutritional imbalances will predispose trees to vitality loss. PMID:27344089

  7. A slight recovery of soils from Acid Rain over the last three decades is not reflected in the macro nutrition of beech (Fagus sylvatica) at 97 forest stands of the Vienna Woods✰

    PubMed Central

    Berger, Pétra; Lindebner, Leopold

    2016-01-01

    Rigorous studies of recovery from soil acidification are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area at different soil depths) and foliar chemistry from three decades ago. It was hypothesized that declining acidic deposition is reflected in soil and foliar chemistry. Top soil pH within the stemflow area increased significantly by 0.6 units in both H2O and KCl extracts from 1984 to 2012. Exchangeable Ca and Mg increased markedly in the stemflow area and to a lower extent in the top soil of the between trees area. Trends of declining base cations in the lower top soil were probably caused by mobilization of organic S and associated leaching with high amounts of sulfate. Contents of C, N and S decreased markedly in the stemflow area from 1984 to 2012, suggesting that mineralization rates of organic matter increased due to more favorable soil conditions. It is concluded that the top soil will continue to recover from acidic deposition. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed. The beech trees of the Vienna Woods showed no sign of recovery from acidification although S deposition levels decreased. Release of historic S even increased foliar S contents. Base cation levels in the foliage declined but are still adequate for beech trees. Increasing N/nutrient ratios over time were considered not the result of marginally higher N foliar contents in 2012 but of diminishing nutrient uptake due to the decrease in ion concentration in soil solution. The mean foliar N/P ratio already increased to the alarming value of 31. Further nutritional imbalances will predispose trees to vitality loss. PMID:27344089

  8. Isolation and characterization of Chinese standard fulvic acid sub-fractions separated from forest soil by stepwise elution with pyrophosphate buffer.

    PubMed

    Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P

    2015-01-01

    XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants. PMID:25735451

  9. Isolation and characterization of Chinese standard fulvic acid sub-fractions separated from forest soil by stepwise elution with pyrophosphate buffer.

    PubMed

    Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P

    2015-03-04

    XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants.

  10. Isolation and Characterization of Chinese Standard Fulvic Acid Sub-fractions Separated from Forest Soil by Stepwise Elution with Pyrophosphate Buffer

    NASA Astrophysics Data System (ADS)

    Bai, Yingchen; Wu, Fengchang; Xing, Baoshan; Meng, Wei; Shi, Guolan; Ma, Yan; Giesy, John P.

    2015-03-01

    XAD-8 adsorption technique coupled with stepwise elution using pyrophosphate buffers with initial pH values of 3, 5, 7, 9, and 13 was developed to isolate Chinese standard fulvic acid (FA) and then separated the FA into five sub-fractions: FApH3, FApH5, FApH7, FApH9 and FApH13, respectively. Mass percentages of FApH3-FApH13 decreased from 42% to 2.5%, and the recovery ratios ranged from 99.0% to 99.5%. Earlier eluting sub-fractions contained greater proportions of carboxylic groups with greater polarity and molecular mass, and later eluting sub-fractions had greater phenolic and aliphatic content. Protein-like components, as well as amorphous and crystalline poly(methylene)-containing components were enriched using neutral and basic buffers. Three main mechanisms likely affect stepwise elution of humic components from XAD-8 resin with pyrophosphate buffers including: 1) the carboxylic-rich sub-fractions are deprotonated at lower pH values and eluted earlier, while phenolic-rich sub-fractions are deprotonated at greater pH values and eluted later. 2) protein or protein-like components can be desorbed and eluted by use of stepwise elution as progressively greater pH values exceed their isoelectric points. 3) size exclusion affects elution of FA sub-fractions. Successful isolation of FA sub-fractions will benefit exploration of the origin, structure, evolution and the investigation of interactions with environmental contaminants.

  11. Asticcacaulis solisilvae sp. nov., isolated from forest soil.

    PubMed

    Kim, Seil; Gong, Gyeongtaek; Park, Tai Hyun; Um, Youngsoon

    2013-10-01

    An obligately aerobic, chemoheterotrophic, mesophilic prosthecate bacterium, designated strain CGM1-3EN(T), was isolated from the enrichment cultures of forest soil from Cheonggyesan Mountain, Republic of Korea. Cells were Gram-reaction-negative, motile rods (1.3-2.4 µm long by 0.30-0.75 µm wide) with single flagella. The strain grew at 10-37 °C (optimum 25-30 °C) and at pH 4.5-9.5 (optimum 5.0-7.0). The major cellular fatty acids were C16 : 0, C18 : 1ω7c 11-methyl, C12 : 1 3-OH and summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c). The genomic DNA G+C content of strain CGM1-3EN(T) was 63.7 mol%. The closest phylogenetic neighbour to strain CGM1-3EN(T) was identified as Asticcacaulis biprosthecium DSM 4723(T) (97.2 % 16S rRNA gene sequence similarity) and the DNA-DNA hybridization value between strain CGM1-3EN(T) and A. biprosthecium DSM 4723(T) was less than 24.5 %. Strain CGM1-3EN(T) used d-glucose, d-fructose, sucrose, maltose, trehalose, d-mannose, d-mannitol, d-sorbitol, d-galactose, cellobiose, lactose, raffinose, fumarate, pyruvate, dl-alanine and glycerol as carbon sources. Based on data from the present polyphasic study, the forest soil isolate CGM1-3EN(T) is considered to represent a novel species of the genus Asticcacaulis, for which the name Asticcacaulis solisilvae sp. nov. is proposed. The type strain is CGM1-3EN(T) ( = AIM0088(T) = KCTC 32102(T) = JCM 18544(T)). PMID:23687055

  12. Soil moisture sensitivity of autotrophic and heterotrophic forest floor respiration in boreal xeric pine and mesic spruce forests

    NASA Astrophysics Data System (ADS)

    Ťupek, Boris; Launiainen, Samuli; Peltoniemi, Mikko; Heikkinen, Jukka; Lehtonen, Aleksi

    2016-04-01

    Litter decomposition rates of the most process based soil carbon models affected by environmental conditions are linked with soil heterotrophic CO2 emissions and serve for estimating soil carbon sequestration; thus due to the mass balance equation the variation in measured litter inputs and measured heterotrophic soil CO2 effluxes should indicate soil carbon stock changes, needed by soil carbon management for mitigation of anthropogenic CO2 emissions, if sensitivity functions of the applied model suit to the environmental conditions e.g. soil temperature and moisture. We evaluated the response forms of autotrophic and heterotrophic forest floor respiration to soil temperature and moisture in four boreal forest sites of the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) by a soil trenching experiment during year 2015 in southern Finland. As expected both autotrophic and heterotrophic forest floor respiration components were primarily controlled by soil temperature and exponential regression models generally explained more than 90% of the variance. Soil moisture regression models on average explained less than 10% of the variance and the response forms varied between Gaussian for the autotrophic forest floor respiration component and linear for the heterotrophic forest floor respiration component. Although the percentage of explained variance of soil heterotrophic respiration by the soil moisture was small, the observed reduction of CO2 emissions with higher moisture levels suggested that soil moisture response of soil carbon models not accounting for the reduction due to excessive moisture should be re-evaluated in order to estimate right levels of soil carbon stock changes. Our further study will include evaluation of process based soil carbon models by the annual heterotrophic respiration and soil carbon stocks.

  13. Phylogenetic analysis on the soil bacteria distributed in karst forest

    PubMed Central

    Zhou, JunPei; Huang, Ying; Mo, MingHe

    2009-01-01

    Phylogenetic composition of bacterial community in soil of a karst forest was analyzed by culture-independent molecular approach. The bacterial 16S rRNA gene was amplified directly from soil DNA and cloned to generate a library. After screening the clone library by RFLP, 16S rRNA genes of representative clones were sequenced and the bacterial community was analyzed phylogenetically. The 16S rRNA gene inserts of 190 clones randomly selected were analyzed by RFLP and generated 126 different RFLP types. After sequencing, 126 non-chimeric sequences were obtained, generating 113 phylotypes. Phylogenetic analysis revealed that the bacteria distributed in soil of the karst forest included the members assigning into Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi (Green nonsulfur bacteria), Bacteroidetes, Verrucomicrobia, Nitrospirae, Actinobacteria (High G+C Gram-positive bacteria), Firmicutes (Low G+C Gram-positive bacteria) and candidate divisions (including the SPAM and GN08). PMID:24031430

  14. Phosphorus Speciation and Sorption Processes in Preferential flow paths and Soil Matrix in Forested Podzolic Till Soil

    NASA Astrophysics Data System (ADS)

    Saastamoinen, S.; Laine-Kaulio, H.; Klöve, B.

    2009-04-01

    The importance of preferential flow paths in nutrient leaching and subsurface transport has been identified in several studies mainly on agricultural soils. In forest soils research, decayed root channels, stone surfaces and other secondary soil structures have shown to affect unsaturated flow in glacial till soil. Until recently, the focus has been on nitrogen and carbon dynamics in the preferential flow paths. Preferential flow may also have a fundamental role in phosphorus (P) sorption processes and transport from forested till soils to surface waters. The main objectives of this study were to determine how preferential flow paths affect to P speciation, sorption and leaching in forested podzolic till soil. Field experiments were conducted in mixed coniferous forest, with soil type of glacial sandy till classified as Haplic Podzol. The first experiment was conducted in Ranua, Northern Finland. The preferential flow paths were identified by introducing Acid Blue 9 dye tracer to a 1 m2 study plot. The soil profile was vertically sliced and samples were collected from the stained preferential flow paths and unstained soil matrix. Ammonium-oxalate extracted trace elements and P, total and inorganic P, inorganic P fractions and organic P forms (31P-NMR spectroscopy) were analyzed from the samples. In the second experiment in Sotkamo, Eastern Finland, three 1 m2 study plots were selected from a forested hillslope: top, middle and bottom slope. The detection of preferential flow paths and the sampling procedure was identical to the first plot experiment. Samples were analyzed for ammonium-oxalate extracted trace elements and P. Also, the effect of reaction time, P concentration and temperature on the sorption process in preferential flow paths and soil matrix was studied by kinetic batch-type sorption experiments. Stone surfaces were the most dominant preferential flow paths and contained lower oxalate-extracted and total P concentrations than the soil matrix in all

  15. Agricultural legacies in forest environments: tree communities, soil properties, and light availability.

    PubMed

    Flinn, Kathryn M; Marks, P L

    2007-03-01

    Temperate deciduous forests across much of Europe and eastern North America reflect legacies of past land use, particularly in the diversity and composition of plant communities. Intense disturbances, such as clearing forests for agriculture, may cause persistent environmental changes that continue to shape vegetation patterns as landscapes recover. We assessed the long-term consequences of agriculture for environmental conditions in central New York forests, including tree community structure and composition, soil physical and chemical properties, and light availability. To isolate the effects of agriculture, we compared 20 adjacent pairs of forests that were never cleared for agriculture (primary forests) and forests that established 85-100 years ago on plowed fields (secondary forests). Tree communities in primary and secondary forests had similar stem density, though secondary forests had 14% greater basal area. Species composition differed dramatically between the two forest types, with primary forests dominated by Acer saccharum and Fagus grandifolia and secondary forests by Acer rubrum and Pinus strobus. Primary and secondary forests showed no consistent differences in soil physical properties or in the principal gradient of soil fertility associated with soil pH. Within stands, however, soil water content and pH were more variable in primary forests. Secondary forest soils had 15% less organic matter, 16% less total carbon, and 29% less extractable phosphorus in the top 10 cm than adjacent primary stands, though the ranges of the forest types mostly overlapped. Understory light availability in primary and secondary forests was similar. These results suggest that, within 100 years, post-agricultural stands have recovered conditions comparable to less disturbed forests in many attributes, including tree size and number, soil physical properties, soil chemical properties associated with pH, and understory light availability. The principal legacies of

  16. Breaking The Enzymatic Latch: Do Anaerobic Conditions Constrain Decomposition In Humid Tropical Forest Soil?

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Silver, W. L.

    2011-12-01

    Anaerobic conditions have been proposed to impose a "latch" on soil organic matter decomposition by inhibiting the activity of extracellular enzymes that catalyze the transformation of organic polymers into monomers for microbial assimilation. Here, we tested the hypothesis that anaerobiosis inhibits soil hydrolytic enzyme activity in a humid tropical forest ecosystem in Puerto Rico. We sampled surface and sub-surface soil from each of 59 plots (n = 118) stratified across distinct topographical zones (ridges, slopes, and valleys) known to vary in soil oxygen (O2) concentrations, and measured the potential activity of five hydrolytic enzymes that decompose carbon (C), nitrogen (N), and phosphorus (P) substrates. We measured reduced iron (Fe (II)) concentrations in soil extractions to provide a spatially and temporally integrated index of anaerobic microbial activity, since iron oxides constitute the dominant anaerobic terminal electron acceptor in this ecosystem. Surprisingly, we observed positive relationships between Fe (II) concentrations and the activity of all enzymes that we assayed. Linear mixed effects models that included Fe (II) concentration, topographic position, and their interaction explained between 30 to 70 % of the variance of enzyme activity of β-1,4-glucosidase, β-cellobiohydrolase, β-xylosidase, N-acetylglucosaminidase, and acid phosphatase. Soils from ridges and slopes contained between 10 and 800 μg Fe (II) g-1 soil, and exhibited consistently positive relationships (p < 0.0001) between Fe (II) and enzyme activity. Valley soils did not display significant relationships between enzyme activity and Fe (II), although they displayed variation in soil Fe (II) concentrations similar to ridges and slopes. Overall, valleys exhibited lower enzyme activity and lower Fe (II) concentrations than ridges or slopes, possibly related to decreased root biomass and soil C. Our data provide no indication that anaerobiosis suppresses soil enzyme activity, but

  17. Soil sustainability study in Lithuanian alien forest stands

    NASA Astrophysics Data System (ADS)

    Čiuldiene, Dovile; Skridlaite, Grazina; Žalūdiene, Gaile; Askelsson, Cecilia; Armolaitis, Kestutis

    2016-04-01

    Tree species are shifting their natural ranges in response to climate changes (Saltré et al., 2013). Northern red oak has originated from North America, but was planted in Europe already in twentieth century. At present, it is considered as invasive species in Poland and at invasive stage in the Lithuanian forests (Riepsas and Straigyte, 2008). European larch naturally grows in Central Europe, but its range has been extended by planting it as far as the Nordic countries. According to a pollen study in peat soils, European larch naturally grew in Lithuania in the sixteenth century and was reintroduced 200 years ago (Jankauskas, 1954). Therefore, the global warming could accelerate the expansion of European larch and Northern red oak into Lithuanian forests. An urgent need appeared to evaluate an impact of those warmth-tolerant species on soil mineral chemistry and quality. New results on the determination of mineral weathering rates in alien forest stands using a PROFILE soil chemistry model were obtained during a doctoral study at the Institute of Forestry. Soil minerals were studied by a Scanning Electron Microscopy at the Institute of Geology and Geography. The results provided a lot of new information on soil weathering rates in Lithuania. The 47 and 157-year-old European larch (Larix decidua Mill.), 45 and 55-year-old Northern red oak (Quercus rubra L.) plantations and adjacent perennial grasslands were chosen for this study. The soils were classified as Luvisols and were developed from glaciofluvial deposits. The PROFILE model requires data of climate conditions (mean annual temperature and precipitation), chemical parameters of atmospheric deposition, forest plantation dendrometric and chemical (wood, foliage litter fall) characteristics, soil physical characteristics and mineral composition. A cation weathering rate (sum of Ca+Mg+ K) is 30% higher in a soil under the Northern red oak than in adjacent perennial grassland. Meanwhile, cation weathering rates

  18. Soil sustainability study in Lithuanian alien forest stands

    NASA Astrophysics Data System (ADS)

    Čiuldiene, Dovile; Skridlaite, Grazina; Žalūdiene, Gaile; Askelsson, Cecilia; Armolaitis, Kestutis

    2016-04-01

    Tree species are shifting their natural ranges in response to climate changes (Saltré et al., 2013). Northern red oak has originated from North America, but was planted in Europe already in twentieth century. At present, it is considered as invasive species in Poland and at invasive stage in the Lithuanian forests (Riepsas and Straigyte, 2008). European larch naturally grows in Central Europe, but its range has been extended by planting it as far as the Nordic countries. According to a pollen study in peat soils, European larch naturally grew in Lithuania in the sixteenth century and was reintroduced 200 years ago (Jankauskas, 1954). Therefore, the global warming could accelerate the expansion of European larch and Northern red oak into Lithuanian forests. An urgent need appeared to evaluate an impact of those warmth-tolerant species on soil mineral chemistry and quality. New results on the determination of mineral weathering rates in alien forest stands using a PROFILE soil chemistry model were obtained during a doctoral study at the Institute of Forestry. Soil minerals were studied by a Scanning Electron Microscopy at the Institute of Geology and Geography. The results provided a lot of new information on soil weathering rates in Lithuania. The 47 and 157-year-old European larch (Larix decidua Mill.), 45 and 55-year-old Northern red oak (Quercus rubra L.) plantations and adjacent perennial grasslands were chosen for this study. The soils were classified as Luvisols and were developed from glaciofluvial deposits. The PROFILE model requires data of climate conditions (mean annual temperature and precipitation), chemical parameters of atmospheric deposition, forest plantation dendrometric and chemical (wood, foliage litter fall) characteristics, soil physical characteristics and mineral composition. A cation weathering rate (sum of Ca+Mg+ K) is 30% higher in a soil under the Northern red oak than in adjacent perennial grassland. Meanwhile, cation weathering rates

  19. Climate change impairs processes of soil and plant N cycling in European beech forests on marginal soil

    NASA Astrophysics Data System (ADS)

    Tejedor, Javier; Gasche, Rainer; Gschwendtner, Silvia; Leberecht, Martin; Bimüller, Carolin; Kögel-Knabner, Ingrid; Pole, Andrea; Schloter, Michael; Rennenberg, Heinz; Simon, Judy; Hanewinkel, Marc; Baltensweiler, Andri; Bilela, Silvija; Dannenmann, Michael

    2014-05-01

    Beech forests of Central Europe are covering large areas with marginal calcareous soils, but provide important ecological services and represent a significant economical value. The vulnerability of these ecosystems to projected climate conditions (higher temperatures, increase of extreme drought and precipitation events) is currently unclear. Here we present comprehensive data on the influence of climate change conditions on ecosystem performance, considering soil nitrogen biogeochemistry, soil microbiology, mycorrhiza ecology and plant physiology. We simultaneously quantified major plant and soil gross N turnover processes by homogenous triple 15N isotope labeling of intact beech natural regeneration-soil-microbe systems. This isotope approach was combined with a space for time climate change experiment, i.e. we transferred intact beech seedling-soil-microbe mesocosms from a slope with N-exposure (representing present day climate conditions) to a slope with S exposure (serving as a warmer and drier model climate for future conditions). Transfers within N slope served as controls. After an equilibration period of 1 year, three isotope labeling/harvest cycles were performed. Reduced soil water content resulted in a persistent decline of ammonia oxidizing bacteria in soil (AOB). Consequently, we found a massive five-fold reduction of gross nitrification in the climate change treatment and a subsequent strong decline in soil nitrate concentrations as well as nitrate uptake by microorganisms and beech. Because nitrate was the major nutrient for beech in this forest type with little importance of ammonium and amino acids, this resulted in a strongly reduced performance of beech natural regeneration with reduced N content, N metabolite concentrations and plant biomass. These findings provided an explanation for a large-scale decline of distribution of beech forests on calcareous soils in Europe by almost 80% until 2080 predicted by statistical modeling. Hence, we

  20. A soil burn severity index for understanding soil-fire relations in tropical forests

    USGS Publications Warehouse

    Jain, T.B.; Gould, W.A.; Graham, R.T.; Pilliod, D.S.; Lentile, L.B.; Gonzalez, G.

    2008-01-01

    Methods for evaluating the impact of fires within tropical forests are needed as fires become more frequent and human populations and demands on forests increase. Short- and long-term fire effects on soils are determined by the prefire, fire, and postfire environments. We placed these components within a fire-disturbance continuum to guide our literature synthesis and develop an integrated soil burn severity index. The soil burn severity index provides a set of indicators that reflect the range of conditions present after a fire. The index consists of seven levels, an unburned level and six other levels that describe a range of postfire soil conditions. We view this index as a tool for understanding the effects of fires on the forest floor, with the realization that as new information is gained, the index may be modified as warranted. ?? Royal Swedish Academy of Sciences 2008.

  1. The mesofauna in different types of soils under southern taiga spruce forests (Tver oblast)

    NASA Astrophysics Data System (ADS)

    Gryuntal, S. Yu.

    2010-11-01

    The soil mesofauna of the burozem, soddy pale-podzolic, and whitish-podzolic soils under three types of southern taiga spruce forests was studied. The mesofauna of all these soils turned out to be similar in terms of the Chilopoda, Staphylinidae (Coleoptera), and Rhagionidae (Diptera) numbers and their predominant concentration in the litter. The zoophages prevailed, and, among the saprophages, primary destroyers were predominant. However, some specific characteristics of the mesofauna in the soils studied were revealed. In the sequence burozem, soddy pale-podzolic, and whitish-podzolic soils, the number of earthworms significantly decreased, while, in the sequence soddy pale-podzolic, burozem, and whitish-podzolic soils, the number of Diplopoda representatives and calciphilic forms became lower and was directly related to the diversity of the deciduous tree species and to the presence of the calcareous moraine close to the surface. In addition, some species can be indicators of particular soil properties. The presence of the road beetle Quedius fuliginosus indicated the elevated moisture of the soils, that of Philonthus decorus pointed to the high humus content, and the presence of the road beetle Tachinus marginellus showed the low acidity of the humus. The low number or the absence of the earthworms Octolasium lacteum and Dendrodril us rubidus f. tenuis indicated higher humus acidity.

  2. Effects of drought on forest soil structure and hydrological soil functions

    NASA Astrophysics Data System (ADS)

    Gimbel, K.; Puhlmann, H.; Weiler, M.

    2012-04-01

    Climate change is predicted to severely affect precipitation patterns across central Europe. Soil structure is closely linked to the activity of soil microbiota and plant roots, which modify flow pathways along roots, organic matter and water repellence of soils. Through shrinkage and fracturing of soil aggregates, soil structure is also responding to changing climate (in particular drought) conditions. We investigate the possible effects on biogeochemical and hydropedological processes in response to predicted future reduced precipitation, and the interaction of these processes with the biodiversity of the forest understorey and soil biota. The hypotheses of this study are: (i) drought causes a change in soil structure, which affects hydrological soil functions (water infiltration, uptake and redistribution); (ii) changes in rooting patterns and microbial community composition, in response to drought, influence the hydrological soil functions. To test our hypotheses, we built adaptive roofing systems on nine sites in Germany, which allow a flexible reduction of precipitation in order to achieve the long-term minimum precipitation of a site. Here we present first measurements of our repeated measuring/sampling campaign, which will be conducted over a period of three years. The aim of our experiments is to analyze soil pore architecture and related flow and transport behaviour with dye tracer sprinkling experiments, soil column experiments with stable isotope (deuterium, oxygen-18) enriched water, computed tomography at soil monoliths (~70 l) and multi-step outflow experiments with 100 ml soil cores. Finally, we sketch our idea how to relate the observed temporal changes of soil structure and hydrological soil functions to the observed dynamics of hydrometeorological site conditions, soil moisture and desiccation as well as changes in rooting patterns, herb layer and soil microbiotic communities. The results of this study may help to assess future behavior of the

  3. Effects of acid rain on forest nutrient status

    SciTech Connect

    Johnson, D.W.; Turner, J.; Kelly, J.M.

    1982-06-01

    The paper presents an extensive literature review that deals with the assessment of the effects of acidic atmospheric inputs on forest nutrient status within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire and fertilization. 123 refs.

  4. Forest floor leaching: contributions from mineral, organic, and carbonic acids in new hampshire subalpine forests.

    PubMed

    Cronan, C S; Reiners, W A; Reynolds, R C; Lang, G E

    1978-04-21

    Analyses of soil water and groundwater samples from a high-elevation coniferous ecosystem in New England indicate that sulfate anions supply 76 percent of the electrical charge balance in the leaching solution. This result implies that atmospheric inputs of sulfuric acid provide the dominant source of both H(+) for cation replacement and mobile anions for cation transport in subalpine soils of the northeastern region affected by acid precipitation. In soils of relatively unpolluted regions, carbonic and organic acids dominate the leaching processes.

  5. Greenhouse Gas Fluxes from Forested Wetland and Upland Soils

    NASA Astrophysics Data System (ADS)

    Savage, K. E.; Davidson, E. A.

    2015-12-01

    Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are the most important greenhouse gases. Soils are the dominant natural source of N2O, and have been shown to be a small sink under N-limited conditions. Wetlands are a significant natural source of CH4, and dry upland soils a natural CH4 sink. Soils release CO2 produced by both autotrophic (root) and heterotrophic (microbial) respiration processes. Variation in soil moisture can be very dynamic, and it is one of the dominant factors controlling soil aeration, and hence the balance between aerobic (predominantly CO2 producing) and anaerobic (both CO2 and CH4 producing) respiration. The production and consumption of N2O is also highly dependent on spatial and temporal variation in soil moisture. Howland forest, ME is a mosaic of well drained upland, wetland and small transitional upland/wetland soils which makes for a unique and challenging environment to measure the effects of soil moisture on the net exchange of these important greenhouse gases. To quantify the flux of CO2, CH4 and N2O from the Howland forest soils, we utilized a previously developed automated chamber system for measuring CO2 efflux (Licor 6252 IRGA) from soils, and configured it to run in-line with a new model quantum cascade laser (QCL) system which measures N2O and CH4 (Aerodyne model QC-TILDAS-CS). This system allowed for simultaneous, high frequency, continuous measurement of all three greenhouse gases. Fourteen sampling chambers were deployed in an upland soil (8), nearby wetland (3) and a transitional upland/wetland (3). Each chamber was measured every 90 minutes. Upland soils were consistent sources of CO2 and sinks for CH4, however the N2O fluxes were transient between sources and sinks. The wetland soils were consistent sources of high CH4 emissions, low CO2 emissions and a consistently small N2O sink. The transitional upland/wetland soil was a consistent source of CO2 but was much more transient between CH4 and N2O sources and

  6. Forest type affects the coupled relationships of soil C and N mineralization in the temperate forests of northern China.

    PubMed

    Quan, Quan; Wang, Changhui; He, Nianpeng; Zhang, Zhen; Wen, Xuefa; Su, Hongxin; Wang, Qing; Xue, Jingyue

    2014-01-01

    Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q10) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C:N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q10 values of soil C and N mineralization. The activation energy (Ea) of soil C and N mineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change. PMID:25322802

  7. Forest type affects the coupled relationships of soil C and N mineralization in the temperate forests of northern China

    PubMed Central

    Quan, Quan; Wang, Changhui; He, Nianpeng; Zhang, Zhen; Wen, Xuefa; Su, Hongxin; Wang, Qing; Xue, Jingyue

    2014-01-01

    Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q10) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C:N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q10 values of soil C and N mineralization. The activation energy (Ea) of soil C and N mineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change. PMID:25322802

  8. [Bacterial community structure and diversity in soils of different forest ages and types in Bao- tianman forest, Henan Province, China].

    PubMed

    Bai, Xiao-xu; Shi, Rong-ju; You, Ye-ming; Sheng, Hua-fang; Han, Si-qin; Zhang, Ying

    2015-08-01

    To compare the microbial compositions and diversities in soils of different forest ages and types in Baotianman forest, Henan Province, China, genomic DNA of forest soils was extracted for amplifying the 16S rRNA V4 hyper variable region by PCR and sequencing by Illumina MiSeq. The BIPES, UCHIME and QIIME were employed to analyze the soil bacterial community. It was shown that 60 phyla were identified, with Proteobacteria, Acidobacteria, and Verrucomicrobia representing the most dominant lineages and accounting for 29%, 18.5% and 10% of all sequences, respectively. At the genus level, 1209 genera were identified, the most abundant phylotypes were DA101 (6.3%), Acidobacteria-2 (5.9%), Candidatus Solibacter (2.9%) and Candidatus Nitrososphaera (2.6%). Different forest age and type soil samples had unique compositions and specific high and rare genus. Forest type and age both impacted the soil microbial community structure, and the influence of the former was stronger than the latter. The soil microbial diversity of the 80-year-old Quercus aliena forest was the lowest among all age and type forest soil samples. Soil pH, soil nitrogen and organic carbon contents were the most important factors affecting soil bacterial community structure.

  9. Comparison of the carbon stock in forest soil of sessile oak and beech forests

    NASA Astrophysics Data System (ADS)

    Horváth, Adrienn; Bene, Zsolt; Bidló, András

    2016-04-01

    Forest ecosystems are the most important carbon sinks. The forest soils play an important role in the global carbon cycle, because the global climate change or the increase of atmospheric CO2 level. We do not have enough data about the carbon stock of soils and its change due to human activities, which have similar value to carbon content of biomass. In our investigation we measured the carbon stock of soil in 10 stands of Quercus petraea and Fagus sylvatica. We took a 1.1 m soil column with soil borer and divided to 11 samples each column. The course organic and root residues were moved. After evaluation, we compared our results with other studies and the carbon stock of forests to each other. Naturally, the amount of SOC was the highest in the topsoil layers. However, we found significant difference between forest stands which stayed on the same homogenous bedrock, but very close to each other (e.g. distance was 1 or 2 km). We detected that different forest utilizations and tree species have an effect on the forest carbon as the litter as well (amount, composition). In summary, we found larger amount (99.1 C t/ha on average) of SOC in soil of stands, where sessile oak were the main stand-forming tree species. The amount of carbon was the least in turkey oak-sessile oak stands (85.4 C t/ha on average). We found the highest SOC (118.3 C t/ha) in the most mixed stand (silver lime-beech-red oak). In the future, it will be very important: How does climate change affect the spread of tree species or on carbon storage? Beech is more sensitive, but even sessile oak. These species are expected to replace with turkey oak, which is less sensitive to drought. Thus, it is possible in the future that we can expect to decrease of forest soil carbon stock capacity, which was confirmed by our experiment. Keywords: carbon sequestration, mitigation, Fagus sylvatica, Quercus petraea, litter Acknowledgements: Research is supported by the "Agroclimate.2" (VKSZ_12-1-2013-0034) EU

  10. Micromonospora zhanjiangensis sp. nov., isolated from mangrove forest soil.

    PubMed

    Zhang, Li; Li, Lei; Deng, Zixin; Hong, Kui

    2015-12-01

    A novel actinomycete, designated strain 2902at01T was isolated from soil collected at a mangrove forest in Zhanjiang, Guangdong province, China. The strain was identified using a polyphasic classification method. The 16S rRNA gene sequence of strain 2902at01T showed the highest similarity to Micromonospora equina Y22T (98.3 %) and Micromonospora pattaloongensis TJ2-2T (98.1 %). Phylogenetic analysis based on the gyrB gene sequence also clearly showed that the strain was different from any previously discovered species of the genus Micromonospora. The characteristic whole-cell sugars were ribose and xylose. The cell-wall hydrolysates contained alanine, asparagine, glycine and meso-diaminopimelic acid. MK-10(H6) and MK-10(H8) were the major menaquinones of the novel strain. The predominant fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. The characteristic polar lipids of strain 2902at01T were phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and diphosphatidylglycerol. The DNA G+C content was 70.2 mol%. DNA-DNA hybridization data combined with other physiological and biochemical features could distinguish strain 2902at01T from the reference strains M. equina Y22T and M. pattaloongensis TJ2-2 T. On the basis of these phenotypic and genotypic data, strain 2902at01T represents a novel species of the genus Micromonospora, for which the name Micromonospora zhanjiangensis sp. nov. is proposed. The type strain is 2902at01T ( = CCTCC AA2014018T = DSM 45902T). PMID:26446196

  11. Impact of Native and Invasive Earthworm Activity on Forest Soil Organic Matter Dynamics

    NASA Astrophysics Data System (ADS)

    Top, Sara; Filley, Timothy

    2010-05-01

    Many northern North American forests are experiencing the introduction of exotic European lumbricid species earthworms with documented losses in litter layers, expansion of A-horizons, loss of the organic horizon, changes in fine root density, and shifts in microbial populations as a result. Some of these forests were previously devoid of these ecosystem engineers. We compare the soil isotope and molecular chemistry from two free air CO2 enrichment (FACE) forest experiments (aspen FACE at Rhinelander, Wisconsin and sweet gum FACE at Oak Ridge National Lab, Tennessee) that lie within the zones of earthworm invasion. These sites exhibit differences in amounts of exotic and native species as well as endogeic (predominantly mineral soil dwelling) and epigeic (litter and organic matter horizon dwelling) types. We investigated the impact of earthworm activity by tracking the relative abundance and stable carbon isotope compositions of lignin and substituted fatty acids extracted from isolated earthworms and their fecal pellets and from host soils. Additionally, 15N-labeled additions to the soil provide additional methods for tracking earthworm impacts. Indications of root vs leaf input to earthworm casts and fecal matter were derived from differences in the chemical composition of cutin, suberin, and lignin. The isotopically depleted CO2 used in FACE and the resulting isotopically depleted plant organic matter afford an excellent opportunity to assess biopolymer-specific turnover dynamics. We find that endogeic species are proportionately more responsible for fine root cycling while some epigeic species are responsible for microaggregation of foliar cutin. CSIA of fecal pellet lignin and SFA indicate how these biopolymer pools can be derived from variable sources, roots, background soil, foliar tissue within one earthworm. Additionally, CSIA indicates the distinct roles that different earthworm types have in "aging" surface soil biopolymer pools through encapsulation and

  12. Soil microclimate monitoring in forested and meadow sites

    NASA Astrophysics Data System (ADS)

    Freyerova, Katerina; Safanda, Jan

    2016-04-01

    It is well known fact that forest microclimate differs from open area microclimate (Geiger 1965). Less attention is paid to soil temperatures and their long-term monitoring. To evaluate and compare these two environments from the soil microclimate point of view, Institute of Geophysics in Prague monitors soil and air temperatures in Bedřichov in the Jizerské Hory Mountains (Czech Republic). The soil temperatures are measured in three depths (20, 50 and 100 cm) in forest (700 m a. s. l.) and meadow (750 m a. s. l.). Air temperatures are measured at 2m height both in forest and meadow. Nowadays, we have more than three years long time series. The most of studies and experiments described in literature are short-term ones (in order of days or weeks). However, from short-term experiments the seasonal behaviour and trends can be hardly identified and conclusions on soil temperature reaction to climatic extremes such as heat waves, drought or freeze cannot be done with confidence. These drawbacks of the short-term experiments are discussed in literature (eg. Morecroft et al. 1998; Renaud et al. 2011). At the same, with progression of the global warming, the expected increasing frequency of climatic extremes will affect the future form of forest vegetation (Von Arx et al. 2012). The soil and air temperature series, both from the forest and meadow sites, are evaluated and interpreted with respect to long term temperature characteristics and seasonal trends. The emphasis is given on the soil temperature responses to extreme climatic situations. We examine variability between the localities and depths and spatial and temporal changes in this variability. This long-term monitoring allows us to better understand and examine the behaviour of the soil temperature in extreme weather situations. Therefore, we hope to contribute to better prediction of future reactions of this specific environments to the climate change. Literature Geiger, R., 1965. The climate near the ground

  13. Soil microclimate monitoring in forested and meadow sites

    NASA Astrophysics Data System (ADS)

    Freyerova, Katerina; Safanda, Jan

    2016-04-01

    It is well known fact that forest microclimate differs from open area microclimate (Geiger 1965). Less attention is paid to soil temperatures and their long-term monitoring. To evaluate and compare these two environments from the soil microclimate point of view, Institute of Geophysics in Prague monitors soil and air temperatures in Bedřichov in the Jizerské Hory Mountains (Czech Republic). The soil temperatures are measured in three depths (20, 50 and 100 cm) in forest (700 m a. s. l.) and meadow (750 m a. s. l.). Air temperatures are measured at 2m height both in forest and meadow. Nowadays, we have more than three years long time series. The most of studies and experiments described in literature are short-term ones (in order of days or weeks). However, from short-term experiments the seasonal behaviour and trends can be hardly identified and conclusions on soil temperature reaction to climatic extremes such as heat waves, drought or freeze cannot be done with confidence. These drawbacks of the short-term experiments are discussed in literature (eg. Morecroft et al. 1998; Renaud et al. 2011). At the same, with progression of the global warming, the expected increasing frequency of climatic extremes will affect the future form of forest vegetation (Von Arx et al. 2012). The soil and air temperature series, both from the forest and meadow sites, are evaluated and interpreted with respect to long term temperature characteristics and seasonal trends. The emphasis is given on the soil temperature responses to extreme climatic situations. We examine variability between the localities and depths and spatial and temporal changes in this variability. This long-term monitoring allows us to better understand and examine the behaviour of the soil temperature in extreme weather situations. Therefore, we hope to contribute to better prediction of future reactions of this specific environments to the climate change. Literature Geiger, R., 1965. The climate near the ground

  14. Acid rain on Acid soil: a new perspective.

    PubMed

    Krug, E C; Frink, C R

    1983-08-01

    Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

  15. Soil organic matter cycling in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Norris, C. E.; Mercier Quideau, S.

    2013-12-01

    The uplands of the western boreal forest of Canada are characterized by a mosaic of pure and mixed stands of aspen (Populus tremuloides Michx.) and spruce (Picea glauca (Moench) Voss). In addition to natural ecosystems, the region is now home to novel ecosystems; i.e., ecosystems composed of reclaimed stands formed from trees planted on constructed anthropogenic soils. To understand potential differences in functioning of these novel ecosystems, we must first better understand the functioning of their natural counterparts. Here we present results on both the characterization and cycling of soil organic matter in novel and natural ecosystems found in the Athabasca oil sands region. Soil organic matter from 42 long term monitoring sites was evaluated for long chain (≥ C21) n-alkane composition. The survey showed that n-alkanes were more concentrated and had distinct signatures in natural compared to novel ecosystems. Mineral soils from reclaimed stands showed a distinct microbial community structure from natural aspen and spruce stands, as was demonstrated using phospholipid fatty acids (PLFAs) as microbial biomarkers following addition of 13C-glucose in a laboratory incubation. Further probing by compound specific analysis of the 13C-enriched PLFAs determined that microbial incorporation of 13C-glucose was different among soils. In a field incubation using 15N labeled aspen litter added to the forest floor of reclaimed, harvested and mature natural aspen stands, the microbial community readily incorporated the tracer and nitrogen was cycled to the above-ground vegetation on all sites. In addition, the amendment of leaf litter to the forest floor also increased soil moisture and soil microbial biomass on both the reclaimed and harvested sites. Utilizing stable isotope tracers in addition to a multi-faceted experimental approach has provided insightful results on the development of soil biogeochemical cycling in novel ecosystems.

  16. Effects of Forest Age on Soil Autotrophic and Heterotrophic Respiration Differ between Evergreen and Deciduous Forests

    PubMed Central

    Wang, Wei; Zeng, Wenjing; Chen, Weile; Yang, Yuanhe; Zeng, Hui

    2013-01-01

    We examined the effects of forest stand age on soil respiration (SR) including the heterotrophic respiration (HR) and autotrophic respiration (AR) of two forest types. We measured soil respiration and partitioned the HR and AR components across three age classes ∼15, ∼25, and ∼35-year-old Pinus sylvestris var. mongolica (Mongolia pine) and Larix principis-rupprechtii (larch) in a forest-steppe ecotone, northern China (June 2006 to October 2009). We analyzed the relationship between seasonal dynamics of SR, HR, AR and soil temperature (ST), soil water content (SWC) and normalized difference vegetation index (NDVI, a plant greenness and net primary productivity indicator). Our results showed that ST and SWC were driving factors for the seasonal dynamics of SR rather than plant greenness, irrespective of stand age and forest type. For ∼15-year-old stands, the seasonal dynamics of both AR and HR were dependent on ST. Higher Q10 of HR compared with AR occurred in larch. However, in Mongolia pine a similar Q10 occurred between HR and AR. With stand age, Q10 of both HR and AR increased in larch. For Mongolia pine, Q10 of HR increased with stand age, but AR showed no significant relationship with ST. As stand age increased, HR was correlated with SWC in Mongolia pine, but for larch AR correlated with SWC. The dependence of AR on NDVI occurred in ∼35-year-old Mongolia pine. Our study demonstrated the importance of separating autotrophic and heterotrophic respiration components of SR when stimulating the response of soil carbon efflux to environmental changes. When estimating the response of autotrophic and heterotrophic respiration to environmental changes, the effect of forest type on age-related trends is required. PMID:24282560

  17. Effects of forest age on soil autotrophic and heterotrophic respiration differ between evergreen and deciduous forests.

    PubMed

    Wang, Wei; Zeng, Wenjing; Chen, Weile; Yang, Yuanhe; Zeng, Hui

    2013-01-01

    We examined the effects of forest stand age on soil respiration (SR) including the heterotrophic respiration (HR) and autotrophic respiration (AR) of two forest types. We measured soil respiration and partitioned the HR and AR components across three age classes ~15, ~25, and ~35-year-old Pinus sylvestris var. mongolica (Mongolia pine) and Larix principis-rupprechtii (larch) in a forest-steppe ecotone, northern China (June 2006 to October 2009). We analyzed the relationship between seasonal dynamics of SR, HR, AR and soil temperature (ST), soil water content (SWC) and normalized difference vegetation index (NDVI, a plant greenness and net primary productivity indicator). Our results showed that ST and SWC were driving factors for the seasonal dynamics of SR rather than plant greenness, irrespective of stand age and forest type. For ~15-year-old stands, the seasonal dynamics of both AR and HR were dependent on ST. Higher Q10 of HR compared with AR occurred in larch. However, in Mongolia pine a similar Q10 occurred between HR and AR. With stand age, Q10 of both HR and AR increased in larch. For Mongolia pine, Q10 of HR increased with stand age, but AR showed no significant relationship with ST. As stand age increased, HR was correlated with SWC in Mongolia pine, but for larch AR correlated with SWC. The dependence of AR on NDVI occurred in ~35-year-old Mongolia pine. Our study demonstrated the importance of separating autotrophic and heterotrophic respiration components of SR when stimulating the response of soil carbon efflux to environmental changes. When estimating the response of autotrophic and heterotrophic respiration to environmental changes, the effect of forest type on age-related trends is required.

  18. Density and pathogenic activity of soil microbes associated with windthrows of temperate deciduous forests in the Allegany national Forest, Pennsylvania

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background/Question/Methods Forest disturbance caused by windthrow events has obvious impacts on forest structure and composition above-ground; however, changes in soil microbial communities are less obvious. Windthrows causing the formation of multiple forest gaps occurred in 2003 throughout the...

  19. [Vertical distribution of soil active carbon and soil organic carbon storage under different forest types in the Qinling Mountains].

    PubMed

    Wang, Di; Geng, Zeng-Chao; She, Diao; He, Wen-Xiang; Hou, Lin

    2014-06-01

    Adopting field investigation and indoor analysis methods, the distribution patterns of soil active carbon and soil carbon storage in the soil profiles of Quercus aliena var. acuteserrata (Matoutan Forest, I), Pinus tabuliformis (II), Pinus armandii (III), pine-oak mixed forest (IV), Picea asperata (V), and Quercus aliena var. acuteserrata (Xinjiashan Forest, VI) of Qinling Mountains were studied in August 2013. The results showed that soil organic carbon (SOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), and easily oxidizable carbon (EOC) decreased with the increase of soil depth along the different forest soil profiles. The SOC and DOC contents of different depths along the soil profiles of P. asperata and pine-oak mixed forest were higher than in the other studied forest soils, and the order of the mean SOC and DOC along the different soil profiles was V > IV > I > II > III > VI. The contents of soil MBC of the different forest soil profiles were 71.25-710.05 mg x kg(-1), with a content sequence of I > V > N > III > II > VI. The content of EOC along the whole soil profile of pine-oak mixed forest had a largest decline, and the order of the mean EOC was IV > V> I > II > III > VI. The sequence of soil organic carbon storage of the 0-60 cm soil layer was V > I >IV > III > VI > II. The MBC, DOC and EOC contents of the different forest soils were significanty correlated to each other. There was significant positive correlation among soil active carbon and TOC, TN. Meanwhile, there was no significant correlation between soil active carbon and other soil basic physicochemical properties.

  20. Tropical forest soil microbial communities couple iron and carbon biogeochemistry

    SciTech Connect

    Dubinsky, E.A.; Silver, W.L.; Firestone, M.K.

    2009-10-15

    We report that iron-reducing bacteria are primary mediators of anaerobic carbon oxidation in upland tropical soils spanning a rainfall gradient (3500 - 5000 mm yr-1) in northeast Puerto Rico. The abundant rainfall and high net primary productivity of these tropical forests provide optimal soil habitat for iron-reducing and iron-oxidizing bacteria. Spatially and temporally dynamic redox conditions make iron-transforming microbial communities central to the belowground carbon cycle in these wet tropical forests. The exceedingly high abundance of iron-reducing bacteria (up to 1.2 x 10{sup 9} cells per gram soil) indicated that they possess extensive metabolic capacity to catalyze the reduction of iron minerals. In soils from the higher rainfall sites, measured rates of ferric iron reduction could account for up to 44 % of organic carbon oxidation. Iron reducers appeared to compete with methanogens when labile carbon availability was limited. We found large numbers of bacteria that oxidize reduced iron at sites with high rates of iron reduction and large numbers of iron-reducers. the coexistence of large populations of ironreducing and iron-oxidizing bacteria is evidence for rapid iron cycling between its reduced and oxidized states, and suggests that mutualistic interactions among these bacteria ultimately fuel organic carbon oxidation and inhibit CH4 production in these upland tropical forests.

  1. Evaporation Dynamics of Moss and Bare Soil in Boreal Forests

    NASA Astrophysics Data System (ADS)

    Dempster, S.; Young, J. M.; Barron, C. G.; Bolton, W. R.

    2013-12-01

    Evaporation dynamics of mosses is a critical process in boreal and arctic systems and represents a key uncertainty in hydrology and climate models. At this point, moss evaporation is not well quantified at the plot or landscape scale. Relative to bare soil or litter evaporation, moss evaporation can be challenging to predict because the water flux is not isolated to the moss surface. Evaporation can originate from nearly 10 cm below the surface. Some mosses can wick moisture from even deeper than 10 cm, which subsequently evaporates. The goal of this study was to use field measurements to quantify the moss evaporation dynamics in a coniferous forest relative to bare ground or litter evaporation dynamics in a deciduous forest in Interior Alaska. Measurements were made in two ecosystem types within the boreal forest of Interior Alaska: a deciduous forest devoid of moss and a coniferous forest with a thick moss layer. A small clear chamber was attached to a LiCor 840 infrared gas analyzer in a closed loop system with a low flow rate. Water fluxes were measured for ~ 90 seconds on each plot in dry and wet soil and moss conditions. Additional measurements included: soil temperature, soil moisture, air temperature, barometric pressure, dew point, relative humidity, and wind speed. Thermal infrared images were also captured in congruence with water flux measurements to determine skin temperature. We found that the moss evaporation rate was over 100% greater than the soil evaporation rate (0.057 g/min vs. 0.024 g/min), and evaporation rates in both systems were most strongly driven by relative humidity and surface temperature. Surface temperature was lower at the birch site than the black spruce site because trees shade the surface beneath the birch. High fluxes associated with high water content were sustained for a longer period of time over the mosses compared to the bare soil. The thermal IR data showed that skin temperature lagged the evaporation flux, such that the

  2. Effects of CO[sub 2] and climate change on forest trees: Soil biology and enzymology

    SciTech Connect

    Moldenke, A.R.; Baumeister, N.; Caldwell, B.A.; Griffith, R.; Ingham, E.R.; Wernz, J. ); Johnson, M.G.; Rygiewicz, P.T.; Tingey, D.T. )

    1994-06-01

    Samples of Teracosm soils were analyzed shortly after initial setup to determine whether initial conditions were equivalent and matched expected values for local soils. Total and active fungal biomass, active bacterial biomass and protozoan numbers were reduced, with greatest decreases occurring in the A horizon. No effect was observed on total bacterial biomass, nematode or anthropod densities, but changes in nematode and arthropod species composition occurred. Significant differences in total density and species composition occurred between the enclosed Teracosms and the open controls. Arthropod and nematode community structure in the three altitudinal field sites had significantly diverged. No significant differences in activities of key soil enzymes in C- and N-cycling (acid phosphatase, protease, B-glucosidase, phenol oxidase and peroxidase) were found between initial samples relative to treatment, but all levels were significantly difference relative to depth in soil profile. Activities were within ranges previously observed in forests of the Pacific Northwest.

  3. Soil acidification and foliar nutrient status of Ontario's deciduous forest in 1986 and 2005.

    PubMed

    Miller, Diane E; Watmough, Shaun A

    2009-02-01

    To assess the impacts of the decline in sulphur (S) deposition over the past 20 years in Ontario, soil chemistry and sugar maple (Acer saccharum Marsh) foliar chemistry were measured at 17 sites in south and central Ontario in 2005 and compared with archived samples collected in 1986. Foliar S concentrations were lower in 2005, reflecting the decline in S deposition whereas foliar N remained unchanged, reflecting the lack of change in N deposition in Ontario. Mineral soil pH, exchangeable base cations were lower in 2005 whereas total S, N and cation exchange capacity (CEC) were unchanged. Foliar concentrations of Ca were positively related to soil Ca levels in the A-horizon and were lower in 2005. Despite evidence of increasing soil acidity and losses of calcium, foliar base cation concentrations at most sites were adequate for sugar maple and forest health in terms of canopy appearance (Decline Index) improved.

  4. Fluxes of trichloroacetic acid through a conifer forest canopy.

    PubMed

    Stidson, R T; Heal, K V; Dickey, C A; Cape, J N; Heal, M R

    2004-11-01

    Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, approximately 1.4 x rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only approximately 1-2% of above-canopy deposition. On average, approximately 800 microg m(-2) of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of approximately 400 and approximately 300 microg m(-2) for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values ( approximately +/- 50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50-200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric

  5. Characteristics and formation of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines

    NASA Astrophysics Data System (ADS)

    Navarrete, Ian A.; Tsutsuki, Kiyoshi; Asio, Victor B.; Kondo, Renzo

    2009-09-01

    This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation of 75-112 m above sea level with an average annual rainfall of 3,000 mm and an average temperature of 28°C. Results indicate that the soils are deep, clayey, and reddish in color, which is indicative of the advanced stage of soil development. They also posses excellent physical condition (friable and highly porous) although they are plastic and sticky when wet as is usual for clayey soils. In terms of chemical characteristics, the soils are acidic with low CEC values and generally low in organic matter and nutrient contents. The clay mineralogy of the soils is dominated by halloysite and kaolinite with minor amounts of goethite and hematite, and they also have generally high dithionite-extractable Fe contents confirming the advanced stage of their development. The soils in the more stable slope positions (PL-1, PL-2, and PL-4) have generally similar characteristics and appeared more developed than the one in the less stable position (PL-3). The most important pedogenic processes that formed the soils appear to be weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation, and structure formation. The nature of the parent rock and climatic conditions prevailing in the area as well as slope position appear to have dominant effects on the development of the soils.

  6. Soil properties in the Tol'yatti pine forest after the 2010 catastrophic wildfires

    NASA Astrophysics Data System (ADS)

    Maksimova, E. Yu.; Tsibart, A. S.; Abakumov, E. V.

    2014-09-01

    The results of the studies of soil changes after the 2010 fires in the forest outliers of the city of Tolyatti have been reviewed. The morphological analysis of postpyrogenic soils has showed that the fire touched only the upper part of their profiles. It has been revealed that the surface fires favor the more intense loss of organic carbon than the crown fires (2.85 and 2.37%, respectively). However, the crown fires are more destructive for soils, because, first, they are a continuation of the surface fires and, second, sheet and linear water erosion of soils develops because of the complete denudation of the soil cover. It has been found that forest fires result in the dehumification of soils, which is related to the destruction of the organic horizons, the mineralization of root residues, and the almost complete absence of fresh plant waste on the postfire areas. The pyrogenic impact increases the portion of humic acids in the organic matter. Along with the transfer of the clay fraction, the translocation of polycyclic aromatic hydrocarbons resulting from the fires to the accumulative geochemical positions is also possible.

  7. Growth of ectomycorrhizal mycelia and composition of soil microbial communities in oak forest soils along a nitrogen deposition gradient.

    PubMed

    Nilsson, Lars Ola; Bååth, Erland; Falkengren-Grerup, Ursula; Wallander, Håkan

    2007-08-01

    Deciduous forests may respond differently from coniferous forests to the anthropogenic deposition of nitrogen (N). Since fungi, especially ectomycorrhizal (EM) fungi, are known to be negatively affected by N deposition, the effects of N deposition on the soil microbial community, total fungal biomass and mycelial growth of EM fungi were studied in oak-dominated deciduous forests along a nitrogen deposition gradient in southern Sweden. In-growth mesh bags were used to estimate the production of mycelia by EM fungi in 19 oak stands in the N deposition gradient, and the results were compared with nitrate leaching data obtained previously. Soil samples from 154 oak forest sites were analysed regarding the content of phospholipid fatty acids (PLFAs). Thirty PLFAs associated with microbes were analysed and the PLFA 18:2omega6,9 was used as an indicator to estimate the total fungal biomass. Higher N deposition (20 kg N ha(-1)y(-1) compared with 10 kg N ha(-1)y(-1)) tended to reduce EM mycelial growth. The total soil fungal biomass was not affected by N deposition or soil pH, while the PLFA 16:1omega5, a biomarker for arbuscular mycorrhizal (AM) fungi, was negatively affected by N deposition, but also positively correlated to soil pH. Other PLFAs positively affected by soil pH were, e.g., i14:0, a15:0, 16:1omega9, a17:0 and 18:1omega7, while some were negatively affected by pH, such as i15:0, 16:1omega7t, 10Me17:0 and cy19:0. In addition, N deposition had an effect on the PLFAs 16:1omega7c and 16:1omega9 (negatively) and cy19:0 (positively). The production of EM mycelia is probably more sensitive to N deposition than total fungal biomass according to the fungal biomarker PLFA 18:2omega6,9. Low amounts of EM mycelia covaried with increased nitrate leaching, suggesting that EM mycelia possibly play an important role in forest soil N retention at increased N input.

  8. Reduced deep soil water uptake through forest conversion to pasture in Amazonia

    SciTech Connect

    Jipp, P.H.; Nepstad, D.C. Woods Hole Research Center, MA )

    1993-06-01

    Forests of eastern Amazonia are being replaced by pastures and secondary forests. We measured soil water storage and flux in adjacent forest and pasture ecosystems using Time Domain Reflectometry sensors installed in the walls of deep (9-m) shafts. The forest withdrew 597+/-25 mm of soil water stored below 1 m depth during the 1991 dry season (Jun-Dec), 1.7 times more than the pasture. Uptake from the bottom of the forest soil profile continued even after rainfall resumed in early 1992. The hydrologic impacts of tropical deforestation may be most severe for evergreen forests with deep rooting zones in areas of seasonal drought.

  9. Tropical rain forest conversion to pasture: Changes in vegetation and soil properties

    SciTech Connect

    Reiners, W.A. ); Bouwman, A.F. ); Parsons, W.F.J. Institute of Marine and Coastal Sciences, Rugers Univ., New Brunswick, NJ ); Keller, M. )

    1994-05-01

    The effect of converting lowland tropical rainforest to pasture, and of subsequent succession of pasture lands to secondary forest, were examined in the Atlantic Zone of Costa Rica. Three replicate sites of each of four land-use types representing this disturbance-recovery sequence were sampled for changes in vegetation, pedological properties, and potential nitrogen mineralization and nitrification. The four land-use types included primary forest, actively grazed pasture (10-36 yr old), abandoned pasture (abandoned 4-10 yr) and secondary forest (abandoned 10-20 yr). Conversion and succession had obvious and significant effects on canopy cover, canopy height, species composition, and species richness; it appeared that succession of secondary forests was proceeding toward a floristic composition like that of the primary forests. Significant changes in soil properties associated with conversion of forest to pasture included: (1) a decrease in acidity and increase in some base exchange properties, (2) and increase in bulk density and a concomitant decrease in porosity, (3) higher concentrations of NH[sub 4][sup +], (4) lower concentrations of NO[sub 3][sup [minus

  10. Effects of soil fertility and topography on tree growth in subtropical forest ecosystems

    NASA Astrophysics Data System (ADS)

    Seitz, Steffen; Goebes, Philipp; Kühn, Peter; Schmidt, Karsten; Song, Zhengshan; Scholten, Thomas

    2016-04-01

    roles. Nevertheless, soil acidity and a high proportion of Al on the exchange complex affected tree height even after only 1-2 years growth. Hence, our study showed that forest nutrition is coupled to a recycling of litter nutrients and does not only depend on subsequent supply of nutrients from the mineral soil. Besides soil fertility, topography affected tree height. We found that especially MCCA as indicator of water availability affected tree growth at small-scale as well as aspect. Overall, our synthesis showed that topographic heterogeneity lead to ecological gradients across geomorphological positions. In this respect, small-scale soil-plant interactions in a young forest can serve as a driver for the future development of vegetation and biodiversity control on soil fertility. In addition, it shows that terrain attributes should be accounted for in ecological research.

  11. [Soil respiration in subtropical forests and model simulation of its relationships with soil temperature and moisture content].

    PubMed

    Jiang, Yan; Wang, Bing; Wang, Yu-ru; Yang, Qing-pei

    2010-07-01

    By using Li-6400-09 system, an in situ measurement on the soil respiration, soil temperature, and soil moisture content in three main forest types (evergreen broadleaved forest, Cunninghamia lanceolata plantation, and Phyllostachys pubescens forest) in subtropical area of China was conducted, with the relationships between soil respiration and soil temperature and moisture content simulated by several models. The C flux of soil respiration in P. pubescens forest, evergreen broadleaved forest, and C. lanceolata plantation was 12.84, 11.70, and 7.12 t C x hm(-2) x a(-1), respectively, and the soil respiration in these three forest types had similar diurnal and seasonal variations, with the maximum value at 11:00-12:00 and the minimum value at 1:00-3:00, and the highest value in August and September while the lowest value in December and January. Van't Hoff equation and Lloyd & Taylor function had less difference in describing the relationships between soil respiration and soil temperature, while the soil respiration rate predicted by Lloyd & Taylor function was smaller than the observed value. Quadratic model and power function model could well simulate the relationship between soil respiration and soil moisture content. Soil moisture content positively or negatively affected soil respiration, but the effects only reached significant level in C. lanceolata plantation. Comparing with single-factor equation, two-factor equation (soil temperature and moisture content) could better describe the responses of soil respiration to changed soil temperature and moisture content. Multivariate analysis of covariance showed that after eliminating the effects of soil temperature and moisture content, forest type had significant effects on soil respiration (R2 = 0.541). Other factors, such as air temperature, air relative humidity, and photosynthetic radiation also affected soil respiration, and the effects of air temperature reached significant level.

  12. Minerals vs. Microbes: Biogeochemical Controls on Carbon Storage in Humid Tropical Forest Soils

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Silver, W. L.

    2012-12-01

    Humid tropical forest soils contain a substantial portion (~500 Pg) of the terrestrial carbon (C) pool, yet their response to climate change remains unclear due to mechanistic uncertainty in the biogeochemical controls on soil C storage in these ecosystems. Poorly-crystalline minerals have long been known to stabilize soil C, but few studies have explored their relative importance in comparison with other likely controls such as rhizosphere processes, oxygen deficiency (anaerobiosis), and C quality. We examined relationships among soil C and a suite of biogeochemical variables measured in 162 samples from surface soils (ultisols and oxisols) collected over scales of landforms to landscapes (m - km) in the Luquillo Experimental Forest, Puerto Rico. We measured iron (Fe), aluminum (Al), and manganese (Mn) oxides in 0.5M hydrochloric acid (HCl), sodium citrate/ascorbic acid (CA), and citrate/dithionite (CD) extractions, along with clay content, root biomass, C quality (C/N ratios), and anaerobiosis using HCl-extractable reduced iron (Fe(II)) concentrations as a proxy. We used mixed-effects models to compare the relative importance of the above variables (normalized by mean and standard deviation) as predictors of soil C, with random effects to account for spatial structure. Poorly-crystalline Al oxide concentrations (CA extraction), soil C/N ratio, and Fe(II) concentrations each had highly significant (p < 0.0001) positive relationships with soil C concentrations that conveyed equivalent explanatory power, assessed by comparing standardized regression coefficients. The optimal mixed model explained 82 % of the variation of the residual sum of squares of soil C concentrations, which varied between 2 - 20 % C among samples. Fine root biomass had a weak but significantly positive association with soil C concentrations (p < 0.05), while crystalline Fe oxide concentrations (CD extraction) displayed a negative correlation (p < 0.01), and clay contents had no significant

  13. Electron Shuttling Capacity of Solid-Phase Organic Matter in Forest Soils

    NASA Astrophysics Data System (ADS)

    Patel, A.; Zhao, Q.; Yang, Y.

    2015-12-01

    Soil organic matter, as an electron shuttle, plays an important role in regulating the biogeochemical cycles of metals, especially the redox reactions for iron. Microorganisms can reduce soil organic matter under anaerobic conditions, and biotically-reduced soil organic matter can abiotically donate electrons to ferric oxides. Such soil organic matter-mediated electron transport can facilitate the interactions between microorganisms and insoluble terminal electron acceptors, i.e. iron minerals. Most previous studies have been focused on the electron shuttling processes through dissolved soil organic matter, and scant information is available for solid-phase soil organic matter. In this study, we aim to quantify the electron accepting capacity for solid-phase organic matter in soils collected from four different forests in the United States, including Truckee (CA), Little Valley (NV), Howland (ME) and Hart (MI). We used Shewanella oneidensisMR-1 to biotically reduce soil slurries, and then quantified the electrons transferred to solid-phase and solution-phase organic matter by reacting them with Fe(III)-nitrilotriacetic acid (Fe(III)-NTA). The generation of Fe(II) was measured by a ferrozine assay to calculate the electron accepting capacity of soil organic matter. Our preliminary results showed that the Truckee soil organic matter can accept 0.51±0.07 mM e-/mol carbon. We will measure the electron accepting capacity for four different soils and correlate them to the physicochemical properties of soils. Potential results will provide information about the electron accepting capacity of solid-phase soil organic matter and its governing factors, with broad implication on the coupled biogeochemical cycles of carbon and iron.

  14. Radionuclide behaviour in forest soils of Russian Federation and Ukraine

    NASA Astrophysics Data System (ADS)

    Shcheglov, A. I.; Tsvetnova, O. B.

    2012-04-01

    Behaviour of radionuclides in soil determines to a great extent the radionuclide root uptake and their further migration in food chains. The radionuclide fate in the soil is determined by a wide spectrum of simultaneously running, often competitive elementary processes, such as adsorption-desorption, diffusion-mass transport, retention-migration, etc. The intensity of each elementary process depends, in turn, on a combination of several factors such as nature of the radionuclide, physicochemical features of the fallout, soil properties, environmental regimes, etc. Radionuclide deposition in soils is known to be a basic criterion of the radioecological situation in the contaminated territory. Our long-term investigations performed in contaminated forests (30-km zone of Chernobyl NPP; Tula, Kaluga and Bryansk regions of the Russian Federation) had shown that radionuclide migration in the forest landscapes was determined primarily by the forest litter presence. The key factors of radionuclide redistribution within the soil litter are (i) permanent addition of the low-contaminated organic matter ("clean" litterfall), and (ii) high rate of transformation. The dynamics and intensity of decontamination processes depends on the forest litter sub-horizon. Leaf (A0l) layer exhibits the highest rate of decontamination: 137Cs content in this layer decreased twofold by the second year after the accident and reached its equilibrium value (about 1% of the total deposition) by the 4-5th year after the fallout. The corresponding quasi-equilibrium radionuclide content in A0f layer (10-20%) is reached by the 8-9th year after the accident. The corresponding equilibrium in A0h layer is not reached yet. Thus, the effective half-life of radionuclides in soils should be calculated for each sub-horizon separately, taking into account the above-discussed features of the radionuclide dynamics. The rate of annual radionuclide replacement from the forest litter to mineral layers depends on the

  15. Maximum temperature accounts for annual soil CO2 efflux in temperate forests of Northern China.

    PubMed

    Zhou, Zhiyong; Xu, Meili; Kang, Fengfeng; Jianxin Sun, Osbert

    2015-01-01

    It will help understand the representation legality of soil temperature to explore the correlations of soil respiration with variant properties of soil temperature. Soil temperature at 10 cm depth was hourly logged through twelve months. Basing on the measured soil temperature, soil respiration at different temporal scales were calculated using empirical functions for temperate forests. On monthly scale, soil respiration significantly correlated with maximum, minimum, mean and accumulated effective soil temperatures. Annual soil respiration varied from 409 g C m(-2) in coniferous forest to 570 g C m(-2) in mixed forest and to 692 g C m(-2) in broadleaved forest, and was markedly explained by mean soil temperatures of the warmest day, July and summer, separately. These three soil temperatures reflected the maximum values on diurnal, monthly and annual scales. In accordance with their higher temperatures, summer soil respiration accounted for 51% of annual soil respiration across forest types, and broadleaved forest also had higher soil organic carbon content (SOC) and soil microbial biomass carbon content (SMBC), but a lower contribution of SMBC to SOC. This added proof to the findings that maximum soil temperature may accelerate the transformation of SOC to CO2-C via stimulating activities of soil microorganisms. PMID:26179467

  16. Spatial and vertical distribution of mercury in upland forest soils across the northeastern United States.

    PubMed

    Richardson, Justin B; Friedland, Andrew J; Engerbretson, Teresa R; Kaste, James M; Jackson, Brian P

    2013-11-01

    Assessing current Hg pools in forest soils of the northeastern U.S. is important for monitoring changes in Hg cycling. The forest floor, upper and lower mineral horizons were sampled at 17 long-term upland forest sites across the northeastern U.S. in 2011. Forest floor Hg concentration was similar across the study region (274 ± 13 μg kg(-1)) while Hg amount at northern sites (39 ± 6 g ha(-1)) was significantly greater than at western sites (11 ± 4 g ha(-1)). Forest floor Hg was correlated with soil organic matter, soil pH, latitude and mean annual precipitation and these variables explained approximately 70% of the variability when multiple regressed. Mercury concentration and amount in the lower mineral soil was correlated with Fe, soil organic matter and latitude, corresponding with Bs horizons of Spodosols (Podzols). Our analysis shows the importance of regional and soil properties on Hg accumulation in forest soils.

  17. Spatial and vertical distribution of mercury in upland forest soils across the northeastern United States

    PubMed Central

    Richardson, Justin B.; Friedland, Andrew J; Engerbretson, Teresa R.; Kaste, James M.; Jackson, Brian P.

    2013-01-01

    Assessing current Hg pools in forest soils of the northeastern U.S. is important for monitoring changes in Hg cycling. The forest floor, upper and lower mineral horizons were sampled at 17 long-term upland forest sites across the northeastern U.S. in 2011. Forest floor Hg concentration was similar across the study region (274 ± 13 μg kg−1) while Hg amount at northern sites (39 ± 6 g ha−1) was significantly greater than at western sites (11 ± 4 g ha−1). Forest floor Hg was correlated with soil organic matter, soil pH, latitude and mean annual precipitation and these variables explained approximately 70% of the variability when multiple regressed. Mercury concentration and amount in the lower mineral soil was correlated with Fe, soil organic matter and latitude, corresponding with Bs horizons of Spodosols (Podzols). Our analysis shows the importance of regional and soil properties on Hg accumulation in forest soils. PMID:23911621

  18. Covariation in plant functional traits and soil fertility within two species-rich forests.

    PubMed

    Liu, Xiaojuan; Swenson, Nathan G; Wright, S Joseph; Zhang, Liwen; Song, Kai; Du, Yanjun; Zhang, Jinlong; Mi, Xiangcheng; Ren, Haibao; Ma, Keping

    2012-01-01

    The distribution of plant species along environmental gradients is expected to be predictable based on organismal function. Plant functional trait research has shown that trait values generally vary predictably along broad-scale climatic and soil gradients. This work has also demonstrated that at any one point along these gradients there is a large amount of interspecific trait variation. The present research proposes that this variation may be explained by the local-scale sorting of traits along soil fertility and acidity axes. Specifically, we predicted that trait values associated with high resource acquisition and growth rates would be found on soils that are more fertile and less acidic. We tested the expected relationships at the species-level and quadrat-level (20 × 20 m) using two large forest plots in Panama and China that contain over 450 species combined. Predicted relationships between leaf area and wood density and soil fertility were supported in some instances, but the majority of the predicted relationships were rejected. Alternative resource axes, such as light gradients, therefore likely play a larger role in determining the interspecific variability in plant functional traits in the two forests studied.

  19. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem.

    PubMed

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-03-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.

  20. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem

    NASA Astrophysics Data System (ADS)

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-03-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.

  1. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem

    PubMed Central

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-01-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models. PMID:26925871

  2. Sensitivity of soil respiration to variability in soil moisture and temperature in a humid tropical forest.

    PubMed

    Wood, Tana E; Detto, Matteo; Silver, Whendee L

    2013-01-01

    Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m(2)), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal controls on soil CO2 efflux from a humid tropical forest in Puerto Rico. We measured hourly soil CO2 efflux, temperature and moisture in control and exclusion plots (n = 6) for 6-months. The variance of each time series was analyzed using orthonormal wavelet transformation and Haar-wavelet coherence. We found strong negative coherence between soil moisture and soil respiration in control plots corresponding to a two-day periodicity. Across all plots, there was a significant parabolic relationship between soil moisture and soil CO2 efflux with peak soil respiration occurring at volumetric soil moisture of approximately 0.375 m(3)/m(3). We additionally found a weak positive coherence between CO2 and temperature at longer time-scales and a significant positive relationship between soil temperature and CO2 efflux when the analysis was limited to the control plots. The coherence between CO2 and both temperature and soil moisture were reduced in exclusion plots. The reduced CO2 response to temperature in exclusion plots suggests that the positive effect of temperature on CO2 is constrained by soil moisture availability.

  3. Sensitivity of soil respiration to variability in soil moisture and temperature in a humid tropical forest.

    PubMed

    Wood, Tana E; Detto, Matteo; Silver, Whendee L

    2013-01-01

    Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m(2)), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal controls on soil CO2 efflux from a humid tropical forest in Puerto Rico. We measured hourly soil CO2 efflux, temperature and moisture in control and exclusion plots (n = 6) for 6-months. The variance of each time series was analyzed using orthonormal wavelet transformation and Haar-wavelet coherence. We found strong negative coherence between soil moisture and soil respiration in control plots corresponding to a two-day periodicity. Across all plots, there was a significant parabolic relationship between soil moisture and soil CO2 efflux with peak soil respiration occurring at volumetric soil moisture of approximately 0.375 m(3)/m(3). We additionally found a weak positive coherence between CO2 and temperature at longer time-scales and a significant positive relationship between soil temperature and CO2 efflux when the analysis was limited to the control plots. The coherence between CO2 and both temperature and soil moisture were reduced in exclusion plots. The reduced CO2 response to temperature in exclusion plots suggests that the positive effect of temperature on CO2 is constrained by soil moisture availability. PMID:24312508

  4. Taibaiella soli sp. nov., isolated from pine forest soil.

    PubMed

    Kim, Min-Kyeong; Kim, Tae-Su; Joung, Yochan; Han, Ji-Hye; Kim, Seung Bum

    2016-08-01

    A Gram-stain-negative, motile by gliding, non-spore-forming and oval-shaped bacterial strain designated T1-10T was isolated from pine forest soil, and its taxonomic position was investigated using a polyphasic approach. Growth occurred at 10-37 °C (optimum, 30 °C), at pH 6-7 and in the presence of 0-1 % (w/v) (optimum, 0 %) NaCl. Flexirubin-type pigments were produced. On the basis of 16S rRNA gene sequence similarity, strain T1-10T was assigned to the genus Taibaiella of the phylum Bacteroidetes, and the most closely related species was Taibaiella koreensis THG-DT86T with 97.11 % sequence similarity, but the strain formed an independent lineage in the phylogenetic tree. The genomic DNA G+C content of strain T1-10T was 42.5 mol%. The main cellular fatty acids were iso-C15 : 1 G, iso-C15 : 0 and iso-C17 : 0 3-OH. The only isoprenoid quinone detected in the strain was MK-7, and the major polyamine was homospermidine. The major polar lipids were phosphatidylethanolamine and unidentified aminophospholipids. Strain T1-10T could be distinguished from related species by physiological and biochemical properties. Phenotypic and phylogenetic data supported that strain T1-10T represents a novel species of the genus Taibaiella, for which the name Taibaiella soli sp. nov. is proposed (type strain T1-10T=KCTC 42277T=JCM 31014T). PMID:27222401

  5. Oceanobacillus halophilum sp. nov. isolated from a mangrove forest soil.

    PubMed

    Tang, Jia; Yang, Guiqin; Wang, Yueqiang; Wu, Chu; Zhou, Shungui

    2014-05-01

    A halophilic, aerobic bacterium, designated GD01(T), was isolated from a mangrove forest soil near the South China Sea. Cells of strain GD01(T) were Gram staining positive, oxidase positive, and catalase positive. The strain was rod shaped and motile by means of peritrichous flagella and produced ellipsoidal endospores. The strain was able to grow with NaCl at concentrations of 0.5-12 % (optimum 3-5 %, w/v), at temperatures of 20-50 °C (optimum 30 °C), and at pH 6.0-8.5 (optimum pH 7.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain GD01(T) formed a cluster with O. profundus DSM 18246(T) (96.4 % 16S rRNA gene sequence similarity), O. caeni KCTC 13061(T) (95.4 %), and O. oncorhynchi JCM 12661(T) (94.5 %). The G+C content of strain GD01(T) was 38.7 mol%. The major respiratory quinone was MK-7. The major cellular fatty acids (>5 %) were anteiso-C15:0, iso-C16:0 (13.7 %), anteiso-C17:0 (12.6 %), iso-C15:0 (9.9 %), iso-C14:0 (9.5 %), and C16:0 (5.0 %). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipid, four unknown lipids, and four unknown phospholipids. Based on phenotypic characteristics, chemotaxonomic features, and phylogenetic analysis based on 16S rRNA gene sequences, the strain was identified to represent a distinct novel species in the genus Oceanobacillus, and the name proposed is Oceanobacillus halophilum sp. nov. with type train GD01(T) (=CCTCC AB 2012863(T) = KCTC 33101(T)).

  6. Effects of tree diversity and environmental factors on the soil microbial community in three soil depth in a Central European beech forest

    NASA Astrophysics Data System (ADS)

    Fornacon, C.; Jacob, M.; Guckland, A.; Meinen, C.; Gleixner, G.

    2009-04-01

    We investigated the link between aboveground and belowground diversity in forest ecosystems. Therefore, we determined the effect of tree composition on amount and composition of the soil microbial community using phospholipid fatty acid profiles in the Hainich National Park in Thuringia, a deciduous mixed forest on loess over limestone in Central Germany. On the one hand we investigated the composition of the microbial community in dependence of leave litter composition, hypothesizing that distinct leave litter compositions activated signature PLFA's. On the other hand we determined if environmental factor like clay content or nutrient status influence the microbial community in deeper soil horizons. Consequently soil was sampled from depth intervals of 0-5 cm, 5-10 cm and 10-20 cm. Plots with highest diversity of leave litter had highest total amounts of fatty acids in the upper 5 cm. Mainly PLFA 16:1?5 was activated in autumn, being a common marker for mycorrhizal fungi. In soil depth below 5 cm the environmental factors like clay and soil nutrients like phosphorus and carbon, explained most of the soil microbial variability. On pure beech sites the total phosphorus content of soil influenced soil microbial diversity, but on sites with higher tree diversity no single factor varying the microbial community could be identified. Tree diversity and environmental factors together effect soil microbial community and are closely related to the link between aboveground and belowground diversity.

  7. Effects of Holocene vegetation change on soils across the forest-grassland transition, northern Minnesota, and implications for erosion processes

    NASA Astrophysics Data System (ADS)

    Mason, Joseph; Kasmerchak, Chase; Keita, Hawa; Liang, Mengyu; Gruley, Kristine

    2016-04-01

    Boundaries between forest and grassland in the midlatitudes and their shifts in response to Holocene climatic change, provide opportunities to detect effects of life on landscapes. In northern Minnesota, USA, paleoecological research has documented that grassland and/or savanna expanded eastward in the dry early to middle Holocene. In the late Holocene, forest cover expanded westward at the expense of savanna and grassland. We studied soils at 20 sites spanning the forest-grassland transition. A dramatic change in soil morphology coincides approximately, though not exactly, with that transition as recorded in 1870s-1880s land surveys, suggesting that soils change rapidly in response to forest expansion (we are attempting to constrain the timescale of response through radiocarbon dating of deep soil organic matter in which stable C isotopes record past presence of grassland). The key changes from grassland to forest are loss of organic matter below a thin surface A horizon and greatly enhanced mobility and downward translocation of clay - particularly smectite - in forest soils. This results in upper soil horizons that have relatively low smectite content and low microaggregate stability (as detected through laser diffraction analysis of aggregate disintegration in laboratory experiments), especially below the thin A horizon. The best explanation for this change appears to involve differences in how OM is added to and accumulated in the soil under forest and grassland; soil acidity and base saturation change more gradually eastward along a gradient more likely to reflect climate than vegetation. Evidence of bioturbation (especially gopher burrowing) is much more common at former grassland sites. In addition to mixing OM downward in the soil, burrowing moves detrital carbonates upward, probably enhancing OM accumulation and aggregate stability. Research on geomorphic response to Holocene climatic change in the Midwestern US has often emphasized higher potential

  8. Increased mercury in forest soils under elevated carbon dioxide.

    PubMed

    Natali, Susan M; Sañudo-Wilhelmy, Sergio A; Norby, Richard J; Zhang, Hong; Finzi, Adrien C; Lerdau, Manuel T

    2008-11-01

    Fossil fuel combustion is the primary anthropogenic source of both CO2 and Hg to the atmosphere. On a global scale, most Hg that enters ecosystems is derived from atmospheric Hg that deposits onto the land surface. Increasing concentrations of atmospheric CO2 may affect Hg deposition to terrestrial systems and storage in soils through CO(2)-mediated changes in plant and soil properties. We show, using free-air CO2 enrichment (FACE) experiments, that soil Hg concentrations are almost 30% greater under elevated atmospheric CO2 in two temperate forests. There were no direct CO2 effects, however, on litterfall, throughfall or stemflow Hg inputs. Soil Hg was positively correlated with percent soil organic matter (SOM), suggesting that CO(2)-mediated changes in SOM have influenced soil Hg concentrations. Through its impacts on SOM, elevated atmospheric CO2 may increase the Hg storage capacity of soils and modulate the movement of Hg through the biosphere. Such effects of rising CO2, ones that transcend the typically studied effects on C and nutrient cycling, are an important next phase for research on global environmental change.

  9. Soil Carbon and Nitrogen Linkages Along an Urban Elevational Gradient in Humid Tropical Forests

    NASA Astrophysics Data System (ADS)

    Cusack, D. F.; Lee, J. K.; McCleery, T. L.

    2011-12-01

    Tropical forests in and around urban centers face a suite of anthropogenic disturbances that may be muted or absent in more remote forests. In particular, urban-proximate forests are likely to have elevated soil nitrogen (N) levels because of local N deposition. High background N availability common in humid tropical soils may result in soil carbon (C) cycling responses that differ from those observed in N-poor Northern soils. Furthermore, N availability and temperature have been shown to have interacting effects on soil C cycling, such that responses may vary over elevational gradients. We used fragments of secondary forest along an urban elevational gradient in Puerto Rico to address the following questions: (a) Is there evidence that increased N availability in urban-proximate tropical forests alters soil C cycling? (b) Do effects of N availability vary over elevational gradients? To address these questions, we measured soil C and N content, soil respiration, mineral N pools, total dissolved N (TDN), dissolved organic C (DOC), pH, microbial biomass, and decomposer enzyme activities. Data from the urban gradient were compared with results for rural and remote Puerto Rican forests. Forest soils along the urban gradient had elevated levels of soil nitrate (NO3-) relative to rural and remote forests, whereas extractable DOC and TDN were both lower in the urban forest soils. Soil pH was significantly higher and more variable in urban forests, ranging from 4.5 to 8.5 across nine forest stands, whereas remote forests had soil pH ranging from 4.4 to 5.2. Dissolved organic C and TDN declined with increases in pH across all sites (R2 = 0.64 and 0.48 respectively, n = 48, p < 0.05). Microbial biomass was not different among the study areas, but several microbial enzyme activities were lower in urban forest soils relative to the remote forests, including phosphorous-acquiring phosphatase, N-acquiring NAGase, and oxidative enzymes that degrade complex C compounds. Soil

  10. Vegetation, soil, and flooding relationships in a blackwater floodplain forest

    USGS Publications Warehouse

    Burke, M.K.; King, S.L.; Gartner, D.; Eisenbies, M.H.

    2003-01-01

    Hydroperiod is considered the primary determinant of plant species distribution in temperate floodplain forests, but most studies have focused on alluvial (sediment-laden) river systems. Few studies have evaluated plant community relationships in blackwater river systems of the South Atlantic Coastal Plain of North America. In this study, we characterized the soils, hydroperiod, and vegetation communities and evaluated relationships between the physical and chemical environment and plant community structure on the floodplain of the Coosawhatchie River, a blackwater river in South Carolina, USA. The soils were similar to previous descriptions of blackwater floodplain soils but had greater soil N and P availability, substantially greater clay content, and lower soil silt content than was previously reported for other blackwater river floodplains. Results of a cluster analysis showed there were five forest communities on the site, and both short-term (4 years) and long-term (50 years) flooding records documented a flooding gradient: water tupelo community > swamp tupelo > laurel oak = overcup oak > mixed oak. The long-term hydrologic record showed that the floodplain has flooded less frequently from 1994 to present than in previous decades. Detrended correspondence analysis of environmental and relative basal area values showed that 27% of the variation in overstory community structure could be explained by the first two axes; however, fitting the species distributions to the DCA axes using Gaussian regression explained 67% of the variation. Axes were correlated with elevation (flooding intensity) and soil characteristics related to rooting volume and cation nutrient availability. Our study suggests that flooding is the major factor affecting community structure, but soil characteristics also may be factors in community structure in blackwater systems. ?? 2003, The Society of Wetland Scientists.

  11. Effect of soil acidification on the growth of Korean pine (Pinus koraiensis) seedlings in a granite-derived forest soil.

    PubMed

    Choi, Dong-Su; Jin, Hyun-O; Lee, Choong-Hwa; Kim, Young-Chai; Kayama, Masazumi

    2005-01-01

    The growth of pine trees has diminished in recent years in industrial areas of Korea. Soil acidification is believed to be responsible. To study its effects, we grew seedlings of three-year-old Korean pine in brown forest soil derived from granite, which had been treated with an acid solution, for 182 days. The anion mol ratio in the solution was SO4(2-):NO3-:Cl-=5:3:2, which is the average in the total precipitation in Korea; six H+ ion concentrations in the soil were studied (0 (control), 10, 30, 60 and 90 mmol H+.kg-1). With increasing amounts of H+ added to the soil, the concentrations of Ca, Mg, K, Al and Mn increased, especially below a soil pH of 3.8. The concentrations of Ca, Mg and K in pine needles and stems increased with increasing H+ added to the soil, whereas their concentrations in the root decreased. Conversely, the concentration of N and P in each organ of the pine plant was higher in all treatments than in controls. Also, the concentrations of Al and Mn increased significantly in all organs of the plant with increasing H+. We also estimated the effect of deliberate soil acidification on tree growth, using the molar ratio (Ca+Mg+K)/Al as an indicator of soil acidification. A strong positive correlation was found between the total dry mass (TDM) of seedlings and the (Ca+Mg+K)/Al molar ratio calculated from the concentrations of water-soluble elements in soil (r=0.99, p<0.001). When the (Ca+Mg+K)/Al molar ratio reached 1.0, the relative TDM had fallen to 40%. These results show that deliberate soil acidification reduces the growth of the Korean pine less than it does the Red pine, which has been the dominant species in Korea.

  12. Assessing relationships between forest structure and soil erosion in mountainous forest using a Cesium-137 tracer technique

    NASA Astrophysics Data System (ADS)

    Choi, Kwanghun; Reineking, Björn

    2016-04-01

    The fallout radionuclides (FRNs) particularly Cesium-137 are known as a quantitatively reliable means of estimating sediment redistribution rates within agricultural landscapes and forested area. However, fewer studies have done using FRNs in forested areas even though understanding soil redistribution patterns in mountainous forest areas is one of the important issues for forest management. The objective of this study is to figure out key forest structures affecting soil redistribution rate. In this study, we estimated soil loss and gain rate at 50 points with various forest types and topography in steep mountainous forest area in the Experimental Forest of Kangwon National University in Kangwon Province, South Korea by the Cesium-137 tracing technique. The results show the factors related to the topography such as slope and water accumulation have little effect on soil redistribution rate. The shrub and small tree layer affect more on soil redistribution rate. Additionally, the data shows relatively higher erosion rate in Korean Pine tree plantation area (Pinus koraiensis Sieb. et Zucc.) than semi-natural deciduous and Quercus forests where shrubs and small trees are more prevalent.

  13. Small-scale spatial variability of soil microbial community composition and functional diversity in a mixed forest

    NASA Astrophysics Data System (ADS)

    Wang, Qiufeng; Tian, Jing; Yu, Guirui

    2014-05-01

    Patterns in the spatial distribution of organisms provide important information about mechanisms that regulate the diversity and complexity of soil ecosystems. Therefore, information on spatial distribution of microbial community composition and functional diversity is urgently necessary. The spatial variability on a 26×36 m plot and vertical distribution (0-10 cm and 10-20 cm) of soil microbial community composition and functional diversity were studied in a natural broad-leaved Korean pine (Pinus koraiensis) mixed forest soil in Changbai Mountain. The phospholipid fatty acid (PLFA) pattern was used to characterize the soil microbial community composition and was compared with the community substrate utilization pattern using Biolog. Bacterial biomass dominated and showed higher variability than fungal biomass at all scales examined. The microbial biomass decreased with soil depths increased and showed less variability in lower 10-20 cm soil layer. The Shannon-Weaver index value for microbial functional diversity showed higher variability in upper 0-10 cm than lower 10-20 cm soil layer. Carbohydrates, carboxylic acids, polymers and amino acids are the main carbon sources possessing higher utilization efficiency or utilization intensity. At the same time, the four carbon source types contributed to the differentiation of soil microbial communities. This study suggests the higher diversity and complexity for this mix forest ecosystem. To determine the driving factors that affect this spatial variability of microorganism is the next step for our study.

  14. Soil bacterial community structure responses to precipitation reduction and forest management in forest ecosystems across Germany.

    PubMed

    Felsmann, Katja; Baudis, Mathias; Gimbel, Katharina; Kayler, Zachary E; Ellerbrock, Ruth; Bruelheide, Helge; Bruehlheide, Helge; Bruckhoff, Johannes; Welk, Erik; Puhlmann, Heike; Weiler, Markus; Gessler, Arthur; Ulrich, Andreas

    2015-01-01

    Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season. PMID:25875835

  15. Soil Bacterial Community Structure Responses to Precipitation Reduction and Forest Management in Forest Ecosystems across Germany

    PubMed Central

    Felsmann, Katja; Baudis, Mathias; Gimbel, Katharina; Kayler, Zachary E.; Ellerbrock, Ruth; Bruehlheide, Helge; Bruckhoff, Johannes; Welk, Erik; Puhlmann, Heike; Weiler, Markus; Gessler, Arthur; Ulrich, Andreas

    2015-01-01

    Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season. PMID:25875835

  16. Taxonomic and functional profiles of soil samples from Atlantic forest and Caatinga biomes in northeastern Brazil

    PubMed Central

    Pacchioni, Ralfo G; Carvalho, Fabíola M; Thompson, Claudia E; Faustino, André L F; Nicolini, Fernanda; Pereira, Tatiana S; Silva, Rita C B; Cantão, Mauricio E; Gerber, Alexandra; Vasconcelos, Ana T R; Agnez-Lima, Lucymara F

    2014-01-01

    Although microorganisms play crucial roles in ecosystems, metagenomic analyses of soil samples are quite scarce, especially in the Southern Hemisphere. In this work, the microbial diversity of soil samples from an Atlantic Forest and Caatinga was analyzed using a metagenomic approach. Proteobacteria and Actinobacteria were the dominant phyla in both samples. Among which, a significant proportion of stress-resistant bacteria associated to organic matter degradation was found. Sequences related to metabolism of amino acids, nitrogen, and DNA and stress resistance were more frequent in Caatinga soil, while the forest sample showed the highest occurrence of hits annotated in phosphorous metabolism, defense mechanisms, and aromatic compound degradation subsystems. The principal component analysis (PCA) showed that our samples are close to the desert metagenomes in relation to taxonomy, but are more similar to rhizosphere microbiota in relation to the functional profiles. The data indicate that soil characteristics affect the taxonomic and functional distribution; these characteristics include low nutrient content, high drainage (both are sandy soils), vegetation, and exposure to stress. In both samples, a rapid turnover of organic matter with low greenhouse gas emission was suggested by the functional profiles obtained, reinforcing the importance of preserving natural areas. PMID:24706600

  17. Comparative resistance and resilience of soil microbial communities and enzyme activities in adjacent native forest and agricultural soils.

    PubMed

    Chaer, Guilherme; Fernandes, Marcelo; Myrold, David; Bottomley, Peter

    2009-08-01

    Degradation of soil properties following deforestation and long-term soil cultivation may lead to decreases in soil microbial diversity and functional stability. In this study, we investigated the differences in the stability (resistance and resilience) of microbial community composition and enzyme activities in adjacent soils under either native tropical forest (FST) or in agricultural cropping use for 14 years (AGR). Mineral soil samples (0 to 5 cm) from both areas were incubated at 40 degrees C, 50 degrees C, 60 degrees C, or 70 degrees C for 15 min in order to successively reduce the microbial biomass. Three and 30 days after the heat shocks, fluorescein diacetate (FDA) hydrolysis, cellulase and laccase activities, and phospholipid-derived fatty acids-based microbial community composition were measured. Microbial biomass was reduced up to 25% in both soils 3 days after the heat shocks. The higher initial values of microbial biomass, enzyme activity, total and particulate soil organic carbon, and aggregate stability in the FST soil coincided with higher enzymatic stability after heat shocks. FDA hydrolysis activity was less affected (more resistance) and cellulase and laccase activities recovered more rapidly (more resilience) in the FST soil relative to the AGR counterpart. In the AGR soil, laccase activity did not show resilience to any heat shock level up to 30 days after the disturbance. Within each soil type, the microbial community composition did not differ between heat shock and control samples at day 3. However, at day 30, FST soil samples treated at 60 degrees C and 70 degrees C contained a microbial community significantly different from the control and with lower biomass regardless of high enzyme resilience. Results of this study show that deforestation followed by long-term cultivation changed microbial community composition and had differential effects on microbial functional stability. Both soils displayed similar resilience to FDA hydrolysis, a

  18. Comparative resistance and resilience of soil microbial communities and enzyme activities in adjacent native forest and agricultural soils.

    PubMed

    Chaer, Guilherme; Fernandes, Marcelo; Myrold, David; Bottomley, Peter

    2009-08-01

    Degradation of soil properties following deforestation and long-term soil cultivation may lead to decreases in soil microbial diversity and functional stability. In this study, we investigated the differences in the stability (resistance and resilience) of microbial community composition and enzyme activities in adjacent soils under either native tropical forest (FST) or in agricultural cropping use for 14 years (AGR). Mineral soil samples (0 to 5 cm) from both areas were incubated at 40 degrees C, 50 degrees C, 60 degrees C, or 70 degrees C for 15 min in order to successively reduce the microbial biomass. Three and 30 days after the heat shocks, fluorescein diacetate (FDA) hydrolysis, cellulase and laccase activities, and phospholipid-derived fatty acids-based microbial community composition were measured. Microbial biomass was reduced up to 25% in both soils 3 days after the heat shocks. The higher initial values of microbial biomass, enzyme activity, total and particulate soil organic carbon, and aggregate stability in the FST soil coincided with higher enzymatic stability after heat shocks. FDA hydrolysis activity was less affected (more resistance) and cellulase and laccase activities recovered more rapidly (more resilience) in the FST soil relative to the AGR counterpart. In the AGR soil, laccase activity did not show resilience to any heat shock level up to 30 days after the disturbance. Within each soil type, the microbial community composition did not differ between heat shock and control samples at day 3. However, at day 30, FST soil samples treated at 60 degrees C and 70 degrees C contained a microbial community significantly different from the control and with lower biomass regardless of high enzyme resilience. Results of this study show that deforestation followed by long-term cultivation changed microbial community composition and had differential effects on microbial functional stability. Both soils displayed similar resilience to FDA hydrolysis, a

  19. Changes in soil respiration components and their specific respiration along three successional forests in the subtropics

    DOE PAGES

    Han, Tianfeng; Liu, Juxiu; Wang, Gangsheng; Huang, Wenjuan; Zhou, Guoyi

    2016-01-16

    1.Understanding how soil respiration components change with forest succession is critical for modelling and predicting soil carbon (C) processes and its sequestration below-ground. The specific respiration (a ratio of respiration to biomass) is increasingly being used as an indicator of forest succession conceptually based on Odum's theory of ecosystem development. However, the hypothesis that specific soil respiration declines with forest succession remains largely untested. 2.We used a trenching method to partition soil respiration into heterotrophic respiration and autotrophic respiration (RH and RA) and then evaluated the specific RH and specific RA in three successional forests in subtropical China. 3.Our resultsmore » showed a clear seasonality in the influence of forest succession on RH, with no significant differences among the three forests in the dry season but a higher value in the old-growth forest than the other two forests in the wet season. RA in the old-growth forest tended to be the highest among the three forests. Both the specific RH and specific RA decreased with the progressive maturity of three forests. 4.Lastly, our results highlight the importance of forest succession in determining the variation of RH in different seasons. With forest succession, soil microbes and plant roots become more efficient to conserve C resources, which would result in a greater proportion of C retained in soils.« less

  20. Atmospheric methane consumption by forest soils and extracted bacteria at different pH values

    SciTech Connect

    Amaral, J.A.; Ren, T.; Knowles, R.

    1998-07-01

    The effect of pH on atmospheric methane (CH{sub 4}) consumption was studied with slurries of forest soils and with bacteria extracted from the same soils. Soil samples were collected from a mixed hardwood stand in New Hampshire, from jackpine and aspen stands at the BOREAS (Boreal Ecosystem Atmosphere Study) site near Thompson, northern Manitoba, from sites in southern Quebec, including a beech stand and a meadow, and from a site in Ontario. Consumption of atmospheric CH{sub 4} occurred at depths of >5 cm in both acidic and alkaline soils. In slurries of acidic soils, maximum activity occurred at different pH values. Bacteria extracted from these soils by high-speed blending and density gradient centrifugation showed pH responses different from the pH responses of the slurries. In all cases, these bacteria had a methanotrophy pH optimum of 5.8 and exhibited no activity at pH 6.8 to 7.0, the pH optimum range for known methanotrophs. This difference in pH responses could be useful in modifying media currently used for isolation of these organisms. Methanotrophic activity was induced in previously non-CH{sub 4}-consuming soils by preincubation with 5% (vol/vol) CH{sub 4} or by liquid enrichment with 20% CH{sub 4}. The bacteria showed pH responses typical of known methanotrophs and not typical of preexisting consumers of ambient CH{sub 4}. Furthermore, methanotrophs induced by high CH{sub 4} levels were more readily extracted from soil than preexisting ambient CH{sub 4} consumers were. In the alkaline soils, preexisting activity either was destroyed or resisted extraction by the procedure used. The results support the hypothesis that consumers of ambient CH{sub 4} in soils are physiologically distinct from the known methanotrophs.

  1. Effect of soil acidity, soil strength and macropores on root growth and morphology of perennial grass species differing in acid-soil resistance.

    PubMed

    Haling, Rebecca E; Simpson, Richard J; Culvenor, Richard A; Lambers, Hans; Richardson, Alan E

    2011-03-01

    It is unclear whether roots of acid-soil resistant plants have significant advantages, compared with acid-soil sensitive genotypes, when growing in high-strength, acid soils or in acid soils where macropores may allow the effects of soil acidity and strength to be avoided. The responses of root growth and morphology to soil acidity, soil strength and macropores by seedlings of five perennial grass genotypes differing in acid-soil resistance were determined, and the interaction of soil acidity and strength for growth and morphology of roots was investigated. Soil acidity and strength altered root length and architecture, root hair development, and deformed the root tip, especially in acid-soil sensitive genotypes. Root length was restricted to some extent by soil acidity in all genotypes, but the adverse impact of soil acidity on root growth by acid-soil resistant genotypes was greater at high levels of soil strength. Roots reacted to soil acidity when growing in macropores, but elongation through high-strength soil was improved. Soil strength can confound the effect of acidity on root growth, with the sensitivity of acid-resistant genotypes being greater in high-strength soils. This highlights the need to select for genotypes that resist both acidity and high soil strength.

  2. Effects of calcite and magnesite application to a declining Masson pine forest on strongly acidified soil in Southwestern China.

    PubMed

    Huang, Yongmei; Kang, Ronghua; Ma, Xiaoxiao; Qi, Yu; Mulder, Jan; Duan, Lei

    2014-05-15

    Liming of strongly acidified soil under a Masson pine (Pinus massoniana Lamb.) forest was studied through a seven-year field manipulation experiment at Tieshanping, Chongqing in Southwestern China. To distinguish between the individual effects of Ca(2+) and Mg(2+) addition, we separately applied calcite (CaCO3) and magnesite (MgCO3), rather than using dolomite [CaMg(CO3)2]. Both calcite and magnesite additions caused a significant increase in pH and a decrease in dissolved inorganic monomeric aluminium (Ali) concentration of soil water. Ecological recovery included increases of herb biomass (both treatments) and Mg content in Masson pine needles (magnesite treatment only). However, the growth rate of Masson pine did not increase under either treatment, possibly because of nutrient imbalance due to phosphorus (P) deficiency or limited observation period. In China, acid deposition in forest ecosystems commonly coincides with large inputs of atmogenic Ca(2+), both enhancing Mg(2+) leaching. Calcite addition may further decrease the Mg(2+) availability in soil water, thereby exacerbating Mg(2+) deficiency in the acidified forest soils of southern and southwestern China. The effect of anthropogenic acidification of naturally acid forest soils on P availability needs further study.

  3. Effects of calcite and magnesite application to a declining Masson pine forest on strongly acidified soil in Southwestern China.

    PubMed

    Huang, Yongmei; Kang, Ronghua; Ma, Xiaoxiao; Qi, Yu; Mulder, Jan; Duan, Lei

    2014-05-15

    Liming of strongly acidified soil under a Masson pine (Pinus massoniana Lamb.) forest was studied through a seven-year field manipulation experiment at Tieshanping, Chongqing in Southwestern China. To distinguish between the individual effects of Ca(2+) and Mg(2+) addition, we separately applied calcite (CaCO3) and magnesite (MgCO3), rather than using dolomite [CaMg(CO3)2]. Both calcite and magnesite additions caused a significant increase in pH and a decrease in dissolved inorganic monomeric aluminium (Ali) concentration of soil water. Ecological recovery included increases of herb biomass (both treatments) and Mg content in Masson pine needles (magnesite treatment only). However, the growth rate of Masson pine did not increase under either treatment, possibly because of nutrient imbalance due to phosphorus (P) deficiency or limited observation period. In China, acid deposition in forest ecosystems commonly coincides with large inputs of atmogenic Ca(2+), both enhancing Mg(2+) leaching. Calcite addition may further decrease the Mg(2+) availability in soil water, thereby exacerbating Mg(2+) deficiency in the acidified forest soils of southern and southwestern China. The effect of anthropogenic acidification of naturally acid forest soils on P availability needs further study. PMID:24631610

  4. Soil respiration from a boreal forest fire scar chronosequence

    NASA Astrophysics Data System (ADS)

    Smith, D.; Kaduk, J.; Balzter, H.; Wooster, M.; Mottram, G.

    2007-12-01

    Climate change predictions suggest that warming is to be most pronounced at high latitudes, with a possibility of boreal forest warming of 4-6°C in the next 50-100 years. This has lead to the suggestion that changes in boreal forest soil carbon (C) storage could significantly alter the global soil C balance. Fire is the most significant factor controlling succession in the boreal forest biome and it is possible that climate change will lead to an increase in fire regime e.g. size, frequency, intensity, or any combination of these. Our research is investigating C flux dynamics in a Canadian boreal forest jack pine (Pinus banksiana Lamb.) dominated fire scar chronosequence. Fieldwork is carried out at Sharpsand Creek experimental burn site, near Thessalon, Ontario, Canada, where there are numerous fire scars of different ages. In June 2006 soil respiration (Rs), soil temperature (Ts) and soil moisture (Ms) were measured on three replicate scars selected from plot last burnt in 1948 and 1991. Rs values were later adjusted for Ts using a Q10 value of 2. There was no significant difference in mean adjusted Rs between the two scar age categories. It is likely that sample sizes were not large enough here to detect significant differences. In May 2007, large areas of the field site burnt as a result of wildfire; this provided an opportunity to take a large number of Rs measurements from recently burnt fire scars, as well as from those areas unaffected by the burn. Rs, Ts and Ms measurements were taken from 1948, 1975 and 1991 scar age categories (three replicate scars each) that were burnt in 2007, as well as a 1948 and 1991 fire scar that was unaffected by the wildfire. Soil samples were taken from three locations per fire scar surveyed and analysed in the laboratory for total C content. There was a significant difference in mean Rs adjusted for Ts and Ms (Rsadj) between the three pre-2007 fire scar age categories 1948, 1975 and 1991, that were all burnt in 2007. Mean

  5. An Integrated Spatially Dynamic Disturbance and Forest Soil Carbon Model: Preliminary Results from Willow Creek Experimental Forest

    NASA Astrophysics Data System (ADS)

    Scheller, R. M.; Hua, D.; Bolstad, P. V.

    2008-12-01

    Total forest carbon (C) storage is determined by forest succession, multiple interacting disturbances, climate and the edaphic properties of a site or region, including soil texture and depth. How these complex processes interact will determine forest carbon dynamics at landscape and regional scales. We have developed a new succession extension for the LANDIS-II forest landscape simulation model that incorporates the belowground soil C dynamics of the Century soil model. This extension simulates three primary soil organic matter (SOM) pools (fast, slow, passive), litter dynamics, and nitrogen (N) feedbacks to overstory production. The extension was validated against data from the Willow Creek experimental forest in Wisconsin, USA. We subsequently initialized the full model to simulate forest dynamics of 10,000 ha of the surrounding forest landscape. We simulated a representative harvest regime and a historic wind throw regime (50 year wind rotation period, including light, moderate, and extreme events), two common disturbances in mesic forests of the Lake States. We also simulated forest change and total C storage assuming no atmospheric N deposition and N deposition equivalent to 2008 rates. Our results indicate a strong feedback from harvesting to litter C and the fast and slow SOM pools. The passive SOM pool was not significantly altered. Wind disturbance had a negligible effect on all pools. Simulations without N deposition significantly underestimated contemporary forest productivity and the system was more sensitive to disturbances when N deposition was excluded. In conclusion, we have developed a robust model of above and belowground C and N cycling that can readily plug into an existing forest modeling framework to simulate landscape and regional scale forest dynamics and the interactions among forest disturbances, climate change, and soil processes.

  6. Modeled effects of soil acidification on long-term ecological and economic outcomes for managed forests in the Adirondack region (USA)

    USGS Publications Warehouse

    Caputo, Jesse PhD.; Beier, Colin M.; Sullivan, Timothy J.; Lawrence, Gregory B.

    2016-01-01

    Sugar maple (Acer saccharum) is among the most ecologically and economically important tree species in North America, and its growth and regeneration is often the focus of silvicultural practices in northern hardwood forests. A key stressor for sugar maple (SM) is acid rain, which depletes base cations from poorly-buffered forest soils and has been associated with much lower SM vigor, growth, and recruitment. However, the potential interactions between forest management and soil acidification – and their implications for the sustainability of SM and its economic and cultural benefits – have not been investigated. In this study, we simulated the development of 50 extant SM stands in the western Adirondack region of NY (USA) for 100 years under different soil chemical conditions and silvicultural prescriptions. We found that interactions between management prescription and soil base saturation will strongly shape the ability to maintain SM in managed forests. Below 12% base saturation, SM did not regenerate sufficiently after harvest and was replaced mainly by red maple (Acer rubrum) and American beech (Fagus grandifolia). Loss of SM on acid-impaired sites was predicted regardless of whether the shelterwood or diameter-limit prescriptions were used. On soils with sufficient base saturation, models predicted that SM will regenerate after harvest and be sustained for future rotations. We then estimated how these different post-harvest outcomes, mediated by acid impairment of forest soils, would affect the potential monetary value of ecosystem services provided by SM forests. Model simulations indicated that a management strategy focused on syrup production – although not feasible across the vast areas where acid impairment has occurred – may generate the greatest economic return. Although pollution from acid rain is declining, its long-term legacy in forest soils will shape future options for sustainable forestry and ecosystem stewardship in the northern

  7. Modeled effects of soil acidification on long-term ecological and economic outcomes for managed forests in the Adirondack region (USA).

    PubMed

    Caputo, Jesse; Beier, Colin M; Sullivan, Timothy J; Lawrence, Gregory B

    2016-09-15

    Sugar maple (Acer saccharum) is among the most ecologically and economically important tree species in North America, and its growth and regeneration is often the focus of silvicultural practices in northern hardwood forests. A key stressor for sugar maple (SM) is acid rain, which depletes base cations from poorly-buffered forest soils and has been associated with much lower SM vigor, growth, and recruitment. However, the potential interactions between forest management and soil acidification - and their implications for the sustainability of SM and its economic and cultural benefits - have not been investigated. In this study, we simulated the development of 50 extant SM stands in the western Adirondack region of NY (USA) for 100years under different soil chemical conditions and silvicultural prescriptions. We found that interactions between management prescription and soil base saturation will strongly shape the ability to maintain SM in managed forests. Below 12% base saturation, SM did not regenerate sufficiently after harvest and was replaced mainly by red maple (Acer rubrum) and American beech (Fagus grandifolia). Loss of SM on acid-impaired sites was predicted regardless of whether the shelterwood or diameter-limit prescriptions were used. On soils with sufficient base saturation, models predicted that SM will regenerate after harvest and be sustained for future rotations. We then estimated how these different post-harvest outcomes, mediated by acid impairment of forest soils, would affect the potential monetary value of ecosystem services provided by SM forests. Model simulations indicated that a management strategy focused on syrup production - although not feasible across the vast areas where acid impairment has occurred - may generate the greatest economic return. Although pollution from acid rain is declining, its long-term legacy in forest soils will shape future options for sustainable forestry and ecosystem stewardship in the northern hardwood

  8. Modeled effects of soil acidification on long-term ecological and economic outcomes for managed forests in the Adirondack region (USA).

    PubMed

    Caputo, Jesse; Beier, Colin M; Sullivan, Timothy J; Lawrence, Gregory B

    2016-09-15

    Sugar maple (Acer saccharum) is among the most ecologically and economically important tree species in North America, and its growth and regeneration is often the focus of silvicultural practices in northern hardwood forests. A key stressor for sugar maple (SM) is acid rain, which depletes base cations from poorly-buffered forest soils and has been associated with much lower SM vigor, growth, and recruitment. However, the potential interactions between forest management and soil acidification - and their implications for the sustainability of SM and its economic and cultural benefits - have not been investigated. In this study, we simulated the development of 50 extant SM stands in the western Adirondack region of NY (USA) for 100years under different soil chemical conditions and silvicultural prescriptions. We found that interactions between management prescription and soil base saturation will strongly shape the ability to maintain SM in managed forests. Below 12% base saturation, SM did not regenerate sufficiently after harvest and was replaced mainly by red maple (Acer rubrum) and American beech (Fagus grandifolia). Loss of SM on acid-impaired sites was predicted regardless of whether the shelterwood or diameter-limit prescriptions were used. On soils with sufficient base saturation, models predicted that SM will regenerate after harvest and be sustained for future rotations. We then estimated how these different post-harvest outcomes, mediated by acid impairment of forest soils, would affect the potential monetary value of ecosystem services provided by SM forests. Model simulations indicated that a management strategy focused on syrup production - although not feasible across the vast areas where acid impairment has occurred - may generate the greatest economic return. Although pollution from acid rain is declining, its long-term legacy in forest soils will shape future options for sustainable forestry and ecosystem stewardship in the northern hardwood

  9. Soil microbial communities and metabolic function of a Northern Alabama forest ecosystem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thinning, prescribed burning, and their combinations, are common forest management practices to restore degraded forest communities and to prevent uncontrollable wildfires. However, their impacts on soil microbial communities, which are vital to global element cycling, are traditionally overlooked. ...

  10. Unravelling the importance of forest age stand and forest structure driving microbiological soil properties, enzymatic activities and soil nutrients content in Mediterranean Spanish black pine(Pinus nigra Ar. ssp. salzmannii) Forest.

    PubMed

    Lucas-Borja, M E; Hedo, J; Cerdá, A; Candel-Pérez, D; Viñegla, B

    2016-08-15

    This study aimed to investigate the effects that stand age and forest structure have on microbiological soil properties, enzymatic activities and nutrient content. Thirty forest compartments were randomly selected at the Palancares y Agregados managed forest area (Spain), supporting forest stands of five ages; from 100 to 80years old to compartments with trees that were 19-1years old. Forest area ranging from 80 to 120years old and without forest intervention was selected as the control. We measured different soil enzymatic activities, soil respiration and nutrient content (P, K, Na, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb and Ca) in the top cm of 10 mineral soils in each compartment. Results showed that the lowest forest stand age and the forest structure created by management presented lower values of organic matter, soil moisture, water holding capacity and litterfall and higher values of C/N ratio in comparison with the highest forest stand age and the related forest structure, which generated differences in soil respiration and soil enzyme activities. The forest structure created by no forest management (control plot) presented the highest enzymatic activities, soil respiration, NH4(+) and NO3(-). Results did not show a clear trend in nutrient content comparing all the experimental areas. Finally, the multivariate PCA analysis clearly clustered three differentiated groups: Control plot; from 100 to 40years old and from 39 to 1year old. Our results suggest that the control plot has better soil quality and that extreme forest stand ages (100-80 and 19-1years old) and the associated forest structure generates differences in soil parameters but not in soil nutrient content.

  11. [Effects of climate change on forest soil organic carbon storage: a review].

    PubMed

    Zhou, Xiao-yu; Zhang, Cheng-yi; Guo, Guang-fen

    2010-07-01

    Forest soil organic carbon is an important component of global carbon cycle, and the changes of its accumulation and decomposition directly affect terrestrial ecosystem carbon storage and global carbon balance. Climate change would affect the photosynthesis of forest vegetation and the decomposition and transformation of forest soil organic carbon, and further, affect the storage and dynamics of organic carbon in forest soils. Temperature, precipitation, atmospheric CO2 concentration, and other climatic factors all have important influences on the forest soil organic carbon storage. Understanding the effects of climate change on this storage is helpful to the scientific management of forest carbon sink, and to the feasible options for climate change mitigation. This paper summarized the research progress about the distribution of organic carbon storage in forest soils, and the effects of elevated temperature, precipitation change, and elevated atmospheric CO2 concentration on this storage, with the further research subjects discussed.

  12. Impact of Nitrogen Fertilization on Soil Organic Matter in Forest Soils (INFOSOM)

    NASA Astrophysics Data System (ADS)

    Forstner, Stefan J.; Tatzber, Michael; Keiblinger, Katharina M.; Schleppi, Patrick; Hagedorn, Frank; Gundersen, Per; Wanek, Wolfgang; Gerzabek, Martin; Zechmeister-Boltenstern, Sohpie

    2014-05-01

    Anthropogenic induced nitrogen (N) deposition has been reported to increase carbon (C) storage in boreal forest soils. However, it is unclear if this also applies to temperate forests where primary production, and hence C inputs to soil, are less limited by N. Likewise, litter decomposition and soil organic matter (SOM) stabilization have been shown to be affected by N inputs, although the exact mechanisms remain unclear. A major obstacle in assessing the net effect of increased N availability on soil C budgets is our limited understanding of the response of soil microorganisms and how this may feedback on SOM stabilization in the long run. To collectively address these questions we make use of two long-time forest N-addition experiments from Klosterhede, Denmark and Alptal, Switzerland which received 50-55 and 25 kg N ha-1 year-1, respectively, for over 20 years. At both sites 15N tracer has been applied with the N-addition treatment enabling isotope-specific analysis. Stands are dominated by Norway spruce (Picea abies) but differ in site characteristics such as soil type, elevation, and mean annual temperature. We investigate the effect of N addition on SOM quantity, quality and depth-distribution using state-of-the-art analytical techniques including isotope ratio mass spectroscopy (IRMS), solid state 13C-NMR, and mid-infrared spectroscopy. Effects on structure and function of soil microbial communities are assessed by standard soil microbiological methods including extracellular enzyme activities and complemented by soil metaproteomics, a rapidly developing novel approach. We hypothesize that long-term N addition will (1) foster the accumulation of soil organic matter (SOM) as well as (2) alter SOM quality and (3) its depth-distribution. Furthermore, N addition will also (4) induce changes in structure and function of microbial communities. First results on N effects on SOM quality and microbial activities in the Ah layer will be presented.

  13. Long-term effects of timber harvesting on hemicellulolytic microbial populations in coniferous forest soils.

    PubMed

    Leung, Hilary T C; Maas, Kendra R; Wilhelm, Roland C; Mohn, William W

    2016-02-01

    Forest ecosystems need to be sustainably managed, as they are major reservoirs of biodiversity, provide important economic resources and modulate global climate. We have a poor knowledge of populations responsible for key biomass degradation processes in forest soils and the effects of forest harvesting on these populations. Here, we investigated the effects of three timber-harvesting methods, varying in the degree of organic matter removal, on putatively hemicellulolytic bacterial and fungal populations 10 or more years after harvesting and replanting. We used stable-isotope probing to identify populations that incorporated (13)C from labeled hemicellulose, analyzing (13)C-enriched phospholipid fatty acids, bacterial 16 S rRNA genes and fungal ITS regions. In soil microcosms, we identified 104 bacterial and 52 fungal hemicellulolytic operational taxonomic units (OTUs). Several of these OTUs are affiliated with taxa not previously reported to degrade hemicellulose, including the bacterial genera Methylibium, Pelomonas and Rhodoferax, and the fungal genera Cladosporium, Pseudeurotiaceae, Capronia, Xenopolyscytalum and Venturia. The effect of harvesting on hemicellulolytic populations was evaluated based on in situ bacterial and fungal OTUs. Harvesting treatments had significant but modest long-term effects on relative abundances of hemicellulolytic populations, which differed in strength between two ecozones and between soil layers. For soils incubated in microcosms, prior harvesting treatments did not affect the rate of incorporation of hemicellulose carbon into microbial biomass. In six ecozones across North America, distributions of the bacterial hemicellulolytic OTUs were similar, whereas distributions of fungal ones differed. Our work demonstrates that diverse taxa in soil are hemicellulolytic, many of which are differentially affected by the impact of harvesting on environmental conditions. However, the hemicellulolytic capacity of soil communities appears

  14. Long-term effects of timber harvesting on hemicellulolytic microbial populations in coniferous forest soils.

    PubMed

    Leung, Hilary T C; Maas, Kendra R; Wilhelm, Roland C; Mohn, William W

    2016-02-01

    Forest ecosystems need to be sustainably managed, as they are major reservoirs of biodiversity, provide important economic resources and modulate global climate. We have a poor knowledge of populations responsible for key biomass degradation processes in forest soils and the effects of forest harvesting on these populations. Here, we investigated the effects of three timber-harvesting methods, varying in the degree of organic matter removal, on putatively hemicellulolytic bacterial and fungal populations 10 or more years after harvesting and replanting. We used stable-isotope probing to identify populations that incorporated (13)C from labeled hemicellulose, analyzing (13)C-enriched phospholipid fatty acids, bacterial 16 S rRNA genes and fungal ITS regions. In soil microcosms, we identified 104 bacterial and 52 fungal hemicellulolytic operational taxonomic units (OTUs). Several of these OTUs are affiliated with taxa not previously reported to degrade hemicellulose, including the bacterial genera Methylibium, Pelomonas and Rhodoferax, and the fungal genera Cladosporium, Pseudeurotiaceae, Capronia, Xenopolyscytalum and Venturia. The effect of harvesting on hemicellulolytic populations was evaluated based on in situ bacterial and fungal OTUs. Harvesting treatments had significant but modest long-term effects on relative abundances of hemicellulolytic populations, which differed in strength between two ecozones and between soil layers. For soils incubated in microcosms, prior harvesting treatments did not affect the rate of incorporation of hemicellulose carbon into microbial biomass. In six ecozones across North America, distributions of the bacterial hemicellulolytic OTUs were similar, whereas distributions of fungal ones differed. Our work demonstrates that diverse taxa in soil are hemicellulolytic, many of which are differentially affected by the impact of harvesting on environmental conditions. However, the hemicellulolytic capacity of soil communities appears

  15. Nitrogenous gas emissions induced by abiotic nitrite reactions with soil organic matter of a Norway spruce forest

    NASA Astrophysics Data System (ADS)

    Wei, Jing; Vereecken, Harry; Schloter, Michael; Brüggemann, Nicolas

    2016-04-01

    As an important intermediate of the nitrogen cycle, nitrite is highly reactive to soil organic matter (SOM) in forest soils under acidic conditions. However, there is little knowledge about how much its abiotic reactions with SOM contribute to nitrogen (N) gas emissions of forest soils till now. In this study, we provide data on N gas (N2O, NO, NO2) emissions from abiotic nitrite reactions with different fractions of soil organic matter in spruce forest soil, as well as the mechanisms involved. Soil samples were taken from the Oh layer at the TERENO-Wüstebach catchment, Germany, where Norway spruce (Picea abies) dominates. SOM was fractionated into dissolved organic matter (DOM), fulvic acid (FA), humic acid (HA) and humin (HN) according to their solubility. The dynamics of simultaneous NOx and N2O emissions were analyzed with a dynamic flow-through chamber system, coupled to an infrared laser absorption analyzer for N2O and a chemo-luminescence analyzer for NOx (NO and NO2), which allowed emission measurements with high time resolution. The 15N labelling technique was used for tracing the fate of nitrite-N towards establishment of a total N balance. When nitrite was added to the soil fractions, a large amount of NOx was immediately emitted, mostly in the form of NO. N2O emission was delayed by approximately 0.5-1 h. The NO and N2O emission pattern could be almost perfectly fitted with the Hill equation. The N2O formation rates increased significantly in the following order: DOM, FA, HA and HN, while the total amounts of the gases emitted increased significantly in the opposite order. These results revealed that abiotic reactions of nitrite with SOM in spruce forest soil play an important role in N gas emissions, while the chemical nature of the different SOM fractions determines the rate and amount of N gas emissions.

  16. Investigation of soil carbon sequestration processes in a temperate deciduous forest using soil respiration experiments

    NASA Astrophysics Data System (ADS)

    Schütze, Claudia; Marañón-Jiménez, Sara; Zöphel, Hendrik; Gimper, Sebastian; Dienstbach, Laura; Garcia Quirós, Inmaculada; Cuntz, Matthias; Rebmann, Corinna

    2016-04-01

    Considering the carbon cycles of terrestrial ecosystems, soils represent a major long-term carbon storage pool. However, the storage capacity depends on several impact parameters based on biotic factors (e.g. vegetation activity, microbial activity, nutrient availability, interactions between vegetation and microbial activity) and abiotic driving factors (e.g. soil moisture, soil temperature, soil composition). Especially, increases in vegetation and microbial activity can lead to raised soil carbon release detectable as higher soil respiration rates. Within the frame of the ICOS project, several soil respiration experiments are under consideration at the temperate deciduous forest site "Hohes Holz" (Central Germany). These experiments started in May 2014. Soil respiration data acquisition was carried out using 8 automatic continuous chambers (LI-COR) and 60 different plots for bi-weekly survey chamber measurements in order to clarify the controlling factors for soil CO2 emissions such as litter availability, above- and belowground vegetation, and activation of microbial activity with temperature, soil moisture and root occurrence. Hence, several treatments (trenched, non-trenched, litter supply) were investigated on different plots within the research area. The data analysis of the 20-month observation period reveals preliminary results of the study. Obviously, significant differences between the trenched and the non-trenched plots concerning the CO2 emissions occurred. Increased soil carbon releases are supposed to be associated to the activation of microbial mineralization of soil organic matter by root inputs. Furthermore, depending on the amount of litter supply, different levels of activation were observed. The data of the continuous chamber measurements with a temporal resolution of one hour sampling interval can be used to show the dependence on above described biogeochemical processes due to abiotic controlling factors. Especially, soil moisture as a

  17. Soil CO2 efflux in an old-growth southern conifer forest (Agathis australis) - magnitude, components and controls

    NASA Astrophysics Data System (ADS)

    Schwendenmann, Luitgard; Macinnis-Ng, Cate

    2016-08-01

    Total soil CO2 efflux and its component fluxes, autotrophic and heterotrophic respiration, were measured in a native forest in northern Aotearoa-New Zealand. The forest is dominated by Agathis australis (kauri) and is on an acidic, clay rich soil. Soil CO2 efflux, volumetric soil water content and soil temperature were measured bi-weekly to monthly at 72 sampling points over 18 months. Trenching and regression analysis was used to partition total soil CO2 efflux into heterotrophic and autotrophic respiration. The effect of tree structure was investigated by calculating an index of local contribution (Ic, based on tree size and distance to the measurement location) followed by correlation analysis between Ic and total soil CO2 efflux, root biomass, litterfall and soil characteristics. The measured mean total soil CO2 efflux was 3.47 µmol m-2 s-1. Autotrophic respiration accounted for 25 % (trenching) or 28 % (regression analysis) of total soil CO2 efflux. Using uni- and bivariate models showed that soil temperature was a poor predictor of the temporal variation in total soil CO2 efflux (< 20 %). In contrast, a stronger temperature sensitivity was found for heterotrophic respiration (around 47 %). We found significant positive relationships between kauri tree size (Ic) and total soil CO2 efflux, root biomass and mineral soil CN ratio within 5-6 m of the sampling points. Using multiple regression analysis revealed that 97 % of the spatial variability in total soil CO2 efflux in this kauri-dominated stand was explained by root biomass and soil temperature. Our findings suggest that biotic factors such as tree structure should be investigated in soil carbon related studies.

  18. Effects of Forest Succession on Exchangeable Cation Concentrations and Nitrogen Mineralization Rates in Soils Following Logging of Eastern Hemlock Forest, Whately, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rhodes, A. L.; Sweezy, T.; Zukswert, J. M.; Dwyer, C. H.

    2012-12-01

    Ecological forest successions associated with invasive species and human disturbance may alter biogeochemical cycles within New England forests. Spread of the invasive insect hemlock woolly adelgid (Adelges tsugae) to eastern North America is causing mortality of the eastern hemlock (Tsuga canadensis), prompting salvage logging. Regrowth by deciduous hardwood trees is often observed. To evaluate whether changes in nutrient cycling could be altered by forest succession, we investigated exchangeable cation chemistry and nitrogen mineralization rates for soil in a mature, eastern hemlock forest and in a juvenile black birch (Betula lenta) forest in western MA. Eastern hemlock on this property was selectively logged 20 years ago, with black birch regrowth succeeding hemlock. We measured soil pH, exchangeable acidity (Al3+ and H+), exchangeable base cations (Ca2+, Mg2+, Na+, and K+), and nitrogen mineralization rates of organic and mineral horizons for 7 incubation periods between May 2011 - July 2012. We also measured the cation exchange capacity and nitrogen mineralization rates of soils from May - July 2012 (2 incubations) in a mature deciduous forest composed primarily of black birch. At each field site, 7 soil cores were collected. Soil horizons (organic and mineral) were separated and homogenized, and 3 replicates of each composite sample were analyzed for soil geochemistry. Organic soils within the juvenile black birch plot (BB) exhibit a low pH (4.3) similar to hemlock organic soils (HEM, pH=4.2). Surprisingly, exchangeable Al3+—the dominant cation in both plots—is significantly greater in organic soils at BB than at HEM (p<.001), and base saturation is less at BB (29%) than at HEM (46%, p<0.001) due to less Ca2+. There are no significant differences in the exchangeable cation chemistry of the mineral horizons at both sites, suggesting that the acidity difference of organic matter is not due to different soil mineralogy. In comparison, organic soil at the

  19. Recharge forest revisited: soils of Brookhaven National Laboratory

    SciTech Connect

    Grafton, J.

    1980-11-01

    Soil samples were collected from terrestrial systems 44 months after they had been subjected to 22 months of sewage spray application. Data on pH, % organic matter, exchangeable hydrogen, phosphorus, potassium, magnesium, calcium, manganese, iron, aluminum, nitrate, and ammonia were generated for each soil horizon in three plots from two forest types. The three plots represent a control, treatment with primary sewage, and treatment with secondary sewage. There were no replicates. Differences in soil chemistry and/or structure between the three plots were assumed to be due to sewage application. Residual difference for a parameter, or changes remaining after 44 months, were considered significant if at least one Analysis of Variance (ANOVA) by horizon produced an F value corresponding to a p of .05. Analyses, data, and pH graphs are presented for future reference.

  20. Available phosphorus in forest soil increases with soil nitrogen but not total phosphorus: evidence from subtropical forests and a pot experiment.

    PubMed

    Liu, Xingzhao; Meng, Wei; Liang, Guohua; Li, Kun; Xu, Weiqiang; Huang, Liujing; Yan, Junhua

    2014-01-01

    This paper aims to establish evidence for available phosphorous (AP) binding with total nitrogen (N) in subtropical forest soils. Soil organic carbon (SOC), total N, total phosphorous (P) and AP concentration were measured for three contrasting forest types in southern China: Masson pine forest (MPF), coniferous and broadleaved mixed forest (CBMF) and monsoon evergreen broadleaved forest (MEBF). A pot experiment with N addition was conducted to confirm the dominant factor to affect on soil AP concentration. The results showed that mean soil total N concentration in 0-10 cm soil layer was 440 ± 50 for MPF, 840 ± 80 for CBMF and 1020 ± 50 mg kg(-1) for MEBF, respectively. The mean soil AP concentration in 0-10 cm soil layer was 2.67 ± 0.87 for MPF, 2.65 ± 0.58 for CBMF, 4.10 ± 0.29 mg kg(-1) for MEBF, respectively. The soil total N concentration could explain about 70% of the variations in soil AP concentration in the top 20 cm soil layers in the three forest types. A pot experiment with N addition also showed an increase of AP concentration from 2.56 to 5.63 mg kg(-1), when N addition increased from 5 g to 17 g NH4NO3. Our results therefore suggested that N addition significantly increased soil AP concentration, which might be beneficial for stabilizing the net primary production of subtropical forests that were limited by soil AP. This finding may provide a theory basis for tropical and subtropical forests management. PMID:24505379

  1. Available phosphorus in forest soil increases with soil nitrogen but not total phosphorus: evidence from subtropical forests and a pot experiment.

    PubMed

    Liu, Xingzhao; Meng, Wei; Liang, Guohua; Li, Kun; Xu, Weiqiang; Huang, Liujing; Yan, Junhua

    2014-01-01

    This paper aims to establish evidence for available phosphorous (AP) binding with total nitrogen (N) in subtropical forest soils. Soil organic carbon (SOC), total N, total phosphorous (P) and AP concentration were measured for three contrasting forest types in southern China: Masson pine forest (MPF), coniferous and broadleaved mixed forest (CBMF) and monsoon evergreen broadleaved forest (MEBF). A pot experiment with N addition was conducted to confirm the dominant factor to affect on soil AP concentration. The results showed that mean soil total N concentration in 0-10 cm soil layer was 440 ± 50 for MPF, 840 ± 80 for CBMF and 1020 ± 50 mg kg(-1) for MEBF, respectively. The mean soil AP concentration in 0-10 cm soil layer was 2.67 ± 0.87 for MPF, 2.65 ± 0.58 for CBMF, 4.10 ± 0.29 mg kg(-1) for MEBF, respectively. The soil total N concentration could explain about 70% of the variations in soil AP concentration in the top 20 cm soil layers in the three forest types. A pot experiment with N addition also showed an increase of AP concentration from 2.56 to 5.63 mg kg(-1), when N addition increased from 5 g to 17 g NH4NO3. Our results therefore suggested that N addition significantly increased soil AP concentration, which might be beneficial for stabilizing the net primary production of subtropical forests that were limited by soil AP. This finding may provide a theory basis for tropical and subtropical forests management.

  2. Profile distribution and temporal changes of sulphate and nitrate contents and related soil properties under beech and spruce forests.

    PubMed

    Tejnecký, Václav; Bradová, Monika; Borůvka, Luboš; Němeček, Karel; Sebek, Ondřej; Nikodem, Antonín; Zenáhlíková, Jitka; Rejzek, Jan; Drábek, Ondřej

    2013-01-01

    The behaviour of principal inorganic anions in forest soils, originating mainly from acid deposition, strongly influences the forest ecosystem response on acidification. The aim of this study was to describe seasonal and temporal changes of sulphate and nitrate contents and related soil properties under beech and spruce forests in a region heavily impacted by acidification. The Jizera Mountains area (Czech Republic) was chosen as such a representative mountainous soil ecosystem. Soil samples were collected at monthly intervals from April to October during the years 2008-2010 under both beech and spruce stands. Soil samples were collected from surface fermentation (F) and humified (H) organic horizons, humic (A) organo-mineral horizons and subsurface mineral (B) horizons (cambic or spodic). A deionised water extract was applied to unsieved fresh samples and the content of anions in these extracts was determined by ion chromatography (IC). In the studied soil profiles, the lowest amount of SO(4)(2-) was found in the organo-mineral A horizons under both types of vegetation. Under spruce the highest amount of SO(4)(2-) was determined in mineral spodic (B) horizons, where a strong sorption influence of Fe and Al oxy-hydroxides is expected. Under beech the highest amount was observed in the surface organic F horizons (forest floor). The amount of NO(3)(-) is highest in the F horizons and decreases with increasing soil profile depth under both types of vegetation. A significantly higher amount of NO(3)(-) was determined in soils under the beech stand compared to spruce. For both soil environments - under beech and also spruce stands - we have determined a general increase of water-extractable SO(4)(2-) and NO(3)(-) during the whole monitoring period. The behaviour of SO(4)(2-) and NO(3)(-) in the soils is strongly related to the dynamics of soil organic matter and particularly to the DOC.

  3. Soil Does Not Explain Monodominance in a Central African Tropical Forest

    PubMed Central

    Peh, Kelvin S. -H.; Sonké, Bonaventure; Lloyd, Jon; Quesada, Carlos A.; Lewis, Simon L.

    2011-01-01

    Background Soil characteristics have been hypothesised as one of the possible mechanisms leading to monodominance of Gilbertiodendron dewerei in some areas of Central Africa where higher-diversity forest would be expected. However, the differences in soil characteristics between the G. dewevrei-dominated forest and its adjacent mixed forest are still poorly understood. Here we present the soil characteristics of the G. dewevrei forest and quantify whether soil physical and chemical properties in this monodominant forest are significantly different from the adjacent mixed forest. Methodology/Principal Findings We sampled top soil (0–5, 5–10, 10–20, 20–30 cm) and subsoil (150–200 cm) using an augur in 6 × 1 ha areas of intact central Africa forest in SE Cameroon, three independent patches of G. dewevrei-dominated forest and three adjacent areas (450–800 m apart), all chosen to be topographically homogeneous. Analysis – subjected to Bonferroni correction procedure – revealed no significant differences between the monodominant and mixed forests in terms of soil texture, median particle size, bulk density, pH, carbon (C) content, nitrogen (N) content, C:N ratio, C:total NaOH-extractable P ratio and concentrations of labile phosphorous (P), inorganic NaOH-extractable P, total NaOH-extractable P, aluminium, barium, calcium, copper, iron, magnesium, manganese, molybdenum, nickel, potassium, selenium, silicon, sodium and zinc. Prior to Bonferroni correction procedure, there was a significant lower level of silicon concentration found in the monodominant than mixed forest deep soil; and a significant lower level of nickel concentration in the monodominant than mixed forest top soil. Nevertheless, these were likely to be the results of multiple tests of significance. Conclusions/Significance Our results do not provide clear evidence of soil mediation for the location of monodominant forests in relation to adjacent mixed forests. It is also likely that G

  4. Does drought alter hydrological functions in forest soils?

    NASA Astrophysics Data System (ADS)

    Gimbel, Katharina F.; Puhlmann, Heike; Weiler, Markus

    2016-04-01

    Climate change is expected to impact the water cycle and severely affect precipitation patterns across central Europe and in other parts of the world, leading to more frequent and severe droughts. Usually when projecting drought impacts on hydrological systems, it is assumed that system properties, like soil properties, remain stable and will not be affected by drought events. To study if this assumption is appropriate, we address the effects of drought on the infiltration behavior of forest soils using dye tracer experiments on six sites in three regions across Germany, which were forced into drought conditions. The sites cover clayey-, loamy- and sandy-textured soils. In each region, we compared a deciduous and a coniferous forest stand to address differences between the main tree species. The results of the dye tracer experiments show clear evidence for changes in infiltration behavior at the sites. The infiltration changed at the clayey plots from regular and homogeneous flow to fast preferential flow. Similar behavior was observed at the loamy plots, where large areas in the upper layers remained dry, displaying signs of strong water repellency. This was confirmed by water drop penetration time (WDPT) tests, which revealed, in all except one plot, moderate to severe water repellency. Water repellency was also accountable for the change of regular infiltration to fingered flow in the sandy soils. The results of this study suggest that the drought history or, more generally, the climatic conditions of a soil in the past are more important than the actual antecedent soil moisture status regarding hydrophobicity and infiltration behavior; furthermore, drought effects on infiltration need to be considered in hydrological models to obtain realistic predictions concerning water quality and quantity in runoff and groundwater recharge.

  5. SOC storage in Swiss forest soils - driven by climate or historical land-use?

    NASA Astrophysics Data System (ADS)

    Gosheva, Sia; Walthert, Lorenz; Niklaus, Pascal; Zimmermann, Stephan; Hagedorn, Frank

    2015-04-01

    Soils store the most carbon of all terrestrial ecosystems, with forest soils being particularly carbon-rich (Schmidt et al. 2011; Hagedorn et al. 2010; Jobaggy & Jackson 2000). The C balance of soils might be altered by land-use changes such as in Switzerland, where the forest cover has increased by approximately 22% in the last century (Ginzler et al. 2011). The objectives of this study were 1) to determine whether historical forest cover change has an impact on soil organic carbon (SOC) storage in Swiss forests, and 2) to estimate the influence of climate on C-stocks in the organic layer and the mineral soil. In our study, we reconstructed forest cover changes for the last 150 years for the coordinates of 1000 soil profiles from the soil database of the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL). We evaluated historical and modern topographic maps using ArcGIS, classifying current forest sites into permanently (≥150y) forested and newly forested sites (<150y). To identify the impact of climate and historic land-use change on SOC storage, we statistically analyzed the influence of the estimated forest ages of the sites and of potentially additional drivers such as topography, climate, and soil properties on SOC stocks. Contrary to our expectations, our results indicate slightly higher SOC stocks in younger forest sites compared to permanently forested ones. This result could be observed in both organic layer (28,65 vs. 22,23 t C ha-1) and mineral soil (131,38 vs. 113,68 t C ha-1). We attribute the slightly smaller SOC stocks in the younger forests to their inherently higher SOC-stocks, as associated with favorable land previously used for grassland. Moreover, we observed higher SOC stocks under coniferous than under deciduous forest - however, this was only evident in the organic layer, but not in the mineral soil. Soil carbon increased significantly with decreasing mean annual temperature (MAT) and increasing precipitation (MAP), in

  6. Controls of Soil Spatial Variability in a Dry Tropical Forest.

    PubMed

    Pulla, Sandeep; Riotte, Jean; Suresh, H S; Dattaraja, H S; Sukumar, Raman

    2016-01-01

    We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2) soil spatial variability in a seasonally dry tropical forest (SDTF) in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm), rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH), and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling) in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(-)-N nor NH4(+)-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief. PMID:27100088

  7. Controls of Soil Spatial Variability in a Dry Tropical Forest.

    PubMed

    Pulla, Sandeep; Riotte, Jean; Suresh, H S; Dattaraja, H S; Sukumar, Raman

    2016-01-01

    We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2) soil spatial variability in a seasonally dry tropical forest (SDTF) in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm), rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH), and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling) in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(-)-N nor NH4(+)-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

  8. Soil fungal communities of montane natural secondary forest types in China.

    PubMed

    Cheng, Fei; Wei, Xin; Hou, Lin; Shang, Zhengchun; Peng, Xiaobang; Zhao, Peng; Fei, Zhaoxue; Zhang, Shuoxin

    2015-06-01

    Distinctive plant communities may provide specific physical and chemical properties with soils by specific litters and root exudates to exert effects on soil microorganisms. Past logging activities in the Qinling Mountains induced diverse natural secondary forest types (NSFTs). How these recovered NSFTs regulate patterns of soil microbial communities remain limited. In the study, we used terminal-restriction fragment length polymorphism (T-RFLP) to precisely determine forest type-specific soil fungal diversity and composition in five NSFTs. Our results indicated that NSFTs had significant impacts on the soil fungal communities. The most diverse fungal species were found in the Armand pine (Pinus armandi) and Chinese pine (Pinus tabulaeformis) forest soils, followed by sharptooth oak (Quercus aliena var. acuteserrata) and Chinese pine-sharptooth oak forest soils, the wilson spruce (Picea wilsonii) forests had the lowest soil fungal diversity. The analyses of community composition suggested that the fungal communities of Armand pine forest soils were similar to those of Chinese pine forest soils, while other communities prominently differed from each other. Stepwise multiple regression analysis revealed that soil silt, clay, pH, and ammonium nitrogen had intimate linkages with soil fungal diversity. Furthermore, the patterns of soil fungal communities were strongly governed by the specific soil environments of the tested NSFTs, as described by canonical correspondence analysis (CCA). Finally, our study showed that soil fungal communities may be mediated by NSFTs via specific soil edaphic status. Hence, such a comparable study may provide fundamental information for fungal diversity and community structure of natural forests and assist with better prediction and understanding how soil fungal composition and function alter with forest type transformation.

  9. Soil fungal communities of montane natural secondary forest types in China.

    PubMed

    Cheng, Fei; Wei, Xin; Hou, Lin; Shang, Zhengchun; Peng, Xiaobang; Zhao, Peng; Fei, Zhaoxue; Zhang, Shuoxin

    2015-06-01

    Distinctive plant communities may provide specific physical and chemical properties with soils by specific litters and root exudates to exert effects on soil microorganisms. Past logging activities in the Qinling Mountains induced diverse natural secondary forest types (NSFTs). How these recovered NSFTs regulate patterns of soil microbial communities remain limited. In the study, we used terminal-restriction fragment length polymorphism (T-RFLP) to precisely determine forest type-specific soil fungal diversity and composition in five NSFTs. Our results indicated that NSFTs had significant impacts on the soil fungal communities. The most diverse fungal species were found in the Armand pine (Pinus armandi) and Chinese pine (Pinus tabulaeformis) forest soils, followed by sharptooth oak (Quercus aliena var. acuteserrata) and Chinese pine-sharptooth oak forest soils, the wilson spruce (Picea wilsonii) forests had the lowest soil fungal diversity. The analyses of community composition suggested that the fungal communities of Armand pine forest soils were similar to those of Chinese pine forest soils, while other communities prominently differed from each other. Stepwise multiple regression analysis revealed that soil silt, clay, pH, and ammonium nitrogen had intimate linkages with soil fungal diversity. Furthermore, the patterns of soil fungal communities were strongly governed by the specific soil environments of the tested NSFTs, as described by canonical correspondence analysis (CCA). Finally, our study showed that soil fungal communities may be mediated by NSFTs via specific soil edaphic status. Hence, such a comparable study may provide fundamental information for fungal diversity and community structure of natural forests and assist with better prediction and understanding how soil fungal composition and function alter with forest type transformation. PMID:26025170

  10. Effect of soil bulk density on forest tree seedlings

    NASA Astrophysics Data System (ADS)

    Kormanek, Mariusz; Banach, Jacek; Sowa, Paweł

    2015-01-01

    The paper presents the results of an analysis of the influence of soil bulk density in a forest nursery plot on the growth and quality parameters of Scots pine and European beech seedlings. Particular density variants were obtained using a tractor device exerting controlled pressure on the soil, while field examinations were performed on an area of `Kłaj' forest nursery in Niepołomice Forest District. Three series of plots were prepared for each species, applying a unit pressure of the values of 50, 100, 150, 200, 250 kPa, corresponding to the dry bulk density in the range of 1.03-1.19 g cm-3, and control plots without the pressure. Seeds of the examined species were sown on the prepared plots, and after 6 months of growth the seedlings were subjected to biometric analysis determining differentiation in root neck diameter, length of the above-ground part and root system, as well as dry mass of particular parts of the plant. The quality of the seedlings was also determined using the method of Schmidt-Vogt. The results obtained show that the change in dry bulk density soil significantly affected most of the growth parameters of the examined seedlings. Especially high negative correlations were obtained for the length and dry mass of the root system. A significant influence of dry bulk density variant on all growth parameters of Scots pine seedlings, and on some parameters of European beech was demonstrated. An increase in soil bulk density clearly caused also a deterioration of European beech seedlings quality

  11. Soil Respiration Declines Following Beetle - Induced Forest Mortality in a Lodgepole Pine Forest

    NASA Astrophysics Data System (ADS)

    Borkhuu, B.; Peckham, S. D.; Norton, U.; Ewers, B. E.; Pendall, E.

    2014-12-01

    Lodgepole pine (Pinus contorta var. latifolia) forests in northern Colorado and southeast Wyoming have been undergoing a major mortality event owing to mountain pine beetle (Dendroctonus ponderosae) infestation since 2007. We studied biotic and abiotic drivers of growing season soil respiration in four mature stands experiencing different levels of mortality between 2008 and 2012 in the Medicine Bow Mountains, southeastern Wyoming, USA. For five years, beetle infestation significantly altered forest structure. Stand mortality was 30% and more than 80% in stands with the lowest and highest mortality, respectively. Understory vegetation cover increased by 50% for five years following beetle infestation. Needlefall was increased by more than 50% during first two years of beetle infestation compared to the pre-disturbance period. We did not observe an immediate increase in soil respiration following beetle infestation as suggested by some researchers. Soil respiration rates in midsummer ranged from 1.4 ± 0.1 μmol m-2 s-1 in stands with highest mortality to 3.1 ± 0.2 μmol m-2s-1 in uninfested stand. Live tree basal area was the dominant factor controlling soil respiration, explaining more than 60% of the interannual and spatial variations in response to the disturbance. In addition, soil respiration was significantly correlated with fine root biomass, which explained 55% of variations, providing strong evidence that autotrophic respiration dominated the forest soil respiration flux. Furthermore, the seasonality of soil respiration was controlled mainly by mean monthly precipitation and mid-day photosynthetically active radiation. Each factor predicted from 30% to 50% of seasonal soil respiration variability with the highest correlation coefficients in stand with the lowest mortality. Our results clearly indicate that the reduction of photosynthesis in trees over the infestation period significantly reduced soil respiration. The remaining activity in dead stands may

  12. Smog nitrogen and the rapid acidification of forest soil, San Bernardino Mountains, southern California.

    PubMed

    Wood, Yvonne A; Fenn, Mark; Meixner, Thomas; Shouse, Peter J; Breiner, Joan; Allen, Edith; Wu, Laosheng

    2007-03-21

    We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the soil surface (72 kg ha(-1) year(-1)) from wet, dry, and fog deposition under a Mediterranean climate. Our research suggests that a soil textural discontinuity, related to a buried ancient landsurface, contributes to this rapid acidification by controlling the spatial and temporal movement of precipitation into the landsurface. As a result, the depth to which dissolved anthropogenic N as nitrate (NO3) is leached early in the winter wet season is limited to within the top approximately 130 cm of soil where it accumulates and increases soil acidity.

  13. Transforming Pinus pinaster forest to recreation site: preliminary effects on LAI, some forest floor, and soil properties.

    PubMed

    Öztürk, Melih; Bolat, İlyas

    2014-04-01

    This study investigates the effects of forest transformation into recreation site. A fragment of a Pinus pinaster plantation forest was transferred to a recreation site in the city of Bartın located close to the Black Sea coast of northwestern Turkey. During the transformation, some of the trees were selectively removed from the forest to generate more open spaces for the recreationists. As a result, Leaf Area Index (LAI) decreased by 0.20 (about 11%). Additionally, roads and pathways were introduced into the site together with some recreational equipment sealing parts of the soil surface. Consequently, forest environment was altered with a semi-natural landscape within the recreation site. The purpose of this study is to assess the effects of forest transformation into recreation site particularly in terms of the LAI parameter, forest floor, and soil properties. Preliminary monitoring results indicate that forest floor biomass is reduced by 26% in the recreation site compared to the control site. Soil temperature is increased by 15% in the recreation site where selective removal of trees expanded the gaps allowing more light transmission. On the other hand, the soil bulk density which is an indicator of soil compaction is unexpectedly slightly lower in the recreation site. Organic carbon (C(org)) and total nitrogen (N(total)) together with the other physical and chemical parameter values indicate that forest floor and soil have not been exposed to much disturbance. However, subsequent removal of trees that would threaten the vegetation, forest floor, and soil should not be allowed. The activities of the recreationists are to be concentrated on the paved spaces rather than soil surfaces. Furthermore, long-term monitoring and management is necessary for both the observation and conservation of the site.

  14. Acid rain mitigation experiment shifts a forested watershed from a net sink to a net source of nitrogen.

    PubMed

    Rosi-Marshall, Emma J; Bernhardt, Emily S; Buso, Donald C; Driscoll, Charles T; Likens, Gene E

    2016-07-01

    Decades of acid rain have acidified forest soils and freshwaters throughout montane forests of the northeastern United States; the resulting loss of soil base cations is hypothesized to be responsible for limiting rates of forest growth throughout the region. In 1999, an experiment was conducted that reversed the long-term trend of soil base cation depletion and tested the hypothesis that calcium limits forest growth in acidified soils. Researchers added 1,189 kg Ca(2+) ha(-1) as the pelletized mineral wollastonite (CaSiO3) to a 12-ha forested watershed within the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. Significant increases in the pH and acid-neutralizing capacity of soils and streamwater resulted, and the predicted increase in forest growth occurred. An unanticipated consequence of this acidification mitigation experiment began to emerge a decade later, with marked increases in dissolved inorganic nitrogen (DIN) exports in streamwater from the treated watershed. By 2013, 30-times greater DIN was exported from this base-treated watershed than from adjacent reference watersheds, and DIN exports resulting from this experiment match or exceed earlier reports of inorganic N losses after severe ice-storm damage within the study watershed. The discovery that CaSiO3 enrichment can convert a watershed from a sink to a source of N suggests that numerous potential mechanisms drive watershed N dynamics and provides new insights into the influence of acid deposition mitigation strategies for both carbon cycling and watershed N export. PMID:27335456

  15. Acid rain mitigation experiment shifts a forested watershed from a net sink to a net source of nitrogen.

    PubMed

    Rosi-Marshall, Emma J; Bernhardt, Emily S; Buso, Donald C; Driscoll, Charles T; Likens, Gene E

    2016-07-01

    Decades of acid rain have acidified forest soils and freshwaters throughout montane forests of the northeastern United States; the resulting loss of soil base cations is hypothesized to be responsible for limiting rates of forest growth throughout the region. In 1999, an experiment was conducted that reversed the long-term trend of soil base cation depletion and tested the hypothesis that calcium limits forest growth in acidified soils. Researchers added 1,189 kg Ca(2+) ha(-1) as the pelletized mineral wollastonite (CaSiO3) to a 12-ha forested watershed within the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire. Significant increases in the pH and acid-neutralizing capacity of soils and streamwater resulted, and the predicted increase in forest growth occurred. An unanticipated consequence of this acidification mitigation experiment began to emerge a decade later, with marked increases in dissolved inorganic nitrogen (DIN) exports in streamwater from the treated watershed. By 2013, 30-times greater DIN was exported from this base-treated watershed than from adjacent reference watersheds, and DIN exports resulting from this experiment match or exceed earlier reports of inorganic N losses after severe ice-storm damage within the study watershed. The discovery that CaSiO3 enrichment can convert a watershed from a sink to a source of N suggests that numerous potential mechanisms drive watershed N dynamics and provides new insights into the influence of acid deposition mitigation strategies for both carbon cycling and watershed N export.

  16. Threshold Responses to Soil Moisture Deficit by Trees and Soil in Tropical Rain Forests: Insights from Field Experiments

    PubMed Central

    Meir, Patrick; Wood, Tana E.; Galbraith, David R.; Brando, Paulo M.; Da Costa, Antonio C. L.; Rowland, Lucy; Ferreira, Leandro V.

    2015-01-01

    Many tropical rain forest regions are at risk of increased future drought. The net effects of drought on forest ecosystem functioning will be substantial if important ecological thresholds are passed. However, understanding and predicting these effects is challenging using observational studies alone. Field-based rainfall exclusion (canopy throughfall exclusion; TFE) experiments can offer mechanistic insight into the response to extended or severe drought and can be used to help improve model-based simulations, which are currently inadequate. Only eight TFE experiments have been reported for tropical rain forests. We examine them, synthesizing key results and focusing on two processes that have shown threshold behavior in response to drought: (1) tree mortality and (2) the efflux of carbon dioxdie from soil, soil respiration. We show that: (a) where tested using large-scale field experiments, tropical rain forest tree mortality is resistant to long-term soil moisture deficit up to a threshold of 50% of the water that is extractable by vegetation from the soil, but high mortality occurs beyond this value, with evidence from one site of increased autotrophic respiration, and (b) soil respiration reaches its peak value in response to soil moisture at significantly higher soil moisture content for clay-rich soils than for clay-poor soils. This first synthesis of tropical TFE experiments offers the hypothesis that low soil moisture–related thresholds for key stress responses in soil and vegetation may prove to be widely applicable across tropical rain forests despite the diversity of these forests. PMID:26955085

  17. Forest ecosystems and the changing patterns of nitrogen input and acid deposition today and in the future based on a scenario.

    PubMed

    Busch, G; Lammel, G; Beese, F O; Feichter, J; Dentener, F J; Roelofs, G J

    2001-01-01

    A global assessment of the impact of the anthropogenic perturbation of the nitrogen and sulfur cycles on forest ecosystems is carried out for both the present-day [1980-1990] and for a projection into the future [2040-2050] under a scenario of economic development which represents a medium path of development according to expert guess [IPCC IS92a]. Results show that forest soils will receive considerably increasing loads of nitrogen and acid deposition and that deposition patterns are likely to change. The regions which are most prone to depletion of soils buffering capacity and supercritical nitrogen deposition are identified in the subtropical and tropical regions of South America and Southeast Asia apart from the well known 'hotspots' North-Eastern America and Central Europe. The forest areas likely to meet these two risks are still a minor fraction of the global forest ecosystems, though. But the bias between eutrophication and acidification will become greater and an enhanced growth triggered by the fertilizing effects of increasing nitrogen input cannot be balanced by the forest soils nutrient pools. Results show increasing loads into forest ecosystems which are likely to account for 46% higher acid loads and 36% higher nitrogen loads in relation to the 1980-1990 situation. Global background deposition of up to 5 kg N ha-1 a-1 will be exceeded at more than 25% of global forest ecosystems and at more than 50% of forest ecosystems on acid sensitive soils. More than 33% of forest ecosystems on acid sensitive soils will receive acid loads which exceeds their buffering capacity. About 25% of forest areas with exceeded acid loads will receive critical nitrogen loads.

  18. Radiocarbon and stable carbon isotope compositions of chemically fractionated soil organic matter in a temperate-zone forest.

    PubMed

    Koarashi, Jun; Iida, Takao; Asano, Tomohiro

    2005-01-01

    To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon ((14)C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of (14)C abundances showed that (1) bomb-derived (14)C has penetrated the first 16cm mineral soil at least; (2) Delta(14)C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived (14)C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived (14)C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales. PMID:15603904

  19. Iron: A Biogeochemical Engine That Drives Carbon, Nitrogen, and Phosphorus Cycling in Humid Tropical Forest Soils

    NASA Astrophysics Data System (ADS)

    Silver, W. L.; Hall, S. J.; Thompson, A.; Yang, W. H.

    2014-12-01

    The abundance of redox active Fe minerals has the potential to alter the storage and loss of C, contribute to gaseous N emissions, and control P retention in upland tropical forest soils. High concentrations of short-range order Fe minerals led to Fe(II) production rates of 26-206 μg g d-1 under short-term low redox conditions (Chacón et al. 2006, Liptzin and Silver 2009, Dubinsky et al. 2010). Potential C mineralization from Fe(II) reduction was 34-263 g CO2-C m-2 y-1, C losses equivalent to approximately 10-60 % of annual litterfall production in this forest. Decreased acidity during Fe reduction can destabilize soil aggregates and lead to C losses. Iron is rapidly reoxidized during aerobic periods, which can subsequently lead to C stabilization via complexation reactions. Fe oxidation can also stimulate C losses via pH-driven dissolved organic C production and directly via Fenton reactions. In laboratory experiments, rates of CO2 production were strongly linearly correlated with Fe(II) loss under aerobic conditions, increasing by 0.51 ± 0.02 µg CO2-C g soil h-1 respired for each mg of Fe(II) g-1 soil oxidized or sorbed (Hall and Silver 2013). Iron oxidation has also been linked to dissimilatory NO3- reduction to NH4+ leading to N retention in ecosystems. Fe(III) reduction coupled with NH4+ oxidation (Feammox) can lead to N losses as dinitrogen gas (N2) or nitrous oxide (N2O), a potent greenhouse gas. Estimates suggest that Feammox resulted in gaseous N losses of 1-4 kg N ha-1 y-1 (Yang et al. 2012), rates equivalent to total denitrification in this forest. Oxidized Fe can strongly bind P decreasing it's availability to plant roots. While this is commonly cited as a potential limitation to net primary production in tropical forests, it also helps to retain P in ecosystems with high rainfall and potential leaching losses. Microbial biomass P availability increased significantly with Fe(II) production, suggesting the P mobilized during Fe(II) reduction was

  20. Persistent episodic acidification of streams linked to acid rain effects on soil

    USGS Publications Warehouse

    Lawrence, G.B.

    2002-01-01

    Episodic acidification of streams, identified in the late 1980s as one of the most significant environmental problems caused by acidic deposition, had not been evaluated since the early 1990s despite decreasing levels of acidic deposition over the past decade. This analysis indicates that episodic acidification of streams in upland regions in the northeastern United States persists, and is likely to be much more widespread than chronic acidification. Depletion of exchangeable Ca in the mineral soil has decreased the neutralization capacity of soils and increased the role of the surface organic horizon in the neutralization of acidic soil water during episodes. Increased accumulation of N and S in the forest floor from decades of acidic deposition will delay the recovery of soil base status, and therefore, the elimination of acidic episodes, which is anticipated from decreasing emissions.

  1. Soil respiration in tropical seasonal forest of Southern Vietnam

    NASA Astrophysics Data System (ADS)

    Avilov, Vitaly; Anichkin, Alexandr; Descherevskaya, Olga; Evdokimova, Elena; Nguyen Van, Thinh; Novichonok, Artyom; Do Phong, Luu; Kurbatova, Julia; Lopes de Gerenyu, Valentin

    2013-04-01

    Soil respiration was monitored as a part of a complex research of carbon balance in Nam Cat Tien National Park in Southern Vietnam (NCT site in AsiaFlux index). The study area is described as a tropical monsoon valley tall-stand forest at altitude about 156 m above sea level, mean annual air temperature is 26.2°C, with fluctuations of monthly averaged temperatures within 4°C; mean annual precipitation is 2470 mm with a distinct alternation of wet and dry seasons (Dong Phu weather station, 1976-1990). Measurements were made every 10-15 days during year 2012 at 6 plots that differ in soil and forest type, mostly in Lagerstroemia- or Dipterocarpus-dominated tree stands. Five chambers Ø162 mm were installed at each plot. CO2 concentration was defined with LI-820 gas analyser and 20 ml syringes (three syringes/samples per chamber) up to August 2012, and by means of closed-loop continuous field analysis from August on. Our studies have shown significant temporal and spatial variability of soil respiration in tropical rainforest. Namely, highest annual CO2 efflux rates were calculated for cambisols under lagerstroemia-dominated tree stand and for light sandy fluvisols under dipterocarpus-dominated tree stand (1694.3±546.0 and 1628.1±442.7 gC•m-2•y-1 respectively). Noteworthy is that the content of organic carbon in these soils varies utterly. Lowest annual CO2 efflux rate was calculated for clay-slate leptosols under dipterocarpus-dominated tree stand (972.7±716.5 gC•m-2•y-1). We also observed a significant impact of termites activity on site-scale spatial variability of soil respiration. Seasonal patterns of soil respiration rates were conformed for all plots except one on sandy soils. The beginning of rainy season in April did not result in higher soil respiration rates, but rates did rise in August - October, at the end of rainy season. Apparently this pattern is related to the accumulation of decomposed organic matter in soil and to the deficient

  2. Metatranscriptomics Reveals the Diversity of Genes Expressed by Eukaryotes in Forest Soils

    PubMed Central

    Damon, Coralie; Lehembre, Frédéric; Oger-Desfeux, Christine; Luis, Patricia; Ranger, Jacques; Fraissinet-Tachet, Laurence; Marmeisse, Roland

    2012-01-01

    Eukaryotic organisms play essential roles in the biology and fertility of soils. For example the micro and mesofauna contribute to the fragmentation and homogenization of plant organic matter, while its hydrolysis is primarily performed by the fungi. To get a global picture of the activities carried out by soil eukaryotes we sequenced 2×10,000 cDNAs synthesized from polyadenylated mRNA directly extracted from soils sampled in beech (Fagus sylvatica) and spruce (Picea abies) forests. Taxonomic affiliation of both cDNAs and 18S rRNA sequences showed a dominance of sequences from fungi (up to 60%) and metazoans while protists represented less than 12% of the 18S rRNA sequences. Sixty percent of cDNA sequences from beech forest soil and 52% from spruce forest soil had no homologs in the GenBank/EMBL/DDJB protein database. A Gene Ontology term was attributed to 39% and 31.5% of the spruce and beech soil sequences respectively. Altogether 2076 sequences were putative homologs to different enzyme classes participating to 129 KEGG pathways among which several were implicated in the utilisation of soil nutrients such as nitrogen (ammonium, amino acids, oligopeptides), sugars, phosphates and sulfate. Specific annotation of plant cell wall degrading enzymes identified enzymes active on major polymers (cellulose, hemicelluloses, pectin, lignin) and glycoside hydrolases represented 0.5% (beech soil)–0.8% (spruce soil) of the cDNAs. Other sequences coding enzymes active on organic matter (extracellular proteases, lipases, a phytase, P450 monooxygenases) were identified, thus underlining the biotechnological potential of eukaryotic metatranscriptomes. The phylogenetic affiliation of 12 full-length carbohydrate active enzymes showed that most of them were distantly related to sequences from known fungi. For example, a putative GH45 endocellulase was closely associated to molluscan sequences, while a GH7 cellobiohydrolase was closest to crustacean sequences, thus suggesting a

  3. Metatranscriptomics reveals the diversity of genes expressed by eukaryotes in forest soils.

    PubMed

    Damon, Coralie; Lehembre, Frédéric; Oger-Desfeux, Christine; Luis, Patricia; Ranger, Jacques; Fraissinet-Tachet, Laurence; Marmeisse, Roland

    2012-01-01

    Eukaryotic organisms play essential roles in the biology and fertility of soils. For example the micro and mesofauna contribute to the fragmentation and homogenization of plant organic matter, while its hydrolysis is primarily performed by the fungi. To get a global picture of the activities carried out by soil eukaryotes we sequenced 2×10,000 cDNAs synthesized from polyadenylated mRNA directly extracted from soils sampled in beech (Fagus sylvatica) and spruce (Picea abies) forests. Taxonomic affiliation of both cDNAs and 18S rRNA sequences showed a dominance of sequences from fungi (up to 60%) and metazoans while protists represented less than 12% of the 18S rRNA sequences. Sixty percent of cDNA sequences from beech forest soil and 52% from spruce forest soil had no homologs in the GenBank/EMBL/DDJB protein database. A Gene Ontology term was attributed to 39% and 31.5% of the spruce and beech soil sequences respectively. Altogether 2076 sequences were putative homologs to different enzyme classes participating to 129 KEGG pathways among which several were implicated in the utilisation of soil nutrients such as nitrogen (ammonium, amino acids, oligopeptides), sugars, phosphates and sulfate. Specific annotation of plant cell wall degrading enzymes identified enzymes active on major polymers (cellulose, hemicelluloses, pectin, lignin) and glycoside hydrolases represented 0.5% (beech soil)-0.8% (spruce soil) of the cDNAs. Other sequences coding enzymes active on organic matter (extracellular proteases, lipases, a phytase, P450 monooxygenases) were identified, thus underlining the biotechnological potential of eukaryotic metatranscriptomes. The phylogenetic affiliation of 12 full-length carbohydrate active enzymes showed that most of them were distantly related to sequences from known fungi. For example, a putative GH45 endocellulase was closely associated to molluscan sequences, while a GH7 cellobiohydrolase was closest to crustacean sequences, thus suggesting a

  4. Using stable and radioactive isotopes to trace atmospherically deposited Pb in montane forest soils.

    PubMed

    Kaste, James M; Friedland, Andrew J; Stürup, Stefan

    2003-08-15

    Atmospheric deposition of lead (Pb) throughout the 1900s resulted in elevated amounts of this toxic metal even in remote forest soils of the northeastern United States. Soils can act as a net sink for metals and thus minimize groundwater and surface water contamination. Recent studies utilizing forest floor temporal data and models of total Pb in precipitation, surface soils, and streams have estimated the time scale of Pb release from soils. However, due to the limited availability and spatial variability of forest floor survey data, other methods for quantifying anthropogenic Pb movement are needed. This study uses the isotopic composition (206Pb/207Pb) of soil Pb and measurements of 210Pb and 226Ra to directly trace the transit of atmospherically deposited Pb in the soil profile. We also report on the recovery of an enriched 207Pb dose applied in 1984 to the surface of a soil plot in the coniferous forest at Camels Hump in Vermont. The isotopic composition of soil Pb in low elevation deciduous forests suggests that approximately 65% of the original atmospheric Pb load has migrated from the forest floor to the upper 10 cm of the mineral soil. Higher elevation sites with coniferous vegetation have thicker forest floors, which have prevented significant amounts of Pb from entering the mineral soil. After 17 years, the soil organic horizon in the coniferous zone prevented any penetration of the applied Pb into the mineral soil. Using 210Pb budgets in different soil compartments, we determine forest floor response times for atmospherically delivered Pb to be approximately 60 years in the low elevation deciduous forest zone and 150 years for the high elevation spruce-fir forest zone at Camels Hump. According to its distribution in the soil profile, we conclude that a dispersed release of anthropogenic Pb to groundwater and surface water is possible this century. Our results also offer independent confirmation of Pb deposition models previously generated for the region.

  5. Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil.

    PubMed

    Xu, Wenhua; Li, Wei; Jiang, Ping; Wang, Hui; Bai, Edith

    2014-10-01

    The roles of substrate availability and quality in determining temperature sensitivity (Q10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q10 of the organic layer was 0.22-0.71 (absolute difference) higher than Q10 of the mineral soil. Q10 in both the organic layer (2.5-3.4) and the mineral soil (2.1-2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q10 over incubation time in both layers suggested that Q10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming.

  6. Early forest soils and their role in Devonian global change

    SciTech Connect

    Retallack, G.J.

    1997-04-25

    A paleosol in the Middle Devonian Aztec Siltstone of Victoria Land, Antarctica, is the most ancient known soil of well-drained forest ecosystems. Clay enrichment and chemical weathering of subsurface horizons in this and other Devonian forested paleosols culminate a long-term increase initiated during the Silurian. From Silurian into Devonian time, red clayey calcareous paleosols show a greater volume of roots and a concomitant decline in the density of animal burrows. These trends parallel the decline in atmospheric carbon dioxide determined from isotopic records of pedogenic carbonate in these same paleosols. The drawdown of carbon dioxide began well before the Devonian appearance of coals, large logs, and diverse terrestrial plants and animals, and it did not correlate with temporal variation in volcanic or metamorphic activity. The early Paleozoic greenhouse may have been curbed by the evolution of rhizospheres with an increased ratio of primary to secondary production and by more effective silicate weathering during Silurian time. 14 refs., 3 figs.

  7. Aspen increase soil moisture, nutrients, organic matter and respiration in Rocky Mountain forest communities.

    PubMed

    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, NO(3) and NH(4) 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.

  8. [Effects of exotic Larix kaempferi on forest soil quality and bacterial diversity].

    PubMed

    Yang, Xin; Cao, Jing; Dong, Mao-Xing; Ma, Xiao-Jun

    2008-10-01

    The study on the soil quality and bacterial diversity under 8-30 years old exotic Larix kaempferi, native Pinus tabulaeformis, and secondary deciduous broadleaf forest stands in Xiaolong-shan Mountains of Gansu, Northwest China showed that the soil pH under different forest stands had no distinct variation, but soil moisture content was increased with increasing age of forest stands. Soil organic matter and nitrogen contents were the highest under secondary deciduous forest, followed by under L. kaermpferi, and P. tabulaeformis. However, the soils under different ages of forest stands had no obvious variations in their organic matter and nitrogen contents, suggesting that tree species was the main factor affecting soil quality. Compared with P. tabulaeformis, exotic L. kaempferi could significantly increase soil organic matter and nitrogen contents. PCR-DGGE banding patterns suggested that the soil under secondary deciduous broadleaf forest had the highest bacterial diversity, followed by under L. kaempferi, and P. tabulaeformis. The sequenced DGGE bands were classified into three bacterial groups, i. e., Proteobacteria, Cytophaga - Flavobacterium - Bacteroides, and high G + C content gram-positive type, among which, Proteobacteria occurred most frequently. Further detailed analyses suggested that the soil bacterial compositions under exotic Larix stands were more similar to each other than those under pine and secondary deciduous broadleaf forests. It was concluded that exotic L. kaempferi induced the changes of microbial diversity in the forest soils of this region.

  9. Denitrification and N2O emission from forested and cultivated alluvial clay soil

    USGS Publications Warehouse

    Ullah, S.; Breitenbeck, G.A.; Faulkner, S.P.

    2005-01-01

    Restored forested wetlands reduce N loads in surface discharge through plant uptake and denitrification. While removal of reactive N reduces impact on receiving waters, it is unclear whether enhanced denitrification also enhances emissions of the greenhouse gas N2O, thus compromising the water-quality benefits of restoration. This study compares denitrification rates and N2O:N2 emission ratios from Sharkey clay soil in a mature bottomland forest to those from an adjacent cultivated site in the Lower Mississippi Alluvial Valley. Potential denitrification of forested soil was 2.4 times of cultivated soil. Using intact soil cores, denitrification rates of forested soil were 5.2, 6.6 and 2.0 times those of cultivated soil at 70, 85 and 100% water-filled pore space (WFPS), respectively. When NO3 was added, N2O emissions from forested soil were 2.2 times those of cultivated soil at 70% WFPS. At 85 and 100% WFPS, N2O emissions were not significantly different despite much greater denitrification rates in the forested soil because N2O:N2 emission ratios declined more rapidly in forested soil as WFPS increased. These findings suggest that restoration of forested wetlands to reduce NO3 in surface discharge will not contribute significantly to the atmospheric burden of N2O. ?? Springer 2005.

  10. Do Forest Age and Soil Depth Affect Carbon and Nitrogen Adsorption in Mineral Horizons?

    NASA Astrophysics Data System (ADS)

    Spina, P. G.; Lovett, G. M.; Fuss, C. B.; Goodale, C. L.; Lang, A.; Fahey, T.

    2015-12-01

    Mineral soils retain large amounts of organic matter through sorption on the surfaces of mineral soils, the largest pools of carbon (C) and nitrogen (N) in the forests of the northeastern U.S. In addition to determining organic matter storage, adsorption and desorption processes are important controllers of runoff chemistry. We are studying adsorption dynamics of mineral soils collected from a chronosequence of hardwood forest sites in the White Mountains, NH to determine how soils vary in their DOM adsorption capacities as a function of effective C and N saturation. We hypothesize that forest age determines proximity to saturation because young forests may need to mine soil organic matter (SOM) in mineral soils to obtain nitrogen to meet growth demands, while the soils of older forests have had time to reaccumulate SOM, eventually reaching C and N saturation. Consequently, we expect adsorption capacities to first increase with forest age in young forests, as the trees mine C and N from mineral surfaces. They will then decrease with forest age in older forests as mining slows and C and N begin to re-accumulate. Batch experiments were conducted with mineral soil samples and dilutions of forest floor leachate. However, preliminary results from a mature forest site (about 100 years old), which we predicted to be a low point of C and N saturation from decades of mining, contradict expectations. Dissolved organic carbon (DOC) adsorption in its shallow mineral soil layers (0-3 cm below E or A horizons) are lower than younger sites ranging from 20 to about 40 years old. In addition to forest age, soil depths also affect N retention dynamics in forest soils. We hypothesized that deeper mineral soils might have greater adsorption capacities due to the fact that they are exposed to less DOC and DON leaching from organic layers and therefore less saturated. Results from the same mature forest site confirm this. Soils from 3-10 cm depth have more potential to adsorb DOC and

  11. Sensitivity of boreal forest carbon balance to soil thaw

    USGS Publications Warehouse

    Goulden, M.L.; Wofsy, S.C.; Harden, J.W.; Trumbore, S.E.; Crill, P.M.; Gower, S.T.; Fries, T.; Daube, B.C.; Fan, S.-M.; Sutton, D.J.; Bazzaz, A.; Munger, J.W.

    1998-01-01

    We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 ?? 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 ?? 0.2 ton C ha-1 year-1 in moss and wood offset by a loss of 0.8 ?? 0.5 ton C ha-1 year-1 from the soil. The soil remained frozen most of the year, and the decomposition of organic matter in the soil increased 10-fold upon thawing. The stability of the soil carbon pool (~150 tons C ha-1) appears sensitive to the depth and duration of thaw, and climatic changes that promote thaw are likely to cause a net efflux of carbon dioxide from the site.

  12. Uncoupling the complexity of forest soil variation: influence of terrain attributes, spectral indices, and spatial variability

    EPA Science Inventory

    Growing concern over climate and management induced changes to soil nutrient status has prompted interest in understanding the spatial distribution of forest soil properties. Recent advancements in remotely sensed geospatial technologies are providing an increasing array of data...

  13. 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.

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

    PubMed Central

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

    2015-01-01

    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 Al3+ replacement of Ca2+ 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++Ca2++Mg2+) 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. PMID:25605567

  15. Mineral Control of Soil Carbon Dynamics in Forest Soils: A Lithosequence Under Ponderosa Pine

    NASA Astrophysics Data System (ADS)

    Heckman, K. A.; Welty-Bernard, A.; Rasmussen, C.; Schwartz, E.; Chorover, J.

    2008-12-01

    The role of soil organic carbon in regulating atmospheric CO2 concentration has spurred interest in both quantifying existing soil C stocks and modeling the behavior of soil C under climate change scenarios. Soil parent material exerts direct control over soil organic carbon content through its influence on soil pH and mineral composition. Soil acidity and mineral composition also influence soil microbial community composition and activity, thereby controlling soil respiration rates and microbial biomass size. We sampled a lithosequence of four parent materials (rhyolite, granite, basalt, limestone) under Pinus ponderosa to examine the effects of soil mineralogy and acidity on soil organic carbon content and soil microbial community. Three soil profiles were examined on each parent material and analyzed by X-ray diffraction, pH, selective dissolution, C and N content, and 13C signature. Soils from each of the four parent materials were incubated for 40 days, and microbial communities were compared on the basis of community composition (as determined through T-RFLP analysis), specific metabolic activity, biomass, δ13C of respired CO2, and cumulative amount of C mineralized over the course of the incubation. Soil C content varied significantly among soils of different parent material, and was strongly and positively associated with the abundance of Al-humus complexes r2 = 0.71; P < 0.0001, Fe-humus complexes r2 = 0.74; P = 0.0003, and crystalline Fe-oxide content r2 = 0.63; P = 0.0023. Microbial community composition varied significantly among soils and showed strong associations with soil pH 1:1 in KCl; r2 = 0.87; P < 0.0001, concentration of exchangeable Al r2 = 0.81; P < 0.0001, amorphous Fe oxide content r2 = 0.59; P < 0.004, and Al-humus content r2 = 0.35; P < 0.04. Mineralization rates, biomass and δ13C of respired CO2 differed among parent materials, and also varied with incubation time as substrate quality and N availability changed. The results demonstrate

  16. Invariant community structure of soil bacteria in subtropical coniferous and broadleaved forests

    PubMed Central

    Wang, Xiaoli; Wang, Xiaoling; Zhang, Weixin; Shao, Yuanhu; Zou, Xiaoming; Liu, Tao; Zhou, Lixia; Wan, Songze; Rao, Xingquan; Li, Zhian; Fu, Shenglei

    2016-01-01

    Soil bacteria may be influenced by vegetation and play important roles in global carbon efflux and nutrient cycling under global changes. Coniferous and broadleaved forests are two phyletically distinct vegetation types. Soil microbial communities in these forests have been extensively investigated but few studies have presented comparable data regarding the characteristics of bacterial communities in subtropical forests. We investigated soil bacterial biomass and community composition in three pairs of coniferous and broadleaved forests across a subtropical climatic gradient. We found that bacterial biomass differed between the coniferous and broadleaved forests across the subtropical climate gradient; however, this difference disappeared at some individual sites. In contrast, the same 90 bacterial genera were found in both forest types, and their relative abundances didn’t differ between the forest types, with the exception of one genus that was more abundant in broadleaved forests. Soil nitrogen or moisture was associated with bacterial groups in the coniferous and broadleaved forests, respectively. Thus, we inferred that these forests can respond differently to future changes in nitrogen deposition or precipitation. This study highlights soil bacterial invariant community composition in contrasting subtropical forests and provides a new perspective on the potential response and feedback of forests to global changes. PMID:26754326

  17. Geology, Soils and Basin-wide variations in Amazon Forest Structure and function

    NASA Astrophysics Data System (ADS)

    Quesada, Carlos Alberto; Phillips, Oliver; Lopes-Gonzales, Gabriela; Lloyd, Jon; Rainfor Team

    2015-04-01

    Forest productivity, tree turnover time and above ground biomass vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil nutrient availability and geology. Forest productivity rates are higher on the most nutrient rich soils close to the Andes while is lower in the ancient, highly weathered soils of central Amazonia. On the other hand above ground biomass is lower in the most productive forests and higher on the least, this being a consequence of higher tree turnover rates in the forests over less weathered and nutrient rich soils. Major geological events have influenced Amazonian soil characteristics profoundly and play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Here we show how geology and soil development combine to shape the functioning of Amazonian forests and its carbon stocks and fluxes. To assess the importance of edaphic properties in affect forest structure and dynamics, soil samples were collected in a total of 154 different forest plots across nine different Amazonian countries. Samples were analyzed for exchangeable cations, C, N, pH with various P fractions and soil physical properties also determined. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions.

  18. Biosolids-derived nitrogen mineralization and transformation in forest soils.

    PubMed

    Wang, Hailong; Kimberley, Mark O; Schlegelmilch, Mirko

    2003-01-01

    Utilization of biosolids through land application is becoming increasingly popular among wastewater managers. To minimize the potential contamination of receiving waters from biosolids-derived nitrogen (N), it is important to understand the availability of N after land application of biosolids. In this study, four secondary biosolids (two municipal and two pulp and paper industrial biosolids) were used in a laboratory incubation experiment to simulate N mineralization and transformation after land application. Municipal biosolids were from either aerobically or anaerobically digested sources, while pulp and paper industrial biosolids were from aerated wastewater stabilization lagoons. These biosolids were mixed with two New Zealand forest soils (top 100 mm of a volcanic soil and a brown soil) and incubated at two temperatures (10 and 20 degrees C) for 26 wk. During incubation, mineralized N was periodically leached from the soil-biosolids mixture with 0.01 M CaCl2 solution and concentrations of NH4 and NO3 in leachate were determined. Mineralization of N from aerobically digested municipal biosolids (32.1%) was significantly more than that from anaerobically digested biosolids (15.2%). Among the two pulp and paper industrial biosolids, little N leached from one, while as much as 18.0% of total organic N was leached from the other. As expected, mineralization of N was significantly greater at 20 degrees C (average 22.8%) than at 10 degrees C (average 9.7%). It was observed that more N in municipal biosolids was mineralized in the brown soil, whereas more N in pulp and paper industrial biosolids mineralized in the volcanic soil. Transformation of NH4 to NO3 was affected by soil type and temperature. PMID:14535329

  19. The temporal changes in saturated hydraulic conductivity of forest soils

    NASA Astrophysics Data System (ADS)

    Kornél Szegedi, Balázs

    2015-04-01

    I investigated the temporal variability of forest soils infiltration capacity through compaction. I performed the measurements of mine in The Botanical Garden of Sopron between 15.09.2014 - 15.10.2014. I performed the measurements in 50-50 cm areas those have been cleaned of vegetation, where I measured the bulk density and volume of soil hydraulic conductivity with Tension Disk Infiltrometer (TDI) in 3-3 repetitions. I took undisturbed 160 cm3 from the upper 5 cm layer of the cleaned soil surface for the bulk density measurements. Then I loosened the top 10-15 cm layer of the soil surface with spade. After the cultivation of the soil I measured the bulk density and volume of water conductivity also 3-3 repetitions. Later I performed the hydraulic conductivity (Ksat) using the TDI and bulk density measurements on undisturbed samples on a weekly basis in the study area. I illustrated the measured hydraulic conductivity and bulk density values as a function of cumulative rainfall by using simple graphical and statistical methods. The rate of the soil compaction pace was fast and smooth based on the change of the measured bulk density values. There was a steady downward trend in hydraulic conductivity parallel the compaction. The cultivation increased the hydraulic conductivity nearly fourfold compared to original, than decreased to half by 1 week. In the following the redeposition rate declined, but based on the literature data, almost 3-4 months enough to return the original state before cultivation of the soil hydraulic conductivity and bulk density values. This publication has been supported by AGRARKLIMA.2 VKSZ_12-1-2013-0034 project.

  20. The carbon balance of forest soils: detectability of changes in soil carbon stocks in temperate and Boreal forests.

    PubMed

    Conen, Frauz; Zerva, Argyro; Arrouays, Dominique; Jolivet, Claude; Jarvis, Paul G; Grace, John; Mencuccini, Maurizio

    2005-01-01

    Estimating soil carbon content as the product of mean carbon concentration and bulk density can result in considerable overestimation. Carbon concentration and soil mass need to be measured on the same sample and carbon contents calculated for each individual sample before averaging. The effect of this bias is likely to be smaller (but still greater than zero) when the primary objective is to determine stock changes over time. Variance and mean carbon content are significantly and positively related to each other, although some sites showed much higher variability than predicted by this relationship, as a likely consequence of their particular site history, forest management, and micro-topography. Because of the proportionality between mean and variance, the number of samples required to detect a fixed change in soil carbon stocks varied directly with the site mean carbon content from less than 10 to several thousands across the range of carbon stocks normally encountered in temperate and Boreal forests. This raises important questions about how to derive an optimal sampling strategy across such a varied range of conditions so as to achieve the aims of the Kyoto Protocol. Overall, on carbon-poor forest sites with little or no disturbance to the soil profile, it is possible to detect changes in total soil organic carbon over time of the order of 0.5 kg (C) m(-2) with manageable sample sizes even using simple random sampling (i.e., about 50 samples per sampling point). More efficient strategies will reveal even smaller differences. On disturbed forest sites (ploughed, windthrow) this is no longer possible (required sample sizes are much larger than 100). Soils developed on coarse aeolian sediments (sand dunes), or where buried logs or harvest residues of the previous rotation are present, can also exhibit large spatial variability in soil carbon. Generally, carbon-rich soils will always require larger numbers of samples. On these sites, simple random sampling is

  1. Role of Native and Exotic Earthworms in Plant Biopolymer Dynamics in Forest Soil

    NASA Astrophysics Data System (ADS)

    Filley, Timothy

    2010-05-01

    Many forests within northern North America are experiencing the introduction of earthworms for the first time, presumably since before the last major glaciation. Forest dynamics are undergoing substantial changes because of the activity of the mainly European lumbricid species. Documented losses in litter layers, expansion of A-horizons, loss of the organic horizon, changes in fine root density, and shifts in microbial populations have all been documented in invaded zones. Two free air CO2 enrichment (FACE) forest experiments (aspen FACE at Rhinelander, Wisconsin and sweet gum FACE at Oak Ridge National Lab, Tennessee) lie within the zones of invasion and exhibit differences in amounts of exotic and native species as well as endogeic (predominantly mineral soil dwelling) and epigeic (litter and organic matter horizon dwelling) types. Considerations of carbon accrual dynamics and relative input of above vs. below ground plant input in these young successional systems do not consider the potential impact of these ecosystem engineers. We investigated the impact of earthworm activity by tracking the relative abundance and stable carbon isotope compositions of lignin and substituted fatty acids extracted from isolated earthworms and their fecal pellets and from host soils. Indications of root vs leaf input to earthworm casts and fecal matter were derived from differences in the chemical composition of cutin, suberin, and lignin. The isotopically depleted CO2 used in FACE and the resulting isotopically depleted plant organic matter afford an excellent opportunity to assess biopolymer-specific turnover dynamics. We find that endogeic species are proportionately more responsible for fine root cycling while some epigeic species are responsible for microaggregation of foliar cutin. CSIA of fecal pellet lignin and SFA indicates how these biopolymer pools can be derived from variable sources, roots, background soil, foliar tissue within one earthworm. Additionally, CSIA

  2. Layer of organic pine forest soil on top of chlorophenol-contaminated mineral soil enhances contaminant degradation.

    PubMed

    Sinkkonen, Aki; Kauppi, Sari; Simpanen, Suvi; Rantalainen, Anna-Lea; Strömmer, Rauni; Romantschuk, Martin

    2013-03-01

    Chlorophenols, like many other synthetic compounds, are persistent problem in industrial areas. These compounds are easily degraded in certain natural environments where the top soil is organic. Some studies suggest that mineral soil contaminated with organic compounds is rapidly remediated if it is mixed with organic soil. We hypothesized that organic soil with a high degradation capacity even on top of the contaminated mineral soil enhances degradation of recalcitrant chlorophenols in the mineral soil below. We first compared chlorophenol degradation in different soils by spiking pristine and pentachlorophenol-contaminated soils with 2,4,6-trichlorophenol in 10-L buckets. In other experiments, we covered contaminated mineral soil with organic pine forest soil. We also monitored in situ degradation on an old sawmill site where mineral soil was either left intact or covered with organic pine forest soil. 2,4,6-Trichlorophenol was rapidly degraded in organic pine forest soil, but the degradation was slower in other soils. If a thin layer of the pine forest humus was added on top of mineral sawmill soil, the original chlorophenol concentrations (high, ca. 70 μg g(-1), or moderate, ca. 20 μg g(-1)) in sawmill soil decreased by >40 % in 24 days. No degradation was noticed if the mineral soil was kept bare or if the covering humus soil layer was sterilized beforehand. Our results suggest that covering mineral soil with an organic soil layer is an efficient way to remediate recalcitrant chlorophenol contamination in mineral soils. The results of the field experiment are promising.

  3. Designer, acidic biochar influences calcareous soil characteristics.

    PubMed

    Ippolito, J A; Ducey, T F; Cantrell, K B; Novak, J M; Lentz, R D

    2016-01-01

    In a proof-of-concept study, an acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 °C) and steam activation (800 °C) to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0%, 1%, 2%, and 10% (by wt.) and soils were destructively sampled at 1, 2, 3, 4, 5, and 6 month intervals. Soil was analyzed for gravimetric water content, pH, NO3-N, plant-available Fe, Zn, Mn, Cu, and P, organic C, CO2 respiration, and microbial enumeration via extractable DNA and 16S rRNA gene copies. Gravimetric soil water content increased with biochar application regardless of rate, as compared to the control. Soil pH decreased between 0.2 and 0.4 units, while plant-available Zn, Mn, and P increased with increasing biochar application rate. Micronutrient availability decreased over time likely due to insoluble mineral species precipitation. Increasing biochar application raised the soil organic C content and remained elevated over time. Increasing biochar application rate also increased respired CO2, yet the CO2 released decreased over time. Soil NO3-N concentrations significantly decreased with increasing biochar application rate likely due to microbial immobilization or denitrification. Depending on application rate, biochar produced a 1.4 to 2.1-fold increase in soil DNA extracted and 1.4- to 2.4-fold increase in 16S rRNA gene abundance over control soils, suggesting microbial stimulation and a subsequent burst of activity upon biochar addition. Our results showed that there is promise in designing a biochar to improve the quality and water relations of eroded calcareous soils.

  4. Designer, acidic biochar influences calcareous soil characteristics.

    PubMed

    Ippolito, J A; Ducey, T F; Cantrell, K B; Novak, J M; Lentz, R D

    2016-01-01

    In a proof-of-concept study, an acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 °C) and steam activation (800 °C) to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0%, 1%, 2%, and 10% (by wt.) and soils were destructively sampled at 1, 2, 3, 4, 5, and 6 month intervals. Soil was analyzed for gravimetric water content, pH, NO3-N, plant-available Fe, Zn, Mn, Cu, and P, organic C, CO2 respiration, and microbial enumeration via extractable DNA and 16S rRNA gene copies. Gravimetric soil water content increased with biochar application regardless of rate, as compared to the control. Soil pH decreased between 0.2 and 0.4 units, while plant-available Zn, Mn, and P increased with increasing biochar application rate. Micronutrient availability decreased over time likely due to insoluble mineral species precipitation. Increasing biochar application raised the soil organic C content and remained elevated over time. Increasing biochar application rate also increased respired CO2, yet the CO2 released decreased over time. Soil NO3-N concentrations significantly decreased with increasing biochar application rate likely due to microbial immobilization or denitrification. Depending on application rate, biochar produced a 1.4 to 2.1-fold increase in soil DNA extracted and 1.4- to 2.4-fold increase in 16S rRNA gene abundance over control soils, suggesting microbial stimulation and a subsequent burst of activity upon biochar addition. Our results showed that there is promise in designing a biochar to improve the quality and water relations of eroded calcareous soils. PMID:26077798

  5. Divergent responses of soil buffering capacity to long-term N deposition in three typical tropical forests with different land-use history.

    PubMed

    Lu, Xiankai; Mao, Qinggong; Mo, Jiangming; Gilliam, Frank S; Zhou, Guoyi; Luo, Yiqi; Zhang, Wei; Huang, Juan

    2015-04-01

    Elevated anthropogenic nitrogen (N) deposition has become an important driver of soil acidification at both regional and global scales. It remains unclear, however, how long-term N deposition affects soil buffering capacity in tropical forest ecosystems and in ecosystems of contrasting land-use history. Here, we expand on a long-term N deposition experiment in three tropical forests that vary in land-use history (primary, secondary, and planted forests) in Southern China, with N addition as NH4NO3 of 0, 50, 100, and 150 kg N ha(-1) yr(-1), respectively. Results showed that all three forests were acid-sensitive ecosystems with poor soil buffering capacity, while the primary forest had higher base saturation and cation exchange capacity than others. However, long-term N addition significantly accelerated soil acidification and decreased soil buffering capacity in the primary forest, but not in the degraded secondary and planted forests. We suggest that ecosystem N status, influenced by different land-use history, is primarily responsible for these divergent responses. N-rich primary forests may be more sensitive to external N inputs than others with low N status, and should be given more attention under global changes in the future, because lack of nutrient cations is irreversible. PMID:25741588

  6. Successional and seasonal variations in soil and litter microbial community structure and function during tropical postagricultural forest regeneration: a multiyear study.

    PubMed

    Smith, A Peyton; Marín-Spiotta, Erika; Balser, Teri

    2015-09-01

    Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. Understanding how microbial communities respond to changes in vegetation is critical for improving predictions of how land-cover change affects belowground carbon storage and nutrient availability. We measured intra- and interannual variability in soil and forest litter microbial community composition and activity via phospholipid fatty acid analysis (PLFA) and extracellular enzyme activity across a well-replicated, long-term chronosequence of secondary forests growing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Microbial community PLFA structure differed between young secondary forests and older secondary and primary forests, following successional shifts in tree species composition. These successional patterns held across seasons, but the microbial groups driving these patterns differed over time. Microbial community composition from the forest litter differed greatly from those in the soil, but did not show the same successional trends. Extracellular enzyme activity did not differ with forest succession, but varied by season with greater rates of potential activity in the dry seasons. We found few robust significant relationships among microbial community parameters and soil pH, moisture, carbon, and nitrogen concentrations. Observed inter- and intrannual variability in microbial community structure and activity reveal the importance of a multiple, temporal sampling strategy when investigating microbial community dynamics with land-use change. Successional control over microbial composition with forest recovery suggests strong links between above and belowground communities. PMID:25873563

  7. Divergent responses of soil buffering capacity to long-term N deposition in three typical tropical forests with different land-use history.

    PubMed

    Lu, Xiankai; Mao, Qinggong; Mo, Jiangming; Gilliam, Frank S; Zhou, Guoyi; Luo, Yiqi; Zhang, Wei; Huang, Juan

    2015-04-01

    Elevated anthropogenic nitrogen (N) deposition has become an important driver of soil acidification at both regional and global scales. It remains unclear, however, how long-term N deposition affects soil buffering capacity in tropical forest ecosystems and in ecosystems of contrasting land-use history. Here, we expand on a long-term N deposition experiment in three tropical forests that vary in land-use history (primary, secondary, and planted forests) in Southern China, with N addition as NH4NO3 of 0, 50, 100, and 150 kg N ha(-1) yr(-1), respectively. Results showed that all three forests were acid-sensitive ecosystems with poor soil buffering capacity, while the primary forest had higher base saturation and cation exchange capacity than others. However, long-term N addition significantly accelerated soil acidification and decreased soil buffering capacity in the primary forest, but not in the degraded secondary and planted forests. We suggest that ecosystem N status, influenced by different land-use history, is primarily responsible for these divergent responses. N-rich primary forests may be more sensitive to external N inputs than others with low N status, and should be given more attention under global changes in the future, because lack of nutrient cations is irreversible.

  8. Successional and seasonal variations in soil and litter microbial community structure and function during tropical postagricultural forest regeneration: a multiyear study.

    PubMed

    Smith, A Peyton; Marín-Spiotta, Erika; Balser, Teri

    2015-09-01

    Soil microorganisms regulate fundamental biochemical processes in plant litter decomposition and soil organic matter (SOM) transformations. Understanding how microbial communities respond to changes in vegetation is critical for improving predictions of how land-cover change affects belowground carbon storage and nutrient availability. We measured intra- and interannual variability in soil and forest litter microbial community composition and activity via phospholipid fatty acid analysis (PLFA) and extracellular enzyme activity across a well-replicated, long-term chronosequence of secondary forests growing on abandoned pastures in the wet subtropical forest life zone of Puerto Rico. Microbial community PLFA structure differed between young secondary forests and older secondary and primary forests, following successional shifts in tree species composition. These successional patterns held across seasons, but the microbial groups driving these patterns differed over time. Microbial community composition from the forest litter differed greatly from those in the soil, but did not show the same successional trends. Extracellular enzyme activity did not differ with forest succession, but varied by season with greater rates of potential activity in the dry seasons. We found few robust significant relationships among microbial community parameters and soil pH, moisture, carbon, and nitrogen concentrations. Observed inter- and intrannual variability in microbial community structure and activity reveal the importance of a multiple, temporal sampling strategy when investigating microbial community dynamics with land-use change. Successional control over microbial composition with forest recovery suggests strong links between above and belowground communities.

  9. Climate dependency of tree growth suppressed by acid deposition effects on soils in northwest Russia.

    PubMed

    Lawrence, Gregory B; Lapenis, Andrei G; Berggren, Dan; Aparin, Boris F; Smith, Kevin T; Shortle, Walter C; Bailey, Scott W; Varlyguin, Dmitry L; Babikov, Boris

    2005-04-01

    Increased tree growth in temperate and boreal forests has been proposed as a direct consequence of a warming climate. Acid deposition effects on nutrient availability may influence the climate dependency of tree growth, however. This study presents an analysis of archived soil samples that has enabled changes in soil chemistry to be tracked with patterns of tree growth through the 20th century. Soil samples collected in 1926, 1964, and 2001, near St. Petersburg, Russia, showed that acid deposition was likely to have decreased root-available concentrations of Ca (an essential element) and increased root-available concentrations of Al (an inhibitor of Ca uptake). These soil changes coincided with decreased diameter growth and a suppression of climate-tree growth relationships in Norway spruce. Expected increases in tree growth from climate warming may be limited by decreased soil fertility in regions of northern and eastern Europe, and eastern North America, where Ca availability has been reduced by acidic deposition.

  10. [Microelement contents of litter, soil fauna and soil in Pinus koraiensis and broad-leaved mixed forest].

    PubMed

    Yin, Xiu-qin; Li, Jin-xia; Dong, Wei-hua

    2007-02-01

    The analysis on the Mn, Zn and Cu contents of litter, soil fauna and soil in Pinus korazenszis and broad-leaved mixed forest in Liangshui Natural Reserve of Xiaoxing' an Mountains showed that the test microelement contents in the litter, soil fauna and soil all followed the sequence of Mn > Zn > Cu, but varied with these environmental components, being in the sequence of soil > litter > soil fauna for Mn, soil fauna > litter and soil for Zn, and soil fauna > soil > litter for Cu. The change range of test microelement contents in litter was larger in broad-leaved forest than in coniferous forest. Different soil fauna differed in their microelement-enrichment capability, e. g. , earthworm, centipede, diplopod had the highest content of Mn, Zn and Cu, respectively. The contents of test microelements in soil fauna had significant correlations with their environmental background values, litter decomposition rate, food habit of soil fauna, and its absorbing selectivity and enrichment to microelements. The microelements contained in 5-20 cm soil layer were more than those in 0-5 cm soil layer, and their dynamics differed in various soil layers.

  11. [Characteristics of soil ammonia-oxidation microbial communities in different subtropical forests, China].

    PubMed

    Li, Yong-Chun; Liu, Bu-Rong; Guo, Shuai; Wu, Qi-Feng; Qin, Hua; Wu, Jia-Sen; Xu, Qiu-Fang

    2014-01-01

    To investigate the effects of different forest stands in subtropical China on the communities of soil ammonia-oxidizing microorganisms, we characterized the abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB), and the community structure of AOA in soils under stands of broad-leaved (BF) , Chinese fir (CF) , Pinus massoniana (PF) and moso bamboo (MB) forests using real-time quantitative PCR and denaturing gradient gel electrophoresis (DGGE). The results showed that the AOA gene copy numbers (1.62 x 10(6)-1.88 x 10(7) per gram of dry soil) were significantly higher than those of AOB genes (2.41 x 10(5)-4.36 x 10(5) per gram of dry soil). Significantly higher soil AOA abundance was detected in the MB than that in the CF (P < 0.05), and the latter was significantly higher than that in the BF and PF soils (P < 0.05). There were no significant differences in the soil AOB abundance among the four forest stands. As indicated by DGGE pattern, soil AOA species varied among the four forest stands. There was a difference in the soil AOA communities between the CF and MB stands. The AOA demonstrated a competitive advantage over the AOB in the soils under these major subtropical forests. Soil pH, concentrations of soil available potassium and organic carbon as well as the forest type were the main factors that influence the variation of AOA community structure and diversity.

  12. Quantifying soil and critical zone variability in a forested catchment through digital soil mapping

    NASA Astrophysics Data System (ADS)

    Holleran, M.; Levi, M.; Rasmussen, C.

    2015-01-01

    Quantifying catchment-scale soil property variation yields insights into critical zone evolution and function. The objective of this study was to quantify and predict the spatial distribution of soil properties within a high-elevation forested catchment in southern Arizona, USA, using a combined set of digital soil mapping (DSM) and sampling design techniques to quantify catchment-scale soil spatial variability that would inform interpretation of soil-forming processes. The study focused on a 6 ha catchment on granitic parent materials under mixed-conifer forest, with a mean elevation of 2400 m a.s.l, mean annual temperature of 10 °C, and mean annual precipitation of ~ 85 cm yr-1. The sample design was developed using a unique combination of iterative principal component analysis (iPCA) of environmental covariates derived from remotely sensed imagery and topography, and a conditioned Latin hypercube sampling (cLHS) scheme. Samples were collected by genetic horizon from 24 soil profiles excavated to the depth of refusal and characterized for soil mineral assemblage, geochemical composition, and general soil physical and chemical properties. Soil properties were extrapolated across the entire catchment using a combination of least-squares linear regression between soil properties and selected environmental covariates, and spatial interpolation or regression residual using inverse distance weighting (IDW). Model results indicated that convergent portions of the landscape contained deeper soils, higher clay and carbon content, and greater Na mass loss relative to adjacent slopes and divergent ridgelines. The results of this study indicated that (i) the coupled application of iPCA and cLHS produced a sampling scheme that captured the greater part of catchment-scale soil variability; (ii) application of relatively simple regression models and IDW interpolation of residuals described well the variance in measured soil properties and predicted spatial correlation of soil

  13. [Temporal variations of soil microbial biomass and enzyme activities during the secondary succession of primary broadleaved-Pinus koraiensis forests in Changbai Mountains of Northeast].

    PubMed

    Hu, Song; Zhang, Ying; Shi, Rong-Jiu; Han, Si-Qin; Li, Hui; Xu, Hui

    2013-02-01

    By the method of space-for-time Substitution, and taking the matured (>200 years old) and over-matured (>200 years old) primary broadleaved-Pinus koraiensis forests and, their secondary forests at different succession stages (20-, 30-, 50-, 80-, and 100 years old Betula platphylla forests) in Changbai Mountains of Northeast China as test objects, this paper studied the temporal variations of soil organic carbon, soil microbial biomass, and soil enzyme activities during the secondary succession of primary broadleaved-Pinus koraiensis forests in the Mountains. Under the 20- and 80 years old B. platphylla forests, the soil organic carbon content in humus layer was the highest (154.8 and 154.3 g.kg-1, respectively); while under the matured and over-matured primary broad-leaved-Pinus koraiensis forests, this organic carbon content was relatively low, being 141. 8 and 133. 4 g.kg , respectively. The soil microbial biomass carbon and microbial quotient and the activities of soil cellulase, peroxidase, acid phosphatase, and cellobiase under the 50- and 80 years old B. platphylla forests were the highest, but the activity of soil polyphenol oxidase was the lowest, which revealed that under middle-aged and matured B. platphylla forests, soil organic carbon had a faster turnover rate, and was probably in a stronger accumulation phase. Statistical analysis showed that the soil microbial biomass carbon had significant positive correlations with the soil organic carbon, total nitrogen, and available phosphorus (r = 0.943, 0. 963, and 0.953, respectively;

  14. Possible method of aluminium speciation in forest soils.

    PubMed

    Drabek, Ondrej; Boruvka, Lubos; Mladkova, Lenka; Kocarek, Martin

    2003-09-15

    Labile Al forms and species can be a threat in acid soils due to their potential toxicity to plants. However, there is no universally accepted extraction method. Several extraction reagents for Al release from soil have been tested. KCl (0.5 or 1 M) is recommended for extraction of exchangeable Al, while 0.5 or 0.3 M CuCl(2) is suggested for extraction of 'weakly organically bound Al'. Both 0.1 and 0.05 M Na(4)P(2)O(7) are shown to be suitable for the extraction of 'total organically bound Al'. These extractions are relatively simple, robust, and applicable to different soils and soil horizons. In the second part of the paper, detailed speciation of exchangeable soil Al by means of an HPLC instrument equipped with an ion column (IC) is presented. An experimental set-up is described and tested on a set of samples. Interpretation of the speciation results is proposed, based on the separation of Al ions and Al complexes according to their charge. Speciation is shown to be dependent mainly on soil pH and organic matter quality. A general scheme of Al fractionation and speciation in soil is proposed. PMID:14507455

  15. Soil-atmosphere exchange of methane in adjacent cultivated and floodplain forest soils

    NASA Astrophysics Data System (ADS)

    Burke, Roger A.; Meyer, Judith L.; Cruse, Jennifer M.; Birkhead, Karen M.; Paul, Michael J.

    1999-04-01

    The soil-atmosphere exchange of methane was measured in adjacent cultivated (corn) and forest (upper floodplain, mixed hardwood) habitats of the southeastern U.S. piedmont for a period of 3 years using closed chambers. We have evaluated the effect of the following factors on soil-atmosphere methane exchange: (1) interannual variability of climatic conditions, (2) landscape position (i.e., river levee versus terrace), and (3) disturbance ranging from intense (cultivation) through moderate (approximately annual flooding events that last from weeks to months) to subtle (approximately annual flooding of a few days duration). We found that mean methane consumption in the cultivated and forested terrace sites was <0.3 mg CH4 m-2 d-1, whereas the mean consumption rate in forested levee sites was about 1.4 mg CH4 m-2 d-1 over the course of the 3 years. Moisture levels in the upper soil (0-5 cm) appear to exert little control of methane exchange in any of the habitats. We observed little seasonal variation in methane flux in the levee sites, in contrast to results observed by others in higher-latitude and tropical forests. Our results suggest that very subtle differences in landscape position and disturbance impact the strength of the soil methane sink. We cannot conclude that agricultural development destroyed the methane sink capacity of these floodplain terrace soils because it was probably already quite low due to periodic disturbance by flooding. Limited measurements of nitrogen cycling suggest that methane flux differences observed among the different habitats are not obviously related to differences in N mineralization or nitrification as in other ecosystems.

  16. Importance of natural soil processes relative to atmospheric deposition in the mobility of aluminium in forested watersheds of the Black Forest.

    PubMed

    Baur, S; Feger, K H

    1992-01-01

    The dynamics of aqueous aluminium in the ARINUS experimental watersheds at Schluchsee (granite) and Villingen (quartz sandstone), Black Forest (South-west Germany), were studied in order to detect the processes and factors controlling its mobility. Aluminium speciation was performed in the seepage of typical soils (podsol, acidic brown earth, stagnogley) at 3 depths (organic layer, 30 cm and 80 cm of the mineral soil) as well as in streamwater. The studies concentrated on the variability in time and space of inorganic monomeric Al (Ali), and organic monomeric Al (Alo). Furthermore, the equilibrium speciation model WATEQF was used to calculate the distribution of inorganic Al species. Natural soil properties and processes, such as DOC mobilization and excess mineralization of NO3(2-) and SO4(2-), appeared to have great influence and outweigh the deposition effects upon Al mobilization in these systems which receive only low to moderate loads of acidic deposition.

  17. [Research progress on unsaturated and saturated soil water movement in forest catchments].

    PubMed

    Yang, Hong; Pei