Science.gov

Sample records for irrigation requirement estimation

  1. Irrigation Requirement Estimation Using Vegetation Indices and Inverse Biophysical Modeling

    NASA Technical Reports Server (NTRS)

    Bounoua, Lahouari; Imhoff, Marc L.; Franks, Shannon

    2010-01-01

    We explore an inverse biophysical modeling process forced by satellite and climatological data to quantify irrigation requirements in semi-arid agricultural areas. We constrain the carbon and water cycles modeled under both equilibrium, balance between vegetation and climate, and non-equilibrium, water added through irrigation. We postulate that the degree to which irrigated dry lands vary from equilibrium climate conditions is related to the amount of irrigation. The amount of water required over and above precipitation is considered as an irrigation requirement. For July, results show that spray irrigation resulted in an additional amount of water of 1.3 mm per occurrence with a frequency of 24.6 hours. In contrast, the drip irrigation required only 0.6 mm every 45.6 hours or 46% of that simulated by the spray irrigation. The modeled estimates account for 87% of the total reported irrigation water use, when soil salinity is not important and 66% in saline lands.

  2. Estimating Irrigation Water Requirements using MODIS Vegetation Indices and Inverse Biophysical Modeling

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc L.; Bounoua, Lahouari; Harriss, Robert; Harriss, Robert; Wells, Gordon; Glantz, Michael; Dukhovny, Victor A.; Orlovsky, Leah

    2007-01-01

    An inverse process approach using satellite-driven (MODIS) biophysical modeling was used to quantitatively assess water resource demand in semi-arid and arid agricultural lands by comparing the carbon and water flux modeled under both equilibrium (in balance with prevailing climate) and non-equilibrium (irrigated) conditions. Since satellite observations of irrigated areas show higher leaf area indices (LAI) than is supportable by local precipitation, we postulate that the degree to which irrigated lands vary from equilibrium conditions is related to the amount of irrigation water used. For an observation year we used MODIS vegetation indices, local climate data, and the SiB2 photosynthesis-conductance model to examine the relationship between climate and the water stress function for a given grid-cell and observed leaf area. To estimate the minimum amount of supplemental water required for an observed cell, we added enough precipitation to the prevailing climatology at each time step to minimize the water stress function and bring the soil to field capacity. The experiment was conducted on irrigated lands on the U.S. Mexico border and Central Asia and compared to estimates of irrigation water used.

  3. SEBAL Model Using to Estimate Irrigation Water Efficiency & Water Requirement of Alfalfa Crop

    NASA Astrophysics Data System (ADS)

    Zeyliger, Anatoly; Ermolaeva, Olga

    2013-04-01

    The sustainability of irrigation is a complex and comprehensive undertaking, requiring an attention to much more than hydraulics, chemistry, and agronomy. A special combination of human, environmental, and economic factors exists in each irrigated region and must be recognized and evaluated. A way to evaluate the efficiency of irrigation water use for crop production is to consider the so-called crop-water production functions, which express the relation between the yield of a crop and the quantity of water applied to it or consumed by it. The term has been used in a somewhat ambiguous way. Some authors have defined the Crop-Water Production Functions between yield and the total amount of water applied, whereas others have defined it as a relation between yield and seasonal evapotranspiration (ET). In case of high efficiency of irrigation water use the volume of water applied is less than the potential evapotranspiration (PET), then - assuming no significant change of soil moisture storage from beginning of the growing season to its end-the volume of water may be roughly equal to ET. In other case of low efficiency of irrigation water use the volume of water applied exceeds PET, then the excess of volume of water applied over PET must go to either augmenting soil moisture storage (end-of-season moisture being greater than start-of-season soil moisture) or to runoff or/and deep percolation beyond the root zone. In presented contribution some results of a case study of estimation of biomass and leaf area index (LAI) for irrigated alfalfa by SEBAL algorithm will be discussed. The field study was conducted with aim to compare ground biomass of alfalfa at some irrigated fields (provided by agricultural farm) at Saratov and Volgograd Regions of Russia. The study was conducted during vegetation period of 2012 from April till September. All the operations from importing the data to calculation of the output data were carried by eLEAF company and uploaded in Fieldlook web

  4. ESTIMATING IRRIGATION COSTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Having accurate estimates of the cost of irrigation is important when making irrigation decisions. Estimates of fixed costs are critical for investment decisions. Operating cost estimates can assist in decisions regarding additional irrigations. This fact sheet examines the costs associated with ...

  5. Reduction of predictive uncertainty in estimating irrigation water requirement through multi-model ensembles and ensemble averaging

    NASA Astrophysics Data System (ADS)

    Multsch, S.; Exbrayat, J.-F.; Kirby, M.; Viney, N. R.; Frede, H.-G.; Breuer, L.

    2015-04-01

    Irrigation agriculture plays an increasingly important role in food supply. Many evapotranspiration models are used today to estimate the water demand for irrigation. They consider different stages of crop growth by empirical crop coefficients to adapt evapotranspiration throughout the vegetation period. We investigate the importance of the model structural versus model parametric uncertainty for irrigation simulations by considering six evapotranspiration models and five crop coefficient sets to estimate irrigation water requirements for growing wheat in the Murray-Darling Basin, Australia. The study is carried out using the spatial decision support system SPARE:WATER. We find that structural model uncertainty among reference ET is far more important than model parametric uncertainty introduced by crop coefficients. These crop coefficients are used to estimate irrigation water requirement following the single crop coefficient approach. Using the reliability ensemble averaging (REA) technique, we are able to reduce the overall predictive model uncertainty by more than 10%. The exceedance probability curve of irrigation water requirements shows that a certain threshold, e.g. an irrigation water limit due to water right of 400 mm, would be less frequently exceeded in case of the REA ensemble average (45%) in comparison to the equally weighted ensemble average (66%). We conclude that multi-model ensemble predictions and sophisticated model averaging techniques are helpful in predicting irrigation demand and provide relevant information for decision making.

  6. Reduction of predictive uncertainty in estimating irrigation water requirement through multi-model ensembles and ensemble averaging

    NASA Astrophysics Data System (ADS)

    Multsch, S.; Exbrayat, J.-F.; Kirby, M.; Viney, N. R.; Frede, H.-G.; Breuer, L.

    2014-11-01

    Irrigation agriculture plays an increasingly important role in food supply. Many evapotranspiration models are used today to estimate the water demand for irrigation. They consider different stages of crop growth by empirical crop coefficients to adapt evapotranspiration throughout the vegetation period. We investigate the importance of the model structural vs. model parametric uncertainty for irrigation simulations by considering six evapotranspiration models and five crop coefficient sets to estimate irrigation water requirements for growing wheat in the Murray-Darling Basin, Australia. The study is carried out using the spatial decision support system SPARE:WATER. We find that structural model uncertainty is far more important than model parametric uncertainty to estimate irrigation water requirement. Using the Reliability Ensemble Averaging (REA) technique, we are able to reduce the overall predictive model uncertainty by more than 10%. The exceedance probability curve of irrigation water requirements shows that a certain threshold, e.g. an irrigation water limit due to water right of 400 mm, would be less frequently exceeded in case of the REA ensemble average (45%) in comparison to the equally weighted ensemble average (66%). We conclude that multi-model ensemble predictions and sophisticated model averaging techniques are helpful in predicting irrigation demand and provide relevant information for decision making.

  7. Irrigation Requirement Estimation using MODIS Vegetation Indices and Inverse Biophysical Modeling; A Case Study for Oran, Algeria

    NASA Technical Reports Server (NTRS)

    Bounoua, L.; Imhoff, M.L.; Franks, S.

    2008-01-01

    the study site, for the month of July, spray irrigation resulted in an irrigation amount of about 1.4 mm per occurrence with an average frequency of occurrence of 24.6 hours. The simulated total monthly irrigation for July was 34.85 mm. In contrast, the drip irrigation resulted in less frequent irrigation events with an average water requirement about 57% less than that simulated during the spray irrigation case. The efficiency of the drip irrigation method rests on its reduction of the canopy interception loss compared to the spray irrigation method. When compared to a country-wide average estimate of irrigation water use, our numbers are quite low. We would have to revise the reported country level estimates downward to 17% or less

  8. Estimation of irrigation requirement for wheat in the southern Spain by using a soil water balance remote sensing driven

    NASA Astrophysics Data System (ADS)

    González, Laura; Bodas, Vicente; Espósito, Gabriel; Campos, Isidro; Aliaga, Jerónimo; Calera, Alfonso

    2013-04-01

    This paper aims to evaluate the use of a remote sensing-driven soil water balance to estimate irrigation water requirements of wheat. The applied methodology is based on the approach of the dual crop coefficient proposed in the FAO-56 manual (Allen et al., 1998), where the basal crop coefficient is derived from a time series of remote sensing multispectral imagery which describes the growing cycle of wheat. This approach allows the estimation of the evapotranspiration (ET) and irrigation water requirements by means of a soil water balance in the root layer. The assimilation of satellite data into the FAO-56 soil water balance is based on the relationship between spectral vegetation indices (VI) and the transpiration coefficient (Campos et al., 2010; Sánchez et al., 2010). Two approaches to plant transpiration estimation were analyzed, the basal crop coefficient methodology and the transpiration coefficient approach described in the FAO-56 (Allen et al., 1998) and FAO-66 (Steduto et al., 2012) manuals respectively. The model is computed at daily time step and the results analyzed in this work are the net irrigation water requirements and water stress estimates. Analysis of results has been done by comparison with irrigation data (irrigation dates and volume applied) provided by farmers in 28 plots of wheat for the period 2004-2012 in the Spanish region of La Mancha, southern Spain, under different meteorological conditions. Total irrigation dose during the growing season varies from 200 mm to 700 mm. In some of plots soil moisture sensors data are available, which allowed the comparison with modeled soil moisture. Net irrigation water requirements estimated by the proposed model shows a good agreement with data, having in account the efficiency of the different irrigation systems. Despite the irrigation doses are generally greater than irrigation water requirements, the crops could suffer water stress periods during the campaign, because real irrigation timing and

  9. WATER REQUIREMENT OF IRRIGATED GARLIC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A replicated field trial was conducted on the West side of the San Joaquin Valley to determine the crop coefficient and water requirements of irrigated garlic. Irrigation systems used included flood irrigation, subsurface drip irrigation, and surface drip irrigation. Irrigation levels were set at 5...

  10. Water Requirements Of Irrigated Garlic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A replicated field trial was conducted on the West side of the San Joaquin Valley to determine the crop coefficient and water requirements of irrigated garlic. Irrigation systems used included flood irrigation, subsurface drip irrigation, and surface drip irrigation. Irrigation levels were set at 5...

  11. Energy requirements in pressure irrigation systems

    NASA Astrophysics Data System (ADS)

    Sánchez, R.; Rodríguez-Sinobas, L.; Juana, L.; Laguna, F. V.; Castañón, G.; Gil, M.; Benítez, J.

    2012-04-01

    Modernization of irrigation schemes, generally understood as transformation of surface irrigation systems into pressure -sprinkler and trickle- irrigation systems, aims at, among others, improving irrigation efficiency and reduction of operation and maintenance efforts made by the irrigators. However, pressure irrigation systems, in contrast, carry a serious energy cost. Energy requirements depend on decisions taken on management strategies during the operation phase, which are conditioned by previous decisions taken on the design project of the different elements which compose the irrigation system. Most of the countries where irrigation activity is significant bear in mind that modernization irrigation must play a key role in the agricultural infrastructure policies. The objective of this study is to characterize and estimate the mean and variation of the energy consumed by common types of irrigation systems and their management possibilities. The work includes all processes involved from the diversion of water into irrigation specific infrastructure to water discharge by the emitters installed on the crop fields. Simulation taking into account all elements comprising the irrigation system has been used to estimate the energy requirements of typical irrigation systems of several crop production systems. It has been applied to extensive and intensive crop systems, such us extensive winter crops, summer crops and olive trees, fruit trees and vineyards and intensive horticulture in greenhouses. The simulation of various types of irrigation systems and management strategies, in the framework imposed by particular cropping systems, would help to develop criteria for improving the energy balance in relation to the irrigation water supply productivity.

  12. In-season time series analysis of Resourcesat-1 AWiFS data for estimating irrigation water requirement

    NASA Astrophysics Data System (ADS)

    Raju, P. V.; Sesha Sai, M. V. R.; Roy, P. S.

    2008-06-01

    AWiFS sensor on board IRS-P6 (Resourcesat-1), with its unique features—wide swath and 5-day revisit capability provides excellent opportunities to carry out in-season analysis of irrigated agriculture. The study carried out in Hirakud command area, Orissa State indicated that the progression of rice crop acreage could be mapped through analysis of time series AWiFS data set. The spectral emergence pattern of rice crop was found useful to identify the period of rice transplantation and its variability across the command area. This information, integrated with agro-meteorological data, was used to quantify 10-daily canal-wise irrigation water requirement. A comparison with field measured actual irrigation supplies indicated an overall supply adequacy of 88% and showed wide variability at lateral canal level ranging between 18% and 109%. The supply pattern also did not correspond with the chronological variations associated with crop water requirement, supplies were 15% excess during initial part of season (December and January) and were 20.1% deficit during later part of season (February to April). Rescheduling the excess supplies of the initial period could have reduced the deficit to 15% during peak season. The study has demonstrated the usefulness of AWiFS data to generate the irrigation water requirement by mid-season, subsequent to which 38% supplies were yet to be allocated. This would support the irrigation managers to reschedule the irrigation water supplies to achieve better synchronization between requirement and supply leading to improved water use efficiency.

  13. A site-specific agricultural water requirement and footprint estimator (SPARE:WATER 1.0) for irrigation agriculture

    NASA Astrophysics Data System (ADS)

    Multsch, S.; Al-Rumaikhani, Y. A.; Frede, H.-G.; Breuer, L.

    2013-01-01

    The water footprint accounting method addresses the quantification of water consumption in agriculture, whereby three types of water to grow crops are considered, namely green water (consumed rainfall), blue water (irrigation from surface or groundwater) and grey water (water needed to dilute pollutants). Most of current water footprint assessments focus on global to continental scale. We therefore developed the spatial decision support system SPARE:WATER that allows to quantify green, blue and grey water footprints on regional scale. SPARE:WATER is programmed in VB.NET, with geographic information system functionality implemented by the MapWinGIS library. Water requirement and water footprints are assessed on a grid-basis and can then be aggregated for spatial entities such as political boundaries, catchments or irrigation districts. We assume in-efficient irrigation methods rather than optimal conditions to account for irrigation methods with efficiencies other than 100%. Furthermore, grey water can be defined as the water to leach out salt from the rooting zone in order to maintain soil quality, an important management task in irrigation agriculture. Apart from a thorough representation of the modelling concept we provide a proof of concept where we assess the agricultural water footprint of Saudi Arabia. The entire water footprint is 17.0 km3 yr-1 for 2008 with a blue water dominance of 86%. Using SPARE:WATER we are able to delineate regional hot spots as well as crop types with large water footprints, e.g. sesame or dates. Results differ from previous studies of national-scale resolution, underlining the need for regional water footprint assessments.

  14. Estimating Temperature Retrieval Accuracy Associated With Thermal Band Spatial Resolution Requirements for Center Pivot Irrigation Monitoring and Management

    NASA Technical Reports Server (NTRS)

    Ryan, Robert E.; Irons, James; Spruce, Joseph P.; Underwood, Lauren W.; Pagnutti, Mary

    2006-01-01

    This study explores the use of synthetic thermal center pivot irrigation scenes to estimate temperature retrieval accuracy for thermal remote sensed data, such as data acquired from current and proposed Landsat-like thermal systems. Center pivot irrigation is a common practice in the western United States and in other parts of the world where water resources are scarce. Wide-area ET (evapotranspiration) estimates and reliable water management decisions depend on accurate temperature information retrieval from remotely sensed data. Spatial resolution, sensor noise, and the temperature step between a field and its surrounding area impose limits on the ability to retrieve temperature information. Spatial resolution is an interrelationship between GSD (ground sample distance) and a measure of image sharpness, such as edge response or edge slope. Edge response and edge slope are intuitive, and direct measures of spatial resolution are easier to visualize and estimate than the more common Modulation Transfer Function or Point Spread Function. For these reasons, recent data specifications, such as those for the LDCM (Landsat Data Continuity Mission), have used GSD and edge response to specify spatial resolution. For this study, we have defined a 400-800 m diameter center pivot irrigation area with a large 25 K temperature step associated with a 300 K well-watered field surrounded by an infinite 325 K dry area. In this context, we defined the benchmark problem as an easily modeled, highly common stressing case. By parametrically varying GSD (30-240 m) and edge slope, we determined the number of pixels and field area fraction that meet a given temperature accuracy estimate for 400-m, 600-m, and 800-m diameter field sizes. Results of this project will help assess the utility of proposed specifications for the LDCM and other future thermal remote sensing missions and for water resource management.

  15. Utility of multi temporal satellite images for crop water requirements estimation and irrigation management in the Jordan Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying the spatial and temporal distribution of crop water requirements is a key for successful management of water resources in the dry areas. Climatic data were obtained from three automated weather stations to estimate reference evapotranspiration (ETO) in the Jordan Valley according to the...

  16. Estimating irrigation water use in the humid eastern United States

    USGS Publications Warehouse

    Levin, Sara B.; Zarriello, Phillip J.

    2013-01-01

    Accurate accounting of irrigation water use is an important part of the U.S. Geological Survey National Water-Use Information Program and the WaterSMART initiative to help maintain sustainable water resources in the Nation. Irrigation water use in the humid eastern United States is not well characterized because of inadequate reporting and wide variability associated with climate, soils, crops, and farming practices. To better understand irrigation water use in the eastern United States, two types of predictive models were developed and compared by using metered irrigation water-use data for corn, cotton, peanut, and soybean crops in Georgia and turf farms in Rhode Island. Reliable metered irrigation data were limited to these areas. The first predictive model that was developed uses logistic regression to predict the occurrence of irrigation on the basis of antecedent climate conditions. Logistic regression equations were developed for corn, cotton, peanut, and soybean crops by using weekly irrigation water-use data from 36 metered sites in Georgia in 2009 and 2010 and turf farms in Rhode Island from 2000 to 2004. For the weeks when irrigation was predicted to take place, the irrigation water-use volume was estimated by multiplying the average metered irrigation application rate by the irrigated acreage for a given crop. The second predictive model that was developed is a crop-water-demand model that uses a daily soil water balance to estimate the water needs of a crop on a given day based on climate, soil, and plant properties. Crop-water-demand models were developed independently of reported irrigation water-use practices and relied on knowledge of plant properties that are available in the literature. Both modeling approaches require accurate accounting of irrigated area and crop type to estimate total irrigation water use. Water-use estimates from both modeling methods were compared to the metered irrigation data from Rhode Island and Georgia that were used to

  17. An Assessment of Global Net Irrigation Water Requirements from Various Water Supply Sources to Sustain Irrigation

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Sayaka; Cho, Jail; Yamada, Hannah; Khajuria, Anupam; Hanasaki, Naota; Kanae, Shinjiro

    2014-05-01

    Water supply sources for irrigation, such as rivers, reservoirs, and groundwater, are critically important for agricultural productivity. The current rapid increase in irrigation water use threatens sustainable food production. In this study, we estimated the time-varying dependence of irrigation water requirements from water supply sources, with a particular focus on variations in irrigation area during the period 1960-2050 using the global water resources model, H08. The H08 model simulates water requirements on a daily basis at a resolution of 1.0° × 1.0° . The sources of irrigation water requirements in the past simulations were specified using four categories: rivers (RIV), large reservoirs (LR) with a storage capacity greater than 1.0 km3, medium-size reservoirs (MSR) with storage capacities ranging from 1.0 km3 to 3.0 M m3, and non-local non-renewable blue water (NNBW). We also estimated future irrigation water requirements from the above four water supply sources and an additional water supply source (ADD) in three future simulation designs; irrigation area change, climate change, and changes in both irrigation area and climate. ADD was defined as the difference between NNBW in the 1990s and NNBW in the 2040s, because it was difficult to distinguish the types of future water supply sources except for RIV. The simulated results showed that RIV, MSR, and NNBW increased significantly through the 1960s to the early 1990s globally, but LR increased at a relatively low rate. After the early 1990s, RIV approached a critical limit due to the continued expansion of the irrigation area. Furthermore, MSR and NNBW increased significantly following the expansion of the irrigation area and the increased storage capacity of the medium-size reservoirs. After the 2020s, MSR could be expected to approach the critical limit without the construction of medium-size reservoirs. ADD would account for 11-23% of the total requirements in the 2040s. We found that an expansion of

  18. Mediterranean irrigation under climate change: more efficient irrigation needed to compensate increases in irrigation water requirements

    NASA Astrophysics Data System (ADS)

    Fader, M.; Shi, S.; von Bloh, W.; Bondeau, A.; Cramer, W.

    2015-08-01

    Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. This study systematically assesses how climate change and increases in atmospheric CO2 concentrations may affect irrigation requirements in the Mediterranean region by 2080-2090. Future demographic change and technological improvements in irrigation systems are accounted for, as is the spread of climate forcing, warming levels and potential realization of the CO2-fertilization effect. Vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL after a large development that comprised the improved representation of Mediterranean crops. At present the Mediterranean region could save 35 % of water by implementing more efficient irrigation and conveyance systems. Some countries like Syria, Egypt and Turkey have higher saving potentials than others. Currently some crops, especially sugar cane and agricultural trees, consume in average more irrigation water per hectare than annual crops. Different crops show different magnitude of changes in net irrigation requirements due to climate change, being the increases most pronounced in agricultural trees. The Mediterranean area as a whole might face an increase in gross irrigation requirements between 4 and 18 % from climate change alone if irrigation systems and conveyance are not improved (2 °C global warming combined with full CO2-fertilization effect, and 5 °C global warming combined with no CO2-fertilization effect, respectively). Population growth increases these numbers to 22 and 74 %, respectively, affecting mainly the Southern and Eastern Mediterranean. However, improved irrigation technologies and conveyance systems have large water saving potentials, especially in the Eastern Mediterranean, and may be able to compensate to some degree the increases due to climate change and

  19. Improved surface volume estimates for surface irrigation balance calculations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volume balance calculations used in surface irrigation engineering analysis require estimates of surface storage. Typically, these calculations use the Manning formula and normal depth assumption to calculate upstream flow depth (and thus flow area), and a constant shape factor to describe the rela...

  20. Estimation of evapotranspiration rate in irrigated lands using stable isotopes

    NASA Astrophysics Data System (ADS)

    Umirzakov, Gulomjon; Windhorst, David; Forkutsa, Irina; Brauer, Lutz; Frede, Hans-Georg

    2013-04-01

    Agriculture in the Aral Sea basin is the main consumer of water resources and due to the current agricultural management practices inefficient water usage causes huge losses of freshwater resources. There is huge potential to save water resources in order to reach a more efficient water use in irrigated areas. Therefore, research is required to reveal the mechanisms of hydrological fluxes in irrigated areas. This paper focuses on estimation of evapotranspiration which is one of the crucial components in the water balance of irrigated lands. Our main objective is to estimate the rate of evapotranspiration on irrigated lands and partitioning of evaporation into transpiration using stable isotopes measurements. Experiments has done in 2 different soil types (sandy and sandy loam) irrigated areas in Ferghana Valley (Uzbekistan). Soil samples were collected during the vegetation period. The soil water from these samples was extracted via a cryogenic extraction method and analyzed for the isotopic ratio of the water isotopes (2H and 18O) based on a laser spectroscopy method (DLT 100, Los Gatos USA). Evapotranspiration rates were estimated with Isotope Mass Balance method. The results of evapotranspiration obtained using isotope mass balance method is compared with the results of Catchment Modeling Framework -1D model results which has done in the same area and the same time.

  1. Comparison of Irrigation Water Use Estimates Calculated from Remotely Sensed Irrigated Acres and State Reported Irrigated Acres in the Lake Altus Drainage Basin, Oklahoma and Texas, 2000 Growing Season

    USGS Publications Warehouse

    Masoner, J.R.; Mladinich, C.S.; Konduris, A.M.; Smith, S. Jerrod

    2003-01-01

    Increased demand for water in the Lake Altus drainage basin requires more accurate estimates of water use for irrigation. The U.S. Geological Survey, in cooperation with the U.S. Bureau of Reclamation, is investigating new techniques to improve water-use estimates for irrigation purposes in the Lake Altus drainage basin. Empirical estimates of reference evapotranspiration, crop evapotranspiration, and crop irrigation water requirements for nine major crops were calculated from September 1999 to October 2000 using a solar radiation-based evapotranspiration model. Estimates of irrigation water use were calculated using remotely sensed irrigated crop acres derived from Landsat 7 Enhanced Thematic Mapper Plus imagery and were compared with irrigation water-use estimates calculated from irrigated crop acres reported by the Oklahoma Water Resources Board and the Texas Water Development Board for the 2000 growing season. The techniques presented will help manage water resources in the Lake Altus drainage basin and may be transferable to other areas with similar water management needs. Irrigation water use calculated from the remotely sensed irrigated acres was estimated at 154,920 acre-feet; whereas, irrigation water use calculated from state reported irrigated crop acres was 196,026 acre-feet, a 23 percent difference. The greatest difference in irrigation water use was in Carson County, Texas. Irrigation water use for Carson County, Texas, calculated from the remotely sensed irrigated acres was 58,555 acrefeet; whereas, irrigation water use calculated from state reported irrigated acres was 138,180 acre-feet, an 81 percent difference. The second greatest difference in irrigation water use occurred in Beckham County, Oklahoma. Differences between the two irrigation water use estimates are due to the differences of irrigated crop acres derived from the mapping process and those reported by the Oklahoma Water Resources Board and Texas Water Development Board.

  2. Quality requirements for irrigation with sewage water

    SciTech Connect

    Bouwer, H.; Idelovitch, E. )

    1987-11-01

    Irrigation is an excellent use for sewage effluent because it is mostly water with nutrients. For small flows, the effluent can be used on special, well-supervised sewage farms, where forage, fiber, or seed crops are grown that can be irrigated with standard primary or secondary effluent. Large-scale use of the effluent requires special treatment so that it meets the public health, agronomic, and aesthetic requirements for unrestricted use. Crops in the unrestricted-use category include those that are consumed raw or brought raw into the kitchen. Most state or government standards deal only with public health aspects, and prescribe the treatment processes or the quality parameters that the effluent must meet before it can be used to irrigate a certain category of crops. However, agronomic aspects related to crops and soils must also be taken into account. Quality parameters to be considered include bacteria, viruses, and other pathogens; total salt content and sodium adsorption ratio of the water; nitrogen; phosphorus; chloride and chlorine; bicarbonate; heavy metals, boron, and other trace elements; pH; and synthetic organics. 23 refs., 9 tabs.

  3. Estimates of Savings Achievable from Irrigation Controller

    SciTech Connect

    Williams, Alison; Fuchs, Heidi; Whitehead, Camilla Dunham

    2014-03-28

    This paper performs a literature review and meta-analysis of water savings from several types of advanced irrigation controllers: rain sensors (RS), weather-based irrigation controllers (WBIC), and soil moisture sensors (SMS).The purpose of this work is to derive average water savings per controller type, based to the extent possible on all available data. After a preliminary data scrubbing, we utilized a series of analytical filters to develop our best estimate of average savings. We applied filters to remove data that might bias the sample such as data self-reported by manufacturers, data resulting from studies focusing on high-water users, or data presented in a non-comparable format such as based on total household water use instead of outdoor water use. Because the resulting number of studies was too small to be statistically significant when broken down by controller type, this paper represents a survey and synthesis of available data rather than a definitive statement regarding whether the estimated water savings are representative.

  4. Estimation of infiltration parameters and the irrigation coefficients with the surface irrigation advance distance.

    PubMed

    Beibei, Zhou; Quanjiu, Wang; Shuai, Tan

    2014-01-01

    A theory based on Manning roughness equation, Philip equation and water balance equation was developed which only employed the advance distance in the calculation of the infiltration parameters and irrigation coefficients in both the border irrigation and the surge irrigation. The improved procedure was validated with both the border irrigation and surge irrigation experiments. The main results are shown as follows. Infiltration parameters of the Philip equation could be calculated accurately only using water advance distance in the irrigation process comparing to the experimental data. With the calculated parameters and the water balance equation, the irrigation coefficients were also estimated. The water advance velocity should be measured at about 0.5 m to 1.0 m far from the water advance in the experimental corn fields. PMID:25061664

  5. [Effect of climate change on rice irrigation water requirement in Songnen Plain, Northeast China].

    PubMed

    Huang, Zhi-gang; Wang, Xiao-li; Xiao, Ye; Yang, Fei; Wang, Chen-xi

    2015-01-01

    Based on meteorological data from China national weather stations and climate scenario grid data through regional climate model provided by National Climate Center, rice water requirement was calculated by using McCloud model and Penman-Monteith model combined with crop coefficient approach. Then the rice irrigation water requirement was estimated by water balance model, and the changes of rice water requirement were analyzed. The results indicated that either in historical period or in climate scenario, rice irrigation water requirement contour lines during the whole growth period and Lmid period decreased along southwest to northeast, and the same irrigation water requirement contour line moved north with decade alternation. Rice irrigation water requirement during the whole growth period increased fluctuantly with decade alternation at 44.2 mm . 10 a-1 in historical period and 19.9 mm . 10 a-1 in climate scenario. The increase in rice irrigation water requirement during the Lmid period with decade alternation was significant in historical period, but not significant in climate scenario. Contribution rate of climate change to rice irrigation water requirement would be fluctuantly increased with decade alternation in climate scenario. Compared with 1970s, contribution rates of climate change to rice irrigation water requirement were 23.6% in 2000s and 34.4% in 2040s, which increased 14.8 x 10(8) m3 irrigation water in 2000s and would increase 21.2 x 10(8) m3 irrigation water in 2040s. PMID:25985678

  6. Water Requirements of Young Blueberry Plants Irrigated by Sprinklers, Microsprays, and Drip

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was done to determine the effects of irrigation method on water use by young northern highbush blueberry (Vaccinium corymbosum L. 'Elliott'). Plants were irrigated by overhead sprinkler, microspray, or drip at 50, 100, and 150% of the estimated crop evapotranspiration (ETc) requirement. Du...

  7. Evapotranspiration Estimates for Deficit Irrigated Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water deficits must be imposed on crops during non-critical growth periods to maximize net economic output per unit of water consumed by the plant. The reference ET-crop coefficient procedure widely used for managing fully irrigated crops would be easiest to implement for irrigation management of d...

  8. ESTIMATING MICROORGANISM DENSITIES IN AEROSOLS FROM SPRAY IRRIGATION OF WASTEWATER

    EPA Science Inventory

    This document summarizes current knowledge about estimating the density of microorganisms in the air near wastewater management facilities, with emphasis on spray irrigation sites. One technique for modeling microorganism density in air is provided and an aerosol density estimati...

  9. Mediterranean agriculture: More efficient irrigation needed to compensate increases in future irrigation water requirements

    NASA Astrophysics Data System (ADS)

    Fader, Marianela; Shi, Sinan; von Bloh, Werner; Bondeau, Alberte; Cramer, Wolfgang

    2016-04-01

    Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. Our research shows that, at present, Mediterranean region could save 35% of water by implementing more efficient irrigation and conveyance systems. Some countries like Syria, Egypt and Turkey have higher saving potentials than others. Currently some crops, especially sugar cane and agricultural trees, consume in average more irrigation water per hectare than annual crops (1). Also under climate change, more efficient irrigation is of vital importance for counteracting increases in irrigation water requirements. The Mediterranean area as a whole might face an increase in gross irrigation requirements between 4% and 18% from climate change alone by the end of the century if irrigation systems and conveyance are not improved. Population growth increases these numbers to 22% and 74%, respectively, affecting mainly the Southern and Eastern Mediterranean. However, improved irrigation technologies and conveyance systems have large water saving potentials, especially in the Eastern Mediterranean, and may be able to compensate to some degree the increases due to climate change and population growth. Both subregions would need around 35% more water than today if they could afford some degree of modernization of irrigation and conveyance systems and benefit from the CO2-fertilization effect (1). However, in some scenarios (in this case as combinations of climate change, irrigation technology, influence of population growth and CO2-fertilization effect) water scarcity may constrain the supply of the irrigation water needed in future in Algeria, Libya, Israel, Jordan, Lebanon, Syria, Serbia, Morocco, Tunisia and Spain (1). In this study, vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL ("Lund-Potsdam-Jena managed Land") after a

  10. Landsat-based estimation of California's irrigated land

    NASA Technical Reports Server (NTRS)

    Wall, S. L.; Brown, C. E.; Thomas, R. W.; Erikkson, M.

    1981-01-01

    The procedure developed uses two-phase sampling, stratification and multidate Landsat imagery to produce the estimate. Maximizing the advantages of both spectral data and field patterns available from Landsat, three dates of Landsat imagery are interpreted to provide county-wide estimates of the proportion of land irrigated. Ground data, collected on a subset of the area interpreted on Landsat, are used to calibrate the satellite estimate. The satellite and ground measurements are reduced to proportion data and linked using a regression estimator to produce the estimate of irrigated land. It is estimated that 3.99 million hectares were irrigated with a relative standard error of + or - 1.18% at the 99% confidence level. Acreage tabulations provided by the Department of Water Resources show that the Landsat-based estimate differed by less than 0.4% at the state level.

  11. Mediterranean irrigation under climate change: more efficient irrigation needed to compensate for increases in irrigation water requirements

    NASA Astrophysics Data System (ADS)

    Fader, M.; Shi, S.; von Bloh, W.; Bondeau, A.; Cramer, W.

    2016-03-01

    Irrigation in the Mediterranean is of vital importance for food security, employment and economic development. This study systematically assesses how climate change and increases in atmospheric CO2 concentrations may affect irrigation requirements in the Mediterranean region by 2080-2090. Future demographic change and technological improvements in irrigation systems are taken into account, as is the spread of climate forcing, warming levels and potential realization of the CO2-fertilization effect. Vegetation growth, phenology, agricultural production and irrigation water requirements and withdrawal were simulated with the process-based ecohydrological and agro-ecosystem model LPJmL (Lund-Potsdam-Jena managed Land) after an extensive development that comprised the improved representation of Mediterranean crops. At present the Mediterranean region could save 35 % of water by implementing more efficient irrigation and conveyance systems. Some countries such as Syria, Egypt and Turkey have a higher savings potential than others. Currently some crops, especially sugar cane and agricultural trees, consume on average more irrigation water per hectare than annual crops. Different crops show different magnitudes of changes in net irrigation requirements due to climate change, the increases being most pronounced in agricultural trees. The Mediterranean area as a whole may face an increase in gross irrigation requirements between 4 and 18 % from climate change alone if irrigation systems and conveyance are not improved (4 and 18 % with 2 °C global warming combined with the full CO2-fertilization effect and 5 °C global warming combined with no CO2-fertilization effect, respectively). Population growth increases these numbers to 22 and 74 %, respectively, affecting mainly the southern and eastern Mediterranean. However, improved irrigation technologies and conveyance systems have a large water saving potential, especially in the eastern Mediterranean, and may be able to

  12. Global net irrigation water requirements from various water supply sources during past and future periods

    NASA Astrophysics Data System (ADS)

    Yoshikawa, S.; Cho, J.; Hanasaki, N.; Kanae, S.

    2014-12-01

    Water supply sources for irrigation (e.g. rivers and reservoirs) are critically important for agricultural productivity. The current rapid increase in irrigation water use is considered unsustainable and threatens food production. In this study, we estimated the time-varying dependence of irrigation water requirements from water supply sources, with a particular focus on variations in irrigation area during past (1960-2001) and future (2002-2050) periods using the global water resources model, H08. The H08 model can simulate water requirements on a daily basis at a resolution of 1.0° × 1.0° latitude and longitude. The sources of irrigation water requirements in the past simulations were specified using four categories: rivers (RIV), large reservoirs (LR), medium-size reservoirs (MSR), and non-local non-renewable blue water (NNBW). The simulated results from 1960 to 2001 showed that RIV, MSR and NNBW increased significantly from the 1960s to the early 1990s globally, but LR increased at a relatively low rate. After the early 1990s, the increase in RIV declined as it approached a critical limit, due to the continued expansion of irrigation area. MSR and NNBW increased significantly, during the same time period, following the expansion of the irrigation area and the increased storage capacity of the medium-size reservoirs. We also estimated future irrigation water requirements from the above four water supply sources and an additional water supply source (ADD) in three future simulation designs; irrigation area change, climate change, and changes in both irrigation area and climate. ADD was defined as a future increase in NNBW. After the 2020s, MSR was predicted to approach the critical limit, and ADD would account for 11-23% of the total requirements in the 2040s.

  13. Stochastic Soil Moisture Estimation and Forecasting for Irrigated Fields

    NASA Astrophysics Data System (ADS)

    Aboitiz, Martin; Labadie, John W.; Heermann, Dale F.

    1986-02-01

    A methodology is developed for estimating and forecasting soil water depletion and crop evapotranspiration, with explicit consideration of modeling errors and stochastic inputs. The water balance of an irrigated field and a time series model for reference crop evapotranspiration are formulated in state-space form, with soil moisture depletion and reference evapotranspiration as state variables. The Kalman filter is used to generate estimates and forecasts of the state variables, together with statistical information on their associated errors. Model calibration and validity tests are performed with two independent data sets from locations in Colorado. Each set includes several years of reference crop evapotranspiration data calculated from climatological observations, one season of soil moisture measurements, and concurrent irrigation applications. The estimates, forecasts, and error covariance information provided by the model can allow irrigation decisions to be made with explicit consideration of the inherent risks of crop damage or failure under limitations in water, energy, labor, and capital.

  14. Empirically Estimating the Existing Irrigation Adaptation to Future Drought Impacts in Kansas Agriculture

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Lin, X.; Yang, X.

    2014-12-01

    More serious drought has been projected due to the climate change in the Kansas State of the U.S., which might threaten the local agriculture and thus require effective adaptation responses to drought, e.g. better irrigation. But the irrigation adaptation on drought at the current technology-level is poorly quantified, therefore challenges to figure out how much additional efforts are required under more aridity of climate. Here, we collect the irrigation application data for maize, soybean, sorghum and wheat in Kansas, and establish a two-stage model to quantify the crop-specific irrigation application responses to changes in climatic drivers, and further estimate the existing effectiveness of the irrigation to adapt future drought based on the IPCC AR5 ensemble PDSI prediction under RCP4.5 scenario. We find that the three summer season crops (maize, soybean and sorghum) would experience 0 - 20% yield losses depending on county due to more serious drought since 2030s, even though increased irrigation application as the response of drought had saved 0 - 10% yields. At the state level, maize receives most benefits from irrigation, whereas the beneficial effects are least for sorghum among the three crops. To wheat, irrigation adaptation is very weak since irrigation water applied is much less than the above three crops. But wheat yields were projected to have a slight increase in central and eastern regions because climate would become more moisture over the growing season of winter wheat in future. Our results highlight that the existing beneficial effects from irrigation would be surpassed by the negative impact of drought in future, which would cause overall yield reduction in Kansas especially for those summer season crops.

  15. Net irrigation requirements for maize (Zea mays L.) in Bocono-Masparro interfluvium area.

    NASA Astrophysics Data System (ADS)

    Farias Ramirez, Asdrubal Jesus; Moreno Pizani, Maria Alejandra

    2013-04-01

    Irrigated agriculture is one of the largest consumers of fresh water. In situations where water resources are limited, the irrigation for crops has led to water use conflicts because of human, hydroelectric and industrial demands. Thus, achieving precise information about water availability and water needs of crops becomes safety factors to guarantee sustainable development of irrigated crops in the future. In Bocono-Masparro interfluvium area located within Barinas and Portuguesa states in Venezuela, there has been a significant increase in intensive farming with maize (Zea mays L.) which made essential to determine the availability of irrigation water to meet the crop requirement and improve the management based on planning designs. Due to the lack of irrigation requirements data for the study area, a methodology was developed to estimate the net irrigation requirements (NIR). Therefore, the available information of this region related to climate, soil and irrigation was used to estimate NIR for maize through CROPWAT 8.0 model. There were established different crop-climate-soil combinations that allowed estimating NIR. It was found that NIR did not exceed the value of 125 mm/month in all of the combinations. Based on these results, a NIR spatial distribution map was obtained through the use of ArcView 3.2 ®. The results showed that the highest NIR were located in the northeast sector of the study area which was associated to the influence of the Weather Station named San Hipolito. Additionally, the estimated availability of groundwater was found to be higher than the surface water, and both combined exceeded the demands of the study area. The model CROPWAT 8.0 provided necessary information for irrigation planning in large scale. A NIR map developed through the proposed methodology represents a useful tool to integrate water balance factors.

  16. Irrigation Management with Remote Sensing Techniques. Crop Water Requirements and Biophysical Indicators

    NASA Astrophysics Data System (ADS)

    Toureiro, Célia; Serralheiro, Ricardo

    2013-04-01

    Saving water in irrigated agriculture is increasingly relevant, as the irrigation sector is in many regions the biggest water consumer, but must be a sustainable activity. Therefore, the need urges for water use control methods and water resources planning. In irrigated agriculture, the right way for saving water is constituted by the increase of efficiency in water management. This work validates procedures and methodologies with remote sensing to determine the water availability in the soil at each moment and therefore the opportunity for the application of the water volume strictly necessary to optimize crop growth (irrigation opportunity and irrigation amount). The analysis applied to the Irrigation District of Divor, Évora, having used 7 experiment plots, which are areas watered by center-pivot systems, cultivated to corn. Data were determined from multispectral and infrared images of the cultivated surface obtained by satellite or by flying unmanned platform and integrated with parameters of the atmosphere and of the crops for calculating biophysical indicators and indices of water stress in the vegetation (NDVI, Kc, Kcb, CWSI). Therefore, evapotranspiration (ETc) was estimated, with which crop water requirement was calculated, with the opportunity and the amount of irrigation water to allocate. As this information is geographic referenced, maps can be prepared with GIS technology, describing water situation and the opportunity for watering crops. If the remote images are available with enough high spatial and temporal resolution, the frequent availability of maps can serve as a basis for a farmers irrigation advice system and for the regional irrigation authority to make decisions on the irrigation management at the regional scale. This can be a significant contribute to an efficient water management technology and a sustainable irrigated agriculture. Key-Words: Remote Sensing, Vegetation Index, Crop Coefficients, Water Balance

  17. Estimated Domestic, Irrigation, and Industrial Water Use in Washington, 2000

    USGS Publications Warehouse

    Lane, R.C.

    2004-01-01

    Since 1950, the U.S. Geological Survey has published a series of Circulars and other reports on the estimated use of water in the United States at 5-year intervals. This report presents State, regional, and county estimates of the amount of water used for domestic, irrigation, and industrial purposes in the State of Washington during the year 2000. Domestic water use was estimated to be 674 million gallons per day and the per-capita rate, 114 gallons per day. Crop-irrigation water use was estimated to be 3,005 million gallons per day and the application rate, 2.2 acre-feet per acre per year, or feet per year. Golf-course irrigation water use was estimated to be 23.6 million gallons per day and the application rate, 1.4 feet per year. Industrial water use was estimated to be 681 million gallons per day. Historically, these core categories account for about 92 percent of the estimated offstream water used in Washington.

  18. An investigation of spectral change as influenced by irrigation and evapotranspiration volume estimation in western Nebraska

    USGS Publications Warehouse

    Seevers, P.M.; Sadowski, F.C.; Lauer, D.T.

    1990-01-01

    Retrospective satellite image data were evaluated for their ability to demonstrate the influence of center-pivot irrigation development in western Nebraska on spectral change and climate-related factors for the region. Periodic images of an albedo index and a normalized difference vegetation index (NDVI) were generated from calibrated Landsat multispectral scanner (MSS) data and used to monitor spectral changes associated with irrigation development from 1972 through 1986. The albedo index was not useful for monitoring irrigation development. For the NDVI, it was found that proportions of counties in irrigated agriculture, as discriminated by a threshold, were more highly correlated with reported ground estimates of irrigated agriculture than were county mean greenness values. A similar result was achieved when using coarse resolution Advanced Very High Resolution Radiometer (AVHRR) image data for estimating irrigated agriculture. The NDVI images were used to evaluate a procedure for making areal estimates of actual evapotranspiration (ET) volumes. Estimates of ET volumes for test counties, using reported ground acreages and corresponding standard crop coefficients, were correlated with the estimates of ET volume using crop coefficients scaled to NDVI values and pixel counts of crop areas. These county estimates were made under the assumption that soil water availability was unlimited. For nonirrigated vegetation, this may result in over-estimation of ET volumes. Ground information regarding crop types and acreages are required to derive the NDVI scaling factor. Potential ET, estimated with the Jensen-Haise model, is common to both methods. These results, achieved with both MSS and AVHRR data, show promise for providing climatologically important land surface information for regional and global climate models. ?? 1990 Kluwer Academic Publishers.

  19. Optimal estimation of irrigation schedule An example of quantifying human interferences to hydrologic processes

    NASA Astrophysics Data System (ADS)

    Wang, Dingbao; Cai, Ximing

    2007-08-01

    Reliable records of water use for irrigation are often lacking. This presents a difficulty for a qualified water use and water availability assessment. Quantification of the hydrologic cycle processes in regions of intensive agricultural practice requires irrigation as an input to hydrologic models. This paper presents a coupled forward-inverse framework to estimate irrigation schedule using remote-sensed data and data assimilation and optimization techniques. Irrigation schedule is treated as an unknown input to a hydro-agronomic simulation model. Remote-sensed data is used to assess actual crop evapotranspiration, which is used as the "observation" of the computed crop evapotranspiration from the simulation model. To handle the impact of model and observation error and the unknown biased error with irrigation inputs, a coupled forward-inverse approach is proposed, implemented and tested. The coupled approach is realized by an integrated ensemble Kalman filter (EnKF) and genetic algorithm (GA). The result from a case study demonstrates that the forward and inverse procedures in the coupled framework are complementary to each other. Further analysis is provided on the impact of model and observation errors on the non-uniqueness problem with inverse modeling and on the exactness of irrigation estimates.

  20. Estimation of furrow irrigation sediment loss using an artificial neural network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The area irrigated by furrow irrigation in the U.S. has been steadily decreasing but still represents about 20% of the total irrigated area in the U.S. Furrow irrigation sediment loss is a major water quality issue and a method for estimating sediment loss is needed to quantify the environmental imp...

  1. Estimating 1980 ground-water pumpage for irrigation on the High Plains in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

    USGS Publications Warehouse

    Heimes, F.J.; Luckey, R.R.

    1983-01-01

    Current ground-water use is required for the High Plains Regional Aquifer-System Analysis. In response to this need, a sampling approach was developed to estimate water pumped for irrigation on the High Plains during 1980. Pumpage was computed by combining application estimates with mapped irrigated-acreage information. Irrigation application (inches of water applied) was measured at 480 sites in 15 counties in the High Plains during the 1980 growing season. The relationship between calculated Blaney-Criddle irrigation demand and measured application was used to estimate application for unsampled areas of the High Plains. Application estimates multiplied by irrigated-acreate estimates, compiled from Landsat-satellite imagery, yielded the volume of ground water pumped for irrigation. The estimate of ground water pumped for irrigation in the High Plains during 1980 and 18,902,000 acre-feet for 13 ,715,000 irrigated areas. The sampled application data were evaluated for significant trends. The application was greater for crops requiring more water such as corn and hay and less for crops such as sorghum, grain, and cotton. The data showed greater application for flood-irrigated systems than for sprinkler-irrigation systems. Areas of the High Plains with thin saturated thickness tended to have a smaller average discharge per well, fewer irrigated acres per well, and a predominance of crops requiring less water crops. (USGS).

  2. The impacts of climate change on global irrigation water requirements

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Cai, X.

    2011-12-01

    Climate change tends to affect the irrigation water requirement of current irrigated agricultural land, and also changes the water availability for current rain-fed land by the end of this century. We use the most up-to-date climatic and crop datasets (e.g., global irrigated/rain-fed crop areas and grid level crop growing calendar (Portmann, Siebert and Döll, 2010, Global Biogeochemical Cycles 24)) to evaluate the requirements of currently irrigated land and the water deficit for rain-fed land for all major crops under current and projected climate. Six general circulation models (GCMs) under two emission scenarios, A1B & B1, are assembled using two methods, the Simple Average Method (SAM) and Root Mean Square Error Ensemble Method (RMSEMM), to deal with the GCM regional variability. It is found that the global irrigation requirement and the water deficit are both going to increase significantly under all scenarios, particularly under the A1B emission scenario. For example, the projected irrigation requirement is expected to increase by about 2500 million m3 for wheat, 3200 million m3 for maize and another 3300 million m3 for rice. At the same time, the water deficit for current rain-fed cropland will be widened by around 3000, 4000, 2100 million m3 for wheat, maize and rice respectively. Regional analysis is conducted for Africa, China, Europe, India, South America and the United States. It is found that the U.S. may expect the greatest rise in irrigation requirements for wheat and maize, while the South America may suffer the greatest increase for rice. In addition, Africa and the U.S. may face a larger water deficit for both wheat and maize on rain-fed land, and South America just for rice. In summary, climate change is likely to bring severe challenges for irrigation systems and make global water shortage even worse by the end of this century. These pressures will call for extensive adaptation measures. The change in crop water requirements and availability

  3. Estimated Colorado Golf Course Irrigation Water Use, 2005

    USGS Publications Warehouse

    Ivahnenko, Tamara

    2009-01-01

    Golf course irrigation water-use data were collected as part of the U.S. Geological Survey National Water Use Program's 2005 compilation to provide baseline information, as no golf course irrigation water-use data (separate from crop irrigation) have been reported in previous compilations. A Web-based survey, designed by the U.S. Geological Survey, in cooperation with the Rocky Mountain Golf Course Superintendents Association (RMGCSA), was electronically distributed by the association to the 237 members in Colorado. Forty-three percent of the members returned the survey, and additional source water information was collected by telephone for all but 20 of the 245 association member and non-member Colorado golf courses. For golf courses where no data were collected at all, an average 'per hole' coefficient, based on returned surveys from that same county, were applied. In counties where no data were collected at all, a State average 'per hole' value of 13.2 acre-feet was used as the coefficient. In 2005, Colorado had 243 turf golf courses (there are 2 sand courses in the State) that had an estimated 2.27 acre-feet per irrigated course acre, and 65 percent of the source water for these courses was surface water. Ground water, potable water (public supply), and reclaimed wastewater, either partially or wholly, were source waters for the remaining courses. Fifty-three of the 64 counties in Colorado have at least one golf course, with the greatest number of courses in Jefferson (23 courses), Arapahoe (22 courses), and El Paso Counties (20 courses). In 2005, an estimated 5,647.8 acre-feet in Jefferson County, 5,402 acre-feet in Arapahoe County, and 4,473.3 acre-feet in El Paso County were used to irrigate the turf grass.

  4. Estimating irrigation demand using satellite remote sensing: a case study of Paphos District area in Cyprus

    NASA Astrophysics Data System (ADS)

    Hadjimitsis, Diofantos G.; Papadavid, Giorgos; Themistokleous, Kyriacos; Kounoudes, Anastasis; Toulios, Leonidas

    2008-10-01

    The monitoring of agricultural areas in Cyprus provides important data for efficient water supply plans and for avoiding unnecessary water lost due to inefficient irrigation. In this context, satellite remote sensing techniques may be useful as an efficient tool for monitoring agricultural areas. The objective of this study is to present the overall methodology for monitoring agricultural areas and estimating the irrigation demand in Cyprus using satellite remote sensing, irrigation models and other auxiliary data. Field spectro-radiometric measurements using SVC-HR 1024 and GER 1500 were undertaken to determine the spectral signature of different types of crops so as to assist our classification techniques. Final crop maps using Landsat TM and ETM+ can be produced and the optimal amount of irrigation demand required for certain types of crops can be determined in order to avoid any non-effective water management. This paper presents the overall methodology of the proposed research study designed to enable the implementation of an integrated approach by combining satellite remote sensing, irrigation models, micro-sensor technology and in-situ spectroradiometric measurements to determine the irrigation demand and finally to validate our results.

  5. Tritium tracer test to estimate aquifer recharge under irrigated conditions

    NASA Astrophysics Data System (ADS)

    Jimenez-Martinez, J.; Tamoh, K.; Candela, L.

    2009-12-01

    Environmental tracers, as tritium, have been generally used to estimate aquifer recharge under natural conditions. A tritium tracer test to estimate recharge under semi-arid and irrigated conditions is presented. The test was carried out in an experimental plot under drip irrigation, located in SE Spain, with annual row crops (rotation lettuce and melon), following common agricultural practices in open air. Tritiated water was applied as an irrigation pulse, soil cores were taken at different depths and a liquid scintillation analyzer was used to measure the concentration of tritium in soil samples. Transport of tritium was simulated with SOLVEG code, a one-dimensional numerical model for simulating transport of heat, water and tritiated water in liquid and gas phase, which has been modified and adapted for this experience, including ground cover, root growth and root water uptake. One crop has been used to calibrate the modeling approach and other three crops to validate it. Results of flow and transport modelling show a good agreement between observed and estimated tritium concentration profile. For the period October 2007-September 2008, total drainage obtained value was 441 mm.

  6. Where Does the Irrigation Water Go? An Estimate of the Contribution of Irrigation to Precipitation Using MERRA

    NASA Technical Reports Server (NTRS)

    Wei, Jiangfeng; Dirmeyer, Paul A.; Wisser, Dominik; Bosilovich, Michael G.; Mocko, David M.

    2013-01-01

    Irrigation is an important human activity that may impact local and regional climate, but current climate model simulations and data assimilation systems generally do not explicitly include it. The European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Interim) shows more irrigation signal in surface evapotranspiration (ET) than the Modern-Era Retrospective Analysis for Research and Applications (MERRA) because ERA-Interim adjusts soil moisture according to the observed surface temperature and humidity while MERRA has no explicit consideration of irrigation at the surface. But, when compared with the results from a hydrological model with detailed considerations of agriculture, the ET from both reanalyses show large deficiencies in capturing the impact of irrigation. Here, a back-trajectory method is used to estimate the contribution of irrigation to precipitation over local and surrounding regions, using MERRA with observation-based corrections and added irrigation-caused ET increase from the hydrological model. Results show substantial contributions of irrigation to precipitation over heavily irrigated regions in Asia, but the precipitation increase is much less than the ET increase over most areas, indicating that irrigation could lead to water deficits over these regions. For the same increase in ET, precipitation increases are larger over wetter areas where convection is more easily triggered, but the percentage increase in precipitation is similar for different areas. There are substantial regional differences in the patterns of irrigation impact, but, for all the studied regions, the highest percentage contribution to precipitation is over local land.

  7. Parameter Estimation for Groundwater Models under Uncertain Irrigation Data.

    PubMed

    Demissie, Yonas; Valocchi, Albert; Cai, Ximing; Brozovic, Nicholas; Senay, Gabriel; Gebremichael, Mekonnen

    2015-01-01

    The success of modeling groundwater is strongly influenced by the accuracy of the model parameters that are used to characterize the subsurface system. However, the presence of uncertainty and possibly bias in groundwater model source/sink terms may lead to biased estimates of model parameters and model predictions when the standard regression-based inverse modeling techniques are used. This study first quantifies the levels of bias in groundwater model parameters and predictions due to the presence of errors in irrigation data. Then, a new inverse modeling technique called input uncertainty weighted least-squares (IUWLS) is presented for unbiased estimation of the parameters when pumping and other source/sink data are uncertain. The approach uses the concept of generalized least-squares method with the weight of the objective function depending on the level of pumping uncertainty and iteratively adjusted during the parameter optimization process. We have conducted both analytical and numerical experiments, using irrigation pumping data from the Republican River Basin in Nebraska, to evaluate the performance of ordinary least-squares (OLS) and IUWLS calibration methods under different levels of uncertainty of irrigation data and calibration conditions. The result from the OLS method shows the presence of statistically significant (p < 0.05) bias in estimated parameters and model predictions that persist despite calibrating the models to different calibration data and sample sizes. However, by directly accounting for the irrigation pumping uncertainties during the calibration procedures, the proposed IUWLS is able to minimize the bias effectively without adding significant computational burden to the calibration processes. PMID:25040235

  8. The future of irrigated agriculture under environmental flow requirements restrictions

    NASA Astrophysics Data System (ADS)

    Pastor, Amandine; Palazzo, Amanda; Havlik, Petr; Kabat, Pavel; Obersteiner, Michael; Ludwig, Fulco

    2016-04-01

    Water is not an infinite resource and demand from irrigation, household and industry is constantly increasing. This study focused on including global water availability including environmental flow requirements with water withdrawal from irrigation and other sectors at a monthly time-step in the GLOBIOM model. This model allows re-adjustment of land-use allocation, crop management, consumption and international trade. The GLOBIOM model induces an endogenous change in water price depending on water supply and demand. In this study, the focus was on how the inclusion of water resources affects land-use and, in particular, how global change will influence repartition of irrigated and rainfed lands at global scale. We used the climate change scenario including a radiative forcing of 8.5 W/m2 (RCP8.5), the socio-economic scenario (SSP2: middle-of-road), and the environmental flow method based on monthly flow allocation (the Variable Monthly Flow method) with high and low restrictions. Irrigation withdrawals were adjusted to a monthly time-step to account for biophysical water limitations at finer time resolution. Our results show that irrigated land might decrease up to 40% on average depending on the choice of EFR restrictions. Several areas were identified as future hot-spots of water stress such as the Mediterranean and Middle-East regions. Other countries were identified to be in safe position in terms of water stress such as North-European countries. Re-allocation of rainfed and irrigated land might be useful information for land-use planners and water managers at an international level to decide on appropriate legislations on climate change mitigation/adaptation when exposure and sensitivity to climate change is high and/or on adaptation measures to face increasing water demand. For example, some countries are likely to adopt measures to increase their water use efficiencies (irrigation system, soil and water conservation practices) to face water shortages, while

  9. An assessment of global net irrigation water requirements from various water supply sources to sustain irrigation: rivers and reservoirs (1960-2050)

    NASA Astrophysics Data System (ADS)

    Yoshikawa, S.; Cho, J.; Yamada, H. G.; Hanasaki, N.; Kanae, S.

    2014-10-01

    Water supply sources for irrigation (e.g. rivers and reservoirs) are critically important for agricultural productivity. The current rapid increase in irrigation water use is considered unsustainable and threatens food production. In this study, we estimated the time-varying dependence of irrigation water requirements from water supply sources, with a particular focus on variations in irrigation area during past (1960-2001) and future (2002-2050) periods using the global water resources model, H08. The H08 model can simulate water requirements on a daily basis at a resolution of 1.0° × 1.0° latitude and longitude. The sources of irrigation water requirements in the past simulations were specified using four categories: rivers (RIV), large reservoirs (LR) with a storage capacity greater than 1.0 × 109 m3, medium-size reservoirs (MSR) with storage capacities ranging from 1.0 × 109 m3 to 3.0 × 106 m3, and non-local non-renewable blue water (NNBW). The simulated results from 1960 to 2001 showed that RIV, MSR and NNBW increased significantly from the 1960s to the early 1990s globally, but LR increased at a relatively low rate. After the early 1990s, the increase in RIV declined as it approached a critical limit, due to the continued expansion of irrigation area. MSR and NNBW increased significantly, during the same time period, following the expansion of the irrigation area and the increased storage capacity of the medium-size reservoirs. We also estimated future irrigation water requirements from the above four water supply sources and an additional water supply source (ADD) in three future simulation designs; irrigation area change, climate change, and changes in both irrigation area and climate. ADD was defined as a future increase in NNBW. After the 2020s, MSR was predicted to approach the critical limit, and ADD would account for 11-23% of the total requirements in the 2040s.

  10. Modelling regional variability of irrigation requirements due to climate change in Northern Germany.

    PubMed

    Riediger, Jan; Breckling, Broder; Svoboda, Nikolai; Schröder, Winfried

    2016-01-15

    The question whether global climate change invalidates the efficiency of established land use practice cannot be answered without systemic considerations on a region specific basis. In this context plant water availability and irrigation requirements, respectively, were investigated in Northern Germany. The regions under investigation--Diepholz, Uelzen, Fläming and Oder-Spree--represent a climatic gradient with increasing continentality from West to East. Besides regional climatic variation and climate change, soil conditions and crop management differ on the regional scale. In the model regions, temporal seasonal droughts influence crop success already today, but on different levels of intensity depending mainly on climate conditions. By linking soil water holding capacities, crop management data and calculations of evapotranspiration and precipitation from the climate change scenario RCP 8.5 irrigation requirements for maintaining crop productivity were estimated for the years 1991 to 2070. Results suggest that water requirement for crop irrigation is likely to increase with considerable regional variation. For some of the regions, irrigation requirements might increase to such an extent that the established regional agricultural practice might be hard to retain. Where water availability is limited, agricultural practice, like management and cultivated crop spectrum, has to be changed to deal with the new challenges. PMID:26410707

  11. Estimating Health Services Requirements

    NASA Technical Reports Server (NTRS)

    Alexander, H. M.

    1985-01-01

    In computer program NOROCA populations statistics from National Center for Health Statistics used with computational procedure to estimate health service utilization rates, physician demands (by specialty) and hospital bed demands (by type of service). Computational procedure applicable to health service area of any size and even used to estimate statewide demands for health services.

  12. A remote sensing approach for estimating the location and rate of urban irrigation in semi-arid climates

    USGS Publications Warehouse

    Johnson, Tyler D.; Belitz, Kenneth

    2012-01-01

    Urban irrigation is an important component of the hydrologic cycle in many areas of the arid and semiarid western United States. This paper describes a new approach that uses readily available datasets to estimate the location and rate of urban irrigation. The approach provides a repeatable methodology at 1/3 km2 resolution across a large urbanized area (500 km2). For this study, Landsat Thematic Mapper satellite imagery, air photos, climatic records, and a land-use map were used to: (1) identify the fraction of irrigated landscaping in urban areas, and (2) estimate the monthly rate of irrigation being applied to those areas. The area chosen for this study was the San Fernando Valley in Southern California. Identifying irrigated areas involved the use of 29 satellite images, air photos, and a land-use map. The fraction of a pixel that consists of irrigated landscaping (Firr) was estimated using a linear-mixture model of two land-cover endmembers (selected pixels within a satellite image that represent a targeted land-cover). The two endmembers were impervious and fully-irrigated landscaping. In the San Fernando Valley, we used airport buildings, runways, and pavement to represent the impervious endmember; golf courses and parks were used to represent the fully irrigated endmember. The average Firr using all 29 satellite scenes was 44%. Firr calculated from hand-digitizing using air photos for 13 randomly selected single-family-residential neighborhoods showed similar results (42%). Estimating the rate of irrigation required identification of a third endmember: areas that consisted of urban vegetation but were not irrigated. This "nonirrigated" endmember was used to compute a Normalized Difference Vegetation Index (NDVI) surplus, defined as the difference between the NDVI signals of the irrigated and nonirrigated endmembers. The NDVI signals from irrigated areas remains relatively constant throughout the year, whereas the signal from nonirrigated areas rises and

  13. A remote sensing approach for estimating the location and rate of urban irrigation in semi-arid climates

    USGS Publications Warehouse

    Johnson, T.D.; Belitz, K.

    2012-01-01

    Urban irrigation is an important component of the hydrologic cycle in many areas of the arid and semiarid western United States. This paper describes a new approach that uses readily available datasets to estimate the location and rate of urban irrigation. The approach provides a repeatable methodology at 1/3km 2 resolution across a large urbanized area (500km 2). For this study, Landsat Thematic Mapper satellite imagery, air photos, climatic records, and a land-use map were used to: (1) identify the fraction of irrigated landscaping in urban areas, and (2) estimate the monthly rate of irrigation being applied to those areas. The area chosen for this study was the San Fernando Valley in Southern California.Identifying irrigated areas involved the use of 29 satellite images, air photos, and a land-use map. The fraction of a pixel that consists of irrigated landscaping (F irr) was estimated using a linear-mixture model of two land-cover endmembers (selected pixels within a satellite image that represent a targeted land-cover). The two endmembers were impervious and fully-irrigated landscaping. In the San Fernando Valley, we used airport buildings, runways, and pavement to represent the impervious endmember; golf courses and parks were used to represent the fully irrigated endmember. The average F irr using all 29 satellite scenes was 44%. F irr calculated from hand-digitizing using air photos for 13 randomly selected single-family-residential neighborhoods showed similar results (42%).Estimating the rate of irrigation required identification of a third endmember: areas that consisted of urban vegetation but were not irrigated. This " nonirrigated" endmember was used to compute a Normalized Difference Vegetation Index (NDVI) surplus, defined as the difference between the NDVI signals of the irrigated and nonirrigated endmembers. The NDVI signals from irrigated areas remains relatively constant throughout the year, whereas the signal from nonirrigated areas rises and

  14. A remote sensing approach for estimating the location and rate of urban irrigation in semi-arid climates

    NASA Astrophysics Data System (ADS)

    Johnson, Tyler D.; Belitz, Kenneth

    2012-01-01

    SummaryUrban irrigation is an important component of the hydrologic cycle in many areas of the arid and semiarid western United States. This paper describes a new approach that uses readily available datasets to estimate the location and rate of urban irrigation. The approach provides a repeatable methodology at 1/3 km 2 resolution across a large urbanized area (500 km 2). For this study, Landsat Thematic Mapper satellite imagery, air photos, climatic records, and a land-use map were used to: (1) identify the fraction of irrigated landscaping in urban areas, and (2) estimate the monthly rate of irrigation being applied to those areas. The area chosen for this study was the San Fernando Valley in Southern California. Identifying irrigated areas involved the use of 29 satellite images, air photos, and a land-use map. The fraction of a pixel that consists of irrigated landscaping ( F irr) was estimated using a linear-mixture model of two land-cover endmembers (selected pixels within a satellite image that represent a targeted land-cover). The two endmembers were impervious and fully-irrigated landscaping. In the San Fernando Valley, we used airport buildings, runways, and pavement to represent the impervious endmember; golf courses and parks were used to represent the fully irrigated endmember. The average F irr using all 29 satellite scenes was 44%. F irr calculated from hand-digitizing using air photos for 13 randomly selected single-family-residential neighborhoods showed similar results (42%). Estimating the rate of irrigation required identification of a third endmember: areas that consisted of urban vegetation but were not irrigated. This "nonirrigated" endmember was used to compute a Normalized Difference Vegetation Index (NDVI) surplus, defined as the difference between the NDVI signals of the irrigated and nonirrigated endmembers. The NDVI signals from irrigated areas remains relatively constant throughout the year, whereas the signal from nonirrigated areas

  15. HYDRUS-1D Modeling of an Irrigated Agricultural Plot with Application to Aquifer Recharge Estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variety of methods are available for estimating aquifer recharge in semi-arid regions, each with advantages and disadvantages. We are investigating a procedure for estimating recharge in an irrigated basin. The method involves computing irrigation return flows based on HYDRUS-1D modeling of root z...

  16. Quickbird satellite versus ground-based multi-spectral data for estimating nitrogen status of irrigated maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In-season nitrogen (N) management of irrigated maize (Zea mays L.) requires frequent acquisition of plant N status estimates to timely assess the onset of crop N deficiency and its spatial variability within a field. This study compared ground-based Exotech nadir-view sensor data and QuickBird satel...

  17. Toward physically based estimation of surface irrigation infiltration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation practitioners continue to use empirical infiltration equations. Theoretical infiltration equations are currently not capable of capturing surface irrigation infiltration behaviour, particularly at short times. An example is shown where the Green-Ampt equation can be adjusted to match fiel...

  18. Deficit Irrigated Corn Evapotranspiration Estimates Using Canopy Temperature Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainability of irrigated agriculture with declining water supplies is a primary agricultural issue in the US Great Plains. Consequently, the paradigm of maximizing production through full irrigation must be abandoned. Imposing water deficits on crops during non-critical growth periods must be i...

  19. Using Cotton Model Simulations to Estimate Optimally Profitable Irrigation Strategies

    NASA Astrophysics Data System (ADS)

    Mauget, S. A.; Leiker, G.; Sapkota, P.; Johnson, J.; Maas, S.

    2011-12-01

    In recent decades irrigation pumping from the Ogallala Aquifer has led to declines in saturated thickness that have not been compensated for by natural recharge, which has led to questions about the long-term viability of agriculture in the cotton producing areas of west Texas. Adopting irrigation management strategies that optimize profitability while reducing irrigation waste is one way of conserving the aquifer's water resource. Here, a database of modeled cotton yields generated under drip and center pivot irrigated and dryland production scenarios is used in a stochastic dominance analysis that identifies such strategies under varying commodity price and pumping cost conditions. This database and analysis approach will serve as the foundation for a web-based decision support tool that will help producers identify optimal irrigation treatments under specified cotton price, electricity cost, and depth to water table conditions.

  20. Estimating phreatic evaporation in irrigated areas using a stable isotope approach

    NASA Astrophysics Data System (ADS)

    Barthold, F. K.; Umirzakov, G.; Schneider, K.; Stulina, G.; Frede, H.; Breuer, L.

    2011-12-01

    Central Asia is characterized by continental arid climate conditions. Mean annual precipitation is 170 mm with a potential evapotranspiration rate of 1200 mm/a. In addition, many regions are affected by a non-sustainable use of the water resources. 90% of the water resources are used for irrigation purposes to grow e.g. cotton and wheat, especially in Uzbekistan. Large amounts of water are needed for cotton growth. Not only does the plant itself require large amounts of water but a substantial part of the water use is ascribed to the inefficient irrigation system and management. The irrigation infrastructure is old and not maintained well and irrigation management is inadequate. Groundwater level rise has been observed in irrigated areas as a result of the inefficient irrigation practices. Capillary raised groundwater is particularly prone to evaporation as it gets closer to the soil surface. The general objective of this study is to quantify the amount of groundwater (or phreatic) evaporation that is due to groundwater table rise on irrigated fields. In this study, we present an approach where we are using stable isotopes of water to estimate phreatic evaporation on irrigated fields. Our specific objective is to estimate phreatic evaporation (Ep) in relation to the groundwater level and varying soil types (sandy, loamy and clay loamy). We chose a stable water isotopes approach to estimate Ep. For this purpose, soil samples along a depth profile were sampled on sites with different groundwater levels and soil types. Samples were taken in 10 cm increments down to the groundwater level. Soil water was extracted using a cryogenic vacuum distillation and the extracted soil water was analyzed for its composition of stable water isotopes, δD and δ18O, using a Liquid Water Isotope Analyzer (Los Gatos Research, Inc.). Ep was calculated by fitting an exponential function to the experimental isotope soil profile. Our results show that in sandy and loamy soils, enrichment

  1. Improving N and P estimates for swine manure lagoon irrigation water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient management plans (NMPs) for confined animal feeding operations (CAFOs) require a record of N and P loads from manure land-applications, including irrigation with lagoon water. Mississippi regulations require nutrient records for lagoon irrigation water be based on at least one annual analy...

  2. An application of METRIC to estimate evapotranspiration of red pepper under four different irrigation levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the METRIC model was used to estimate evapotranspiration (ET) of red pepper under fully irrigated and water stress conditions, in the semi-humid Bafra Plains located in northern Turkey. Field experiments were conducted under four different irrigation levels for red pepper from rainfed...

  3. Drainage estimation to aquifer and water use irrigation efficiency in semi-arid zone for a long period of time

    NASA Astrophysics Data System (ADS)

    Jiménez-Martínez, J.; Molinero-Huguet, J.; Candela, L.

    2009-04-01

    Water requirements for different crop types according to soil type and climate conditions play not only an important role in agricultural efficiency production, though also for water resources management and control of pollutants in drainage water. The key issue to attain these objectives is the irrigation efficiency. Application of computer codes for irrigation simulation constitutes a fast and inexpensive approach to study optimal agricultural management practices. To simulate daily water balance in the soil, vadose zone and aquifer the VisualBALAN V. 2.0 code was applied to an experimental area under irrigation characterized by its aridity. The test was carried out in three experimental plots for annual row crops (lettuce and melon), perennial vegetables (artichoke), and fruit trees (citrus) under common agricultural practices in open air for October 1999-September 2008. Drip irrigation was applied to crops production due to the scarcity of water resources and the need for water conservation. Water level change was monitored in the top unconfined aquifer for each experimental plot. Results of water balance modelling show a good agreement between observed and estimated water level values. For the study period, mean drainage obtained values were 343 mm, 261 mm and 205 mm for lettuce and melon, artichoke and citrus respectively. Assessment of water use efficiency was based on the IE indicator proposed by the ASCE Task Committee. For the modelled period, water use efficiency was estimated as 73, 71 and 78 % of the applied dose (irrigation + precipitation) for lettuce and melon, artichoke and citrus, respectively.

  4. Improving estimates of N and P loads in irrigation water from swine manure lagoons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The implementation of nutrient management plans (NMPs) for confined animal feeding operations (CAFOs) requires recording N and P loads from land-applied manure, including nutrients applied in irrigation water from manure treatment lagoons. By regulation, lagoon irrigation water nutrient records in ...

  5. ESTIMATING THE COST OF DELAYING IRRIGATION FOR MIDSOUTH COTTON ON CLAY SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many years, cotton producers in the Midsouth delay the first irrigation to allow time for other operations such as pesticide and fertilizer application. The problem is especially common on clay soils that require several days to dry after furrow irrigation. However, the cost to the producer of de...

  6. Advances in Estimation of Parameters for Surface Irrigation Modeling and Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mathematical models of the surface irrigation process are becoming standard tools for analyzing the performance of irrigation systems and developing design and operational recommendations. A continuing challenge to the practical use of these tools is the difficulty in characterizing required model ...

  7. Estimated Yield of Some Alternative Crops Under Varying Irrigation in Northeast Colorado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much of the irrigated acres in northeastern Colorado are devoted to corn grain production. Diversifying irrigated agricultural production in this region could result in water savings if alternative crops were grown that have lower water requirements than corn. Making such crop choice decisions initi...

  8. Gaussian processes-based predictive models to estimate reference ET from alternative meteorological data sources for irrigation scheduling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate estimates of daily crop evapotranspiration (ET) are needed for efficient irrigation management, especially in arid and semi-arid irrigated regions where crop water demand exceeds rainfall. The impact of inaccurate ET estimates can be tremendous in both irrigation cost and the increased dema...

  9. Projected irrigation requirements for upland crops using soil moisture model under climate change in South Korea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An increase in abnormal climate change patterns and unsustainable irrigation in uplands cause drought and affect agricultural water security, crop productivity, and price fluctuations. In this study, we developed a soil moisture model to project irrigation requirements (IR) for upland crops under cl...

  10. Simulation of temporal and spatial distribution of required irrigation water by crop models and the pan evaporation coefficient method

    NASA Astrophysics Data System (ADS)

    Yang, Yan-min; Yang, Yonghui; Han, Shu-min; Hu, Yu-kun

    2009-07-01

    Hebei Plain is the most important agricultural belt in North China. Intensive irrigation, low and uneven precipitation have led to severe water shortage on the plain. This study is an attempt to resolve this crucial issue of water shortage for sustainable agricultural production and water resources management. The paper models distributed regional irrigation requirement for a range of cultivated crops on the plain. Classic crop models like DSSAT- wheat/maize and COTTON2K are used in combination with pan-evaporation coefficient method to estimate water requirements for wheat, corn, cotton, fruit-trees and vegetables. The approach is more accurate than the static approach adopted in previous studies. This is because the combination use of crop models and pan-evaporation coefficient method dynamically accounts for irrigation requirement at different growth stages of crops, agronomic practices, and field and climatic conditions. The simulation results show increasing Required Irrigation Amount (RIA) with time. RIA ranges from 5.08×109 m3 to 14.42×109 m3 for the period 1986~2006, with an annual average of 10.6×109 m3. Percent average water use by wheat, fruit trees, vegetable, corn and cotton is 41%, 12%, 12%, 11%, 7% and 17% respectively. RIA for April and May (the period with the highest irrigation water use) is 1.78×109 m3 and 2.41×109 m3 respectively. The counties in the piedmont regions of Mount Taihang have high RIA while the central and eastern regions/counties have low irrigation requirement.

  11. Probabilistic description of crop development and irrigation water requirements with stochastic rainfall

    NASA Astrophysics Data System (ADS)

    Vico, Giulia; Porporato, Amilcare

    2013-03-01

    Supplemental irrigation represents one of the main strategies to mitigate the effects of climatic variability on agroecosystems, stabilizing yields and profits. Because of the significant investments and water requirements associated with irrigation, strategic choices are needed to preserve productivity and profitability while ensuring a sustainable water management, a nontrivial task given rainfall unpredictability. Decision-making under uncertainty requires the knowledge of the probability density function (pdf) of the outcome variable (yield and economic return) for the different management alternatives to be considered (here, irrigation strategies). A stochastic framework is proposed, linking probabilistically the occurrence of rainfall events and irrigation applications to crop development during the growing season. Based on these linkages, the pdf of yields and the corresponding irrigation requirements are obtained analytically as a function of climate, soil, and crop parameters, for different irrigation strategies and both unlimited and limited water availability. Approximate expressions are also presented to facilitate their application. Our results employ relatively few parameters and are thus broadly applicable to different crops and sites, under current- and future-climate scenarios, offering a quantitative tool to quantify the impact of irrigation strategies and water allocation on yields. As a tool for decision-making under uncertainty (e.g., via expected utility theory), our framework will be useful for the assessment of the feasibility of different irrigation strategies and water allocations, toward a sustainable management of water resources for human and environmental needs.

  12. Simultaneous soil moisture and properties estimation for a drip irrigated field by assimilating cosmic-ray neutron intensity

    NASA Astrophysics Data System (ADS)

    Han, Xujun; Hendricks Franssen, Harrie-Jan; Jiménez Bello, Miguel Ángel; Rosolem, Rafael; Bogena, Heye; Alzamora, Fernando Martínez; Chanzy, André; Vereecken, Harry

    2016-08-01

    Neutron intensity measured by the aboveground cosmic-ray neutron intensity probe (CRP) allows estimating soil moisture content at the field scale. In this work, synthetic neutron intensities were used to remove the bias of simulated soil moisture content or update soil hydraulic properties (together with soil moisture) in the Community Land Model (CLM) using the Local Ensemble Transform Kalman Filter. The cosmic-ray forward model COSMIC was used as the non-linear measurement operator which maps between neutron intensity and soil moisture. The novel aspect of this work is that synthetically measured neutron intensity was used for real time updating of soil states and soil properties (or soil moisture bias) and posterior use for the real time scheduling of irrigation (data assimilation based real-time control approach). Uncertainty of model forcing and soil properties (sand fraction, clay fraction and organic matter density) were considered in the ensemble predictions of the soil moisture profiles. Horizontal and vertical weighting of soil moisture was introduced in the data assimilation in order to handle the scale mismatch between the cosmic-ray footprint and the CLM grid cell. The approach was illustrated in a synthetic study with the real-time irrigation scheduling of fields of citrus trees. After adjusting soil moisture content by assimilating neutron intensity, the irrigation requirements were calculated based on the water deficit method. Model bias was introduced by using coarser soil texture in the data assimilation experiments than in reality. A series of experiments was done with different combinations of state, parameter and bias estimation in combination with irrigation scheduling. Assimilation of CRP neutron intensity improved soil moisture characterization. Irrigation requirement was overestimated if biased soil properties were used. The soil moisture bias was reduced by 35% after data assimilation. The scenario of joint state-parameter estimation

  13. [Spatial and temporal characteristics of flue-cured tobacco water requirement and irrigation requirement index in Yunnan Province, China].

    PubMed

    Zheng, Dong-fang; Xu, Jia-yang; Lu, Xiu-ping; Xu, Zi-cheng; Li, Jun-ying; Pang, Tao; Zhang, Ya-jie; Wang, Pei-wen

    2015-07-01

    Based on the daily meteorological data of 124 agricultural meteorological sites during 1977-2010 in Yunnan Province, using recommended Penman-Monteith formula by FAO, water requirement and irrigation requirement index in the growth period of flue-cured tobacco were calculated to analyze their spatial and temporal characteristics and change patterns. The results showed that water requirements of flue-cured tobacco in root extending, vigorous, mature periods and field growth period during 1977-2010 were 76.73-174.73, 247.50-386.64, 180.28-258.14 and 528.18-764.08 mm, respectively, and the water requirement of vigorous period was the highest. The average irrigation demand index of each period was -0.02, 0.38, 0.17 and 0.26, respectively. Effective precipitation could meet the demand of flue-cured tobacco in root extending period. Water requirement of flue-cured tobacco in Yunnan Province decreased annually, and the rates of water requirement under the climate change trend in the four periods abovementioned were -12. 42, -21.46, -7.17 and -47.15 mm . (10 a)-1, respectively. The smallest irrigation demand index was observed in Dehong, and the largest in Diqing. The irrigation demand indexes of Dehong, Xishuangbanna and Puer regions were negative in flue-cured tobacco field growth period. The reference crop evapotranspiration, water requirement and effective precipitation decreased, but the irrigation requirement and irrigation requirement index increased with the increase of latitude. The effective precipitation decreased, but the irrigation requirement and irrigation requirement index increased with the increase of altitude. PMID:26710637

  14. Water and nitrogen requirements of subsurface drip irrigated pomegranate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface drip irrigation is a well-developed practice for both annual and perennial crops. The use of subsurface drip is a well-established practice in many annual row crops, e.g. tomatoes, strawberries, lettuce. However, the use of subsurface drip on perennial crops has been slow to develop. With th...

  15. A Coupled Remote Sensing and Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration from Irrigated Fields

    PubMed Central

    Senay, Gabriel B.; Budde, Michael; Verdin, James P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250-m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  16. A coupled remote sensing and simplified surface energy balance approach to estimate actual evapotranspiration from irrigated fields

    USGS Publications Warehouse

    Senay, G.B.; Budde, M.; Verdin, J.P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  17. Estimated demand for agricultural water for irrigation use in New Jersey, 1990

    USGS Publications Warehouse

    Titus, E.O.; Clawges, R.M.; Qualls, C.L.

    1990-01-01

    As part of an effort to determine if an adequate supply of agricultural water for irrigation use will be available to farmers, the U.S. Geological Survey prepared preliminary estimates of demand for agricultural water for irrigation use for the year 1990 on the basis of six possible scenarios. These scenarios incorporate normal and drought climatic conditions and three alternative estimates of the total acreage of farmland that may be irrigated in 1990. Preliminary estimates of water demand based on soil-moisture deficits were made using methods for calculating climatic water budgets. These estimates ranged from 3.0 billion gal/growing season (May through September), under normal climatic conditions and a 2% annual decline in irrigated acreage since 1984, to 28. 9 billion gal/growing season, under drought conditions and a 2% annual increase in irrigated acreage since 1984. Preliminary estimates of water demand made for the 1986 growing season reasonably approximate reported water use for that period. (USGS)

  18. Impact of climate change on irrigation requirements in terms of groundwater resources

    NASA Astrophysics Data System (ADS)

    Zhou, Yu; Zwahlen, François; Wang, Yanxin; Li, Yilian

    2010-11-01

    Climate change affects not only water resources but also water demand for irrigation. A large proportion of the world’s agriculture depends on groundwater, especially in arid and semi-arid regions. In several regions, aquifer resources face depletion. Groundwater recharge has been viewed as a by-product of irrigation return flow, and with climate change, aquifer storage of such flow will be vital. A general review, for a broad-based audience, is given of work on global warming and groundwater resources, summarizing the methods used to analyze the climate change scenarios and the influence of these predicted changes on groundwater resources around the world (especially the impact on regional groundwater resources and irrigation requirements). Future challenges of adapting to climate change are also discussed. Such challenges include water-resources depletion, increasing irrigation demand, reduced crop yield, and groundwater salinization. The adaptation to and mitigation of these effects is also reported, including useful information for water-resources managers and the development of sustainable groundwater irrigation methods. Rescheduling irrigation according to the season, coordinating the groundwater resources and irrigation demand, developing more accurate and complete modeling prediction methods, and managing the irrigation facilities in different ways would all be considered, based on the particular cases.

  19. Evaluation of sampling methods used to estimate irrigation pumpage in Chase, Dundy, and Perkins counties, Nebraska

    USGS Publications Warehouse

    Heimes, F.J.; Luckey, R.R.; Stephens, D.M.

    1986-01-01

    Combining estimates of applied irrigation water, determined for selected sample sites, with information on irrigated acreage provides one alternative for developing areal estimates of groundwater pumpage for irrigation. The reliability of this approach was evaluated by comparing estimated pumpage with metered pumpage for two years for a three-county area in southwestern Nebraska. Meters on all irrigation wells in the three counties provided a complete data set for evaluation of equipment and comparison with pumpage estimates. Regression analyses were conducted on discharge, time-of-operation, and pumpage data collected at 52 irrigation sites in 1983 and at 57 irrigation sites in 1984 using data from inline flowmeters as the independent variable. The standard error of the estimate for regression analysis of discharge measurements made using a portable flowmeter was 6.8% of the mean discharge metered by inline flowmeters. The standard error of the estimate for regression analysis of time of operation determined from electric meters was 8.1% of the mean time of operation determined from in-line and 15.1% for engine-hour meters. Sampled pumpage, calculated by multiplying the average discharge obtained from the portable flowmeter by the time of operation obtained from energy or hour meters, was compared with metered pumpage from in-line flowmeters at sample sites. The standard error of the estimate for the regression analysis of sampled pumpage was 10.3% of the mean of the metered pumpage for 1983 and 1984 combined. The difference in the mean of the sampled pumpage and the mean of the metered pumpage was only 1.8% for 1983 and 2.3% for 1984. Estimated pumpage, for each county and for the study area, was calculated by multiplying application (sampled pumpage divided by irrigated acreages at sample sites) by irrigated acreage compiled from Landsat (Land satellite) imagery. Estimated pumpage was compared with total metered pumpage for each county and the study area

  20. COMPARISON OF METHODS FOR ESTIMATING GROUND-WATER PUMPAGE FOR IRRIGATION.

    USGS Publications Warehouse

    Frenzel, Steven A.

    1985-01-01

    Ground-water pumpage for irrigation was measured at 32 sites on the eastern Snake River Plain in southern Idaho during 1983. Pumpage at these sites also was estimated by three commonly used methods, and pumpage estimates were compared to measured values to determine the accuracy of each estimate. Statistical comparisons of estimated and metered pumpage using an F-test showed that only estimates made using the instantaneous discharge method were not significantly different ( alpha equals 0. 01) from metered values. Pumpage estimates made using the power consumption method reflect variability in pumping efficiency among sites. Pumpage estimates made using the crop-consumptive use method reflect variability in water-management practices. Pumpage estimates made using the instantaneous discharge method reflect variability in discharges at each site during the irrigation season.

  1. Crop-specific seasonal estimates of irrigation-water demand in South Asia

    NASA Astrophysics Data System (ADS)

    Biemans, Hester; Siderius, Christian; Mishra, Ashok; Ahmad, Bashir

    2016-05-01

    Especially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight into these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent. This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation-water demand resulting from the typical practice of multiple cropping in South Asia was accounted for by introducing double cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest state-level statistics of India, Pakistan, Bangladesh and Nepal. The improvements in seasonal land use and cropping periods lead to lower estimates of irrigation-water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation-water demand differs sharply between seasons and regions; in Pakistan, winter (rabi) and monsoon summer (kharif) irrigation demands are almost equal, whereas in Bangladesh the rabi demand is ~ 100 times higher. Moreover, the relative importance of irrigation supply versus rain decreases sharply from west to east. Given the size and importance of South Asia improved regional estimates of food production and its irrigation-water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple cropping and monsoon-dependent planting dates should not be ignored.

  2. Crop-specific seasonal estimates of irrigation water demand in South Asia

    NASA Astrophysics Data System (ADS)

    Biemans, H.; Siderius, C.; Mishra, A.; Ahmad, B.

    2015-08-01

    Especially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight in these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent. This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation water demand resulting from the typical practice of multiple-cropping in South Asia was accounted for by introducing double-cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest subnational statistics of India, Pakistan, Bangladesh and Nepal. The representation of seasonal land use and more accurate cropping periods lead to lower estimates of irrigation water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation water demand differs sharply between seasons and regions; in Pakistan, winter (Rabi) and summer (Kharif) irrigation demands are almost equal, whereas in Bangladesh the Rabi demand is ~ 100 times higher. Moreover, the relative importance of irrigation supply vs. rain decreases sharply from west to east. Given the size and importance of South Asia, improved regional estimates of food production and its irrigation water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple-cropping and monsoon-dependent planting dates should not be ignored.

  3. Irrigation Trials for ET Estimation and Water Management in California Specialty Crops

    NASA Astrophysics Data System (ADS)

    Johnson, L.; Cahn, M.; Martin, F.; Lund, C.; Melton, F. S.

    2012-12-01

    Accurate estimation of crop evapotranspiration (ETc) can support efficient irrigation water management, which in turn brings benefits including surface water conservation, mitigation of groundwater depletion/degradation, energy savings, and crop quality assurance. Past research in California has revealed strong relationships between canopy fractional cover (Fc) and ETc of certain specialty crops, while additional research has shown the potential of monitoring Fc by satellite remote sensing. California's Central Coast is the leading region of cool season vegetable production in the U.S. Monterey County alone produces more than 80,000 ha of lettuce and broccoli (about half of U.S. production), valued at $1.5 billion in 2009. Under this study, we are conducting ongoing irrigation trials on these crops at the USDA Agricultural Research Station (Salinas) to compare irrigation scheduling via plant-based ETc approaches, by way of Fc, with current industry standard-practice. The following two monitoring approaches are being evaluated - 1) a remote sensing model employed by NASA's prototype Satellite Irrigation Management System, and 2) an online irrigation scheduling tool, CropManage, recently developed by U.C. Cooperative Extension. Both approaches utilize daily grass-reference ETo data as provided by the California Irrigation Management Irrigation System (CIMIS). A sensor network is deployed to monitor applied irrigation, volumetric soil water content, soil water potential, deep drainage, and standard meteorologic variables in order to derive ETc by a water balance approach. Evaluations of crop yield and crop quality are performed by the research team and by commercial growers. Initial results to-date indicate that applied water reductions based on Fc measurements are possible with little-to-no impact on yield of crisphead lettuce (Lactuca sativa). Additional results for both lettuce and broccoli trials, conducted during summer-fall 2012, are presented with respect to

  4. Heat as a Tracer for Estimation of Soil Drainage Following Irrigation Above a Tile Drain System

    NASA Astrophysics Data System (ADS)

    Callaghan, M. V.; Bentley, L. R.; Cey, E. E.

    2009-05-01

    Salt-affected soil is one of the most common environmental issues facing the petroleum hydrocarbon industry. Large quantities of brines are often co-produced with gas and oil and have been introduced into the environment through, for example, flare pits, drilling operations and pipe line breaks. Salt must be flushed from the soil and tile drain systems can be used to collect salt water which is then be routed for disposal. An accelerated remediation experiment by soil flushing over a 2 m deep tile drain system was monitored by tensiometers, and thermocouples. Water table elevation was monitored with pressure transducers. A 20 m by 20 m experimental plot was irrigated with 10 m3 of water on each of three consecutive days for an approximate total of 75 mm of water. The irrigation event was repeated three times over a period of 4 weeks. Due to a lack of access to the individual tile drains, direct measurement of drainage rates was not possible. One component of evaluating the success of the accelerated remediation experiment is the fraction of applied irrigation water that infiltrated to depth. Drainage rates beneath the irrigated plot were estimated by heat transport modeling using HYDRUS-1D, a numerical code for the solution of Richards unsaturated flow equation and the heat equation. Temperature and soil matric potential time series were recorded beneath the irrigated plot and at a control location at four depths, 0.3, 0.6, 1.0, and 1.5 m, at 15 minute intervals. Data was recorded for the duration of the irrigation period and for 8 weeks following. The temperature time series beneath the irrigated plot shows a broad increase relative to the control and shorter duration increases in direct response to the irrigation events. Heat modelling results are compared to field measurements.

  5. Estimating the ratio of pond size to irrigated soybeans land in Mississippi: A case study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although more on-farm storage ponds have been constructed in recent years to mitigate groundwater resources depletion in Mississippi, little effort has been devoted to estimating the ratio of pond size to irrigated crop land based on pond matric and its hydrological conditions. Knowledge of this ra...

  6. How irrigation affects soil erosion estimates of RUSLE2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RUSLE2 is a robust and computationally efficient conservation planning tool that estimates soil, climate, and land management effects on sheet and rill erosion and sediment delivery from hillslopes, and also estimates the size distribution and clay enrichment of sediment delivered to the channel sys...

  7. Establishing a method for estimating crop water requirements using the SEBAL method in Cyprus

    NASA Astrophysics Data System (ADS)

    Papadavid, G.; Toulios, L.; Hadjimitsis, D.; Kountios, G.

    2014-08-01

    Water allocation to crops has always been of great importance in agricultural process. In this context, and under the current conditions, where Cyprus is facing a severe drought the last five years, purpose of this study is basically to estimate the needed crop water requirements for supporting irrigation management and monitoring irrigation on a systematic basis for Cyprus using remote sensing techniques. The use of satellite images supported by ground measurements has provided quite accurate results. Intended purpose of this paper is to estimate the Evapotranspiration (ET) of specific crops which is the basis for irrigation scheduling and establish a procedure for monitoring and managing irrigation water over Cyprus, using remotely sensed data from Landsat TM/ ETM+ and a sound methodology used worldwide, the Surface Energy Balance Algorithm for Land (SEBAL). The methodology set in this paper refers to COST action ES1106 (Agri-Wat) for determining crop water requirements as part of the water footprint and virtual water-trade.

  8. Estimating spatio-temporal trends of urban irrigation extent and rate using SPOT 5 imagery in a Mediterranean climate city

    NASA Astrophysics Data System (ADS)

    Chen, Ying-Jung

    Urban irrigation is a crucial component that influences urban water use budgets, particularly in Mediterranean climate cities where water availability is limited during dry summers. The main function of urban irrigation is to maintain landscape vegetation greenness and growth. The objectives of this study were (1) to examine the relationships and distributions among urban vegetation greenness, irrigated areas, and irrigation rates within single-family residential (SFR) areas; and (2) to assess irrigation rates via landscape vegetation water demand to better understand trends of SFR water consumption. A time series of SPOT 5 satellite images (10-m resolution) was used to derive a Normalized Difference Vegetation Index (NDVI) thresholding approach for mapping irrigated areas in connection with monthly SFR water billing records for 2005-2007 in the City of Los Angeles, California. The water needs for landscape vegetation were estimated using a vegetation water demand model that included climate, vegetation, and irrigated areas variables. A water conservation ratio was calculated to elucidate the relationships between irrigation and vegetation water demand, and to assess spatio-temporal patterns of SFR outdoor water consumption. The lower vegetation greenness suggested that vegetation was enduring water-stress conditions even though estimated outdoor water consumption is typically highest in dry years. The distributions of irrigated areas, irrigation rates and vegetation greenness revealed distinct patterns of land lot sizes owned by SFR households within different areas. The results from the relationship between irrigation rates, vegetation water demand and vegetation greenness highlighted the potential applications of household irrigation systems and selection of landscape vegetation species. The irrigation rates were influenced by climate variability through different water years (i.e., precipitation and ETo). The water conservation ratio could also detect over-irrigation

  9. Remote sensing estimates of actual evapotranspiration in an irrigation district

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate estimates of the spatial distribution of actual evapotranspiration (AET) are useful in hydrology, but can be difficult to obtain. Remote sensing provides a potential capability for routinely monitoring AET by combining remotely sensed surface temperature and vegetation cover observations w...

  10. Propagation of biases in humidity in the estimation of global irrigation water

    NASA Astrophysics Data System (ADS)

    Masaki, Y.; Hanasaki, N.; Takahashi, K.; Hijioka, Y.

    2015-07-01

    Future projections on irrigation water under a changing climate are highly dependent on meteorological data derived from general circulation models (GCMs). Since climate projections include biases, bias correction is widely used to adjust meteorological elements, such as the atmospheric temperature and precipitation, but less attention has been paid to biases in humidity. Hence, in many cases, uncorrected humidity data have been directly used to analyze the impact of future climate change. In this study, we examined how the biases remaining in the humidity data of five GCMs propagate into the estimation of irrigation water demand and consumption from rivers using the global hydrological model (GHM) H08. First, to determine the effects of humidity bias across GCMs, we ran H08 with GCM-based meteorological forcing data sets distributed by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). A state-of-the-art bias correction method was applied to the data sets without correcting biases in humidity. Differences in the monthly relative humidity amounted to 11.7 to 20.4 % RH (percentage relative humidity) across the GCMs and propagated into differences in the estimated irrigation water demand, resulting in a range between 1152.6 and 1435.5 km3 yr-1 for 1971-2000. Differences in humidity also propagated into future projections. Second, sensitivity analysis with hypothetical humidity biases of ±5 % RH added homogeneously worldwide revealed the large negative sensitivity of irrigation water abstraction in India and East China, which are heavily irrigated. Third, we performed another set of simulations with bias-corrected humidity data to examine whether bias correction of the humidity can reduce uncertainties in irrigation water across the GCMs. The results showed that bias correction, even with a primitive methodology that only adjusts the monthly climatological relative humidity, helped reduce uncertainties across the GCMs: by using bias-corrected humidity

  11. Using Satellite-based Evapotranspiration Estimation to Characterize Agricultural Irrigation Water Use

    NASA Astrophysics Data System (ADS)

    Zheng, B.; Myint, S. W.; Hendrickx, J. M. H.

    2014-12-01

    The satellite-based evapotranspiration (ET) model permits estimation of water consumption across space and time in a systematic way. Developing tools to monitor water availability and water use is critical to meet future water shortage challenges in the American West. This study applied METRIC (Mapping Evapotranspiration at high Resolution and with Internalized Calibration) to 2001 Landsat imagery to estimate ET of various crop types in Phoenix. The total annual ET estimates are correlated well with the actual water use at the irrigation district level (r=0.99). We further incorporated a crop type map to estimate annual ET for the major crop types in the region, and to examine variability in crop water use among different irrigation districts. Our results show that alfalfa and double crops consume more water than other crop types with mean annual ET estimations of 1300 to 1580 mm/year, and that cotton uses more water (1162 mm/year) than corn (838 mm/year) and sorghum (829 mm/year) as expected. Crop water use varies from one irrigation district to another due to differences in soil quality, water quality, and farming practices. Results from our study suggest that the ET maps derived from METRIC can be used to quantify the spatial distribution of ET and to characterize agricultural water use by crop types at different spatial scales.

  12. Evaluation and comparison of methods to estimate irrigation withdrawal for the National Water Census Focus Area Study of the Apalachicola-Chattahoochee-Flint River Basin in southwestern Georgia

    USGS Publications Warehouse

    Painter, Jaime A.; Torak, Lynn J.; Jones, John W.

    2015-01-01

    Methods to estimate irrigation withdrawal using nationally available datasets and techniques that are transferable to other agricultural regions were evaluated by the U.S. Geological Survey as part of the Apalachicola-Chattahoochee-Flint (ACF) River Basin focus area study of the National Water Census (ACF–FAS). These methods investigated the spatial, temporal, and quantitative distributions of water withdrawal for irrigation in the southwestern Georgia region of the ACF–FAS, filling a vital need to inform science-based decisions regarding resource management and conservation. The crop– demand method assumed that only enough water is pumped onto a crop to satisfy the deficit between evapotranspiration and precipitation. A second method applied a geostatistical regimen of variography and conditional simulation to monthly metered irrigation withdrawal to estimate irrigation withdrawal where data do not exist. A third method analyzed Landsat satellite imagery using an automated approach to generate monthly estimates of irrigated lands. These methods were evaluated independently and compared collectively with measured water withdrawal information available in the Georgia part of the ACF–FAS, principally in the Chattahoochee-Flint River Basin. An assessment of each method’s contribution to the National Water Census program was also made to identify transfer value of the methods to the national program and other water census studies. None of the three methods evaluated represent a turnkey process to estimate irrigation withdrawal on any spatial (local or regional) or temporal (monthly or annual) extent. Each method requires additional information on agricultural practices during the growing season to complete the withdrawal estimation process. Spatial and temporal limitations inherent in identifying irrigated acres during the growing season, and in designing spatially and temporally representative monitor (meter) networks, can belie the ability of the methods to

  13. Evaluation of Irrigation Methods for Highbush Blueberry. I. Growth and Water Requirements of Young Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted in a new field of northern highbush blueberry (Vaccinium corymbosum L. 'Elliott') to determine the effects of different irrigation methods on growth and water requirements of uncropped plants during the first 2 years after planting. The plants were grown on mulched, raised beds...

  14. Simulating Irrigation Requirements And Water Withdrawals: The Role Of Agricultural Irrigation In Basin Hydrology And Non-Sustainable Water Use

    NASA Astrophysics Data System (ADS)

    Wisser, D.; Douglas, E. M.; Schumann, A. H.; Vörösmarty, C. J.

    2006-05-01

    The development of irrigation can cause drastic alterations of the water cycle both through changed evaporation patterns, water abstractions, and (in the case of paddy rice), increased percolation rates. The interactions of irrigation development and large-scale water cycles have traditionally not been accounted for in macroscale hydrological models. We use a modified version an existing water balance model (the WBM model) to explicitly consider the effects of irrigation on regional and continental water cycles. The irrigation module is based on the FAO-CROPWAT approach and uses a daily soil moisture balance to simulate crop consumptive water use. Time series of irrigated areas and the distribution of crops and cropping patterns are derived from a combination of remotely sensed data and national and sub-national statistics. An assessment is made of (1) how irrigation water is supplied and (2) how much of this water is abstracted in excess of the renewable water supply in the basin considering different time horizons. Using different scenarios of water availability and irrigation water demand, the response of irrigation water use to water supply and the potential threats to food security are investigated. Case studies in a few river basins that are heavily influenced by irrigated agriculture and that represent different regions of the world will be presented.

  15. Propagation of biases in humidity in the estimation of global irrigational water

    NASA Astrophysics Data System (ADS)

    Masaki, Y.; Hanasaki, N.; Takahashi, K.; Hijioka, Y.

    2015-01-01

    Future projections on irrigational water under a changing climate are highly dependent on meteorological data derived from general circulation models (GCMs). Since climate projections include biases, bias correction is widely used to adjust meteorological elements, such as the atmospheric temperature and precipitation, but less attention has been paid to biases in humidity. Hence, in many cases, raw GCM outputs have been directly used to analyze the impact of future climate change. In this study, we examined how the biases remaining in the humidity data of five GCMs propagate into the estimation of irrigational water demand and abstraction from rivers using the global hydrological model (GHM) H08. First, to determine the effects of humidity bias across GCMs, we used meteorological data sets to which a state-of-the-art bias correction method was applied except to the humidity. Uncorrected GCM outputs were used for the humidity. We found that differences in the monthly relative humidity of 11.7 to 20.4% RH (percent used as the unit of relative humidity) from observations across the GCMs caused the estimated irrigational water abstraction from rivers to range between 1217.7 and 1341.3 km3 yr-1 for 1971-2000. Differences in humidity also propagate into future projections. Second, sensitivity analysis with hypothetical humidity biases of ±5% RH added homogeneously worldwide revealed the large negative sensitivity of irrigational water abstraction in India and East China, which have high areal fractions of irrigated cropland. Third, we performed another set of simulations with bias-corrected humidity data to examine whether bias correction of the humidity can reduce uncertainties in irrigational water across the GCMs. The results showed that bias correction, even with a primitive methodology that only adjusts the monthly climatological relative humidity, helped reduce uncertainties across the GCMs. Although the GHMs have different sensitivities to atmospheric humidity

  16. Use of Dehydrated Agar to Estimate Microbial Water Quality for Horticulture Irrigation.

    PubMed

    Meador, Dustin P; Fisher, Paul R; Guy, Charles L; Harmon, Philip F; Peres, Natalia A; Teplitski, Max

    2016-07-01

    Petrifilms are dehydrated agar culture plates that have been used to quantify colony forming units (CFU) mL of either aerobic bacteria (Petrifilm-AC) or fungus (Petrifilm-YM), depending on substrate composition. Microbes in irrigation systems can indicate biofilm risk and potential clogging of irrigation emitters. The research objective was to compare counts on Petrifilms versus traditional, hydrated-agar plates using samples collected from recirculated irrigation waters and cultures of isolated known species. The estimated count (in CFU mL) from a recirculated irrigation sample after 7 d of incubation on Petrifilm-YM was only 5.5% of the count quantified using sabouraud dextrose agar (SDA) with chloramphenicol after 14 d. In a separate experiment with a known species, Petrifilm-YM did not successfully culture zoospores of . Isolates of viable zoospores were cultured successfully on potato-dextrose agar (PDA), with comparable counts with a vegetable juice medium supplemented with the antibiotics pimaricin, ampicillin, rifamycin, pentochloronitrobenzene and hymexazol (PARP-H). The quantification of pv. Begoniaceae on Petrifilm-AC was not significantly different ( < 0.05) than on PDA, but was lower than on Reasoner and Goldrich agar (R2A) or with a hemocytometer. The current formulation of Petrifilm-YM is unlikely to be a useful monitoring method for plant pathogens in irrigation water because of the inability to successfully culture oomycetes. However, Petrifilm-AC was an effective method to quantify bacteria and can provide an easy-to-use on-farm tool to monitor biofilm risk and microbial density. PMID:27380096

  17. Validation of an improved energy balance model to estimate actual evapotranspiration in irrigated cotton ecosystems of Central Asia

    NASA Astrophysics Data System (ADS)

    Knoefel, Patrick; Conrad, Christopher; Falk, Ulrike; Bauer-Marschallinger, Bernhard

    2014-05-01

    improved using the physically based method. While the empirical equation leads to RMSEs of 80 W/m² and r² of 0.09, the improved approach for G shows RMSE of about 35 W/m² and r² of 0.46. Whereat, the impact of the improvement in G estimation on the ET modelling is low due the relatively small proportion of G in the total energy balance, compared to the components Rn, H, and LE. For cotton, the seasonal actual ET varies between 500 mm in dry years and 750 mm in years with higher water availability. Hence, WUE is small compared to other irrigated cotton ecosystems with seasonal ET of about 400 mm. Considering the required amount of irrigation water for the entire area of the irrigation system of 10 mio. ha with a proportion of cotton of about 30%, illustrates the dimension of water diversion in CA. Thus, in the studied case only cotton disturbs the natural cycles by ET in the desert ecosystem. However, for an exact quantification transfer of this method into other irrigated systems of CA, regional meteorological observations are necessary.

  18. A field and statistical modeling study to estimate irrigation water use at Benchmark Farms study sites in southwestern Georgia, 1995-96

    USGS Publications Warehouse

    Fanning, Julia L.; Schwarz, Gregory E.; Lewis, William C.

    2001-01-01

    A benchmark irrigation monitoring network of farms located in a 32-county area in southwestern Georgia was established in 1995 to improve estimates of irrigation water use. A stratified random sample of 500 permitted irrigators was selected from a data base--maintained by the Georgia Department of Natural Resources, Georgia Environmental Protection Division, Water Resources Management Branch--to obtain 180 voluntary participants in the study area. Site-specific irrigation data were collected at each farm using running-time totalizers and noninvasive flowmeters. Data were collected and compiled for 50 farms for 1995 and 130 additional farms for the 1996 growing season--a total of 180 farms. Irrigation data collected during the 1996 growing season were compiled for 180 benchmark farms and used to develop a statistical model to estimate irrigation water use in 32 counties in southwestern Georgia. The estimates derived were developed from using a statistical approach know as ?bootstrap analysis? that allows for the estimation of precision. Five model components--whether-to-irrigate, acres irrigated, crop selected, seasonal-irrigation scheduling, and the amount of irrigation applied--compose the irrigation model and were developed to reflect patterns in the data collected at Benchmark Farms Study area sites. The model estimated that peak irrigation for all counties in the study area occurred during July with significant irrigation also occurring during May, June, and August. Irwin and Tift were the most irrigated and Schley and Houston were the least irrigated counties in the study area. High irrigation intensity primarily was located along the eastern border of the study area; whereas, low irrigation intensity was located in the southwestern quadrant where ground water was the dominant irrigation source. Crop-level estimates showed sizable variations across crops and considerable uncertainty for all crops other than peanuts and pecans. Counties having the most

  19. Estimating nitrogen losses in furrow irrigated soil amended by compost using HYDRUS-2D model

    NASA Astrophysics Data System (ADS)

    Iqbal, Shahid; Guber, Andrey; Zaman Khan, Haroon; ullah, Ehsan

    2014-05-01

    Furrow irrigation commonly results in high nitrogen (N) losses from soil profile via deep infiltration. Estimation of such losses and their reduction is not a trivial task because furrow irrigation creates highly nonuniform distribution of soil water that leads to preferential water and N fluxes in soil profile. Direct measurements of such fluxes are impractical. The objective of this study was to assess applicability of HYDRUS-2D model for estimating nitrogen balance in manure amended soil under furrow irrigation. Field experiments were conducted in a sandy loam soil amended by poultry manure compost (PMC) and pressmud compost (PrMC) fertilizers. The PMC and PrMC contained 2.5% and 0.9% N and were applied at 5 rates: 2, 4, 6, 8 and 10 ton/ha. Plots were irrigated starting from 26th day from planting using furrows with 1x1 ridge to furrow aspect ratio. Irrigation depths were 7.5 cm and time interval between irrigations varied from 8 to 15 days. Results of the field experiments showed that approximately the same corn yield was obtained with considerably higher N application rates using PMC than using PrMC as a fertilizer. HYDRUS-2D model was implemented to evaluate N fluxes in soil amended by PMC and PrMC fertilizers. Nitrogen exchange between two pools of organic N (compost and soil) and two pools of mineral N (soil NH4-N and soil NO3-N) was modeled using mineralization and nitrification reactions. Sources of mineral N losses from soil profile included denitrification, root N uptake and leaching with deep infiltration of water. HYDRUS-2D simulations showed that the observed increases in N root water uptake and corn yields associated with compost application could not be explained by the amount of N added to soil profile with the compost. Predicted N uptake by roots significantly underestimated the field data. Good agreement between simulated and field-estimated values of N root uptake was achieved when the rate of organic N mineralization was increased

  20. Health risks in wastewater irrigation: comparing estimates from quantitative microbial risk analyses and epidemiological studies.

    PubMed

    Mara, D D; Sleigh, P A; Blumenthal, U J; Carr, R M

    2007-03-01

    The combination of standard quantitative microbial risk analysis (QMRA) techniques and 10,000-trial Monte Carlo risk simulations was used to estimate the human health risks associated with the use of wastewater for unrestricted and restricted crop irrigation. A risk of rotavirus infection of 10(-2) per person per year (pppy) was used as the reference level of acceptable risk. Using the model scenario of involuntary soil ingestion for restricted irrigation, the risk of rotavirus infection is approximately 10(-2) pppy when the wastewater contains < or =10(6) Escherichia coli per 100ml and when local agricultural practices are highly mechanised. For labour-intensive agriculture the risk of rotavirus infection is approximately 10(-2) pppy when the wastewater contains < or = 10(5) E. coli per 100ml; however, the wastewater quality should be < or = 10(4) E. coli per 100ml when children under 15 are exposed. With the model scenario of lettuce consumption for unrestricted irrigation, the use of wastewaters containing < or =10(4) E. coli per 100ml results in a rotavirus infection risk of approximately 10(-2) pppy; however, again based on epidemiological evidence from Mexico, the current WHO guideline level of < or =1,000 E. coli per 100ml should be retained for root crops eaten raw. PMID:17402278

  1. Spatio-temporal estimation of consumptive water use for assessment of irrigation system performance and management of water resources in irrigated Indus Basin, Pakistan

    NASA Astrophysics Data System (ADS)

    Usman, M.; Liedl, R.; Awan, U. K.

    2015-06-01

    Reallocation of water resources in any irrigation scheme is only possible by detailed assessment of current irrigation performance. The performance of the Lower Chenab Canal (LCC) irrigation system in Pakistan was evaluated at large spatial and temporal scales. Evaporative Fraction (EF) representing the key element to assess the three very important performance indicators of equity, adequacy and reliability, was determined by the Surface Energy Balance Algorithm (SEBAL) using Moderate Resolution Imaging Spectroradiometer (MODIS) images. Spatially based estimations were performed at irrigation subdivisions, lower and upper LCC and, whole LCC scales, while temporal scales covered months, seasons and years for the study period from 2005 to 2012. Differences in consumptive water use between upper and lower LCC were estimated for different crops and possible water saving options were explored. The assessment of equitable water distribution indicates smaller coefficients of variation and hence less inequity within each subdivision except Sagar (0.08) and Bhagat (0.10). Both adequacy and reliability of water resources are found lower during kharif as compared to rabi with variation from head to tail reaches. Reliability is quite low from July to September and in February/March. This is mainly attributed to seasonal rainfalls. Average consumptive water use estimations indicate almost doubled water use (546 mm) in kharif as compared to (274 mm) in rabi with significant variability for different cropping years. Crop specific consumptive water use reveals rice and sugarcane as major water consumers with average values of 593 mm and 580 mm, respectively, for upper and lower LCC, followed by cotton and kharif fodder. The water uses for cotton are 555 mm and 528 mm. For kharif fodder, corresponding values are 525 mm and 494 mm for both regions. Based on the differences in consumptive water use, different land use land cover change scenarios were evaluated with regard to savings

  2. Use of landsat thematic mapper data to identify crop types and estimate irrigated acreage, Uvalde and Medina counties, Texas, 1991

    USGS Publications Warehouse

    Raymond, L.H.; McFarlane, S.I.

    1994-01-01

    Landsat Thematic Mapper (TM) data were used to estimate that about 51,000 acres of crops were irrigated with water pumped from the Edwards aquifer in Uvalde and Medina Counties, Texas in 1991. Areas calculated for irrigated crops were 31,000 acres for Uvalde County and 20,000 acres for Medina County. Quantities of water pumped from the Edwards aquifer to irrigate crops in 1991 were estimated as 65,000 acre-feet for Uvalde County and 18,000 acre-feet for Medina County. Differences in estimates of ground water used for irrigation in the two counties were attributed primarily to greater pre- cipitation in Medina County than in Uvalde County. The total number of acres of irrigated crops estimated using Landsat TM data was about 9 percent lower in Uvalde County and about 13 percent lower in Medina County than the number of acres calculated from data reported by the U.S. Department of Agriculture, Agricultural Stabilization and Conservation Service (ASCS). The total quantity of water pumped from the Edwards aquifer in 1991 for irrigation in the two counties, about 83,000 acre- feet, was about 5 percent greater developed than the quantity calculated from data reported by the ASCS.

  3. Minimum Irrigation Requirements for Cottonwood (Populus fremontii and P. deltoides) and Willow (Salix gooddingii) Grown in a Desert Environment

    NASA Astrophysics Data System (ADS)

    Glenn, E. P.; Hartwell, S.; Morino, K.; Nagler, P. L.

    2009-12-01

    Native tree plots have been established in riverine irrigation districts in the western U.S. to provide habitat for threatened and endangered birds. Information is needed on the minimum effective irrigation requirements of the target species. We summarize preliminary (or unpublished) findings of a study or cottonwood (Populus spp.) and willow (Salix gooddingii) trees that were grown for seven years in an outdoor plot in a desert environment in Tucson, Arizona to determine plant water use. Plants were allowed to achieve a nearly complete canopy cover over the first four years, then were subjected to three summer irrigation schedules: 6.2 mm d-1; 8.26 mm d-1 and 15.7 mm d-1. The lowest irrigation rate was sufficient to maintain growth and high leaf area index for cottonwoods over three years, but willows suffered partial die-back on this rate, and required 8.26 mm d-1 to maintain growth. These irrigation rates were required April 15 - September 15, but only 0.88 mm d-1 was required during the dormant periods of the year. Expressed as a fraction of reference crop evapotranspiration (ET/ETo), annual water requirements were 0.83 ETo for cottonwood and 1.01 ETo for willow, which includes irrigation plus precipitation. Current practices tend to over-irrigate restoration plots, and this study can provide guidelines for more efficient water use.

  4. Using FAO-56 model to estimate soil and crop water status: Application to a citrus orchard under regulated deficit irrigation

    NASA Astrophysics Data System (ADS)

    Provenzano, Giuseppe; Gonzàles-Altozano, Pablo; Manzano-Juàrez, Juan; Rallo, Giovanni

    2015-04-01

    Agro-hydrological models allow schematizing exchange processes in the soil-plant-atmosphere continuum (SPAC) on a wide range of spatial and temporal scales. Each section of the SPAC system is characterized by complex behaviours arising, for instance, the adaptive plant strategies in response to soil water deficit conditions. Regulated deficit irrigation (RDI) has been considered as one of the potential strategies for sustainable crop production in regions characterized by water scarcity. Moreover, reducing water supply at certain growth stages can improve water use efficiency (WUE) and quality of productions, without affecting significantly crop yield. Environmental policy requires to improve WUE in crops with high water requirements, so that it is necessary to identify easy-to-use tools aimed at irrigation water saving strategies, without the need of tedious and time consuming experiments. Accurate evaluation of crop water status and actual transpiration plays a key role in irrigation scheduling under RDI, in order to avoid that water stress becomes too severe and detrimental to yield and fruit quality. Objective of the research was to assess the suitability of FAO56 agro-hydrological model (Allen et al., 1998) on citrus orchards under different water deficit conditions, to estimate soil and crop water status. The ability of the model to predict actual crop water stress was evaluated based on the temporal dynamic of simulated relative transpirations and on the similarities with the corresponding dynamic of measured midday stem water potentials, MSWP. During dry periods, simulated relative crop transpiration was correlated to MSWP with the aim to assess the model ability to predict crop water stress and to identify "plant-based" irrigation scheduling parameters. Experiments were carried out during three years from 2009 and 2011 in Senyera (39° 3' 35.4" N, 0° 30' 28.2" W), Spain, in a commercial orchard planted with Navelina/Cleopatra citrus trees. Three RDI

  5. Irrigated rice area estimation using remote sensing techniques: Project's proposal and preliminary results. [Rio Grande do Sul, Brazil

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Deassuncao, G. V.; Moreira, M. A.; Novaes, R. A.

    1984-01-01

    The development of a methodology for annual estimates of irrigated rice crop in the State of Rio Grande do Sul, Brazil, using remote sensing techniques is proposed. The project involves interpretation, digital analysis, and sampling techniques of LANDSAT imagery. Results are discussed from a preliminary phase for identifying and evaluating irrigated rice crop areas in four counties of the State, for the crop year 1982/1983. This first phase involved just visual interpretation techniques of MSS/LANDSAT images.

  6. Combined estimation of specific yield and natural recharge in a semi-arid groundwater basin with irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Maréchal, J. C.; Dewandel, B.; Ahmed, S.; Galeazzi, L.; Zaidi, F. K.

    2006-09-01

    SummaryA water budget approach is developed to jointly estimate specific yield and natural recharge in an unconfined aquifer with significant seasonal water table fluctuations. Water table fluctuations are due to distinct seasonality in groundwater recharge. The separation of the hydrologic year into two (or more) extended seasons of recharge (wet season) and no-recharge (dry season) with accompanying changes in water table allows for a split use of the water table fluctuation (WTF) method, first to estimate specific yield from the water table drop during the dry season (no recharge) and, second, to estimate recharge from the water table rise during the wet season, after considering all other water budget components explicitly. The latter includes explicit computation of groundwater storage with the WTF method. The application of the WTF method requires a large number of water level measurements throughout the unconfined aquifer before and after each season. The advantage of the method is that specific yield and recharge are estimated at the scale of interest to basin hydrologic studies and that the method requires no extensive in situ instrumentation network. Here, the method is demonstrated through a case study in a fractured hard-rock aquifer subject to intensive groundwater pumping for irrigation purposes.

  7. Estimation of surface energy fluxes using surface renewal and flux variance techniques over an advective irrigated agricultural site

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation of surface energy fluxes over irrigated agriculture is needed to monitor crop water use. Estimates are commonly done using well-established techniques such as eddy covariance (EC) and weighing lysimetry, but implementing these to collect spatially distributed observations is complex and c...

  8. Estimability analysis for optimization of hysteretic soil hydraulic parameters using data of a field irrigation experiment

    NASA Astrophysics Data System (ADS)

    Ngo, Viet V.; Gerke, Horst H.; Badorreck, Annika

    2014-05-01

    The estimability analysis has been proposed to improve the quality of parameter optimization. For field data, wetting and drying processes may complicate optimization of soil hydraulic parameters. The objectives of this study were to apply estimability analysis for improving optimization of soil hydraulic parameters and compare models with and without considering hysteresis. Soil water pressure head data of a field irrigation experiment were used. The one-dimensional vertical water movement in variably-saturated soil was described with the Richards equation using the HYDRUS-1D code. Estimability of the unimodal van Genuchten - Mualem hydraulic model parameters as well as of the hysteretic parameter model of Parker and Lenhard was classified according to a sensitivity coefficient matrix. The matrix was obtained by sequentially calculating effects of initial parameter variations on changes in the simulated pressure head values. Optimization was carried out by means of the Levenberg-Marquardt method as implemented in the HYDRUS-1D code. The parameters α, Ks, θs, and n in the nonhysteretic model were found sensitive and parameter θs and n strongly correlated with parameter n in the nonhysteretic model. When assuming hysteresis, the estimability was highest for αw and decreased with soil depth for Ks and αd, and increased for θs and n. The hysteretic model could approximate the pressure heads in the soil by considering parameters from wetting and drying periods separately as initial estimates. The inverse optimization could be carried out more efficiently with most estimable parameters. Despite the weaknesses of the local optimization algorithm and the inflexibility of the unimodal van Genuchten model, the results suggested that estimability analysis could be considered as a guidance to better define the optimization scenarios and then improved the determination of soil hydraulic parameters.

  9. Use of thermal and visible imagery for estimating crop water status of irrigated grapevine.

    PubMed

    Möller, M; Alchanatis, V; Cohen, Y; Meron, M; Tsipris, J; Naor, A; Ostrovsky, V; Sprintsin, M; Cohen, S

    2007-01-01

    Achieving high quality wine grapes depends on the ability to maintain mild to moderate levels of water stress in the crop during the growing season. This study investigates the use of thermal imaging for monitoring water stress. Experiments were conducted on a wine-grape (Vitis vinifera cv. Merlot) vineyard in northern Israel. Irrigation treatments included mild, moderate, and severe stress. Thermal and visible (RGB) images of the crop were taken on four days at midday with a FLIR thermal imaging system and a digital camera, respectively, both mounted on a truck-crane 15 m above the canopy. Aluminium crosses were used to match visible and thermal images in post-processing and an artificial wet surface was used to estimate the reference wet temperature (T(wet)). Monitored crop parameters included stem water potential (Psi(stem)), leaf conductance (g(L)), and leaf area index (LAI). Meteorological parameters were measured at 2 m height. CWSI was highly correlated with g(L) and moderately correlated with Psi(stem). The CWSI-g(L) relationship was very stable throughout the season, but for that of CWSI-Psi(stem) both intercept and slope varied considerably. The latter presumably reflects the non-direct nature of the physiological relationship between CWSI and Psi(stem). The highest R(2) for the CWSI to g(L) relationship, 0.91 (n=12), was obtained when CWSI was computed using temperatures from the centre of the canopy, T(wet) from the artificial wet surface, and reference dry temperature from air temperature plus 5 degrees C. Using T(wet) calculated from the inverted Penman-Monteith equation and estimated from an artificially wetted part of the canopy also yielded crop water-stress estimates highly correlated with g(L) (R(2)=0.89 and 0.82, respectively), while a crop water-stress index using 'theoretical' reference temperatures computed from climate data showed significant deviations in the late season. Parameter variability and robustness of the different CWSI estimates

  10. Use of Sharpened Land Surface Temperature for Daily Evapotranspiration Estimation over Irrigated Crops in Arid Lands

    NASA Astrophysics Data System (ADS)

    Rosas Aguilar, J.; McCabe, M. F.; Houborg, R.; Gao, F.

    2014-12-01

    Satellite remote sensing provides data on land surface characteristics, useful for mapping land surface energy fluxes and evapotranspiration (ET). Land-surface temperature (LST) derived from thermal infrared (TIR) satellite data has been reliably used as a remote indicator of ET and surface moisture status. However, TIR imagery usually operates at a coarser resolution than that of shortwave sensors on the same satellite platform, making it sometimes unsuitable for monitoring of field-scale crop conditions. This study applies the data mining sharpener (DMS; Gao et al., 2012) technique to data from the Moderate Resolution Imaging Spectroradiometer (MODIS), which sharpens the 1 km thermal data down to the resolution of the optical data (250-500 m) based on functional LST and reflectance relationships established using a flexible regression tree approach. The DMS approach adopted here has been enhanced/refined for application over irrigated farming areas located in harsh desert environments in Saudi Arabia. The sharpened LST data is input to an integrated modeling system that uses the Atmosphere-Land Exchange Inverse (ALEXI) model and associated flux disaggregation scheme (DisALEXI) in conjunction with model reanalysis data and remotely sensed data from polar orbiting (MODIS) and geostationary (MSG; Meteosat Second Generation) satellite platforms to facilitate daily estimates of evapotranspiration. Results are evaluated against available flux tower observations over irrigated maize near Riyadh in Saudi Arabia. Successful monitoring of field-scale changes in surface fluxes are of importance towards an efficient water use in areas where fresh water resources are scarce and poorly monitored. Gao, F.; Kustas, W.P.; Anderson, M.C. A Data Mining Approach for Sharpening Thermal Satellite Imagery over Land. Remote Sens. 2012, 4, 3287-3319.

  11. Estimating the own-price elasticity of demand for irrigation water in the Musi catchment of India

    NASA Astrophysics Data System (ADS)

    Davidson, Brian; Hellegers, Petra

    2011-10-01

    SummaryAs irrigation water is an input into a production process, its demand must be 'derived'. According to theory, a derived demand schedule should be downward sloping and dependent on the outputs produced from it, the prices of other inputs and the price of the water itself. Problems arise when an attempt is made to estimate the demand for irrigation water and the resulting own-price elasticity of demand, as the uses to which water is put are spatially, temporarily and geographically diverse. Because water is not generally freely traded, what normally passes for an estimate of the own-price elasticity of demand for irrigation water is usually a well argued assumption or an estimate that is derived from a simulation model of a hypothesized producer. Such approaches tend to provide an inadequate explanation of what is an extremely complex and important relationship. An adequate explanation of the relationship between the price and the quantity demanded of water should be one that not only accords with the theoretical expectations, but also accounts for the diversity of products produced from water (which includes the management practices of farmers), the seasons in which it is used and over the region within which it is used. The objective in this article is to present a method of estimating the demand curve for irrigation water. The method uses actual field data which is collated using the Residual Method to determine the value of the marginal product of water deployed over a wide range of crops, seasons and regions. These values of the marginal products, all which must lie of the input demand schedule for water, are then ordered from the highest value to the lowest. Then, the amount of irrigation water used for each product, in each season and in each region is cumulatively summed over the range of uses according to the order of the values of the marginal products. This data, once ordered, is then used to econometrically estimate the demand schedule from which

  12. Estimates of deep percolation beneath native vegetation, irrigated fields, and the Amargosa-River Channel, Amargosa Desert, Nye County, Nevada

    USGS Publications Warehouse

    Stonestrom, David A.; Prudic, David E.; Laczniak, Randell J.; Akstin, Katherine C.; Boyd, Robert A.; Henkelman, Katherine K.

    2003-01-01

    The presence and approximate rates of deep percolation beneath areas of native vegetation, irrigated fields, and the Amargosa-River channel in the Amargosa Desert of southern Nevada were evaluated using the chloride mass-balance method and inferred downward velocities of chloride and nitrate peaks. Estimates of deep-percolation rates in the Amargosa Desert are needed for the analysis of regional ground-water flow and transport. An understanding of regional flow patterns is important because ground water originating on the Nevada Test Site may pass through the area before discharging from springs at lower elevations in the Amargosa Desert and in Death Valley. Nine boreholes 10 to 16 meters deep were cored nearly continuously using a hollow-stem auger designed for gravelly sediments. Two boreholes were drilled in each of three irrigated fields in the Amargosa-Farms area, two in the Amargosa-River channel, and one in an undisturbed area of native vegetation. Data from previously cored boreholes beneath undisturbed, native vegetation were compared with the new data to further assess deep percolation under current climatic conditions and provide information on spatial variability. The profiles beneath native vegetation were characterized by large amounts of accumulated chloride just below the root zone with almost no further accumulation at greater depths. This pattern is typical of profiles beneath interfluvial areas in arid alluvial basins of the southwestern United States, where salts have been accumulating since the end of the Pleistocene. The profiles beneath irrigated fields and the Amargosa-River channel contained more than twice the volume of water compared to profiles beneath native vegetation, consistent with active deep percolation beneath these sites. Chloride profiles beneath two older fields (cultivated since the 1960?s) as well as the upstream Amargosa-River site were indicative of long-term, quasi-steady deep percolation. Chloride profiles beneath the

  13. Unmanned Aerial Vehicles unique cost estimating requirements

    NASA Astrophysics Data System (ADS)

    Malone, P.; Apgar, H.; Stukes, S.; Sterk, S.

    Unmanned Aerial Vehicles (UAVs), also referred to as drones, are aerial platforms that fly without a human pilot onboard. UAVs are controlled autonomously by a computer in the vehicle or under the remote control of a pilot stationed at a fixed ground location. There are a wide variety of drone shapes, sizes, configurations, complexities, and characteristics. Use of these devices by the Department of Defense (DoD), NASA, civil and commercial organizations continues to grow. UAVs are commonly used for intelligence, surveillance, reconnaissance (ISR). They are also use for combat operations, and civil applications, such as firefighting, non-military security work, surveillance of infrastructure (e.g. pipelines, power lines and country borders). UAVs are often preferred for missions that require sustained persistence (over 4 hours in duration), or are “ too dangerous, dull or dirty” for manned aircraft. Moreover, they can offer significant acquisition and operations cost savings over traditional manned aircraft. Because of these unique characteristics and missions, UAV estimates require some unique estimating methods. This paper describes a framework for estimating UAV systems total ownership cost including hardware components, software design, and operations. The challenge of collecting data, testing the sensitivities of cost drivers, and creating cost estimating relationships (CERs) for each key work breakdown structure (WBS) element is discussed. The autonomous operation of UAVs is especially challenging from a software perspective.

  14. Estimation of recharge from irrigation flows; Analysis of field and laboratory data and modeling.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work is aimed at quantifying aquifer recharge due to irrigation in the Campo de Cartagena (SE Spain). A study of recharge was conducted on an experiment plot cropped in lettuce and irrigated with a drip system. The physico-chemical and hydraulic properties of the vadose zone were characterized ...

  15. A ROOT ZONE MODELLING APPROACH TO ESTIMATING GROUNDWATER RECHARGE FROM IRRIGATED AREAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In irrigated semi-arid and arid regions, accurate knowledge of groundwater recharge is important for the sustainable management of scarce water resources. The Campo de Cartagena area of southeast Spain is a semi-arid region where irrigation return flow accounts for a substantial portion of recharge....

  16. Deficit irrigation in a production setting; Canopy temperature as an adjunct to ET estimates.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water available for agricultural use is declining worldwide as a result of both declining water resources and increasing application costs. Managing crop irrigation under conditions where the water need cannot be fully met represents the future of irrigation in many areas. On the southern high pla...

  17. A stochastic simulation-optimization approach for estimating highly reliable soil tension threshold values in sensor-based deficit irrigation

    NASA Astrophysics Data System (ADS)

    Kloss, S.; Schütze, N.; Walser, S.; Grundmann, J.

    2012-04-01

    In arid and semi-arid regions where water is scarce, farmers heavily rely on irrigation in order to grow crops and to produce agricultural commodities. The variable and often severely limited water supply thereby poses a serious challenge for farmers to cope with and demand sophisticated irrigation strategies that allow an efficient management of the available water resources. The general aim is to increase water productivity (WP) and one of these strategies to achieve this goal is controlled deficit irrigation (CDI). One way to realize CDI is by defining soil water status specific threshold values (either in soil tension or moisture) at which irrigation cycles are triggered. When utilizing CDI, irrigation control is of utmost importance and yet thresholds are likely chosen by trial and error and thus unreliable. Hence, for CDI to be effective systematic investigations for deriving reliable threshold values that account for different CDI strategies are needed. In this contribution, a method is presented that uses a simulation-based stochastic approach for estimating threshold values with a high reliability. The approach consist of a weather generator offering statistical significance to site-specific climate series, an optimization algorithm that determines optimal threshold values under limiting waters supply, and a crop model for simulating plant growth and water consumption. The study focuses on threshold values of soil tension for different CDI strategies. The advantage of soil-tension-based threshold values over soil-moisture-based lies in their universal and soil type independent applicability. The investigated CDI strategies comprised schedules of constant threshold values, crop development stage dependent threshold values, and different minimum irrigation intervals. For practical reasons, fixed irrigation schedules were tested as well. Additionally, a full irrigation schedule served as reference. The obtained threshold values were then tested in field

  18. Estimating irrigation water use and withdrawal of ground water on the High Plains, U.S.A.

    NASA Astrophysics Data System (ADS)

    Wray, James R.

    In four decades following the Dust Bowl days of the 1930's, extensive areas of dry farming and rangeland on the semi-arid U.S. High Plains were transformed into a vast region of irrigated oases, producing meat and grain for much of the world. The agricultural economy has experienced such rapid growth in part because of the availability of ground water and because of development of new irrigation technology to use that water for agriculture. However, more water is being used than is being replaced. To estimate both the volume of water withdrawn and the regional scope of the problem a technique has been developed that combines multispectral data from Earth-orbiting satellite with known pumpage data for the same growing season. The location and extent of irrigated cropland-some with different crops watered at different times-is inventoried using computer-assisted analysis of the data from Landsat. The amount of water used is estimated by multiplying and summing surface area of irrigated agriculture and the average measured pumpage from sampled sites. Published findings to date are cited in the Selected References. All suggest transferability of a promising technology to the study of land transformation processes elsewhere.

  19. Estimating irrigation water use and withdrawal of ground water on the High Plains, U.S.A.

    USGS Publications Warehouse

    Wray, J.R.

    1982-01-01

    In four decades following the Dust Bowl days of the 1930's, extensive areas of dry farming and rangeland on the semi-arid U.S. High Plains were transformed into a vast region of irrigated oases, producing meat and grain for much of the world. The agricultural economy has experienced such rapid growth in part because of the availability of ground water and because of development of new irrigation technology to use that water for agriculture. However, more water is being used than is being replaced. To estimate both the volume of water withdrawn and the regional scope of the problem a technique has been developed that combines multispectral data from Earth-orbiting satellite with known pumpage data for the same growing season. The location and extent of irrigated cropland-some with different crops watered at different times-is inventoried using computer-assisted analysis of the data from Landsat. The amount of water used is estimated by multiplying and summing surface area of irrigated agriculture and the average measured pumpage from sampled sites. Published findings to date are cited in the Selected References. All suggest transferability of a promising technology to the study of land transformation processes elsewhere. ?? 1983.

  20. Characterizing irrigation water requirements for rice production from the Arkansas Rice Research Verification Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated rice irrigation water use in the University of Arkansas Rice Research Verification Program between the years of 2003 and 2011. Irrigation water use averaged 747 mm (29.4 inches) over the nine years. A significant 40% water savings was reported for rice grown under a zero gr...

  1. Planning and Estimation of Operations Support Requirements

    NASA Technical Reports Server (NTRS)

    Newhouse, Marilyn E.; Barley, Bryan; Bacskay, Allen; Clardy, Dennon

    2010-01-01

    Life Cycle Cost (LCC) estimates during the proposal and early design phases, as well as project replans during the development phase, are heavily focused on hardware development schedules and costs. Operations (phase E) costs are typically small compared to the spacecraft development and test costs. This, combined with the long lead time for realizing operations costs, can lead to de-emphasizing estimation of operations support requirements during proposal, early design, and replan cost exercises. The Discovery and New Frontiers (D&NF) programs comprise small, cost-capped missions supporting scientific exploration of the solar system. Any LCC growth can directly impact the programs' ability to fund new missions, and even moderate yearly underestimates of the operations costs can present significant LCC impacts for deep space missions with long operational durations. The National Aeronautics and Space Administration (NASA) D&NF Program Office at Marshall Space Flight Center (MSFC) recently studied cost overruns and schedule delays for 5 missions. The goal was to identify the underlying causes for the overruns and delays, and to develop practical mitigations to assist the D&NF projects in identifying potential risks and controlling the associated impacts to proposed mission costs and schedules. The study found that 4 out of the 5 missions studied had significant overruns at or after launch due to underestimation of the complexity and supporting requirements for operations activities; the fifth mission had not launched at the time of the mission. The drivers behind these overruns include overly optimistic assumptions regarding the savings resulting from the use of heritage technology, late development of operations requirements, inadequate planning for sustaining engineering and the special requirements of long duration missions (e.g., knowledge retention and hardware/software refresh), and delayed completion of ground system development work. This paper updates the D

  2. Estimation of crop water requirements using remote sensing for operational water resources management

    NASA Astrophysics Data System (ADS)

    Vasiliades, Lampros; Spiliotopoulos, Marios; Tzabiras, John; Loukas, Athanasios; Mylopoulos, Nikitas

    2015-06-01

    An integrated modeling system, developed in the framework of "Hydromentor" research project, is applied to evaluate crop water requirements for operational water resources management at Lake Karla watershed, Greece. The framework includes coupled components for operation of hydrotechnical projects (reservoir operation and irrigation works) and estimation of agricultural water demands at several spatial scales using remote sensing. The study area was sub-divided into irrigation zones based on land use maps derived from Landsat 5 TM images for the year 2007. Satellite-based energy balance for mapping evapotranspiration with internalized calibration (METRIC) was used to derive actual evapotranspiration (ET) and crop coefficient (ETrF) values from Landsat TM imagery. Agricultural water needs were estimated using the FAO method for each zone and each control node of the system for a number of water resources management strategies. Two operational strategies of hydro-technical project development (present situation without operation of the reservoir and future situation with the operation of the reservoir) are coupled with three water demand strategies. In total, eight (8) water management strategies are evaluated and compared. The results show that, under the existing operational water resources management strategies, the crop water requirements are quite large. However, the operation of the proposed hydro-technical projects in Lake Karla watershed coupled with water demand management measures, like improvement of existing water distribution systems, change of irrigation methods, and changes of crop cultivation could alleviate the problem and lead to sustainable and ecological use of water resources in the study area.

  3. Nonlinear models for estimating GSFC travel requirements

    NASA Technical Reports Server (NTRS)

    Buffalano, C.; Hagan, F. J.

    1974-01-01

    A methodology is presented for estimating travel requirements for a particular period of time. Travel models were generated using nonlinear regression analysis techniques on a data base of FY-72 and FY-73 information from 79 GSFC projects. Although the subject matter relates to GSFX activities, the type of analysis used and the manner of selecting the relevant variables would be of interest to other NASA centers, government agencies, private corporations and, in general, any organization with a significant travel budget. Models were developed for each of six types of activity: flight projects (in-house and out-of-house), experiments on non-GSFC projects, international projects, ART/SRT, data analysis, advanced studies, tracking and data, and indirects.

  4. Evaluation of the use of remote-sensing data to identify crop types and estimate irrigated acreage, Uvalde and Medina counties, Texas, 1989

    USGS Publications Warehouse

    Raymond, L.H.; Nalley, G.M.; Rettman, P.L.

    1992-01-01

    Results were verified using crop acreages reported by the U.S. Department of Agriculture, Agricultural Stabilization and Conservation Service (ASCS). The total areas for all irrigated crops estimated using remote-sensing data were about 8 percent higher for Uvalde County and about 4 percent higher for Medina County than the areas reported by the ASCS. Irrigated-crop areas subsequently were multiplied by the respective duties of water to calculate the total quantity of water pumped from the aquifer for irrigation. Pumpage did not differ for the two estimates of crop areas for Uvalde County and differed by about 3 percent for Medina County.

  5. Evaluation of SEBS for estimation of actual evapotranspiration using ASTER satellite data for irrigation areas of Australia

    NASA Astrophysics Data System (ADS)

    Ma, Weiqiang; Hafeez, Mohsin; Ishikawa, Hirohiko; Ma, Yaoming

    2013-05-01

    Spatial knowledge of land surface evapotranspiration (ET) is of prime interest for environmental applications, such as optimizing irrigation water use, irrigation system performance, crop water deficit, drought mitigation strategies, and accurate initialization of climate prediction models especially in arid and semiarid catchments where water shortage is a critical problem. The recent drought in Australia and concerns about climate change have highlighted the need to manage water resources more sustainably especially in the Murrumbidgee catchment which utilizes bulk water for food production. This study deals with the application of a Surface Energy Balance System (SEBS) algorithm based on Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) data and field observations has been proposed and tested for deriving ET over Coleambally Irrigation Area, located in the southwest of NSW, Australia. We have used 12 ASTER scenes covering the time period of 2002, 2003, 2004, 2005, 2006, and 2009 for estimating the actual ET over the study area. To validate the proposed methodology, the ground-measured ET was compared to the ASTER-derived actual ET values for the study area. The derived ET value over the study area is much closer to the field measurement. From the remote sensing results and observations, the root mean square error is 0.89 and the mean absolute percentage difference is 2.87 %, which demonstrate the reasonability of SEBS ET estimation for the study area.

  6. Molecular techniques in ecohealth research toolkit: facilitating estimation of aggregate gastroenteritis burden in an irrigated periurban landscape.

    PubMed

    Tserendorj, Ariuntuya; Anceno, Alfredo J; Houpt, Eric R; Icenhour, Crystal R; Sethabutr, Orntipa; Mason, Carl S; Shipin, Oleg V

    2011-09-01

    Assessment of microbial hazards associated with certain environmental matrices, livelihood strategies, and food handling practices are constrained by time-consuming conventional microbiological techniques that lead to health risk assessments of narrow geographic or time scope, often targeting very few pathogens. Health risk assessment based on one or few indicator organisms underestimates true disease burden due a number of coexisting causative pathogens. Here, we employed molecular techniques in a survey of Cryptosporidium parvum, Giardia lamblia, Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Shigella spp., Vibrio cholera, and Rotavirus A densities in canal water with respect to seasonality and spatial distribution of point-nonpoint pollution sources. Three irrigational canals stretching across nearly a 150-km(2) periurban landscape, traditionally used for agricultural irrigation but function as vital part of municipal wastewater stabilization in recent years, were investigated. Compiled stochastic data (pathogen concentration, susceptible populations) and literature-obtained deterministic data (pathogen dose-response model parameter values) were used in estimating waterborne gastroenteritis burden. Exposure scenarios include swimming or fishing, consuming canal water-irrigated vegetables, and ingesting or inhaling water aerosols while working in canal water-irrigated fields. Estimated annual gastroenteritis burden due individual pathogens among the sampling points was -10.6log(10) to -2.2log(10) DALYs. Aggregated annual gastroenteritis burden due all the target pathogens per sampling point was -3.1log(10) to -1.9log(10) DALYs, far exceeding WHO acceptable limit of -6.0log(10) DALYs. The present approach will facilitate the comprehensive collection of surface water microbiological baseline data and setting of benchmarks for interventions aimed at reducing microbial hazards in similar landscapes worldwide. PMID:22146856

  7. Irrigation Monitoring Project Results

    NASA Technical Reports Server (NTRS)

    Terrie, Gregory; Berglund, Judith; Ryan, Robert; Harrington, Gary; Stewart, Randy; Spiering, Bruce

    2003-01-01

    The objective of this project is to investigate remote sensing requirements for irrigation scheduling to define future systems. Temperature-based crop stress indicators have been developed that could be used for irrigation management. This viewgraph presentation describes an experiment to use airborne and satellite thermal imagery to evaulate the water requirements of irrigated crops.

  8. Sampling strategies for the estimation of salt and nitrate loads in irrigation return flows: La Violada Gully (Spain) as a case study

    NASA Astrophysics Data System (ADS)

    Isidoro, D.; Quílez, D.; Aragüés, R.

    2003-02-01

    Appropriate estimates of salt and nitrate loads exported by irrigated agriculture are needed to ascertain the potential negative impacts on the quality of the receiving water bodies. The irrigation return flows of the La Violada irrigation district (NE Spain), collected by La Violada Gully, were monitored for 4 years (1995-1998) in order to estimate salt and nitrate loads. The existence of a daily cycle in the Gully flow during the April to September 1995 irrigation season, associated with a cycle in the electrical conductivity, made it necessary to analyse the influence of the sampling hour on the daily estimates of salt and nitrate loads. Interpolation and regression methods were evaluated using nine 2-days surveys with samples taken at all even hours. The interpolation approach proved to be reliable for daily load estimations, whereas the regression approach was unacceptable due to the poor salinity-flow and nitrate concentration-flow relationships. The sampling time was important for the determination of salt load by the interpolation method, but resulted almost irrelevant for the estimation of nitrate load. Although the biases represent a small percentage of the mean (<7% for both salt and nitrate load estimates), the lack of consideration of the sampling hour will result, depending on the time of sampling, in a systematic over- or under-estimation of the measured loads. The number of samples needed to estimate salt and nitrate loads within a pre-specified margin of error was determined using the 1995 and 1996 irrigation seasons series and confirmed through a Monte Carlo test for the four irrigation seasons. A systematic sampling interval of 9 days (i.e. 21 samples along the irrigation season) allowed estimating salt loading within a 5% error and nitrating loading within a 10% error at the 95% confidence level.

  9. Estimating the Effects of Conversion of Agricultural Land to Urban Land on Deep Percolation of Irrigation Water in the Grand Valley, Western Colorado

    USGS Publications Warehouse

    Mayo, John W.

    2008-01-01

    The conversion of agricultural land to urban residential land is associated with rapid population growth in the Grand Valley of western Colorado. Information regarding the effects of this land-use conversion on deep percolation, irrigation-water application, and associated salt loading to the Colorado River is needed to support water-resource planning and conservation efforts. The Natural Resources Conservation Service (NRCS) assessed deep percolation and estimated salt loading derived from irrigated agricultural lands in the Grand Valley in a 1985 to 2002 monitoring and evaluation study (NRCS M&E). The U.S. Geological Survey (USGS), in cooperation with the Colorado River Salinity Control Forum and the Mesa Conservation District, quantified the current (2005-2006) deep percolation and irrigation-water application characteristics of 1/4-acre residential lots and 5-acre estates, urban parks, and urban orchard grass fields in the Grand Valley, and compared the results to NRCS M&E results from alfalfa-crop sites. In addition, pond seepage from three irrigation-water holding ponds was estimated. Salt loading was estimated for the urban study results and the NRCS M&E results by using standard salt-loading factors. A daily soil-moisture balance calculation technique was used at all urban study irrigated sites. Deep percolation was defined as any water infiltrating below the top 12 inches of soil. Deep percolation occurred when the soil-moisture balance in the first 12 inches of soil exceeded the field capacity for the soil type at each site. Results were reported separately for urban study bluegrass-only sites and for all-vegetation type (bluegrass, native plants, and orchard grass) sites. Deep percolation and irrigation-water application also were estimated for a complete irrigation season at three subdivisions by using mean site data from each subdivision. It was estimated that for the three subdivisions, 37 percent of the developed acreage was irrigated (the balance

  10. Mapping Irrigation Potential in the Upper East Region of Ghana

    NASA Astrophysics Data System (ADS)

    Akomeah, E.; Odai, S. N.; Annor, F. O.; Adjei, K. A.; Barry, B.

    2009-04-01

    The Upper East Region together with the other two regions in Northern Ghana (Upper West and Northern Region) is seen as the locus of perennial food deficit (GPRS, 2003). Despite, the provision of over 200 small scale dams and various mechanisms aimed at poverty alleviation, the region is still plagued with poverty and yearly food shortages. To achieve food security and alleviate poverty in the region however, modernization of agriculture through irrigation is deemed inevitable. While it is true that considerable potential still exists for future expansion of irrigation, it cannot be refuted that water is becoming scarcer in the regions where the need for irrigation is most important, hence mapping the irrigation potential of the region will be the first step toward ensuring sound planning and sustainability of the irrigation developments. In this study, an attempt has been made to map out the irrigation potential of the Upper East Region. The river basin approach was used in assessing the irrigation potential. The catchments drained by The White Volta river, Red volta river, River Sissili and River Kulpawn were considered in the assessment. The irrigation potential for the sub basins was computed by combining information on gross irrigation water requirements for the selected cash crops, area of soil suitable for irrigation and available water resources. The capacity of 80%, 70%, 60% and 50% time of exceedance flow of the available surface water resources in the respective sub basins was estimated. The area that can be irrigated with this flow was computed with selected cropping pattern. Combining the results of the potential irrigable areas and the land use map of the respective sub basins, an irrigation potential map has been generated showing potential sites in the upper east region that can be brought under irrigation. Keywords: Irrigation potential, irrigation water requirement, land evaluation, dependable flow

  11. 31 CFR 205.23 - What requirements apply to estimates?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false What requirements apply to estimates... Treasury-State Agreement § 205.23 What requirements apply to estimates? The following requirements apply when we and a State negotiate a mutually agreed upon funds transfer procedure based on an estimate...

  12. Documentation of methods and inventory of irrigation data collected for the 2000 and 2005 U.S. Geological Survey Estimated use of water in the United States, comparison of USGS-compiled irrigation data to other sources, and recommendations for future compilations

    USGS Publications Warehouse

    Dickens, Jade M.; Forbes, Brandon T.; Cobean, Dylan S.; Tadayon, Saeid

    2011-01-01

    An indirect method for estimating irrigation withdrawals is presented and results are compared to the 2005 USGS-reported irrigation withdrawals for selected States. This method is meant to demonstrate a way to check data reported or received from a third party, if metered data are unavailable. Of the 11 States where this method was applied, 8 States had estimated irrigation withdrawals that were within 15 percent of what was reported in the 2005 water-use compilation, and 3 States had estimated irrigation withdrawals that were more than 20 percent of what was reported in 2005. Recommendations for improving estimates of irrigated acreage and irrigation withdrawals also are presented in this report. Conveyance losses and irrigation-system efficiencies should be considered in order to achieve a more accurate representation of irrigation withdrawals. Better documentation of data sources and methods used can help lead to more consistent information in future irrigation water-use compilations. Finally, a summary of data sources and methods used to estimate irrigated acreage and irrigation withdrawals for the 2000 and 2005 compilations for each WSC is presented in appendix 1.

  13. Irrigation Systems Operation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective operation of an irrigation system requires matching the operational characteristics of a system to the soil, crop, field, and water supply. Each of these components will affect the quality of the irrigation system performance. The performance measures used to characterize the irrigation sy...

  14. Reimagining cost recovery in Pakistan's irrigation system through willingness-to-pay estimates for irrigation water from a discrete choice experiment

    NASA Astrophysics Data System (ADS)

    Bell, Andrew Reid; Shah, M. Azeem Ali; Ward, Patrick S.

    2014-08-01

    It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies.

  15. Reimagining cost recovery in Pakistan's irrigation system through willingness-to-pay estimates for irrigation water from a discrete choice experiment

    PubMed Central

    Bell, Andrew Reid; Shah, M Azeem Ali; Ward, Patrick S

    2014-01-01

    It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies. PMID:25552779

  16. 48 CFR 252.215-7002 - Cost estimating system requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Cost estimating system... of Provisions And Clauses 252.215-7002 Cost estimating system requirements. As prescribed in 215.408(2), use the following clause: Cost Estimating System Requirements (DEC 2012) (a)...

  17. 48 CFR 252.215-7002 - Cost estimating system requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Cost estimating system... of Provisions And Clauses 252.215-7002 Cost estimating system requirements. As prescribed in 215.408(2), use the following clause: Cost Estimating System Requirements (DEC 2012) (a)...

  18. 48 CFR 252.215-7002 - Cost estimating system requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Cost estimating system... of Provisions And Clauses 252.215-7002 Cost estimating system requirements. As prescribed in 215.408(2), use the following clause: Cost Estimating System Requirements (FEB 2012) (a)...

  19. 48 CFR 252.215-7002 - Cost estimating system requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Cost estimating system... of Provisions And Clauses 252.215-7002 Cost estimating system requirements. As prescribed in 215.408(2), use the following clause: Cost Estimating System Requirements (DEC 2006) (a)...

  20. Estimate of uptake and translocation of emerging organic contaminants from irrigation water concentration in lettuce grown under controlled conditions.

    PubMed

    Hurtado, Carlos; Domínguez, Carmen; Pérez-Babace, Lorea; Cañameras, Núria; Comas, Jordi; Bayona, Josep M

    2016-03-15

    The widespread distribution of emerging organic contaminants (EOCs) in the water cycle can lead to their incorporation in irrigated crops, posing a potential risk for human consumption. To gain further insight into the processes controlling the uptake of organic microcontaminants, Batavia lettuce (Lactuca sativa) grown under controlled conditions was watered with EOCs (e.g., non-steroidal anti-inflammatories, sulfonamides, β-blockers, phenolic estrogens, anticonvulsants, stimulants, polycyclic musks, biocides) at different concentrations (0-40μgL(-1)). Linear correlations were obtained between the EOC concentrations in the roots and leaves and the watering concentrations for most of the contaminants investigated. However, large differences were found in the root concentration factors ( [Formula: see text] =0.27-733) and leaf translocation concentration factors ( [Formula: see text] =0-3) depending on the persistence of the target contaminants in the rhizosphere and the specific physicochemical properties of each one. With the obtained dataset, a simple predictive model based on a linear regression and the root bioconcentration and translocation factors can be used to estimate the concentration of the target EOCs in leaves based on the dose supplied in the irrigation water or the soil concentration. Finally, enantiomeric fractionation of racemic ibuprofen from the initial spiking mixture suggests that biodegradation mainly occurs in the rhizosphere. PMID:26651071

  1. Estimating the economic benefits of maintaining residential lake levels at an irrigation reservoir: A contingent valuation study

    NASA Astrophysics Data System (ADS)

    Loomis, John; Smith, Adam; Huszar, Paul

    2005-08-01

    The contingent valuation method (CVM) was used to estimate homeowners' willingness to pay for water leasing to maintain stable lake levels at an irrigation reservoir in a residential neighborhood. A binary logit model was used to analyze households' voter referendum responses for maintaining the lake level. The median willingness to pay (WTP) was found to be 368 per year for lakefront residents and 59 per year for off-lake residents. The median WTP for lakefront residents was significantly different from off-lake residents at the 90% confidence level. Using the median WTP for lakefront and nonlakefront residents, we found that the increase in homeowner association fees would generate approximately $43,000, enough money to lease sufficient water to reach the target higher lake level in a normal water year.

  2. Estimating the economic benefits of maintaining residential lake levels at an irrigation reservoir: A contingent valuation study

    NASA Astrophysics Data System (ADS)

    Loomis, John; Smith, Adam; Huszar, Paul

    2005-08-01

    The contingent valuation method (CVM) was used to estimate homeowners' willingness to pay for water leasing to maintain stable lake levels at an irrigation reservoir in a residential neighborhood. A binary logit model was used to analyze households' voter referendum responses for maintaining the lake level. The median willingness to pay (WTP) was found to be $368 per year for lakefront residents and $59 per year for off-lake residents. The median WTP for lakefront residents was significantly different from off-lake residents at the 90% confidence level. Using the median WTP for lakefront and nonlakefront residents, we found that the increase in homeowner association fees would generate approximately $43,000, enough money to lease sufficient water to reach the target higher lake level in a normal water year.

  3. Estimation of soil salinity in a drip irrigation system by using joint inversion of multicoil electromagnetic induction measurements

    NASA Astrophysics Data System (ADS)

    Jadoon, Khan Zaib; Moghadas, Davood; Jadoon, Aurangzeb; Missimer, Thomas M.; Al-Mashharawi, Samir K.; McCabe, Matthew F.

    2015-05-01

    Low frequency electromagnetic induction (EMI) is becoming a useful tool for soil characterization due to its fast measurement capability and sensitivity to soil moisture and salinity. In this research, a new EMI system (the CMD mini-Explorer) is used for subsurface characterization of soil salinity in a drip irrigation system via a joint inversion approach of multiconfiguration EMI measurements. EMI measurements were conducted across a farm where Acacia trees are irrigated with brackish water. In situ measurements of vertical bulk electrical conductivity (σb) were recorded in different pits along one of the transects to calibrate the EMI measurements and to compare with the modeled electrical conductivity (σ) obtained by the joint inversion of multiconfiguration EMI measurements. Estimates of σ were then converted into the universal standard of soil salinity measurement (i.e., electrical conductivity of a saturated soil paste extract - ECe). Soil apparent electrical conductivity (ECa) was repeatedly measured with the CMD mini-Explorer to investigate the temperature stability of the new system at a fixed location, where the ambient air temperature increased from 26°C to 46°C. Results indicate that the new EMI system is very stable in high temperature environments, especially above 40°C, where most other approaches give unstable measurements. In addition, the distribution pattern of soil salinity is well estimated quantitatively by the joint inversion of multicomponent EMI measurements. The approach of joint inversion of EMI measurements allows for the quantitative mapping of the soil salinity distribution pattern and can be utilized for the management of soil salinity.

  4. A rule-of-thumb approach to estimate annual deep percolation and runoff in irrigated landscapes at field to farm scales

    NASA Astrophysics Data System (ADS)

    Selle, B.; Githui, F.; Thayalakumaran, T.

    2009-04-01

    The rootzone of a field or farm in irrigated landscapes is the logical unit that can be managed or influenced by farmers, catchment managers and water authorities. Increasing scarcity, variability and expensive nature of water supplies necessitates better understanding of the rootzone water balance in irrigated landscapes. The major terms of the annual water balance in the rootzone include rainfall, irrigation, evapotranspiration, deep percolation below the rootzone and runoff. While information on annual rainfall, irrigation and evapotranspiration can often be readily obtained at field to farm scales, deep percolation and runoff are typically unavailable as their continuous measurement is difficult and/or uneconomical. Consequently, these terms are often calculated using models that are able to simulate the rootzone water balance. In this case study, we developed a rule-of-thumb approach to estimate annual deep percolation and runoff for the Barr Creek catchment in northern Victoria, Australia. Firstly, annual deep percolation and runoff were calculated at field to farm scales using an integrated SWAT-MODFLOW model calibrated against a comprehensive data set including drain flows and salinity, remotely sensed evapotranspiration and watertable levels. Secondly, a rule-of-thumb approach was developed to approximate annual deep percolation and runoff from readily available information on annual irrigation, rainfall, evapotranspiration, soils, watertable levels and landuse. This rule-of-thumb approach can be applied to continuously estimate deep percolation and runoff.

  5. Irrigated lands assessment for water management: Technique test. [California

    NASA Technical Reports Server (NTRS)

    Wall, S. L.; Brown, C. E.; Eriksson, M.; Grigg, C. A.; Thomas, R. W.; Colwell, R. N.; Estes, J. E.; Tinney, L. R.; Baggett, J. O.; Sawyer, G.

    1981-01-01

    A procedure for estimating irrigated land using full frame LANDSAT imagery was demonstrated. Relatively inexpensive interpretation of multidate LANDSAT photographic enlargements was used to produce a map of irrigated land in California. The LANDSAT and ground maps were then linked by regression equations to enable precise estimation of irrigated land area by county, basin, and statewide. Land irrigated at least once in California in 1979 was estimated to be 9.86 million acres, with an expected error of less than 1.75% at the 99% level of confidence. To achieve the same level of error with a ground-only sample would have required 3 to 5 times as many ground sample units statewide. A procedure for relatively inexpensive computer classification of LANDSAT digital data to irrigated land categories was also developed. This procedure is based on ratios of MSS band 7 and 5, and gave good results for several counties in the Central Valley.

  6. Improving Soil Moisture and Temperature Profile and Surface Turbulent Fluxes Estimations in Irrigated Field by Assimilating Multi-source Data into Land Surface Model

    NASA Astrophysics Data System (ADS)

    Chen, Weijing; Huang, Chunlin; Shen, Huanfeng; Wang, Weizhen

    2016-04-01

    The optimal estimation of hydrothermal conditions in irrigation field is restricted by the deficiency of accurate irrigation information (when and how much to irrigate). However, the accurate estimation of soil moisture and temperature profile and surface turbulent fluxes are crucial to agriculture and water management in irrigated field. In the framework of land surface model, soil temperature is a function of soil moisture - subsurface moisture influences the heat conductivity at the interface of layers and the heat storage in different layers. In addition, soil temperature determines the phase of soil water content with the transformation between frozen and unfrozen. Furthermore, surface temperature affects the partitioning of incoming radiant energy into ground (sensible and latent heat flux), as a consequence changes the delivery of soil moisture and temperature. Given the internal positive interaction lying in these variables, we attempt to retrieve the accurate estimation of soil moisture and temperature profile via assimilating the observations from the surface under unknown irrigation. To resolve the input uncertainty of imprecise irrigation quantity, original EnKS is implemented with inflation and localization (referred to as ESIL) aiming at solving the underestimation of the background error matrix and the extension of observation information from the top soil to the bottom. EnKS applied in this study includes the states in different time points which tightly connect with adjacent ones. However, this kind of relationship gradually vanishes along with the increase of time interval. Thus, the localization is also employed to readjust temporal scale impact between states and filter out redundant or invalid correlation. Considering the parameter uncertainty which easily causes the systematic deviation of model states, two parallel filters are designed to recursively estimate both states and parameters. The study area consists of irrigated farmland and is

  7. Prospective changes in irrigation water requirements caused by agricultural expansion and climate changes in the eastern arc mountains of Kenya.

    PubMed

    Maeda, Eduardo Eiji; Pellikka, Petri K E; Clark, Barnaby J F; Siljander, Mika

    2011-03-01

    Water resources and land use are closely linked with each other and with regional climate, assembling a very complex system. The understanding of the interconnecting relations involved in this system is an essential step for elaborating public policies that can effectively lead to the sustainable use of water resources. In this study, an integrated modelling framework was assembled in order to investigate potential impacts of agricultural expansion and climate changes on Irrigation Water Requirements (IWR) in the Taita Hills, Kenya. The framework comprised a land use change simulation model, a reference evapotranspiration model and synthetic precipitation datasets generated through a Monte Carlo simulation. In order to generate plausible climate change scenarios, outputs from General Climate Models were used as reference to perturbing the Monte Carlo simulations. The results indicate that throughout the next 20 years the low availability of arable lands in the hills will drive agricultural expansion to areas with higher IWR in the foothills. If current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. This expansion will increase by approximately 40% the annual water volume necessary for irrigation. Climate change may slightly decrease crops' IWR in April and November by 2030, while in May a small increase will likely be observed. The integrated assessment of these environmental changes allowed a clear identification of priority regions for land use allocation policies and water resources management. PMID:21111528

  8. On the irrigation requirements of cottonwood (Populus fremontii and Populus deltoides var. wislizenii) and willow (Salix gooddingii) grown in a desert environment

    USGS Publications Warehouse

    Hartwell, S.; Morino, K.; Nagler, P.L.; Glenn, E.P.

    2010-01-01

    Native tree plots have been established in river irrigation districts in the western U.S. to provide habitat for threatened and endangered birds. Information is needed on the effective irrigation requirements of the target species. Cottonwood (Populus spp.) and willow (Salix gooddingii) trees were grown for seven years in an outdoor plot in a desert environment in Tucson, Arizona. Plants were allowed to achieve a nearly complete canopy cover over the first four years, then were subjected to three daily summer irrigation schedules of 6.20??mm??d-1; 8.26??mm??d-1 and 15.7??mm??d-1. The lowest irrigation rate was sufficient to maintain growth and high leaf area index for cottonwoods over three years, while willows suffered considerable die-back on this rate in years six and seven. These irrigation rates were applied April 15-September 15, but only 0.88??mm??d-1 was applied during the dormant period of the year. Expressed as a fraction of reference crop evapotranspiration (ETo), recommended annual water applications plus precipitation (and including some deep drainage) were 0.83 ETo for cottonwood and 1.01 ETo for willow. Current practices tend to over-irrigate restoration plots, and this study can provide guidelines for more efficient water use. ?? 2010 Elsevier Ltd.

  9. Approximate sample sizes required to estimate length distributions

    USGS Publications Warehouse

    Miranda, L.E.

    2007-01-01

    The sample sizes required to estimate fish length were determined by bootstrapping from reference length distributions. Depending on population characteristics and species-specific maximum lengths, 1-cm length-frequency histograms required 375-1,200 fish to estimate within 10% with 80% confidence, 2.5-cm histograms required 150-425 fish, proportional stock density required 75-140 fish, and mean length required 75-160 fish. In general, smaller species, smaller populations, populations with higher mortality, and simpler length statistics required fewer samples. Indices that require low sample sizes may be suitable for monitoring population status, and when large changes in length are evident, additional sampling effort may be allocated to more precisely define length status with more informative estimators. ?? Copyright by the American Fisheries Society 2007.

  10. A Real-time Irrigation Forecasting System in Jiefangzha Irrigation District, China

    NASA Astrophysics Data System (ADS)

    Cong, Z.

    2015-12-01

    In order to improve the irrigation efficiency, we need to know when and how much to irrigate in real time. If we know the soil moisture content at this time, we can forecast the soil moisture content in the next days based on the rainfall forecasting and the crop evapotranspiration forecasting. Then the irrigation should be considered when the forecasting soil moisture content reaches to a threshold. Jiefangzha Irrigation District, a part of Hetao Irrigation District, is located in Inner Mongolia, China. The irrigated area of this irrigation district is about 140,000 ha mainly planting wheat, maize and sunflower. The annual precipitation is below 200mm, so the irrigation is necessary and the irrigation water comes from the Yellow river. We set up 10 sites with 4 TDR sensors at each site (20cm, 40cm, 60cm and 80cm depth) to monitor the soil moisture content. The weather forecasting data are downloaded from the website of European Centre for Medium-Range Weather Forecasts (ECMWF). The reference evapotranspiration is estimated based on FAO-Blaney-Criddle equation with only the air temperature from ECMWF. Then the crop water requirement is forecasted by the crop coefficient multiplying the reference evapotranspiration. Finally, the soil moisture content is forecasted based on soil water balance with the initial condition is set as the monitoring soil moisture content. When the soil moisture content reaches to a threshold, the irrigation warning will be announced. The irrigation mount can be estimated through three ways: (1) making the soil moisture content be equal to the field capacity; (2) making the soil moisture saturated; or (3) according to the irrigation quota. The forecasting period is 10 days. The system is developed according to B2C model with Java language. All the databases and the data analysis are carried out in the server. The customers can log in the website with their own username and password then get the information about the irrigation forecasting

  11. Irrigation and groundwater in Pakistan

    NASA Astrophysics Data System (ADS)

    Ertsen, Maurits; Iftikhar Kazmi, Syed

    2010-05-01

    Introduction of large gravity irrigation system in the Indus Basin in late nineteenth century without a drainage system resulted in water table rise consequently giving rise to water logging and salinity problems over large areas. In order to cope with the salinity and water logging problem government initiated salinity control and reclamation project (SCARP) in 1960. Initially 10,000 tube wells were installed in different areas, which not only resulted in the lowering of water table, but also supplemented irrigation. Resulting benefits from the full irrigation motivated framers to install private tube wells. Present estimate of private tube wells in Punjab alone is around 0.6 million and 48 billion cubic meter of groundwater is used for irrigation, contributing is 1.3 billion to the economy. The Punjab meets 40% of its irrigation needs from groundwater abstraction. Today, farmers apply both surface water flows and groundwater from tubewells, creating a pattern of private and public water control. As the importance of groundwater in sustaining human life and ecology is evident so are the threats to its sustainability due to overexploitation, but sufficient information for its sustainable management especially in developing countries is still required. Sustainable use of groundwater needs proper quantification of the resource and information on processes involved in its recharge and discharge. Groundwater recharge is broadly defined as water that reaches the aquifer from any direction (Lerner 1997). Sustainability and proper management of groundwater resource requires reliable quantification of the resource. In order to protect the resource from contamination and over exploitation, identification of recharge sources and their contribution to resource is a basic requirement. Physiochemical properties of some pesticides and their behavior in soil and water can make them potential tracers of subsurface moisture movement. Pesticides are intensively used in the area to

  12. Water requirements and management of maize under drip and sprinkler irrigation. 1999 annual report for Agricultural Technology Utilization and Transfer (ATUT) project

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the second year of this project, research continued at Ismailia, Egypt on irrigation management of maize, fava bean, wheat, and alfalfa. Research at Bushland, Texas, continued on alfalfa and grass reference evapotranspiration (ET), means of estimating those values from Bowen ratio meterological m...

  13. Estimation of infectious risks in residential populations exposed to airborne pathogens during center pivot irrigation of dairy wastewaters.

    PubMed

    Dungan, Robert Stephen

    2014-05-01

    In the western United States where dairy wastewaters are commonly land applied, there are concerns over individuals being exposed to airborne pathogens. In response, a quantitative microbial risk assessment (QMRA) was performed to estimate infectious risks after inhalation exposure of pathogens aerosolized during center pivot irrigation of diluted dairy wastewaters. The dispersion of pathogens (Campylobacter jejuni, Escherichia coli O157:H7, non-O157 E. coli, Listeria monocytogenes, and Salmonella spp.) was modeled using the atmospheric dispersion model, AERMOD. Pathogen concentrations at downwind receptors were used to calculate infectious risks during one-time (1, 8, and 24 h) and multiday (7 d at 1 h d(-1)) exposure events using a β-Poisson dose-response model. This assessment considered risk of infection in residential populations that were 1 to 10 km from a center pivot operation. In the simulations, infectious risks were estimated to be the greatest in individuals closest to the center pivot, as a result of a higher pathogen dose. On the basis of the results from this QMRA, it is recommended that wastewaters only be applied during daylight hours when inactivation and dilution of airborne pathogens is highest. Further refinement of the dispersion and dose-response models should be considered to increase the utility of this QMRA. PMID:24697271

  14. Irrigation: Erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation is essential for global food production. However, irrigation erosion can limit the ability of irrigation systems to reliably produce food and fiber in the future. The factors affecting soil erosion from irrigation are the same as rainfall—water detaches and transports sediment. However, t...

  15. A Site-sPecific Agricultural water Requirement and footprint Estimator (SPARE:WATER 1.0)

    NASA Astrophysics Data System (ADS)

    Multsch, S.; Al-Rumaikhani, Y. A.; Frede, H.-G.; Breuer, L.

    2013-07-01

    The agricultural water footprint addresses the quantification of water consumption in agriculture, whereby three types of water to grow crops are considered, namely green water (consumed rainfall), blue water (irrigation from surface or groundwater) and grey water (water needed to dilute pollutants). By considering site-specific properties when calculating the crop water footprint, this methodology can be used to support decision making in the agricultural sector on local to regional scale. We therefore developed the spatial decision support system SPARE:WATER that allows us to quantify green, blue and grey water footprints on regional scale. SPARE:WATER is programmed in VB.NET, with geographic information system functionality implemented by the MapWinGIS library. Water requirements and water footprints are assessed on a grid basis and can then be aggregated for spatial entities such as political boundaries, catchments or irrigation districts. We assume inefficient irrigation methods rather than optimal conditions to account for irrigation methods with efficiencies other than 100%. Furthermore, grey water is defined as the water needed to leach out salt from the rooting zone in order to maintain soil quality, an important management task in irrigation agriculture. Apart from a thorough representation of the modelling concept, we provide a proof of concept where we assess the agricultural water footprint of Saudi Arabia. The entire water footprint is 17.0 km3 yr-1 for 2008, with a blue water dominance of 86%. Using SPARE:WATER we are able to delineate regional hot spots as well as crop types with large water footprints, e.g. sesame or dates. Results differ from previous studies of national-scale resolution, underlining the need for regional estimation of crop water footprints.

  16. SEBAL for estimating hourly ET fluxes over irrigated and dryland cotton during BEAREX08

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous energy balance (EB) algorithms have been developed to make use of remote sensing data for mapping evapotranspiration (ET) on a regional basis. Adopting any or a combination of these models for an operational ET remote sensing program requires thorough evaluation. The main objective of this ...

  17. Estimating the impacts of a reservoir for improved water use in irrigation in the Yarabamba region, Peru

    NASA Astrophysics Data System (ADS)

    Swiech, Theoclea; Ertsen, Maurits W.; Pererya, Carlos Machicao

    The pressure on irrigation is increasing worldwide, not only because of - perceived or real - high water consumption in the irrigated sector, but also because an increased world population puts stress on food production. Numerous irrigated areas around the world face similar issues of water scarcity, disparity in water distribution and deficient infrastructure. As a result, farmers are typically restricted in their production strategies. A general strategy in the irrigation sector is the introduction of so-called modern techniques in existing irrigation systems, with the aim to increase agricultural production. This paper discusses such a modernization effort in the sub-basin of Yarabamba, Arequipa, Peru, in which a reservoir is being constructed to improve water use and stimulate economic development. Based on fieldwork, including interviews and scenario modeling with WEAP, the relationships between water users, their irrigation systems and the water balances in the basin were studied. Scenario studies showed that the reservoir might alleviate the current water shortages in the sub-basin, but that restrictions in the current infrastructure and management of irrigation may be of more importance than the reservoir. Especially existing interests and actions of upstream and downstream areas appear to be important factors; these will not be automatically solved with the new reservoir.

  18. Determining the required accuracy of LST products for estimating surface energy fluxes

    NASA Astrophysics Data System (ADS)

    Pinheiro, A. C.; Reichle, R.; Sujay, K.; Arsenault, K.; Privette, J. L.; Yu, Y.

    2006-12-01

    Land Surface Temperature (LST) is an important parameter to assess the energy state of a surface. Synoptic satellite observations of LST must be used when attempting to estimate fluxes over large spatial scales. Due to the close coupling between LST, root level water availability, and mass and energy fluxes at the surface, LST is particularly useful over agricultural areas to help determine crop water demands and facilitate water management decisions (e.g., irrigation). Further, LST can be assimilated into land surface models to help improve estimates of latent and sensible heat fluxes. However, the accuracy of LST products and its impact on surface flux estimation is not well known. In this study, we quantify the uncertainty limits in LST products for accurately estimating latent heat fluxes over agricultural fields in the Rio Grande River basin of central New Mexico. We use the Community Land Model (CLM) within the Land Information Systems (LIS), and adopt an Ensemble Kalman Filter approach to assimilate the LST fields into the model. We evaluate the LST and assimilation performance against field measurements of evapotranspiration collected at two eddy-covariance towers in semi-arid cropland areas. Our results will help clarify sensor and LST product requirements for future remote sensing systems.

  19. Web based irrigation scheduler

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing use of water in the Mid-South has led to depletion of water levels in aquifers, with few guidelines in place for farmers as to when and how much to irrigate. Irrigation can increase crop yields when water is applied correctly. Wise water management requires knowledge of how much water the...

  20. Irrigation water quality assessments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing demands on fresh water supplies by municipal and industrial users means decreased fresh water availability for irrigated agriculture in semi arid and arid regions. There is potential for agricultural use of treated wastewaters and low quality waters for irrigation but this will require co...

  1. Investigating irrigation scheduling for rice using variable rate irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because almost all US rice is produced with continuous flood irrigation, little information addresses irrigation scheduling for rice; however, successful production of rice without a continuous flood will require scheduling, or timely irrigation. A field study conducted at the University of Missouri...

  2. Estimating yield of irrigated potatoes using aerial and satellite remote sensing

    NASA Astrophysics Data System (ADS)

    Sivarajan, Saravanan

    Multispectral aerial and satellite remote sensing plays a major role in crop yield prediction due to its ability to detect crop growth conditions on spatial and temporal scales in a cost effective manner. Many empirical relationships have been established in the past between spectral vegetation indices and leaf area index, fractional ground cover, and crop growth rates for different crops through ground sampling. Remote sensing-based vegetation index (VI) yield models using airborne and satellite data have been developed only for grain crops like barley, corn, wheat, and sorghum. So it becomes important to validate and extend the VI-based model for tuber crops like potato, taking into account the most significant parameters that affect the final crop yield of these crops. This research involved developing and validating yield models for potato crop in southern Idaho fields using high-resolution airborne and satellite remote sensing. High-resolution multispectral airborne imagery acquired on three dates throughout the growing season in 2004 was used to develop a VI-based statistical yield model by integrating the area under the Soil Adjusted Vegetation Index (SAVI) curve. The model was developed using hand-dug samples collected in two center pivots based on soil variability and crop growth patterns to account for variability in the leaf area duration and yields. The three-date Integrated SAVI (ISAVI) model developed was then validated using 2005 spot yield samples collected from two center pivot fields and also tested for 2004 and 2005 whole field data over dozens of center pivot fields. The three- date model was applied using 2004 and 2005 satellite images and tested. The eight-date ISAVI yield model was also extended to satellite images to estimate the potato yield. The overall yield estimation using the eight-date ISAVI model was better than the three-date model as the image inputs covered the complete growth cycle of the crop from emergence to harvest. Actual

  3. Optimizing desalinated sea water blending with other sources to meet magnesium requirements for potable and irrigation waters.

    PubMed

    Avni, Noa; Eben-Chaime, Moshe; Oron, Gideon

    2013-05-01

    Sea water desalination provides fresh water that typically lacks minerals essential to human health and to agricultural productivity. Thus the rising proportion of desalinated sea water consumed by both the domestic and agricultural sectors constitutes a public health risk. Research on low-magnesium water irrigation showed that crops developed magnesium deficiency symptoms that could lead to plant death, and tomato yields were reduced by 10-15%. The World Health Organization (WHO) reported on a relationship between sudden cardiac death rates and magnesium intake deficits. An optimization model, developed and tested to provide recommendations for Water Distribution System (WDS) quality control in terms of meeting optimal water quality requirements, was run in computational experiments based on an actual regional WDS. The expected magnesium deficit due to the operation of a large Sea Water Desalination Plant (SWDP) was simulated, and an optimal operation policy, in which remineralization at the SWDP was combined with blending desalinated and natural water to achieve the required quality, was generated. The effects of remineralization costs and WDS physical layout on the optimal policy were examined by sensitivity analysis. As part of the sensitivity blending natural and desalinated water near the treatment plants will be feasible up to 16.2 US cents/m(3), considering all expenses. Additional chemical injection was used to meet quality criteria when blending was not feasible. PMID:23537704

  4. Estimation of Time Variant Water Availability and Irrigation Potential of Small Ponds in a Semi-arid Region of Rajasthan, India

    NASA Astrophysics Data System (ADS)

    Ali, Shakir

    2016-03-01

    A field experiment was conducted to assess water availability and irrigation potential of two small, shallow and Ephemeral ponds located in a small watershed of the semi-arid region of Rajasthan, India. The Holistic Water Depth Simulation (HWDS) model was employed for estimating the pond water availability with 3 years field data (2006-2008). The analysis revealed that the value of depth of water in the selected ponds predicted by the HWDS model had closed match to the field data. The index of agreement between measured and predicted values of depth of water in the selected ponds was found to be ranged from 0.93 to 0.94 for the pool data sets. The F and Student's T test between measured and predicted values revealed that model estimates were not statistically different from measured values at 0.01 % level of significance. Analysis revealed that mean pond volumetric water availability for the selected ponds ranged from 1448 to 5001 m3 during the study period. During the off monsoon seasons, water availability period was varied between 35 and 78 days with a mean of 61 days. Analyses revealed that water availability in the selected ponds lasted at least 48-61 days. The off monsoon season irrigation potential of ponds with one and two irrigations for the rainfed crops at critical growth stage in the region was estimated to be 12.6 and 6.3 ha, respectively.

  5. Application of the Viterbi Algorithm in Hidden Markov Models for Exploring Irrigation Decision Series

    NASA Astrophysics Data System (ADS)

    Andriyas, S.; McKee, M.

    2014-12-01

    Anticipating farmers' irrigation decisions can provide the possibility of improving the efficiency of canal operations in on-demand irrigation systems. Although multiple factors are considered during irrigation decision making, for any given farmer there might be one factor playing a major role. Identification of that biophysical factor which led to a farmer deciding to irrigate is difficult because of high variability of those factors during the growing season. Analysis of the irrigation decisions of a group of farmers for a single crop can help to simplify the problem. We developed a hidden Markov model (HMM) to analyze irrigation decisions and explore the factor and level at which the majority of farmers decide to irrigate. The model requires observed variables as inputs and the hidden states. The chosen model inputs were relatively easily measured, or estimated, biophysical data, including such factors (i.e., those variables which are believed to affect irrigation decision-making) as cumulative evapotranspiration, soil moisture depletion, soil stress coefficient, and canal flows. Irrigation decision series were the hidden states for the model. The data for the work comes from the Canal B region of the Lower Sevier River Basin, near Delta, Utah. The main crops of the region are alfalfa, barley, and corn. A portion of the data was used to build and test the model capability to explore that factor and the level at which the farmer takes the decision to irrigate for future irrigation events. Both group and individual level behavior can be studied using HMMs. The study showed that the farmers cannot be classified into certain classes based on their irrigation decisions, but vary in their behavior from irrigation-to-irrigation across all years and crops. HMMs can be used to analyze what factor and, subsequently, what level of that factor on which the farmer most likely based the irrigation decision. The study shows that the HMM is a capable tool to study a process

  6. Minimizing instrumentation requirement for estimating crop water stress index and transpiration of maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research was conducted in northern Colorado in 2011 to estimate the Crop Water Stress Index (CWSI) and actual water transpiration (Ta) of maize under a range of irrigation regimes. The main goal was to obtain these parameters with minimum instrumentation and measurements. The results confirmed that ...

  7. Estimation of the exertion requirements of coal mining work

    SciTech Connect

    Harber, P.; Tamimie, J.; Emory, J.

    1984-02-01

    The work requirements of coal mining work were estimated by studying a group of 12 underground coal miners. A two level (rest, 300 kg X m/min) test was performed to estimate the linear relationship between each subject's heart rate and oxygen consumption. Then, heart rates were recorded during coal mining work with a Holter type recorder. From these data, the distributions of oxygen consumptions during work were estimated, allowing characterization of the range of exertion throughout the work day. The average median estimated oxygen consumption was 3.3 METS, the average 70th percentile was 4.3 METS, and the average 90th percentile was 6.3 METS. These results should be considered when assessing an individual's occupational fitness.

  8. SURFACE VOLUME ESTIMATES FOR INFILTRATION PARAMETER ESTIMATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volume balance calculations used in surface irrigation engineering analysis require estimates of surface storage. These calculations are often performed by estimating upstream depth with a normal depth formula. That assumption can result in significant volume estimation errors when upstream flow d...

  9. Soil management and conservation: Irrigation: Methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation applies water to soil to improve crop production. The three main methods of irrigation are surface, sprinkler and micro. Surface irrigation is used on 85% of the irrigated land in the world. It generally requires lower capital investment because the soil conveys water within the field, ra...

  10. Wireless sensor networks for irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustaining an adequate food supply for the world's population will require advancements in irrigation technology and improved irrigation management. Site-specific irrigation and automatic irrigation scheduling are examples of strategies to deal with declining arable land and limited fresh water reso...

  11. Estimating preseason irrigation losses by characterizing evaporation of effective precipitation under bare soil conditions using large weighing lysimeters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation scheduling is one of the most cost effective means of conserving limited groundwater resources, particularly in semi-arid regions. Effective precipitation, or the net amount of water from precipitation that can be used in field water balance equations, is essential to accurate and effecti...

  12. Estimated water requirements for gold heap-leach operations

    USGS Publications Warehouse

    Bleiwas, Donald I.

    2012-01-01

    This report provides a perspective on the amount of water necessary for conventional gold heap-leach operations. Water is required for drilling and dust suppression during mining, for agglomeration and as leachate during ore processing, to support the workforce (requires water in potable form and for sanitation), for minesite reclamation, and to compensate for water lost to evaporation and leakage. Maintaining an adequate water balance is especially critical in areas where surface and groundwater are difficult to acquire because of unfavorable climatic conditions [arid conditions and (or) a high evaporation rate]; where there is competition with other uses, such as for agriculture, industry, and use by municipalities; and where compliance with regulatory requirements may restrict water usage. Estimating the water consumption of heap-leach operations requires an understanding of the heap-leach process itself. The task is fairly complex because, although they all share some common features, each gold heap-leach operation is unique. Also, estimating the water consumption requires a synthesis of several fields of science, including chemistry, ecology, geology, hydrology, and meteorology, as well as consideration of economic factors.

  13. Preventing pesticide contamination of groundwater while maximizing irrigated crop yield

    NASA Astrophysics Data System (ADS)

    Peralta, R. C.; Hegazy, M. A.; Musharrafieh, G. R.

    1994-11-01

    A simulation/optimization model is developed for maximizing irrigated crop yield while avoiding unacceptable pesticide leaching. The optimization model is designed to help managers prevent non-point source contamination of shallow groundwater aquifers. It computes optimal irrigation amounts for given soil, crop, chemical, and weather data and irrigation frequencies. It directly computes the minimum irrigated crop yield reduction needed to prevent groundwater contamination. Constraint equations used in the model maintain a layered soil moisture volume balance; describe percolation, downward unsaturated zone solute transport and pesticide degradation; and limit the amount of pesticide reaching groundwater. Constraints are linear, piecewise linear, nonlinear, and exponential. The problem is solved using nonlinear programming optimization. The model is tested for different scenarios of irrigating corn. The modeling approach is promising as a tool to aid in the development of environmentally sound agricultural production practices. It allows direct estimation of trade-offs between crop production and groundwater protection for different management approaches. More frequent irrigation tends to give better crop yield and reduce solute movement. Trade-offs decrease with increasing irrigation frequency. More frequent irrigation reduces yield loss due to moisture stress and requires less water to fill the root zone to field capacity. This prevents the solute from moving to deeper soil layers. Yield-environmental quality trade-offs are smaller for deeper groundwater tables because deeper groundwater allows more time for chemical degradation.

  14. Global rain-fed, irrigated, and paddy croplands: A new high resolution map derived from remote sensing, crop inventories and climate data

    NASA Astrophysics Data System (ADS)

    Salmon, J. Meghan; Friedl, Mark A.; Frolking, Steve; Wisser, Dominik; Douglas, Ellen M.

    2015-06-01

    Irrigation accounts for 70% of global water use by humans and 33-40% of global food production comes from irrigated croplands. Accurate and timely information related to global irrigation is therefore needed to manage increasingly scarce water resources and to improve food security in the face of yield gaps, climate change and extreme events such as droughts, floods, and heat waves. Unfortunately, this information is not available for many regions of the world. This study aims to improve characterization of global rain-fed, irrigated and paddy croplands by integrating information from national and sub-national surveys, remote sensing, and gridded climate data sets. To achieve this goal, we used supervised classification of remote sensing, climate, and agricultural inventory data to generate a global map of irrigated, rain-fed, and paddy croplands. We estimate that 314 million hectares (Mha) worldwide were irrigated circa 2005. This includes 66 Mha of irrigated paddy cropland and 249 Mha of irrigated non-paddy cropland. Additionally, we estimate that 1047 Mha of cropland are managed under rain-fed conditions, including 63 Mha of rain-fed paddy cropland and 985 Mha of rain-fed non-paddy cropland. More generally, our results show that global mapping of irrigated, rain-fed, and paddy croplands is possible by combining information from multiple data sources. However, regions with rapidly changing irrigation or complex mixtures of irrigated and non-irrigated crops present significant challenges and require more and better data to support high quality mapping of irrigation.

  15. Guidelines for Estimating Unmetered Landscaping Water Use

    SciTech Connect

    McMordie Stoughton, Kate

    2010-07-28

    The document lays-out step by step instructions to estimate landscaping water using two alternative approaches: evapotranspiration method and irrigation audit method. The evapotranspiration method option calculates the amount of water needed to maintain a healthy turf or landscaped area for a given location based on the amount of water transpired and evaporated from the plants. The evapotranspiration method offers a relatively easy “one-stop-shop” for Federal agencies to develop an initial estimate of annual landscape water use. The document presents annual irrigation factors for 36 cities across the U.S. that represents the gallons of irrigation required per square foot for distinct landscape types. By following the steps outlined in the document, the reader can choose a location that is a close match their location and landscape type to provide a rough estimate of annual irrigation needs without the need to research specific data on their site. The second option presented in the document is the irrigation audit method, which is the physical measurement of water applied to landscaped areas through irrigation equipment. Steps to perform an irrigation audit are outlined in the document, which follow the Recommended Audit Guidelines produced by the Irrigation Association.[5] An irrigation audit requires some knowledge on the specific procedures to accurately estimate how much water is being consumed by the irrigation equipment.

  16. Nitrogen Requirements for Growth and Early Fruit Development of Drip-Irrigated Processing Tomato (Lycopersicon esculentum Mill.) in Portugal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of continuous application of small quantities of nitrogen (N) in irrigation water and N applied as starter on growth and development of processing tomato (Lycopersicon esculentum Mill.), from transplanting to beginning of fruit set, was studied in two experiments: a pot experiment and a f...

  17. Estimates of galactic cosmic ray shielding requirements during solar minimum

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.; Nealy, John E.; Wilson, John W.; Simonsen, Lisa C.

    1990-01-01

    Estimates of radiation risk from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different arbitrary constituents per layer. Calculated galactic cosmic ray fluxes, dose and dose equivalents behind various thicknesses of aluminum, water and liquid hydrogen shielding are presented for the solar minimum period. Estimates of risk to the skin and the blood-forming organs (BFO) are made using 0-cm and 5-cm depth dose/dose equivalent values, respectively, for water. These results indicate that at least 3.5 g/sq cm (3.5 cm) of water, or 6.5 g/sq cm (2.4 cm) of aluminum, or 1.0 g/sq cm (14 cm) of liquid hydrogen shielding is required to reduce the annual exposure below the currently recommended BFO limit of 0.5 Sv. Because of large uncertainties in fragmentation parameters and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as a factor of 2 or more. The effects of these potential exposure uncertainties or shield thickness requirements are analyzed.

  18. A root zone model for estimating soil water balance and crop yield responses to deficit irrigation in the North China Plain

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Song, X.; Feng, S.

    2012-12-01

    This study proposed a new soil water balance model by quantifying drainage out of the root zone with the simplification of the Darcy's law, which combined the advantages of conceptual and physically based models. This model was connected with the Jensen crop water production function to simulate soil water components and relative crop yield. Field experiments with the winter wheat-summer corn cropping system were conducted in Beijing area in the North China Plain (2007-2009) to evaluate the model. The model could give quite reasonable predictions of soil water content in the root zone with the average root mean square error (RMSE), mean relative error (RE) and model efficiency (EF) of 0.02 cm3/cm3, 6.69% and 0.78, respectively. Furthermore, the predicted soil water flux through the bottom of root zone agreed well with the measured ones supported by the values of RMSE (0.10 mm/d) and EF (0.92). The Jensen crop water production function with the calculated actual evapotranspitation from the soil water balance model could satisfactorily evaluate crop yield response to deficit irrigation with the EF values greater than 0.95 and the RE values lower than 6%. As an application, the model was used to obtain the optimal irrigation management schedules for the hydrologic years of 75%, 50% and 25% in the study area. The average amount of irrigation saving and reduction of water losses through drainage under optimal irrigation alternative were about 175 mm and 101.9 mm, respectively. This study indicates that the developed root zone model is more available for agricultural water management as it has minimal input requirement, robust physical meaning and satisfactory simulation performance.

  19. The Impact of Climate and Its Variability on Crop Yield and Irrigation

    NASA Astrophysics Data System (ADS)

    Li, X.; Troy, T.

    2014-12-01

    As the global population grows and the climate changes, having a secure food supply is increasingly important especially under water stressed-conditions. Although irrigation is a positive climate adaptation mechanism for agriculture, it has a potentially negative effect on water resources. It is therefore important to understand how crop yields due to irrigation are affected by climate variability and how irrigation may buffer against climate, allowing for more resilient agricultural systems. Efforts to solve these barely exposed questions can benefit from comprehending the influence of climate variability on crop yield and irrigation water use in the past. To do this, we use historical climate data,irrigation water use data and rainfed and irrigated crop yields over the US to analyze the relationship among climate, irrigation and delta crop yields, gained by subtracting rainfed yield from irrigated yield since 1970. We find that the increase in delta crop yield due to irrigation is larger for certain climate conditions, such that there are optimal climate conditions where irrigation provides a benefit and other conditions where irrigation proves to have marginal benefits when temperature increased to certain degrees. We find that crop water requirements are linked to potential evapotranspiration, yet actual irrigation water use is largely decoupled from the climate conditions but related with other causes. This has important implications for agricultural and water resource system planning, as it implies there are optimal climate zones where irrigation is productive and that changes in water use, both temporally and spatially, could lead to increased water availability without negative impacts on crop yields. Furthermore, based on the exposed relationship between crop yield gained by irrigation and climate variability, those models predicting the global harvest will be redress to estimate crop production in the future more accurately.

  20. Joint inversion of multi-configuration electromagnetic induction measurements to estimate soil wetting patterns during surface drip irrigation

    NASA Astrophysics Data System (ADS)

    Jadoon, Khan Z.; Moghadas, Davood; Jadoon, Aurangzeb; Missimer, Thomas M.; McCabe, Matthew

    2014-05-01

    In arid and semi-arid regions, development of precise information on the soil wetting pattern is important to optimize drip irrigation system design for sustainable agricultural water management. Usually mathematical models are commonly used to describe infiltration from a point source to design and manage drip irrigation systems. The extent to which water migrates laterally and vertically away from the drip emitter depends on many factors, including dripper discharge rate, the frequency of water application, duration of drip emission, the soil hydraulic characteristics, initial conditions, evaporation, root water uptake and root distribution patterns. However, several simplified assumptions in the mathematical models affect their utility to provide useful design information. In this respect, non-invasive geophysical methods, i.e., low frequency electromagnetic induction (EMI) systems are becoming powerful tools to map spatial and temporal soil moisture patterns due to fast measurement capability and sensitivity to soil water content and salinity. In this research, a new electromagnetic system, the CMD mini-Explorer, is used for soil characterization to measure the wetting patterns of drip irrigation systems using joint inversion of multi-configuration EMI measurements. Six transects of EMI measurements were carried out in a farm where Acacia trees are irrigated with brackish water using a drip irrigation system. EMI reference data (ground-truths) were calculated using vertical soil electrical conductivity recorded in different trenches along one of the measurement transects. Reference data is used for calibration to minimize the instrumental shifts which often occur in EMI data. Global and local optimization algorithms are used sequentially, to minimize the misfit between the measured and modeled apparent electrical conductivity (δa) to reconstruct the vertical electrical conductivity profile. The electromagnetic forward model based on full solution of Maxwell

  1. Determination of irrigation pumpage in parts of Kearny and Finney Counties, southwestern Kansas

    USGS Publications Warehouse

    Lindgren, R.J.

    1982-01-01

    Irrigation pumpage was determined for parts of Kearny and Finney Counties in Southwestern Kansas using crop-acreage data and consumptive, irrigation-water requirements. Irrigated acreages for 1974-80 were compiled for wheat, grain sorghum, corn, and alfalfa using records from the U.S. Agricultural Stabilization and Conservation Service. Consumptive-irrigation requirements were computed using a soil-moisture model. The model tabulated monthly soil-moisture and crop-water demand for various crops and computed the volume of irrigation water needed to maintain the available moisture at 50% for loamy soils or at 60% for sandy soils. Irrigated acres in the study area increased from 265,000 acres during 1974 to 321,000 acres during 1980. Irrigation pumpage increased from 584,000 acre-feet during 1974 to 738,000 acre-feet during 1980. Decreased consumptive-irrigation requirements during 1979 resulted in a comparatively small irrigation-pumpage estimate of 458,000 acre-feet. (USGS)

  2. Comparison of soil water sensing methods for irrigation management and research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As irrigation water resources decrease and deficit irrigation becomes more common across the Great Plains, greater accuracy in irrigation scheduling will be required. Researchers investigating deficit irrigation practices and developing management practices must also have accurate measures of soil w...

  3. Web-based irrigation scheduler

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Currently, few web-based irrigation scheduling tools are available for the humid growing environments of the Mid-South. Common irrigation scheduling systems rely on soil or weather data to estimate crop water use, and are more commonly calibrated for dry growing environments. Increasing use of water...

  4. A History-based Estimation for LHCb job requirements

    NASA Astrophysics Data System (ADS)

    Rauschmayr, Nathalie

    2015-12-01

    The main goal of a Workload Management System (WMS) is to find and allocate resources for the given tasks. The more and better job information the WMS receives, the easier will be to accomplish its task, which directly translates into higher utilization of resources. Traditionally, the information associated with each job, like expected runtime, is defined beforehand by the Production Manager in best case and fixed arbitrary values by default. In the case of LHCb's Workload Management System no mechanisms are provided which automate the estimation of job requirements. As a result, much more CPU time is normally requested than actually needed. Particularly, in the context of multicore jobs this presents a major problem, since single- and multicore jobs shall share the same resources. Consequently, grid sites need to rely on estimations given by the VOs in order to not decrease the utilization of their worker nodes when making multicore job slots available. The main reason for going to multicore jobs is the reduction of the overall memory footprint. Therefore, it also needs to be studied how memory consumption of jobs can be estimated. A detailed workload analysis of past LHCb jobs is presented. It includes a study of job features and their correlation with runtime and memory consumption. Following the features, a supervised learning algorithm is developed based on a history based prediction. The aim is to learn over time how jobs’ runtime and memory evolve influenced due to changes in experiment conditions and software versions. It will be shown that estimation can be notably improved if experiment conditions are taken into account.

  5. Advances in Irrigation

    NASA Astrophysics Data System (ADS)

    Gardner, W. R.

    This is the first volume of Advances in Irrigation, a new serial publication by the publishers of Advances in Agronomy and Advances in Hydroscience and designed to follow the same format. The editor is a well-known researcher and writer on irrigation and related subjects and has assembled a collection of highly regarded and respected authors for the initial volume. The readership for this volume will probably be mainly specialists and students interested in irrigation and an occasional design engineer.The seven contributions in this volume fall roughly into two classes: research and practice. Three papers (“Conjunctive Use of Rainfall and Irrigation in Semi-arid Regions,” by Stewart and Musik, “Irrigation Scheduling Using Soil Moisture Measurements: Theory and Practice,” by G. S. and M. D. Campbell, and “Use of Solute Transport Models to Estimate Salt Balance Below Irrigated Cropland,” by Jury) cover topics that have been the subject of a number of reviews. The contributions here provide brief, well-written, and authoritative summaries of the chosen topics and serve as good introductions or reviews. They should lend themselves well to classroom use in various ways. They also should be helpful to the nonspecialist interested in getting a sense of the subject without going into great detail.

  6. A Combined Approach for Estimating Health Staff Requirements

    PubMed Central

    FAKHRI, Ali; SEYEDIN, Hesam; DAVIAUD, Emmanuelle

    2014-01-01

    Abstract Background Many studies have been carried out and many methods have been used for estimating health staff re-quirements in health facilities or system, each have different advantages and disadvantages. Differences in the extent to which utilization matches needs in different conditions intensify the limitations of each approach when used in iso-lation. Is the utilization-based approach efficient in a situation of over servicing? Is it sufficient in a situation of under-utilization? These questions can be similarly asked about the needs-based approach. This study is looking for a flexible approach to estimate the health staff requirements efficiently in these different conditions. Method This study was carried out in 2011 in some stages: It was conducted in order to identify the formula used in the different approaches. The basic formulas used in the utilization-based approach and the needs-based approach were identified and then combined using simple mathematical principles to develop a new formula. Finally, the new formula was piloted by assessing family health staff requirements in the health posts in Kashan City, Iran. Results Comparison of the two formulas showed that the basic formulas used in the two approaches can be com-bined by including the variable ‘Coverage’. The pilot study confirmed the role of coverage in the suggested combined approach. Conclusions The variables in the developed formula allow combining needs-based, target-based and utilization-based approaches. A limitation of this approach is applicability to a given service package. PMID:26060687

  7. Evaluation of zigzag furrow irrigation in Andean communities

    NASA Astrophysics Data System (ADS)

    Roldán Cañas, José; Chipana, Gladys; Chipana, René; Fátima Moreno Pérez, María

    2014-05-01

    It is estimated that the area under irrigation in Bolivia represents 9.7% of the cultivated area, ie 253,100 ha. Traditional surface irrigation is the main system used in Bolivia. Currently, 40,000 ha are irrigated in the La Paz Department. The largest irrigated surface and the areas that produce most food in the Department are located in the eastern and western mountain ranges. However, the region's abrupt terrain makes it impossible to use conventional surface irrigation methods. . As a result, farmers in the inter-Andean valleys have used other surface irrigation methods intensively for hundreds of years like zigzag furrow. In this study, we conducted field trials in the rural community of Cebollullo of the municipality of Palca of La Paz Department. Cebollullo is located at an altitude of 2,780 m above sea level. Its geographic coordinates are 16°41'90.1"S to 16°43'12"S latitude and 67°52'13"W to 67°59'15"W longitude. The irrigated area is characterized by its steep slopes and zigzag corrugated furrow irrigation method is used. The main objective of this study is to evaluate the performance of zigzag furrow irrigation in this community. The study plot has an area of 728 m2 and the average slope is 16.46%. For irrigation evaluation, the data of a middle furrow were taken to avoid boundary effects. Irrigation events recorded during the crop development were 21, with irrigation frequency of 2 to 3 days, of which 10 events were evaluated weekly. Due to the low flow rates used for irrigation, the inflow and outflow measurement of the furrows was made volumetrically. These flow measurements were made at five-minute intervals during irrigation. The zigzag corrugated irrigation method uses low flow discharges in order to decrease the rate of irrigation allowing infiltration of required volume by the crops and reducing soil erosion. Application efficiencies in the study plot ranged between 7.55% and 30.31%, with losses by surface runoff from 45.90% to 85.83% and

  8. Estimates of the maximum time required to originate life

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Fogleman, Guy

    1989-01-01

    Fossils of the oldest microorganisms exist in 3.5 billion year old rocks and there is indirect evidence that life may have existed 3.8 billion years ago (3.8 Ga). Impacts able to destroy life or interrupt prebiotic chemistry may have occurred after 3.5 Ga. If large impactors vaporized the oceans, sterilized the planets, and interfered with the origination of life, life must have originated in the time interval between these impacts which increased with geologic time. Therefore, the maximum time required for the origination of life is the time that occurred between sterilizing impacts just before 3.8 Ga or 3.5 Ga, depending upon when life first appeared on earth. If life first originated 3.5 Ga, and impacts with kinetic energies between 2 x 10 the the 34th and 2 x 10 to the 35th were able to vaporize the oceans, using the most probable impact flux, it is found that the maximum time required to originate life would have been 67 to 133 million years (My). If life originated 3.8 Ga, the maximum time to originate life was 2.5 to 11 My. Using a more conservative estimate for the flux of impacting objects before 3.8 Ga, a maximum time of 25 My was found for the same range of impactor kinetic energies. The impact model suggests that it is possible that life may have originated more than once.

  9. Quantifying canal leakage rates using a mass-balance approach and heat-based hydraulic conductivity estimates in selected irrigation canals, western Nebraska, 2007 through 2009

    USGS Publications Warehouse

    Hobza, Christopher M.; Andersen, Michael J.

    2010-01-01

    The water supply in areas of the North Platte River Basin in the Nebraska Panhandle has been designated as fully appropriated or overappropriated by the Nebraska Department of Natural Resources (NDNR). Enacted legislation (Legislative Bill 962) requires the North Platte Natural Resources District (NPNRD) and the NDNR to develop an Integrated Management Plan (IMP) to balance groundwater and surface-water supply and demand in the NPNRD. A clear understanding of the groundwater and surface-water systems is critical for the development of a successful IMP. The primary source of groundwater recharge in parts of the NPNRD is from irrigation canal leakage. Because canal leakage constitutes a large part of the hydrologic budget, spatially distributing canal leakage to the groundwater system is important to any management strategy. Surface geophysical data collected along selected reaches of irrigation canals has allowed for the spatial distribution of leakage on a relative basis; however, the actual magnitude of leakage remains poorly defined. To address this need, the U.S. Geological Survey, in cooperation with the NPNRD, established streamflow-gaging stations at upstream and downstream ends from two selected canal reaches to allow a mass-balance approach to be used to calculate daily leakage rates. Water-level and sediment temperature data were collected and simulated at three temperature monitoring sites to allow the use of heat as a tracer to estimate the hydraulic conductivity of canal bed sediment. Canal-leakage rates were estimated by applying Darcy's Law to modeled vertical hydraulic conductivity and either the estimated or measured hydraulic gradient. This approach will improve the understanding of the spatial and temporal variability of canal leakage in varying geologic settings identified in capacitively coupled resistivity surveys. The high-leakage potential study reach of the Tri-State Canal had two streamflow-gaging stations and two temperature monitoring

  10. 48 CFR 252.215-7002 - Cost estimating system requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Contractor's policies, procedures, and practices for budgeting and planning controls, and generating...) Flow of work, coordination, and communication; and (5) Budgeting, planning, estimating methods... personnel have sufficient training, experience, and guidance to perform estimating and budgeting tasks...

  11. How do current irrigation practices perform? Evaluation of different irrigation scheduling approaches based on experiements and crop model simulations

    NASA Astrophysics Data System (ADS)

    Seidel, Sabine J.; Werisch, Stefan; Barfus, Klemens; Wagner, Michael; Schütze, Niels; Laber, Hermann

    2014-05-01

    coefficients, and (ii) one treatment was automatically drip irrigated using tensiometers (irrigation of 15 mm at a soil tension of -250 hPa at 30 cm soil depth). In treatment (iii), the irrigation schedule was estimated (using the same critera as in the tension-based treatment) applying the model Daisy partially calibrated against data of 2012. Moreover, one control treatment was minimally irrigated. Measured yield was highest for the tension-based treatment with a low irrigation water input (8.5 DM t/ha, 120 mm). Both SWB treatments showed lower yields and higher irrigation water input (both 8.3 DM t/ha, 306 and 410 mm). The simulation model based treatment yielded lower (7.5 DM t/ha, 106 mm) mainly due to drought stress caused by inaccurate simulation of the soil water dynamics and thus an overestimation of the soil moisture. The evaluation using the calibrated model estimated heavy deep percolation under both SWB treatments. Targeting the challenge to increase water productivity, soil water tension-based irrigation should be favoured. Irrigation scheduling based on SWB calculation requires accurate estimates of crop coefficients. A robust calibration of mechanistic crop models implies a high effort and can be recommended to farmers only to some extent but enables comprehensive crop growth and site analyses.

  12. Estimating irrigation water demand using an improved method and optimizing reservoir operation for water supply and hydropower generation: a case study of the Xinfengjiang reservoir in southern China

    USGS Publications Warehouse

    Wu, Yiping; Chen, Ji

    2013-01-01

    The ever-increasing demand for water due to growth of population and socioeconomic development in the past several decades has posed a worldwide threat to water supply security and to the environmental health of rivers. This study aims to derive reservoir operating rules through establishing a multi-objective optimization model for the Xinfengjiang (XFJ) reservoir in the East River Basin in southern China to minimize water supply deficit and maximize hydropower generation. Additionally, to enhance the estimation of irrigation water demand from the downstream agricultural area of the XFJ reservoir, a conventional method for calculating crop water demand is improved using hydrological model simulation results. Although the optimal reservoir operating rules are derived for the XFJ reservoir with three priority scenarios (water supply only, hydropower generation only, and equal priority), the river environmental health is set as the basic demand no matter which scenario is adopted. The results show that the new rules derived under the three scenarios can improve the reservoir operation for both water supply and hydropower generation when comparing to the historical performance. Moreover, these alternative reservoir operating policies provide the flexibility for the reservoir authority to choose the most appropriate one. Although changing the current operating rules may influence its hydropower-oriented functions, the new rules can be significant to cope with the increasingly prominent water shortage and degradation in the aquatic environment. Overall, our results and methods (improved estimation of irrigation water demand and formulation of the reservoir optimization model) can be useful for local watershed managers and valuable for other researchers worldwide.

  13. Irrigation effects in the northern lake states: Wisconsin central sands revisited.

    PubMed

    Kraft, George J; Clancy, Katherine; Mechenich, David J; Haucke, Jessica

    2012-01-01

    Irrigated agriculture has expanded greatly in the water-rich U.S. northern lake states during the past half century. Source water there is usually obtained from glacial aquifers strongly connected to surface waters, so irrigation has a potential to locally decrease base flows in streams and water levels in aquifers, lakes, and wetlands. During the nascent phase of the irrigation expansion, water availability was explored in works of some fame in the Wisconsin central sands by Weeks et al. (1965) on the Little Plover River and Weeks and Stangland (1971) on "headwater area" streams and lakes. Four decades later, and after irrigation has grown to a dominant landscape presence, we revisited irrigation effects on central sands hydrology. Irrigation effects have been substantial, on average decreasing base flows by a third or more in many stream headwaters and diminishing water levels by more than a meter in places. This explains why some surface waters have become flow and stage impaired, sometimes to the point of drying, with attendant losses of aquatic ecosystems. Irrigation exerts its effects by increasing evapotranspiration by an estimated 45 to 142 mm/year compared with pre-irrigated land cover. We conclude that irrigation water availability in the northern lake states and other regions with strong groundwater-surface water connections is tied to concerns for surface water health, requiring a focus on managing the upper few meters of aquifers on which surface waters depend rather than the depletability of an aquifer. PMID:21707615

  14. Crop water productivity and irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern irrigation systems offer large increases in crop water productivity compared with rainfed or gravity irrigation, but require different management approaches to achieve this. Flood, sprinkler, low-energy precision application, LEPA, and subsurface drip irrigation methods vary widely in water a...

  15. Identification and estimation of the area planted with irrigated rice based on the visual interpretation of LANDSAT MSS data

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Moreira, M. A.; Assuncao, G. V.; Novaes, R. A.; Mendoza, A. A. B.; Bauer, C. A.; Ritter, I. T.; Barros, J. A. I.; Perez, J. E.; Thedy, J. L. O.

    1983-01-01

    The objective was to test the feasibility of the application of MSS-LANDSAT data to irrigated rice crop identification and area evaluation, within four rice growing regions of the Rio Grande do Sul state, in order to extend the methodology for the whole state. The applied methodology was visual interpretation of the following LANDSAT products: channels 5 and 7 black and white imageries and color infrared composite imageries all at the scale of 1:250.000. For crop identification and evaluation, the multispectral criterion and the seasonal variation were utilized. Based on the results it was possible to conclude that: (1) the satellite data were efficient for crop area identification and evaluation; (2) the utilization of the multispectral criterion, allied to the seasonal variation of the rice crop areas from the other crops and, (3) the large cloud cover percentage found in the satellite data made it impossible to realize a rice crop spectral monitoring and, therefore, to define the best dates for such data acquisition for rice crop assessment.

  16. Irrigation market for solar thermal parabolic dish systems

    NASA Technical Reports Server (NTRS)

    Habib-Agahi, H.; Jones, S. C.

    1981-01-01

    The potential size of the onfarm-pumped irrigation market for solar thermal parabolic dish systems in seven high-insolation states is estimated. The study is restricted to the displacement of three specific fuels: gasoline, diesel and natural gas. The model was developed to estimate the optimal number of parabolic dish modules per farm based on the minimum cost mix of conventional and solar thermal energy required to meet irrigation needs. The study concludes that the potential market size for onfarm-pumped irrigation applications ranges from 101,000 modules when a 14 percent real discount rate is assumed to 220,000 modules when the real discount rate drops to 8 percent. Arizona, Kansas, Nebraska, New Mexico and Texas account for 98 percent of the total demand for this application, with the natural gas replacement market accounting for the largest segment (71 percent) of the total market.

  17. Using a System Model for Irrigation Management

    NASA Astrophysics Data System (ADS)

    de Souza, Leonardo; de Miranda, Eu; Sánchez-Román, Rodrigo; Orellana-González, Alba

    2014-05-01

    When using Systems Thinking variables involved in any process have a dynamic behavior, according to nonstatic relationships with the environment. In this paper it is presented a system dynamics model developed to be used as an irrigation management tool. The model involves several parameters related to irrigation such as: soil characteristics, climate data and culture's physiological parameters. The water availability for plants in the soil is defined as a stock in the model, and this soil water content will define the right moment to irrigate and the water depth required to be applied. The crop water consumption will reduce soil water content; it is defined by the potential evapotranspiration (ET) that acts as an outflow from the stock (soil water content). ET can be estimated by three methods: a) FAO Penman-Monteith (ETPM), b) Hargreaves-Samani (ETHS) method, based on air temperature data and c) Class A pan (ETTCA) method. To validate the model were used data from the States of Ceará and Minas Gerais, Brazil, and the culture was bean. Keyword: System Dynamics, soil moisture content, agricultural water balance, irrigation scheduling.

  18. Implications of Irrigation Method and Amount of Water Application on Phytophthora and Pythium Infection and Severity of Root Rot in Highbush Blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Northern highbush blueberry (Vaccinium corymbosum L. 'Duke') was planted in April 2004 and irrigated by overhead sprinklers, microsprays, or drip. Irrigation was applied by each system at 50, 100, and 150% of the estimated crop evapotranspiration requirement (ETc). By the end of the first season, ...

  19. Comment on "Technical Note: On the Matt-Shuttleworth approach to estimate crop water requirements" by Lhomme et al. (2014)

    NASA Astrophysics Data System (ADS)

    Shuttleworth, W. J.

    2014-05-01

    It is clear from Lhomme et al. (2014) that aspects of the explanation of the Matt-Shuttleworth approach can generate confusion. Presumably this is because the description in Shuttleworth (2006) was not sufficiently explicit and simple. This paper explains the logic behind the Matt-Shuttleworth approach clearly, simply and concisely. It shows how the Matt-Shuttleworth can be implemented using a few simple equations and provides access to ancillary calculation resources that can be used for such implementation. If the crop water requirement community decided that it is preferable to use the Penman-Monteith equation to estimate crop water requirements directly for all crops, the United Nations Food and Agriculture Organization could now update Irrigation and Drainage Paper 56 using the Matt-Shuttleworth approach by deriving tabulated values of surface resistance from Table 12 of Allen et al. (1998), with the estimation of crop evaporation then being directly made in a one-step calculation using an equation similar to that already recommended by the United Nations Food and Agriculture Organization for calculating reference crop evaporation.

  20. Comment on "Technical Note: On the Matt-Shuttleworth approach to estimate crop water requirements" by Lhomme et al. (2014)

    NASA Astrophysics Data System (ADS)

    Shuttleworth, W. J.

    2014-11-01

    It is clear from Lhomme et al. (2014) that aspects of the explanation of the Matt-Shuttleworth approach can generate confusion. Presumably this is because the description in Shuttleworth (2006) was not sufficiently explicit and simple. This paper explains the logic behind the Matt-Shuttleworth approach clearly, simply and concisely. It shows how the Matt-Shuttleworth can be implemented using a few simple equations and provides access to ancillary calculation resources that can be used for such implementation. If the crop water requirement community decided that it is preferable to use the Penman-Monteith equation to estimate crop water requirements directly for all crops, the United Nations Food and Agriculture Organization could now update Irrigation and Drainage Paper 56 using the Matt-Shuttleworth approach by deriving tabulated values of surface resistance from Table 12 of Allen et al. (1998), with the estimation of crop evaporation then being directly made in a one-step calculation using an equation similar to that already recommended by the United Nations Food and Agriculture Organization for calculating reference crop evaporation.

  1. Irrigation System

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Under contract with Marshall Space Flight Center, Midwest Research Institute compiled a Lubrication Handbook intended as a reference source for designers and manufacturers of aerospace hardware and crews responsible for maintenance of such equipment. Engineers of Lindsay Manufacturing Company learned of this handbook through NASA Tech Briefs and used it for supplemental information in redesigning gear boxes for their center pivot agricultural irrigation system.

  2. Data concurrency is required for estimating urban heat island intensity.

    PubMed

    Zhao, Shuqing; Zhou, Decheng; Liu, Shuguang

    2016-01-01

    Urban heat island (UHI) can generate profound impacts on socioeconomics, human life, and the environment. Most previous studies have estimated UHI intensity using outdated urban extent maps to define urban and its surrounding areas, and the impacts of urban boundary expansion have never been quantified. Here, we assess the possible biases in UHI intensity estimates induced by outdated urban boundary maps using MODIS Land surface temperature (LST) data from 2009 to 2011 for China's 32 major cities, in combination with the urban boundaries generated from urban extent maps of the years 2000, 2005 and 2010. Our results suggest that it is critical to use concurrent urban extent and LST maps to estimate UHI at the city and national levels. Specific definition of UHI matters for the direction and magnitude of potential biases in estimating UHI intensity using outdated urban extent maps. PMID:26243476

  3. FIRST ORDER ESTIMATES OF ENERGY REQUIREMENTS FOR POLLUTION CONTROL

    EPA Science Inventory

    This report presents estimates of the energy demand attributable to environmental control of pollution from 'stationary point sources.' This class of pollution source includes powerplants, factories, refineries, municipal waste water treatment plants, etc., but excludes 'mobile s...

  4. Application of future remote sensing systems to irrigation

    NASA Technical Reports Server (NTRS)

    Miller, L. D.

    1982-01-01

    Area estimates of irrigated crops and knowledge of crop type are required for modeling water consumption to assist farmers, rangers, and agricultural consultants in scheduling irrigation for distributed management of crop yields. Information on canopy physiology and soil moisture status on a spatial basis is potentially available from remote sensors, so the questions to be addressed relate to: (1) timing (data frequency, instantaneous and integrated measurement); and scheduling (widely distributed spatial demands); (2) spatial resolution; (3) radiometric and geometric accuracy and geoencoding; and (4) information/data distribution. This latter should be overnight, with no central storage, onsite capture, and low cost.

  5. Agricultural land-use classification using landsat imagery data, and estimates of irrigation water use in Gooding, Jerome, Lincoln, and Minidoka counties, 1992 water year, Upper Snake River basin, Idaho and western Wyoming

    USGS Publications Warehouse

    Maupin, Molly A.

    1997-01-01

    As part of the U.S. Geological Survey's National Water-Quality Assessment Program in the upper Snake River Basin study unit, land- and water-use data were used to describe activities that have potential effects on water quality, including biological conditions, in the basin. Land-use maps and estimates of water use by irrigated agriculture were needed for Gooding, Jerome, Lincoln, and Minidoka Counties (south-central Idaho), four of the most intensively irrigated counties in the study unit. Land use in the four counties was mapped from Landsat Thematic Mapper imagery data for the 1992 water year using the SPECTRUM computer program. Land-use data were field verified in 108 randomly selected sections (640 acres each); results compared favorably with land-use maps from other sources. Water used for irrigation during the 1992 water year was estimated using land-use and ancillary data. In 1992, a drought year, estimated irrigation withdrawals in the four counties were about 2.9 million acre-feet of water. Of the 2.9 million acre-feet, an estimated 2.12 million acre-feet of water was withdrawn from surface water, mainly the Snake River, and nearly 776,000 acre-feet was withdrawn from ground water. One-half of the 2.9 million acre-feet of water withdrawn for irrigation was considered to be lost during conveyance or was returned to the Snake River; the remainder was consumptively used by crops during the growing season.

  6. Adaptive management of irrigation and crops' biodiversity: a case study on tomato

    NASA Astrophysics Data System (ADS)

    De Lorenzi, Francesca; Alfieri, Silvia Maria; Basile, Angelo; Bonfante, Antonello; Monaco, Eugenia; Riccardi, Maria; Menenti, Massimo

    2013-04-01

    We have assessed the impacts of climate change and evaluated options to adapt irrigation management in the face of predicted changes of agricultural water demand. We have evaluated irrigation scheduling and its effectiveness (versus crop transpiration), and cultivars' adaptability. The spatial and temporal variations of effectiveness and adaptability were studied in an irrigated district of Southern Italy. Two climate scenarios were considered: reference (1961-90) and future (2021-2050) climate, the former from climatic statistics, and the latter from statistical downscaling of general circulation models (AOGCM). Climatic data consist of daily time series of maximum and minimum temperature, and daily rainfall on a grid with a spatial resolution of 35 km. The work was carried out in the Destra Sele irrigation scheme (18.000 ha. Twenty-five soil units were identified and their hydrological properties were determined (measured or estimated from texture through pedo-transfer functions). A tomato crop, in a rotation typical of the area, was considered. A mechanistic model of water flow in the soil-plant-atmosphere system (SWAP) was used to study crop water requirements and water consumption. The model was calibrated and validated in the same area for many different crops. Tomato crop input data and model parameters were estimated on the basis of scientific literature and assumed to be generically representative of the species. Simulations were performed for reference and future climate, and for different irrigation scheduling options. In all soil units, six levels of irrigation volumes were applied: full irrigation (100%), deficit irrigation (80%, 60%, 40%, 20%), no irrigation. From simulation runs, indicators of soil water availability were calculated, moreover the marginal increases of transpiration per unit of irrigation volume, i.e. the effectiveness of irrigation (ΔT/I), were computed, in both climate scenarios. Indicators and marginal increases were used to

  7. Estimation of infectious risks in residential populations exposed to airborne pathogens during center pivot irrigation of dairy wastewaters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the western United States where dairy wastewaters are commonly land applied, there are concerns over individuals being exposed to airborne pathogens. In response, a quantitative microbial risk assessment (QMRA) was performed to estimate infectious risks after inhalation exposure of pathogens aero...

  8. Water Stress & Biomass Monitoring and SWAP Modeling of Irrigated Crops in Saratov Region of Russia

    NASA Astrophysics Data System (ADS)

    Zeyliger, Anatoly; Ermolaeva, Olga

    2016-04-01

    Development of modern irrigation technologies are balanced between the need to maximize production and the need to minimize water use which provides harmonious interaction of irrigated systems with closely-spaced environment. Thus requires an understanding of complex interrelationships between landscape and underground of irrigated and adjacent areas in present and future conditions aiming to minimize development of negative scenarios. In this way in each irrigated areas a combination of specific factors and drivers must be recognized and evaluated. Much can be obtained by improving the efficiency use of water applied for irrigation. Modern RS monitoring technologies offers the opportunity to develop and implement an effective irrigation control program permitting today to increase efficiency of irrigation water use. These technologies provide parameters with both high temporal and adequate spatial needed to monitor agrohydrological parameters of irrigated agricultural crops. Combination of these parameters with meteorological and biophysical parameters can be used to estimate crop water stress defined as ratio between actual (ETa) and potential (ETc) evapotranspiration. Aggregation of actual values of crop water stress with biomass (yield) data predicted by agrohydrological model based on weather forecasting and scenarios of irrigation water application may be used for indication of both rational timing and amount of irrigation water allocation. This type of analysis facilitating an efficient water management can be easily extended to irrigated areas by developing maps of water efficiency application serving as an irrigation advice system for farmers at his fields and as a decision support tool for the authorities on the large perimeter irrigation management. This contribution aims to communicate an illustrative explanation about the practical application of a data combination of agrohydrological modeling and ground & space based monitoring. For this aim some

  9. ESTIMATING SAMPLE REQUIREMENTS FOR FIELD EVALUATIONS OF PESTICIDE LEACHING

    EPA Science Inventory

    A method is presented for estimating the number of samples needed to evaluate pesticide leaching threats to ground water at a desired level of precision. Sample size projections are based on desired precision (exhibited as relative tolerable error), level of confidence (90 or 95%...

  10. FIELD INFORMATION-BASED SYSTEM FOR ESTIMATING FISH TEMPERATURE REQUIREMENTS

    EPA Science Inventory

    In 1979, Biesinger et al. described a technique for spatial and temporal matching of records of stream temperatures and fish sampling events to obtain estimates of yearly temperature regimes for freshwater fishes of the United States. his article describes the state of this Fish ...

  11. 48 CFR 2452.216-77 - Estimated quantities-requirements contract.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Estimated quantities... Provisions and Clauses 2452.216-77 Estimated quantities—requirements contract. As prescribed in 2416.506-70(c), insert the following provision: Estimated Quantities—Requirements Contract (FEB 2006) In accordance...

  12. Drainage water quality and end-member identification in La Violada irrigation district (Spain)

    NASA Astrophysics Data System (ADS)

    Isidoro, D.; Quílez, D.; Aragüés, R.

    2010-03-01

    SummaryThe identification of the different components in a water course is required to individualize and assess the actual contribution of irrigated agriculture to the pollution of the water course. This paper aimed at identifying and assessing the composition of the end-members in La Violada irrigation district (VID) and establishing a statistical procedure to reduce the sampling effort needed to establish drainage water quality. The quality of irrigation water, groundwater, and irrigated-land drainage water in VID was monitored during three hydrologic years to identify the components of flow in La Violada Gully, the natural exit course of VID. A network of sampling points in the secondary ditches and main drains of VID allowed identifying and separating those collecting irrigated-land drainage waters from those conveying high proportions of irrigation waters. Three end-member flows were identified in La Violada Gully during the irrigation season: (a) irrigation water arising from tail-waters, leakages and spills from the irrigation canals, very low in salts; (b) groundwater originating from the non-irrigated upper reaches of La Violada Gully watershed, high in Cl - and Na +; and (c) VID drainage water, high in SO42- and Ca 2+. The overall VID drainage water quality was accurately assessed through a simplified sampling scheme of only four sampling points that produced low errors of 0.1 dS/m for EC and 0.1 mmol c/L for Cl -. The separation of La Violada Gully flow in these three components is essential for estimating the actual contribution of irrigation in VID to the salt and nitrogen loads in La Violada Gully.

  13. Evaluating the accuracy of soil water sensors for irrigation scheduling to conserve freshwater

    NASA Astrophysics Data System (ADS)

    Ganjegunte, Girisha K.; Sheng, Zhuping; Clark, John A.

    2012-06-01

    In the Trans-Pecos area, pecan [ Carya illinoinensis (Wangenh) C. Koch] is a major irrigated cash crop. Pecan trees require large amounts of water for their growth and flood (border) irrigation is the most common method of irrigation. Pecan crop is often over irrigated using traditional method of irrigation scheduling by counting number of calendar days since the previous irrigation. Studies in other pecan growing areas have shown that the water use efficiency can be improved significantly and precious freshwater can be saved by scheduling irrigation based on soil moisture conditions. This study evaluated the accuracy of three recent low cost soil water sensors (ECH2O-5TE, Watermark 200SS and Tensiometer model R) to monitor volumetric soil water content (θv) to develop improved irrigation scheduling in a mature pecan orchard in El Paso, Texas. Results indicated that while all three sensors were successful in following the general trends of soil moisture conditions during the growing season, actual measurements differed significantly. Statistical analyses of results indicated that Tensiometer provided relatively accurate soil moisture data than ECH2O-5TE and Watermark without site-specific calibration. While ECH2O-5TE overestimated the soil water content, Watermark and Tensiometer underestimated. Results of this study suggested poor accuracy of all three sensors if factory calibration and reported soil water retention curve for study site soil texture were used. This indicated that sensors needed site-specific calibration to improve their accuracy in estimating soil water content data.

  14. Projected Cropping Patterns, Livestock Enterprises, Processing Activities, Capital Requirements, Employment, Income, and Training Needs for Alternative Farm Organizational Structures for the Navajo Indian Irrigation Project. A Special Report to the Four Corners Regional Commission.

    ERIC Educational Resources Information Center

    Gorman, William D.; And Others

    Information on the expected cropping patterns, livestock enterprises, processing and related activities, income and employment opportunities, capital needs, and training requirements for alternative farm organizational structures that could be selected for development of the Navajo Indian Irrigation Project is presented in this report. The major…

  15. Impact of spatial and temporal aggregation of input parameters on the assessment of irrigation scheme performance

    NASA Astrophysics Data System (ADS)

    Lorite, I. J.; Mateos, L.; Fereres, E.

    2005-01-01

    SummaryThe simulations of dynamic, spatially distributed non-linear models are impacted by the degree of spatial and temporal aggregation of their input parameters and variables. This paper deals with the impact of these aggregations on the assessment of irrigation scheme performance by simulating water use and crop yield. The analysis was carried out on a 7000 ha irrigation scheme located in Southern Spain. Four irrigation seasons differing in rainfall patterns were simulated (from 1996/1997 to 1999/2000) with the actual soil parameters and with hypothetical soil parameters representing wider ranges of soil variability. Three spatial aggregation levels were considered: (I) individual parcels (about 800), (II) command areas (83) and (III) the whole irrigation scheme. Equally, five temporal aggregation levels were defined: daily, weekly, monthly, quarterly and annually. The results showed little impact of spatial aggregation in the predictions of irrigation requirements and of crop yield for the scheme. The impact of aggregation was greater in rainy years, for deep-rooted crops (sunflower) and in scenarios with heterogeneous soils. The highest impact on irrigation requirement estimations was in the scenario of most heterogeneous soil and in 1999/2000, a year with frequent rainfall during the irrigation season: difference of 7% between aggregation levels I and III was found. Equally, it was found that temporal aggregation had only significant impact on irrigation requirements predictions for time steps longer than 4 months. In general, simulated annual irrigation requirements decreased as the time step increased. The impact was greater in rainy years (specially with abundant and concentrated rain events) and in crops which cycles coincide in part with the rainy season (garlic, winter cereals and olive). It is concluded that in this case, average, representative values for the main inputs of the model (crop, soil properties and sowing dates) can generate results

  16. Assessing irrigated agriculture's surface water and groundwater consumption by combining satellite remote sensing and hydrologic modelling.

    PubMed

    Peña-Arancibia, Jorge L; Mainuddin, Mohammed; Kirby, John M; Chiew, Francis H S; McVicar, Tim R; Vaze, Jai

    2016-01-15

    Globally, irrigation accounts for more than two thirds of freshwater demand. Recent regional and global assessments indicate that groundwater extraction (GWE) for irrigation has increased more rapidly than surface water extraction (SWE), potentially resulting in groundwater depletion. Irrigated agriculture in semi-arid and arid regions is usually from a combination of stored surface water and groundwater. This paper assesses the usefulness of remotely-sensed (RS) derived information on both irrigation dynamics and rates of actual evapotranspiration which are both input to a river-reach water balance model in order to quantify irrigation water use and water provenance (either surface water or groundwater). The assessment is implemented for the water-years 2004/05-2010/11 in five reaches of the Murray-Darling Basin (Australia); a heavily regulated basin with large irrigated areas and periodic droughts and floods. Irrigated area and water use are identified each water-year (from July to June) through a Random Forest model which uses RS vegetation phenology and actual evapotranspiration as predicting variables. Both irrigated areas and actual evapotranspiration from irrigated areas were compared against published estimates of irrigated areas and total water extraction (SWE+GWE).The river-reach model determines the irrigated area that can be serviced with stored surface water (SWE), and the remainder area (as determined by the Random Forest Model) is assumed to be supplemented by groundwater (GWE). Model results were evaluated against observed SWE and GWE. The modelled SWE generally captures the observed interannual patterns and to some extent the magnitudes, with Pearson's correlation coefficients >0.8 and normalised root-mean-square-error<30%. In terms of magnitude, the results were as accurate as or better than those of more traditional (i.e., using areas that fluctuate based on water resource availability and prescribed crop factors) irrigation modelling. The RS

  17. How much water do we need for irrigation under Climate Change in the Mediterranean?

    NASA Astrophysics Data System (ADS)

    Fader, Marianela; Alberte, Bondeau; Wolfgang, Cramer; Simon, Decock; Sinan, Shi

    2014-05-01

    Anthropogenic climate change will very likely alter the hydrological system of already water-limited agricultural landscapes around the Mediterranean. This includes the need for, as well as the availability of irrigation water. On top of that Mediterranean agroecosystems are very likely to be under strong pressure in the near future through changes in consumer demands and diets, increasing urbanization, demographic change, and new markets for agricultural exportation. As a first step to assess the water demand of the agricultural sector, we use an ecohydrological model (the Lund-Potsdam-Jena managed land model, LPJmL) to estimate current and future irrigation water requirements of this region, considering various climate and socio-economic scenarios. LPJmL is a process-based, agricultural and water balance model, where plant growth is ecophysiologically coupled with hydrological variables. For these simulations, the model was adapted to the Mediterranean region in terms of agrosystems as well as crop parameters, and a sensitivity analysis for the irrigation system efficiency was performed. Patterns of current irrigation water requirements differ strongly spatially within the Mediterranean region depending mainly on potential evapotranspiration, the combination of crops cultivated and the extension of irrigated areas. The simulations for the future indicate that the Mediterranean may need considerable additional amounts of irrigation water. However, the regional patterns differ strongly depending on changes in length of growing periods, changes in transpirational rate (temperature and precipitation change, CO2-fertilization), and the consideration of potential improvements in irrigation system efficiency.

  18. EURRECA-Estimating zinc requirements for deriving dietary reference values.

    PubMed

    Lowe, Nicola M; Dykes, Fiona C; Skinner, Anna-Louise; Patel, Sujata; Warthon-Medina, Marisol; Decsi, Tamás; Fekete, Katalin; Souverein, Olga W; Dullemeijer, Carla; Cavelaars, Adriënne E; Serra-Majem, Lluis; Nissensohn, Mariela; Bel, Silvia; Moreno, Luis A; Hermoso, Maria; Vollhardt, Christiane; Berti, Cristiana; Cetin, Irene; Gurinovic, Mirjana; Novakovic, Romana; Harvey, Linda J; Collings, Rachel; Hall-Moran, Victoria

    2013-01-01

    Zinc was selected as a priority micronutrient for EURRECA, because there is significant heterogeneity in the Dietary Reference Values (DRVs) across Europe. In addition, the prevalence of inadequate zinc intakes was thought to be high among all population groups worldwide, and the public health concern is considerable. In accordance with the EURRECA consortium principles and protocols, a series of literature reviews were undertaken in order to develop best practice guidelines for assessing dietary zinc intake and zinc status. These were incorporated into subsequent literature search strategies and protocols for studies investigating the relationships between zinc intake, status and health, as well as studies relating to the factorial approach (including bioavailability) for setting dietary recommendations. EMBASE (Ovid), Cochrane Library CENTRAL, and MEDLINE (Ovid) databases were searched for studies published up to February 2010 and collated into a series of Endnote databases that are available for the use of future DRV panels. Meta-analyses of data extracted from these publications were performed where possible in order to address specific questions relating to factors affecting dietary recommendations. This review has highlighted the need for more high quality studies to address gaps in current knowledge, in particular the continued search for a reliable biomarker of zinc status and the influence of genetic polymorphisms on individual dietary requirements. In addition, there is a need to further develop models of the effect of dietary inhibitors of zinc absorption and their impact on population dietary zinc requirements. PMID:23952091

  19. Estimated water requirements for the conventional flotation of copper ores

    USGS Publications Warehouse

    Bleiwas, Donald I.

    2012-01-01

    This report provides a perspective on the amount of water used by a conventional copper flotation plant. Water is required for many activities at a mine-mill site, including ore production and beneficiation, dust and fire suppression, drinking and sanitation, and minesite reclamation. The water required to operate a flotation plant may outweigh all of the other uses of water at a mine site, [however,] and the need to maintain a water balance is critical for the plant to operate efficiently. Process water may be irretrievably lost or not immediately available for reuse in the beneficiation plant because it has been used in the production of backfill slurry from tailings to provide underground mine support; because it has been entrapped in the tailings stored in the TSF, evaporated from the TSF, or leaked from pipes and (or) the TSF; and because it has been retained as moisture in the concentrate. Water retained in the interstices of the tailings and the evaporation of water from the surface of the TSF are the two most significant contributors to water loss at a conventional flotation circuit facility.

  20. Irrigation as a determinant of the land use impacts of biofuels

    NASA Astrophysics Data System (ADS)

    Liu, J.; Hertel, T. W.; Taheripour, F.

    2011-12-01

    Previous research into the global land use impacts of biofuels has assumed that cropland area could expand in most regions of the world. Indeed, such expansion into more carbon-rich land cover such as grassland or forest is the focus of research into the contributions of indirect land use to the GHG impacts of biofuels. Several studies have examined the global land use consequences of biofuel production. However, all of these studies have effectively treated all cropland as being rainfed. The role of irrigation in biofuel-induced cropland expansion has been wholly ignored. Irrigated croplands typically have much higher yields than their rainfed counterparts. As a consequence, irrigated lands that represent 20% global cropland cover account for 42% of global crop production. Thus, the question of whether expansion of biofuel involves irrigated or rainfed lands makes a significant difference in terms of how much new land will be required to provide the additional production called for in the presence of biofuels. If the new lands are irrigated, and therefore have higher yields than rainfed lands in the same Agro Ecological Zone (AEZs), then less land conversion will be required. However, this land conversion saving may be impossible because expansion of irrigated area is often constrained, either by insufficient water, or insufficient capacity. In this paper we explore the impact on iLUC estimates if irrigated area cannot be expanded. Since earlier studies have assumed the opposite (no constraint whatsoever on expansion), this paper offers an upper bound on the change in land use patterns once one accounts for irrigation. Results show that the change in global cropland area is 15% larger when the irrigation constraint is imposed. This is a direct consequence of the lower yields in rainfed areas. The figure is larger in the US, where the elimination of potential for expanding irrigated areas results in 23% more cropland cover change. The results also show that the

  1. Variable rate irrigation management for peanut in the eastern Coastal Plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variable rate irrigation provides farmers with a tool to spatially allocate limited water resources while potentially increasing profits. Optimal management of these variable rate irrigation systems will likely require rapid and reliable spatial data. We conducted variable rate irrigation experiment...

  2. Infiltration of unconsumed irrigation water in Utah

    USGS Publications Warehouse

    Brothers, William C.; Thiros, Susan A.

    1991-01-01

    The ground-water hydrology of Panguitch Valley and adjacent areas, south-central Utah, was studied during 1988-90. One objective of the study was to measure ground-water recharge from infiltration of unconsumed irrigation water. Water-level and soil-moisture data were used to estimate travel times for water moving down through the soil profile, and to compare quantities of water reaching the water table after application of flood and sprinkler irrigation. During this study, estimates of travel times from land surface to the water table ranged from 11 days in June 1989 to 2 days in September 1989. Estimates of irrigation water recharging the ground-water system ranged from 25 to 75 percent of the water applied to the flood-irrigated field. Virtually no recharge was apparent for the sprinkler-irrigated field.

  3. Operational Irrigation Scheduling for Citrus Trees with Soil Moisture Data Assimilation and Weather Forecast

    NASA Astrophysics Data System (ADS)

    Han, Xujun; Hendricks Franssen, Harrie-Jan; Martínez Alzamora, Fernando; Ángel Jiménez Bello, Miguel; Chanzy, André; Vereecken, Harry

    2015-04-01

    Agricultural areas in the Mediterranean are expected to face more drought stress in the future due to climate change and human activities. Irrigation scheduling is necessary to allocate the optimal water amount at the right time period to avoid unnecessary water losses. An operational data assimilation framework was set-up to combine model predictions and soil moisture measurements in an optimal way for characterizing the soil water status of the root zone. Irrigation amounts for the next days are optimized on the basis of the soil water status of the root zone and meteorological ensemble predictions. In these experiments, the uncertainties of atmospheric forcings and soil properties were considered. The uncertain model forcings were taken from an ensemble of weather forecasts by ECMWF, and delivered by MeteoFrance in this project. The improved soil moisture profile was used to calculate the irrigation requirement taking into account the root distribution of citrus trees in the subsurface. The approach was tested operationally for the experimental site near Picassent, Valencia, Spain. Three fields were irrigated according to our approach in the years 2013 and 2014. Three others were irrigated traditionally, based on FAO-criteria. Soil moisture was measured by FDR probes at 10 cm and 30 cm depth at various fields and these real time data were assimilated by the Local Ensemble Transform Kalman Filter (LETKF) into the Community Land Model (CLM) to improve the estimation of the soil moisture profile. The measured soil moisture was assimilated five times per day before the start of the next drip irrigation. The final results (total amount of irrigated water, stem water potential and citrus production) show that our strategy resulted in significantly less irrigated water compared to the FAO-irrigated fields, but without indications of increased water stress. Soil moisture contents did not decline over time in our approach, stem water potential measurements did not

  4. 19 CFR 141.102 - When deposit of estimated duties, estimated taxes, or both not required.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... regulations of the Bureau of Alcohol, Tobacco and Firearms (27 CFR part 251). (c) Deferral of payment of taxes on alcoholic beverages. An importer may pay on a semimonthly basis the estimated internal revenue taxes on all the alcoholic beverages entered or withdrawn for consumption during that period, under...

  5. 19 CFR 141.102 - When deposit of estimated duties, estimated taxes, or both not required.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... regulations of the Bureau of Alcohol, Tobacco and Firearms (27 CFR part 251). (c) Deferral of payment of taxes on alcoholic beverages. An importer may pay on a semimonthly basis the estimated internal revenue taxes on all the alcoholic beverages entered or withdrawn for consumption during that period, under...

  6. 19 CFR 141.102 - When deposit of estimated duties, estimated taxes, or both not required.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... regulations of the Bureau of Alcohol, Tobacco and Firearms (27 CFR part 251). (c) Deferral of payment of taxes on alcoholic beverages. An importer may pay on a semimonthly basis the estimated internal revenue taxes on all the alcoholic beverages entered or withdrawn for consumption during that period, under...

  7. 19 CFR 141.102 - When deposit of estimated duties, estimated taxes, or both not required.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... regulations of the Bureau of Alcohol, Tobacco and Firearms (27 CFR part 251). (c) Deferral of payment of taxes on alcoholic beverages. An importer may pay on a semimonthly basis the estimated internal revenue taxes on all the alcoholic beverages entered or withdrawn for consumption during that period, under...

  8. 19 CFR 141.102 - When deposit of estimated duties, estimated taxes, or both not required.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... regulations of the Bureau of Alcohol, Tobacco and Firearms (27 CFR part 251). (c) Deferral of payment of taxes on alcoholic beverages. An importer may pay on a semimonthly basis the estimated internal revenue taxes on all the alcoholic beverages entered or withdrawn for consumption during that period, under...

  9. Practical implications of applied irrigation research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Groundwater is essential to irrigated agriculture in the semi-arid Texas High Plains. Concerns over groundwater depletion have led to increased emphasis on water conservation. Irrigation scheduling coupled with accurate crop water use (ET) estimation is one of the most effective means to both conser...

  10. Reducing irrigation water demand with cotton production in West Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to declining water availability from the Ogallala Aquifer and increasing pumping costs, irrigation management options for cotton are analyzed. The study concludes that supplemental irrigation while meeting crop evapotranspiration (ET) requirements is the most profitable option. Switching from co...

  11. Testing an Irrigation Decision Support Tool for California Specialty Crops

    NASA Astrophysics Data System (ADS)

    Johnson, L.; Cahn, M.; Benzen, S.; Zaragoza, I.; Murphy, L.; Melton, F. S.; Martin, F.; Quackenbush, A.; Lockhart, T.

    2015-12-01

    Estimation of crop evapotranspiration supports efficiency of irrigation water management, which in turn can mitigate nitrate leaching, groundwater depletion, and provide energy savings. Past research in California and elsewhere has revealed strong relationships between photosynthetically active vegetation fraction (Fc) and crop evapotranspiration (ETc). Additional research has shown the potential of monitoring Fc by satellite remote sensing. The U.C. Cooperative Extension developed and operates CropManage (CM) as on-line database irrigation (and nitrogen) scheduling tool. CM accounts for the rapid growth and typically brief cycle of cool-season vegetables, where Fc and fraction of reference ET can change daily during canopy development. The model automates crop water requirement calculations based on reference ET data collected by California Dept. Water Resources. Empirically-derived equations are used to estimate daily Fc time-series for a given crop type primarily as a function of planting date and expected harvest date. An application programming interface (API) is under development to provide a check on modeled Fc of current crops and facilitate CM expansion to new crops. The API will enable CM to extract field scale Fc observations from NASA's Satellite Irrigation Management Support (SIMS). SIMS is mainly Landsat based and currently monitors Fc over about 8 million irrigation acres statewide, with potential for adding data from ESA/Sentinel for improved temporal resolution. In the current study, a replicated irrigation trial was performed on romaine lettuce at the USDA Agricultural Research Station in Salinas, CA. CropManage recommendations were used to guide water treatments by drip irrigation at 50%, 75%, 100% ETc replacement levels, with an added treatment at 150% ET representing grower standard practice. Experimental results indicate that yields from the 100% and 150% treatments were not significantly different and were in-line with industry average, while

  12. Pumpage data from irrigation wells in eastern Laramie County, Wyoming, and Kimball County, Nebraska

    USGS Publications Warehouse

    Avery, Charles

    1983-01-01

    Quantitative information concerning pumpage by irrigation wells is an integral component of the U.S. Geological Survey High Plains Regional Aquifer System Analysis. Thus, operation time, discharge rate, and irrigated acreage were measured at approximately 450 randomly selected irrigation wells within 10 areas of the High Plains during the 1980 irrigation season. The data were used to estimate the seasonal mean application of water to crops and to project total pumpage by irrigation wells in 1980 throughout the High Plains area. As part of the sampling effort, 50 irrigation wells were randomly chosen from the area of eastern Laramie County, Wyoming, and Kimball County, Nebraska. Required information was collected on only 40 of the wells. For these wells, the seasonal mean application of water on the irrigated land was 15.2 inches. For the major crop types, the seasonal mean application, in inches, were as follows: alfalfa, 19.8; corn, 15.4; potatoes, 13.8; beans, 12.8; and small grains 10.2. (USGS)

  13. Irrigation scheduling by ET and soil water sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation scheduling is the process of deciding when, where and how much to irrigate, usually with the goal of optimizing economic return on investment in land, equipment, inputs and personnel. This hour-long seminar presents methods of irrigation scheduling based, on the one hand on estimates of t...

  14. Application of a crop model forced with remote sensing data at high spatio-temporal resolution to estimate evaporation and yields of irrigated grasslands in the South Eastern France

    NASA Astrophysics Data System (ADS)

    Couralt, D.; Hadria, R.; Ruget, F.; Duchemin, B.; Hagolle, O.

    2009-09-01

    This study focused on the feasibility of using remote sensing data acquired at high spatial and temporal resolution (FORMOSAT-2 images(http://www.spotimage.fr/web/en/977--formosat-2-images.php) for crop monitoring at regional scale. The monitoring of agricultural practices such as grassland mowing and irrigation is essential to simulate accurately all processes related to crop system. This information is needed for example in crop simulation models to estimate production, water and fertilizer consumption and can thus serve to better understand the interactions between agriculture and climate. The analysis of these interactions is especially important in Mediterranean region where the effects of climate changes and crop management modifications are increasingly marked. In this context, an experiment was conducted in 2006 in Crau region in the South-Eastern France. In this area, permanent grassland represents 67 % of the usable agricultural area, and it is often used with irrigation (47 % of the permanent grassland). A time series of 36 FORMOSAT-2 images was acquired with a three days frequency from March to October 2006. Information concerning grassland mowing and irrigation was collected through a survey over 120 fields. The high FORMOSAT-2 revisit frequency allowed replicating the dynamics of Leaf Area index (LAI), and detecting to some extents cultural practices like vegetation cut. Simple automatic algorithms were developed to obtain daily values of LAI for each grasslands field linked with the main agricultural practices performed (cut and irrigation dates). This information was then used in a crop model called STICS (http://147.100.66.194/stics/) to estimate the spatial variability of evapotranspiration and drainage associated with the aerial biomass productions. Comparisons between simulated and observed yields gave satisfactory results. The great spatial variations of evapotranspiration were strongly related to the crop and water management. Such

  15. Irrigation management with remote sensing. [Navajo Indian Irrigation Project

    NASA Technical Reports Server (NTRS)

    Harlan, C.; Heilman, J. L.; Moore, D.; Myers, V. (Principal Investigator)

    1982-01-01

    Two visible/near IR hand held radiometers and a hand held thermoradiometer were used along with soil moisture and lysimetric measurements in a study of soil moisture distribution in afalfa fields on the Navajo Indian Irrigation Project near farmington, New Mexico. Radiances from irrigated plots were measured and converted to reflectances. Surface soil water contents (o cm to 4 cm) were determined gravimetrically on samples collected at the same time as the spectral measurements. The relationship between the spectral measurements and the crop coefficient were evaluated to demonstrate potential for using spectral measurement to estimate crop coefficient.

  16. Spectral reflectance indices for estimating yield and water content in spring wheat genotypes under well irrigated, water stress, and high temperature conditions

    NASA Astrophysics Data System (ADS)

    Gutierrez-Rodriguez, Mario

    Scope and Method of Study. Alternative methods for selecting, detecting, and identifying higher yielding genotypes in wheat breeding programs are important for obtaining major genetic gains. The water indices can be used as an indirect selection tool because of their strong association with different physiological and yield components. Diverse spring wheat advanced lines were used, which corresponded to three international trials developed by the International Maize and Wheat Improvement Center (CIMMYT); 24th Elite Spring Wheat Yield Trial (ESWYT) with 25 lines, 11th Semi-Arid Wheat Yield Trial (SAWYT) with 40 lines, and 11th High Temperature Wheat Yield Trial (HTWYT) with 18 lines. Two other experiments also employed advanced lines for testing the relationship between water indices and water content parameters (10-16 lines) and for evaluating the influence of morphological traits (20 lines) over the water indices. Several water indices and other reflectance indices were estimated at three growth stages (booting, heading, and grain filling) using a field portable spectrometer (Analytical Spectral Devices, Boulder, CO). Field plots were planted in Northwest Mexico during three growing seasons (2006, 2007, and 2007). Grain yield, biomass, and some water status parameters were determined in diverse experiments. Findings and Conclusions. There were high correlations (phenotypic and genetic) between grain yield and the water indices showing high heritability, response to selection and correlated response, relative selection efficiency, and efficiency in selecting the higher yielding genotypes. Two water indices showed the strongest relationships (NWI-1 and NWI-3) for all the parameters determined in the well irrigated, water stress, and high temperature environments. In addition, the water indices were related with parameters commonly employed for assessing the crop water status ( i.e., water potential) during booting, anthesis and grain filling under water stress

  17. Soil salinisation and irrigation management of date palms in a Saharan environment.

    PubMed

    Haj-Amor, Zied; Ibrahimi, Mohamed-Khaled; Feki, Nissma; Lhomme, Jean-Paul; Bouri, Salem

    2016-08-01

    The continuance of agricultural production in regions of the world with chronic water shortages depends upon understanding how soil salinity is impacted by irrigation practises such as water salinity, irrigation frequency and amount of irrigation. A two-year field study was conducted in a Saharan oasis of Tunisia (Lazala Oasis) to determine how the soil electrical conductivity was affected by irrigation of date palms with high saline water. The study area lacked a saline shallow water table. Field results indicate that, under current irrigation practises, soil electrical conductivity can build up to levels which exceed the salt tolerance of date palm trees. The effects of irrigation practises on the soil electrical conductivity were also evaluated using model simulations (HYDRUS-1D) of various irrigation regimes with different frequencies, different amounts of added water and different water salinities. The comparison between the simulated and observed results demonstrated that the model gave an acceptable estimation of water and salt dynamics in the soil profile, as indicated by the small values of root mean square error (RMSE) and the high values of the Nash-Sutcliffe model efficiency coefficient (NSE). The simulations demonstrated that, under field conditions without saline shallow groundwater, saline irrigation water can be used to maintain soil electrical conductivity and soil water content at safe levels (soil electrical conductivity <4 dS m(-1) and soil water content >0.04 cm(3) cm(-3)) if frequent irrigations with small amounts of water (90 % of the evapotranspiration requirements) were applied throughout the year. PMID:27476071

  18. Deficit irrigation for reducing agricultural water use.

    PubMed

    Fereres, Elias; Soriano, María Auxiliadora

    2007-01-01

    At present and more so in the future, irrigated agriculture will take place under water scarcity. Insufficient water supply for irrigation will be the norm rather than the exception, and irrigation management will shift from emphasizing production per unit area towards maximizing the production per unit of water consumed, the water productivity. To cope with scarce supplies, deficit irrigation, defined as the application of water below full crop-water requirements (evapotranspiration), is an important tool to achieve the goal of reducing irrigation water use. While deficit irrigation is widely practised over millions of hectares for a number of reasons - from inadequate network design to excessive irrigation expansion relative to catchment supplies - it has not received sufficient attention in research. Its use in reducing water consumption for biomass production, and for irrigation of annual and perennial crops is reviewed here. There is potential for improving water productivity in many field crops and there is sufficient information for defining the best deficit irrigation strategy for many situations. One conclusion is that the level of irrigation supply under deficit irrigation should be relatively high in most cases, one that permits achieving 60-100% of full evapotranspiration. Several cases on the successful use of regulated deficit irrigation (RDI) in fruit trees and vines are reviewed, showing that RDI not only increases water productivity, but also farmers' profits. Research linking the physiological basis of these responses to the design of RDI strategies is likely to have a significant impact in increasing its adoption in water-limited areas. PMID:17088360

  19. Water requirements and management of maize under drip and sprinkler irrigation. 2000 annual report for Agricultural Technology Utilization and Transfer (ATUT) project

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research at Ismailia, Egypt, focused on irrigation management of maize, fava bean, wheat, and alfalfa. In 1998, the two weighing lysimeters at Ismailia were recalibrated successfully with precision of 0.01 mm; and a state-of-the-art time domain reflectometry (TDR) system for soil water balance measu...

  20. Visual Estimation of Spatial Requirements for Locomotion in Novice Wheelchair Users

    ERIC Educational Resources Information Center

    Higuchi, Takahiro; Takada, Hajime; Matsuura, Yoshifusa; Imanaka, Kuniyasu

    2004-01-01

    Locomotion using a wheelchair requires a wider space than does walking. Two experiments were conducted to test the ability of nonhandicapped adults to estimate the spatial requirements for wheelchair use. Participants judged from a distance whether doorlike apertures of various widths were passable or not passable. Experiment 1 showed that…

  1. Irrigation as an Historical Climate Forcing

    NASA Technical Reports Server (NTRS)

    Cook, Benjamin I.; Shukla, Sonali P.; Puma, Michael J.; Nazarenko, Larissa S.

    2014-01-01

    Irrigation is the single largest anthropogenic water use, a modification of the land surface that significantly affects surface energy budgets, the water cycle, and climate. Irrigation, however, is typically not included in standard historical general circulation model (GCM) simulations along with other anthropogenic and natural forcings. To investigate the importance of irrigation as an anthropogenic climate forcing, we conduct two 5-member ensemble GCM experiments. Both are setup identical to the historical forced (anthropogenic plus natural) scenario used in version 5 of the Coupled Model Intercomparison Project, but in one experiment we also add water to the land surface using a dataset of historically estimated irrigation rates. Irrigation has a negligible effect on the global average radiative balance at the top of the atmosphere, but causes significant cooling of global average surface air temperatures over land and dampens regional warming trends. This cooling is regionally focused and is especially strong in Western North America, the Mediterranean, the Middle East, and Asia. Irrigation enhances cloud cover and precipitation in these same regions, except for summer in parts of Monsoon Asia, where irrigation causes a reduction in monsoon season precipitation. Irrigation cools the surface, reducing upward fluxes of longwave radiation (increasing net longwave), and increases cloud cover, enhancing shortwave reflection (reducing net shortwave). The relative magnitude of these two processes causes regional increases (northern India) or decreases (Central Asia, China) in energy availability at the surface and top of the atmosphere. Despite these changes in net radiation, however, climate responses are due primarily to larger magnitude shifts in the Bowen ratio from sensible to latent heating. Irrigation impacts on temperature, precipitation, and other climate variables are regionally significant, even while other anthropogenic forcings (anthropogenic aerosols

  2. Irrigation As an Historical Climate Forcing

    NASA Astrophysics Data System (ADS)

    Cook, B.; Puma, M. J.; McDermid, S. P.; Nazarenko, L.

    2014-12-01

    Irrigation is the single largest anthropogenic water use, a modification of the land surface that significantly affects surface energy budgets, the water cycle, and climate. Irrigation, however, is typically not included in standard historical general circulation model (GCM) simulations along with other anthropogenic and natural forcings. To investigate the importance of irrigation as an anthropogenic climate forcing, we conduct two 5-member ensemble GCM experiments. Both are setup identical to the historical forced (anthropogenic plus natural) scenario used in version 5 of the Coupled Model Intercomparison Project, but in one experiment we also add water to the land surface using a dataset of historically estimated irrigation rates. Irrigation has a negligible effect on the global average radiative balance at the top of the atmosphere, but causes significant cooling of global average surface air temperatures over land and dampens regional warming trends. This cooling is regionally focused and is especially strong in Western North America, the Mediterranean, the Middle East, and Asia. Irrigation enhances cloud cover and precipitation in these same regions, except for summer in parts of Monsoon Asia, where irrigation causes a reduction in monsoon season precipitation. Irrigation cools the surface, reducing upward fluxes of longwave radiation (increasing net longwave), and increases cloud cover, enhancing shortwave reflection (reducing net shortwave). The relative magnitude of these two processes causes regional increases (northern India) or decreases (Central Asia, China) in energy availability at the surface and top of the atmosphere. Despite these changes in net radiation, however, climate responses are due primarily to larger magnitude shifts in the Bowen ratio from sensible to latent heating. Irrigation impacts on temperature, precipitation, and other climate variables are regionally significant, even while other anthropogenic forcings (anthropogenic aerosols

  3. Irrigation as an historical climate forcing

    NASA Astrophysics Data System (ADS)

    Cook, Benjamin I.; Shukla, Sonali P.; Puma, Michael J.; Nazarenko, Larissa S.

    2015-03-01

    Irrigation is the single largest anthropogenic water use, a modification of the land surface that significantly affects surface energy budgets, the water cycle, and climate. Irrigation, however, is typically not included in standard historical general circulation model (GCM) simulations along with other anthropogenic and natural forcings. To investigate the importance of irrigation as an anthropogenic climate forcing, we conduct two 5-member ensemble GCM experiments. Both are setup identical to the historical forced (anthropogenic plus natural) scenario used in version 5 of the Coupled Model Intercomparison Project, but in one experiment we also add water to the land surface using a dataset of historically estimated irrigation rates. Irrigation has a negligible effect on the global average radiative balance at the top of the atmosphere, but causes significant cooling of global average surface air temperatures over land and dampens regional warming trends. This cooling is regionally focused and is especially strong in Western North America, the Mediterranean, the Middle East, and Asia. Irrigation enhances cloud cover and precipitation in these same regions, except for summer in parts of Monsoon Asia, where irrigation causes a reduction in monsoon season precipitation. Irrigation cools the surface, reducing upward fluxes of longwave radiation (increasing net longwave), and increases cloud cover, enhancing shortwave reflection (reducing net shortwave). The relative magnitude of these two processes causes regional increases (northern India) or decreases (Central Asia, China) in energy availability at the surface and top of the atmosphere. Despite these changes in net radiation, however, climate responses are due primarily to larger magnitude shifts in the Bowen ratio from sensible to latent heating. Irrigation impacts on temperature, precipitation, and other climate variables are regionally significant, even while other anthropogenic forcings (anthropogenic aerosols

  4. Irrigation strategies using subsurface drip irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subsurface drip irrigation (SDI) is practiced on approximately 60,000 ha in the Texas High Plains region of the USA. Adoption of SDI continues to increase in the region. This has been attributed to record drought in Texas and the US Southwest in recent years, declining irrigation well yields, and ev...

  5. Impacts of Change in Irrigation Water Availability on Food Production in the Yellow River Basin under Climate Change

    NASA Astrophysics Data System (ADS)

    Yin, Y. Y.; Tang, Q.

    2014-12-01

    Approximately 9 percent of China's population and 17 percent of its agricultural area are settled in the Yellow River Basins. Irrigation, which plays an important role in agricultural production, occupies the largest share of human consumptive water use in the basin. Given increasing water demands, the basin faces acute water scarcity. Previous studies have suggested that decrease in irrigation water availability under climate change might have an overall adverse impact on the food production of the basin. The timing and area that would face severe water stress are yet to be identified. We used a land surface hydrological model forced with the bias-corrected climatic variables from 5 climate models under 4 Representative Concentration Pathways (RCPs) to estimate total water availability in the sub-basins of the Yellow River basin. The future socioeconomic conditions, the Shared Socioeconomic Pathways (SSPs), were used to estimate the water requirement in the nonagricultural water use sectors. The irrigation water availability was estimated from the total water availability and nonagricultural water use, and the irrigation water demands were estimated based on the current irrigation project efficiencies. The timing and area of irrigation water shortage were shown and the implication of change in irrigation water availability on food production was assessed. The results show that the sub-basins with high population density and gross domestic product (GDP) are likely to confront severe water stress and reduction in food production earlier because irrigation water was to be appropriated by the rapid increase in nonagricultural water use sectors. The study stresses the need for adaptive management of water to balance agriculture and nonagricultural demands in northern China.

  6. Irrigation Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop water use (evapotranspiration = ET) is often estimated as ET = Kc x ETo, where ETo is a reference ET calculated from weather data and Kc is a crop coefficient that is specific to a crop variety and stage of growth. This paradigm has become the dominant one in state and federal efforts to provid...

  7. Surface drip irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For many years, surface drip irrigation has been used to irrigation high value vegetable crops. In recent years, surface drip of row crops has been increasing throughout the United States. Surface drip irrigation can precisely deliver water and nutrients to the crop root zone. This article provides ...

  8. Planning for deficit irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigators with limited water supplies that lead to deficit irrigation management need to make decisions about crop selection, water allocations to each crop, and irrigation schedules. Many of these decisions need to occur before the crop is planted and depend on yield-evapotranspiration (ET) and yi...

  9. Closing the irrigation deficit in Cambodia: Implications for transboundary impacts on groundwater and Mekong River flow

    NASA Astrophysics Data System (ADS)

    Erban, Laura E.; Gorelick, Steven M.

    2016-04-01

    Rice production in Cambodia, essential to food security and exports, is largely limited to the wet season. The vast majority (96%) of land planted with rice during the wet season remains fallow during the dry season. This is in large part due to lack of irrigation capacity, increases in which would entail significant consequences for Cambodia and Vietnam, located downstream on the Mekong River. Here we quantify the extent of the dry season "deficit" area in the Cambodian Mekong River catchment, using a recent agricultural survey and our analysis of MODIS satellite data. Irrigation of this land for rice production would require a volume of water up to 31% of dry season Mekong River flow to Vietnam. However, the two countries share an aquifer system in the Mekong Delta, where irrigation demand is increasingly met by groundwater. We estimate expansion rates of groundwater-irrigated land to be >10% per year in the Cambodian Delta using LANDSAT satellite data and simulate the effects of future expansion on groundwater levels over a 25-year period. If groundwater irrigation continues to expand at current rates, the water table will drop below the lift limit of suction pump wells, used for domestic supply by >1.5 million people, throughout much of the area within 15 years. Extensive groundwater irrigation jeopardizes access for shallow domestic water supply wells, raises the costs of pumping for all groundwater users, and may exacerbate arsenic contamination and land subsidence that are already widespread hazards in the region.

  10. IRRIMET: a web 2.0 advisory service for irrigation water management

    NASA Astrophysics Data System (ADS)

    De Michele, Carlo; Anzano, Enrico; Colandrea, Marco; Marotta, Luigi; Mula, Ileana; Pelosi, Anna; D'Urso, Guido; Battista Chirico, Giovanni

    2016-04-01

    Irrigation agriculture is one the biggest consumer of water in Europe, especially in southern regions, where it accounts for up to 70% of the total water consumption. The EU Common Agricultural Policy, combined with the Water Framework Directive, imposes to farmers and irrigation managers a substantial increase of the efficiency in the use of water in agriculture for the next decade. Irrigating according to reliable crop water requirement estimates is one of the most convincing solution to decrease agricultural water use. Here we present an innovative irrigation advisory service, applied in Campania region (Southern Italy), where a satellite assisted irrigation advisory service has been operating since 2006. The advisory service is based on the optimal combination of VIS-NIR high resolution satellite images (Landsat, Deimos, Rapideye) to map crop vigour, and high resolution numerical weather prediction for assessing the meteorological variables driving the crop water needs in the short-medium range. The advisory service is broadcasted with a simple and intuitive web app interface which makes daily real time irrigation and evapotranspiration maps and customized weather forecasts (based on Cosmo Leps model) accessible from desktop computers, tablets and smartphones.

  11. Corn Nutritional Properties and Yields with Surface Drip Irrigation in Topographically Variable Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of a method to effectively irrigate row crops that requires less capital investment than current methods will improve the economic feasibility of irrigation. A surface drip irrigation system was installed and investigated to irrigate a corn field with very little topographic variation a...

  12. Irrigation management using an expert system, soil water potentials, and vegetative indices for spatial applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variable rate irrigation (VRI) systems are irrigation systems that are capable of applying different water depths both in the direction of travel and along the length of the irrigation system. However, when compared to traditional irrigation systems, VRI systems require a higher level of management...

  13. Role of irrigation and irrigation automation in improving crop water use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In arid climates, irrigation is required for significant agricultural production. In subhumid and semiarid climates, supplemental irrigation is recognized as both economically necessary (prevention of crop losses in periodic droughts) and as a means to improve overall crop water use effi...

  14. Sustaining Irrigated Agriculture In The Central High Plains With Limited Irrigation Water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing demands on limited water supplies will require maximizing crop production per unit water. Field studies are being carried out to develop water production functions for crops grown in the Great Plains. Irrigation water is applied through drip irrigation systems; precipitation and reference...

  15. Desert landscape irrigation

    SciTech Connect

    Quinones, R.

    1995-06-01

    Industrialization can take place in an arid environment if a long term, overall water management program is developed. The general rule to follow is that recharge must equal or exceed use. The main problem encountered in landscape projects is that everyone wants a lush jungle setting, tall shade trees, ferns, with a variety of floral arrangements mixed in. What we want, what we can afford, and what we get are not always the same. Vegetation that requires large quantities of water are not native to any desert. Surprisingly; there are various types of fruit trees, and vegetables that will thrive in the desert. Peaches, plums, nut trees, do well with drip irrigation as well as tomatoes. Shaded berry plans will also do well, the strawberry being one. In summary; if we match our landscape to our area, we can then design our irrigation system to maintain our landscape and grow a variety of vegetation in any arid or semiarid environment. The application of science and economics to landscaping has now come of age.

  16. Coupled Hydro-Economic Dynamics of Groundwater Irrigated Agriculture in a Hard Rock Region of India

    NASA Astrophysics Data System (ADS)

    Modi, V.; Fishman, R.; Siegfried, T. U.; Raj, P.; Vasquez, V.; Narula, K.; Lall, U.

    2009-12-01

    We analyze the dynamics of groundwater and irrigated agriculture in a semi-arid, hard rock region of India, which is characterized by low-yield, limited storativity aquifers. Telengana, in western Andhra Pradesh has witnessed a relentless expansion of the total irrigated area. Total crop irrigation water requirements have increased by more than 50 percent over the last 30 years. Nowadays, more than 80 percent of the net irrigated area in the region is irrigated from groundwater. Given limited, period monsoonal recharge to the aquifers, it can be estimated that groundwater irrigation intensity is surpassing sustainable allocation levels by a factor of 3. It is not further surprising that the region is increasingly affected by widespread groundwater depletion, with negative consequences for farmers and the energy sector as well as the natural environment. Using data on water tables, precipitation and agricultural land use, we show how both rainfall and farmers’ choices effect water tables and how these, in turn, re-effect farmers choices and agricultural outcomes in a dynamic relationship that allows us to model the interaction between the natural hydrological and agricultural-social dynamics. We use the model to elucidate and quantify the meaning of groundwater mining in this hard rock environment. In contrast to deep alluvial aquifers, excessive extraction does not lead to sustained long term deepening of the water table, but to increased fluctuations in the supply of groundwater for irrigation and the loss of the buffering capacity. For the farmers, this potentially translates into increasingly perilous agricultural production outcomes during monsoonal failures. Furthermore, the dry season agricultural production that entirely depends on the availability of sufficient amounts of irrigation water is progressively threatened under the current allocation scenario. Alternative management practices to address the aquifer depletion issues are discussed. We show that

  17. Adaptability of Irrigation to a Changing Monsoon in India: How far can we go?

    NASA Astrophysics Data System (ADS)

    Zaveri, E.; Grogan, D. S.; Fisher-Vanden, K.; Frolking, S. E.; Wrenn, D. H.; Nicholas, R.

    2014-12-01

    Agriculture and the monsoon are inextricably linked in India. A large part of the steady rise in agricultural production since the onset of the Green Revolution in the 1960's has been attributed to irrigation. Irrigation is used to supplement and buffer crops against precipitation shocks, but water availability for such use is itself sensitive to the erratic, seasonal and spatially heterogeneous nature of the monsoon. We provide new evidence on the relationship between monsoon changes, irrigation variability and water availability by linking a process based hydrology model with an econometric model for one of the world's most water stressed countries. India uses more groundwater for irrigation than any other country, and there is substantial evidence that this has led to depletion of groundwater aquifers. First, we build an econometric model of historical irrigation decisions using detailed agriculture and weather data spanning 35 years. Multivariate regression models reveal that for crops grown in the wet season, irrigation is sensitive to distribution and total monsoon rainfall but not to ground or surface water availability. For crops grown in the dry season, total monsoon rainfall matters most, and its effect is sensitive to groundwater availability. The historical estimates from the econometric model are used to calculate future irrigated areas under three different climate model predictions of monsoon climate for the years 2010 - 2050. These projections are then used as input to a physical hydrology model, which quantifies supply of irrigation water from sustainable sources such as rechargeable shallow groundwater, rivers and reservoirs, to unsustainable sources such as non- rechargeable groundwater. We find that the significant variation in monsoon projections lead to very different results. Crops grown in the dry season show particularly divergent trends between model projections, leading to very different groundwater resource requirements.

  18. Using models to determine irrigation applications for water management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple models are used by field researchers and production agriculture to estimate crop water use for the purpose of scheduling irrigation applications. These are generally based on a simple volume balance approach based on estimates of soil water holding capacity, irrigation application amounts, pr...

  19. Nitrate contamination and its relationship with flood irrigation management

    NASA Astrophysics Data System (ADS)

    García-Garizábal, I.; Causapé, J.; Abrahao, R.

    2012-06-01

    SummaryNitrate contamination is a significant unresolved environmental issue for agriculture in the 21st century, with longstanding challenges in its control and allocation to a specified territory. In order to address these challenges, real-world meticulous irrigation area studies are required. The objective of this investigation is to analyze the evolution of nitrate contamination in relation to agronomic and management changes within a traditionally irrigated land. Specifically, the impact of changes in irrigation allowance assignment, changes in irrigation method from rotation to on-demand flood irrigation, and creation of water consumption accounts were analyzed. To this end, nitrogen monitoring and annual balances were carried out in a small irrigated hydrological basin (95 ha) located in Northeastern Spain throughout the years of 2001 and 2005-2008. The evolution of the nitrate contamination index was also analyzed, which relates the mass of nitrates exported to the fertilization necessities of a specific irrigated area. The results demonstrated that although changes in crop pattern caused a 33% reduction in the nitrogen required through fertilization, the fertilization rates applied are still double the necessities. Changes in irrigation management decreased the mass of nitrates exported by half and the nitrate contamination index by 24%, but the nitrate levels present are still approximately double of those registered in modern irrigation areas. The changes implemented by the Irrigation District in the irrigation management were effective. However, this study confirms that a greater effort is still required to achieve adequate nitrogen fertilization matching the crop necessities.

  20. Estimating resource costs of compliance with EU WFD ecological status requirements at the river basin scale

    NASA Astrophysics Data System (ADS)

    Riegels, Niels; Jensen, Roar; Bensasson, Lisa; Banou, Stella; Møller, Flemming; Bauer-Gottwein, Peter

    2011-01-01

    SummaryResource costs of meeting EU WFD ecological status requirements at the river basin scale are estimated by comparing net benefits of water use given ecological status constraints to baseline water use values. Resource costs are interpreted as opportunity costs of water use arising from water scarcity. An optimization approach is used to identify economically efficient ways to meet WFD requirements. The approach is implemented using a river basin simulation model coupled to an economic post-processor; the simulation model and post-processor are run from a central controller that iterates until an allocation is found that maximizes net benefits given WFD requirements. Water use values are estimated for urban/domestic, agricultural, industrial, livestock, and tourism water users. Ecological status is estimated using metrics that relate average monthly river flow volumes to the natural hydrologic regime. Ecological status is only estimated with respect to hydrologic regime; other indicators are ignored in this analysis. The decision variable in the optimization is the price of water, which is used to vary demands using consumer and producer water demand functions. The price-based optimization approach minimizes the number of decision variables in the optimization problem and provides guidance for pricing policies that meet WFD objectives. Results from a real-world application in northern Greece show the suitability of the approach for use in complex, water-stressed basins. The impact of uncertain input values on model outcomes is estimated using the Info-Gap decision analysis framework.

  1. Estimating N requirements for corn using indices developed from a canopy reflectance sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the increasing cost of fertilizer N, there is a renewed emphasis on developing new technologies for quantifying in-season N requirements for corn. The objectives of this research are (i) to evaluate different vegetative indices derived from an active reflectance sensor in estimating in-season N...

  2. Brief to the Committee on University Affairs. Estimates of Operating Grant Requirements for 1970-71.

    ERIC Educational Resources Information Center

    Committee of Presidents of Universities of Ontario, Toronto.

    This brief contains a refinement and amplification of preliminary estimates of operating fund requirements of the provincially assisted universities of Ontario for 1970-71. Part B of the report contains quantitative descriptors of university operations including budgeted operating expenditures for 1969-70, faculty income unit ratios in 1969-70,…

  3. Use Of Crop Canopy Size To Estimate Water Requirements Of Vegetable Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting time, plant density, variety, and cultural practices vary widely for horticultural crops. It is difficult to estimate crop water requirements for crops with these variations. Canopy size, or factional ground cover, as an indicator of intercepted sunlight, is related to crop water use. We...

  4. Evaluating Multiple Indices from a Canopy Reflectance Sensor to Estimate Corn N Requirements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the increasing cost of fertilizer N, there is a renewed emphasis on developing new technologies for quantifying in-season N requirements for corn. The objectives of this research are (i) to evaluate different vegetative indices derived from an active reflectance sensor in estimating in-season N...

  5. Estimation of Managerial and Technical Personnel Requirements in Selected Industries. Training for Industry Series, No. 2.

    ERIC Educational Resources Information Center

    United Nations Industrial Development Organization, Vienna (Austria).

    The need to develop managerial and technical personnel in the cement, fertilizer, pulp and paper, sugar, leather and shoe, glass, and metal processing industries of various nations was studied, with emphasis on necessary steps in developing nations to relate occupational requirements to technology, processes, and scale of output. Estimates were…

  6. Water balance in irrigation districts. Uncertainty in on-demand pressurized networks

    NASA Astrophysics Data System (ADS)

    Sánchez-Calvo, Raúl; Rodríguez-Sinobas, Leonor; Juana, Luis; Laguna, Francisco Vicente

    2015-04-01

    In on-demand pressurized irrigation distribution networks, applied water volume is usually controlled opening a valve during a calculated time interval, and assuming constant flow rate. In general, pressure regulating devices for controlling the discharged flow rate by irrigation units are needed due to the variability of pressure conditions. A pressure regulating valve PRV is the commonly used pressure regulating device in a hydrant, which, also, executes the open and close function. A hydrant feeds several irrigation units, requiring a wide range in flow rate. In addition, some flow meters are also available, one as a component of the hydrant and the rest are placed downstream. Every land owner has one flow meter for each group of field plots downstream the hydrant. Ideal PRV performance would maintain a constant downstream pressure. However, the true performance depends on both upstream pressure and the discharged flow rate. Theoretical flow rates values have been introduced into a PRV behavioral model, validated in laboratory, coupled with an on-demand irrigation district waterworks, composed by a distribution network and a multi-pump station. Variations on flow rate are simulated by taking into account the consequences of variations on climate conditions and also decisions in irrigation operation, such us duration and frequency application. The model comprises continuity, dynamic and energy equations of the components of both the PRV and the water distribution network. In this work the estimation of water balance terms during the irrigation events in an irrigation campaign has been simulated. The effect of demand concentration peaks has been estimated.

  7. The Sustainability of Irrigation Schemes Under Climate Change

    NASA Astrophysics Data System (ADS)

    Naabil, E.; Lamptey, B. L.; Arnault, J.; Ayorinde, O. A.; Kunstmann, H.

    2015-12-01

    Irrigation is considered to be one of the best practices in agriculture to ensure food security. However water resources that are used for Irrigation activities are increasingly coming under stress, either due to extraction or climate variability and change. To adequately plan and manage water resources so as to ensure their sustainability requires a long term investigations of streamflow and climate. Streamflow analysis and forecasting gives signal of the occurrence of floods and drought situations. However the ability to maximise these early warning signal, especially for small watersheds, require the use of rainfall predictions approaches (Yucel et al., 2015). One approach to extend the predictions of these early warning signals is the coupling of mesoscale numerical weather prediction (NWP) model precipitation estimates with a spatial resolution hydrological model into streamflow estimates (Jasper et al. 2002;Wardah et al. 2008; Yucel et al. 2015). The study explored (1) the potential of the NWP model (WRF) in reproducing observed precipitation over the Tono basin in West Africa, and (2) the potential of a coupled version of WRF with a physics-based hydrological model (WRF-Hydro) in estimating river streamflow. In order to cope with the lack of discharge observation in the Tono basin, the WRF-Hydro performances are evaluated with a water balance approach and dam level observation. The WRF-Hydro predicted dam level is relatively close to the observation (dam level) from January to August (R2=0.93). After this period the deviation from observation increases (R2=0.62). This could be attributed to surface runoff due to peak rainfall (in August) resulting in soil saturation (soil reaching infiltration capacity) into the dam which has not been accounted for in the water balance model. WRF-Hydro has shown to give good estimation of streamflow especially for ungauged stations. Further works requires using WRF-Hydro modeling system for climate projection, and assess the

  8. Estimating Agricultural Water Use using the Operational Simplified Surface Energy Balance Evapotranspiration Estimation Method

    NASA Astrophysics Data System (ADS)

    Forbes, B. T.

    2015-12-01

    Due to the predominantly arid climate in Arizona, access to adequate water supply is vital to the economic development and livelihood of the State. Water supply has become increasingly important during periods of prolonged drought, which has strained reservoir water levels in the Desert Southwest over past years. Arizona's water use is dominated by agriculture, consuming about seventy-five percent of the total annual water demand. Tracking current agricultural water use is important for managers and policy makers so that current water demand can be assessed and current information can be used to forecast future demands. However, many croplands in Arizona are irrigated outside of areas where water use reporting is mandatory. To estimate irrigation withdrawals on these lands, we use a combination of field verification, evapotranspiration (ET) estimation, and irrigation system qualification. ET is typically estimated in Arizona using the Modified Blaney-Criddle method which uses meteorological data to estimate annual crop water requirements. The Modified Blaney-Criddle method assumes crops are irrigated to their full potential over the entire growing season, which may or may not be realistic. We now use the Operational Simplified Surface Energy Balance (SSEBop) ET data in a remote-sensing and energy-balance framework to estimate cropland ET. SSEBop data are of sufficient resolution (30m by 30m) for estimation of field-scale cropland water use. We evaluate our SSEBop-based estimates using ground-truth information and irrigation system qualification obtained in the field. Our approach gives the end user an estimate of crop consumptive use as well as inefficiencies in irrigation system performance—both of which are needed by water managers for tracking irrigated water use in Arizona.

  9. Space transfer vehicle concepts and requirements study. Volume 3, book 1: Program cost estimates

    NASA Astrophysics Data System (ADS)

    Peffley, Al F.

    1991-04-01

    The Space Transfer Vehicle (STV) Concepts and Requirements Study cost estimate and program planning analysis is presented. The cost estimating technique used to support STV system, subsystem, and component cost analysis is a mixture of parametric cost estimating and selective cost analogy approaches. The parametric cost analysis is aimed at developing cost-effective aerobrake, crew module, tank module, and lander designs with the parametric cost estimates data. This is accomplished using cost as a design parameter in an iterative process with conceptual design input information. The parametric estimating approach segregates costs by major program life cycle phase (development, production, integration, and launch support). These phases are further broken out into major hardware subsystems, software functions, and tasks according to the STV preliminary program work breakdown structure (WBS). The WBS is defined to a low enough level of detail by the study team to highlight STV system cost drivers. This level of cost visibility provided the basis for cost sensitivity analysis against various design approaches aimed at achieving a cost-effective design. The cost approach, methodology, and rationale are described. A chronological record of the interim review material relating to cost analysis is included along with a brief summary of the study contract tasks accomplished during that period of review and the key conclusions or observations identified that relate to STV program cost estimates. The STV life cycle costs are estimated on the proprietary parametric cost model (PCM) with inputs organized by a project WBS. Preliminary life cycle schedules are also included.

  10. Space transfer vehicle concepts and requirements study. Volume 3, book 1: Program cost estimates

    NASA Technical Reports Server (NTRS)

    Peffley, Al F.

    1991-01-01

    The Space Transfer Vehicle (STV) Concepts and Requirements Study cost estimate and program planning analysis is presented. The cost estimating technique used to support STV system, subsystem, and component cost analysis is a mixture of parametric cost estimating and selective cost analogy approaches. The parametric cost analysis is aimed at developing cost-effective aerobrake, crew module, tank module, and lander designs with the parametric cost estimates data. This is accomplished using cost as a design parameter in an iterative process with conceptual design input information. The parametric estimating approach segregates costs by major program life cycle phase (development, production, integration, and launch support). These phases are further broken out into major hardware subsystems, software functions, and tasks according to the STV preliminary program work breakdown structure (WBS). The WBS is defined to a low enough level of detail by the study team to highlight STV system cost drivers. This level of cost visibility provided the basis for cost sensitivity analysis against various design approaches aimed at achieving a cost-effective design. The cost approach, methodology, and rationale are described. A chronological record of the interim review material relating to cost analysis is included along with a brief summary of the study contract tasks accomplished during that period of review and the key conclusions or observations identified that relate to STV program cost estimates. The STV life cycle costs are estimated on the proprietary parametric cost model (PCM) with inputs organized by a project WBS. Preliminary life cycle schedules are also included.

  11. Assimilation of cosmic-ray neutron counts for updating of soil moisture and soil properties with application to irrigation scheduling

    NASA Astrophysics Data System (ADS)

    Han, Xujun; Hendricks Franssen, Harrie-Jan; Ángel Jiménez Bello, Miguel; Rosolem, Rafael; Bogena, Heye; Martínez Alzamora, Fernando; Chanzy, André; Vereecken, Harry

    2014-05-01

    The soil moisture is a good indicator of water stress during the irrigation scheduling. The cosmic-ray probes can measure the soil moisture at an intermediate scale through the interaction between the land surface neutron counts and soil moisture profile. This study investigated the assimilation of neutron measurements by a cosmic-ray probe for updating root zone soil moisture as well as soil properties (sand fraction, clay fraction and organic matter density) in Community Land Model (CLM) using the Local Ensemble Transform Kalman Filter (LETKF) for the real time optimal scheduling of irrigation. In order to map the soil moisture into measured neutron counts, the new COSMIC model is used as the non-linear measurement operator. The background uncertainties in CLM forecast were described by the uncertain model forcings and soil properties in the assimilation. Two groups of synthetic scenarios were studied for the optimization of real-time irrigation scheduling for fields of citrus trees: for the first group of scenarios soil texture was systematically finer with more clay and less sand than in the reference ('Wet bias') whereas for the second group of scenarios soil texture was coarser with less clay and more sand than in reality ('Dry bias'). The irrigation requirements were calculated based on the water deficit method using as input updated soil moisture contents after assimilation of neutron counts. For each of these two groups of scenarios seven scenarios, in which different combinations of ensemble weather forecast, data assimilation, soil properties optimization, were defined to estimate the irrigation requirement. Results show that the joint soil moisture and soil properties updating results overall in the best estimation of soil moisture, actual evapotranspiration and irrigation requirement. The characterization of soil moisture and soil properties can be improved after assimilation of cosmic-ray neutron counts. The biased soil properties result in wrong

  12. Evaluation of thermal X/5-detector Skylab S-192 data for estimating evapotranspiration and thermal properties of soils for irrigation management

    NASA Technical Reports Server (NTRS)

    Moore, D. G.; Horton, M. L.; Russell, M. J.; Myers, V. I.

    1975-01-01

    An energy budget approach to evaluating the SKYLAB X/5-detector S-192 data for prediction of soil moisture and evapotranspiration rate was pursued. A test site which included both irrigated and dryland agriculture in Southern Texas was selected for the SL-4 SKYLAB mission. Both vegetated and fallow fields were included. Data for a multistage analysis including ground, NC-130B aircraft, RB-57F aircraft, and SKYLAB altitudes were collected. The ground data included such measurements as gravimetric soil moisture, percent of the ground covered by green vegetation, soil texture, net radiation, soil temperature gradients, surface emittance, soil heat flux, air temperature and humidity gradients, and cultural practices. Ground data were used to characterize energy budgets and to evaluate the utility of an energy budget approach for determining soil moisture differences among twelve specific agricultural fields.

  13. Simulated errors in deep drainage beneath irrigated settings: Partitioning vegetation, texture and irrigation effects using Monte Carlo

    NASA Astrophysics Data System (ADS)

    Gibson, J. P.; Gates, J. B.; Nasta, P.

    2014-12-01

    Groundwater in irrigated regions is impacted by timing and rates of deep drainage. Because field monitoring of deep drainage is often cost prohibitive, numerical soil water models are frequently the main method of estimation. Unfortunately, few studies have quantified the relative importance of likely error sources. In this study, three potential error sources are considered within a Monte Carlo framework: water retention parameters, rooting depth, and irrigation practice. Error distributions for water retention parameters were determined by 1) laboratory hydraulic measurements and 2) pedotransfer functions. Error distributions for rooting depth were developed from literature values. Three irrigation scheduling regimes were considered: one representing pre-scheduled irrigation ignoring preceding rainfall, one representing pre-scheduled irrigation that was altered based on preceding rainfall, and one representing algorithmic irrigation scheduling informed by profile matric potential sensors. This approach was applied to an experimental site in Nebraska with silt loam soils and irrigated corn for 2002-2012. Results are based on Six Monte-Carlo simulations, each consisting of 1000 Hydrus 1D simulations at daily timesteps, facilitated by parallelization on a 12-node computing cluster. Results indicate greater sensitivity to irrigation regime than to hydraulic or vegetation parameters (median values for prescheduled irrigation, prescheduled irrigation altered by rainfall, and algorithmic irrigation were 310 ,100, and 110 mm/yr, respectively). Error ranges were up to 700% higher for pedotransfer functions than for laboratory-measured hydraulic functions. Deep drainage was negatively correlated with alpha and maximum root zone depth and, for some scenarios, positively correlated with n. The relative importance of error sources differed amongst the irrigation scenarios because of nonlinearities amongst parameter values, profile wetness, and deep drainage. Compared to pre

  14. Accurate Inventories Of Irrigated Land

    NASA Technical Reports Server (NTRS)

    Wall, S.; Thomas, R.; Brown, C.

    1992-01-01

    System for taking land-use inventories overcomes two problems in estimating extent of irrigated land: only small portion of large state surveyed in given year, and aerial photographs made on 1 day out of year do not provide adequate picture of areas growing more than one crop per year. Developed for state of California as guide to controlling, protecting, conserving, and distributing water within state. Adapted to any large area in which large amounts of irrigation water needed for agriculture. Combination of satellite images, aerial photography, and ground surveys yields data for computer analysis. Analyst also consults agricultural statistics, current farm reports, weather reports, and maps. These information sources aid in interpreting patterns, colors, textures, and shapes on Landsat-images.

  15. Bioenergetics model for estimating food requirements of female Pacific walruses (Odobenus rosmarus divergens)

    USGS Publications Warehouse

    Noren, S.R.; Udevitz, M.S.; Jay, C.V.

    2012-01-01

    Pacific walruses Odobenus rosmarus divergens use sea ice as a platform for resting, nursing, and accessing extensive benthic foraging grounds. The extent of summer sea ice in the Chukchi Sea has decreased substantially in recent decades, causing walruses to alter habitat use and activity patterns which could affect their energy requirements. We developed a bioenergetics model to estimate caloric demand of female walruses, accounting for maintenance, growth, activity (active in-water and hauled-out resting), molt, and reproductive costs. Estimates for non-reproductive females 0–12 yr old (65−810 kg) ranged from 16359 to 68960 kcal d−1 (74−257 kcal d−1 kg−1) for years with readily available sea ice for which we assumed animals spent 83% of their time in water. This translated into the energy content of 3200–5960 clams per day, equivalent to 7–8% and 14–9% of body mass per day for 5–12 and 2–4 yr olds, respectively. Estimated consumption rates of 12 yr old females were minimally affected by pregnancy, but lactation had a large impact, increasing consumption rates to 15% of body mass per day. Increasing the proportion of time in water to 93%, as might happen if walruses were required to spend more time foraging during ice-free periods, increased daily caloric demand by 6–7% for non-lactating females. We provide the first bioenergetics-based estimates of energy requirements for walruses and a first step towards establishing bioenergetic linkages between demography and prey requirements that can ultimately be used in predicting this population’s response to environmental change.

  16. Space Station: Estimated total US funding requirements. Report to Congressional Requesters

    NASA Astrophysics Data System (ADS)

    1995-06-01

    This report reviews current estimated costs of the NASA space station, in particular the total U.S. funding requirements for the program and program uncertainties that may affect those requirements. U.S. funds required to design, launch, and operate the International Space Station will total about $94 billion through 2012 (about $77 billion in fiscal year 1995 constant dollars). This total may decrease to the extent NASA accomplishes its goal for achieving station operational efficiencies over the period 2003 to 2012, or efficiencies currently being studied in the space shuttle program materialize. Despite major progress, the program faces formidable challenges in completing all its tasks on schedule and within its budget. The program estimates through fiscal year 1997 show limited annual financial reserves - about 6 percent to 11 percent of estimated costs. Inadequate reserves would hinder program managers' ability to cope with unanticipated technical problems. In addition, the space station's current launch and assembly schedule is ambitious, and the shuttle program may have difficulty supporting it. Moreover, the prime contract target cost could increase if the contractor is unable to negotiate subcontractor agreements for the expected price.

  17. Model requirements for estimating and reporting soil C stock changes in national greenhouse gas inventories

    NASA Astrophysics Data System (ADS)

    Didion, Markus; Blujdea, Viorel; Grassi, Giacomo; Hernández, Laura; Jandl, Robert; Kriiska, Kaie; Lehtonen, Aleksi; Saint-André, Laurent

    2016-04-01

    Globally, soils are the largest terrestrial store of carbon (C) and small changes may contribute significantly to the global C balance. Due to the potential implications for climate change, accurate and consistent estimates of C fluxes at the large-scale are important as recognized, for example, in international agreements such as the United Nations Framework Convention on Climate Change (UNFCCC). Under the UNFCCC and also under the Kyoto Protocol it is required to report C balances annually. Most measurement-based soil inventories are currently not able to detect annual changes in soil C stocks consistently across space and representative at national scales. The use of models to obtain relevant estimates is considered an appropriate alternative under the UNFCCC and the Kyoto Protocol. Several soil carbon models have been developed but few models are suitable for a consistent application across larger-scales. Consistency is often limited by the lack of input data for models, which can result in biased estimates and, thus, the reporting criteria of accuracy (i.e., emission and removal estimates are systematically neither over nor under true emissions or removals) may be met. Based on a qualitative assessment of the ability to meet criteria established for GHG reporting under the UNFCCC including accuracy, consistency, comparability, completeness, and transparency, we identified the suitability of commonly used simulation models for estimating annual C stock changes in mineral soil in European forests. Among six discussed simulation models we found a clear trend toward models for providing quantitative precise site-specific estimates which may lead to biased estimates across space. To meet reporting needs for national GHG inventories, we conclude that there is a need for models producing qualitative realistic results in a transparent and comparable manner. Based on the application of one model along a gradient from Boreal forests in Finland to Mediterranean forests

  18. Surgical Care Required for Populations Affected by Climate-related Natural Disasters: A Global Estimation

    PubMed Central

    Lee, Eugenia E.; Stewart, Barclay; Zha, Yuanting A.; Groen, Thomas A.; Burkle, Frederick M.; Kushner, Adam L.

    2016-01-01

    Background: Climate extremes will increase the frequency and severity of natural disasters worldwide.  Climate-related natural disasters were anticipated to affect 375 million people in 2015, more than 50% greater than the yearly average in the previous decade. To inform surgical assistance preparedness, we estimated the number of surgical procedures needed.   Methods: The numbers of people affected by climate-related disasters from 2004 to 2014 were obtained from the Centre for Research of the Epidemiology of Disasters database. Using 5,000 procedures per 100,000 persons as the minimum, baseline estimates were calculated. A linear regression of the number of surgical procedures performed annually and the estimated number of surgical procedures required for climate-related natural disasters was performed. Results: Approximately 140 million people were affected by climate-related natural disasters annually requiring 7.0 million surgical procedures. The greatest need for surgical care was in the People’s Republic of China, India, and the Philippines. Linear regression demonstrated a poor relationship between national surgical capacity and estimated need for surgical care resulting from natural disaster, but countries with the least surgical capacity will have the greatest need for surgical care for persons affected by climate-related natural disasters. Conclusion: As climate extremes increase the frequency and severity of natural disasters, millions will need surgical care beyond baseline needs. Countries with insufficient surgical capacity will have the most need for surgical care for persons affected by climate-related natural disasters. Estimates of surgical are particularly important for countries least equipped to meet surgical care demands given critical human and physical resource deficiencies. PMID:27617165

  19. ESTABLISHING DIFFERENTIAL IRRIGATION LEVELS USING TEMPERATURE-TIME THRESHOLDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The requirements of precision crop management or limited water supply requires that either plant water status be varied to optimize crop performance or a continuous level of limited irrigation must be practiced to match irrigation water availability. Canopy temperature (TC) has been used to time ir...

  20. Irrigation Systems. Student's Guide.

    ERIC Educational Resources Information Center

    Amarillo Coll., TX.

    This guide is intended for use by individuals preparing for a career in commercial and residential irrigation. The materials included are geared toward students who have had some experience in the irrigation business; they are intended to be presented in 10 six-hour sessions. The first two sections deal with using this guide and preparing for the…

  1. Irrigation Systems. Instructor's Guide.

    ERIC Educational Resources Information Center

    Amarillo Coll., TX.

    This guide is intended for use by licensed irrigators who wish to teach others how to design and install residential and commercial irrigation systems. The materials included in the guide have been developed under the assumption that the instructors who use it have little or no formal training as teachers. The first section presents detailed…

  2. 'Smart' Irrigation Systems

    SciTech Connect

    Hastbacka, Mildred; Dieckmann, John; Brodrick, James

    2012-08-31

    The article discusses the ASHRAE Standard 189, with mandatory and optional provisions related to water use efficiency, then focuses on the use of water efficient irrigation systems and the use of recycled water such as air conditioner condensate for landscaping irrigation. Benefits of such practices include both water and energy savings.

  3. Improving Surface Irrigation Performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface irrigation systems often have a reputation for poor performance. One key feature of efficient surface irrigation systems is precision (e.g. laser-guided) land grading. Poor land grading can make other improvements ineffective. An important issue, related to land shaping, is developing the pr...

  4. Irrigation Without Waste

    ERIC Educational Resources Information Center

    Shea, Kevin P.

    1975-01-01

    A new means of irrigation, called the drip or trickle system, has been proven more efficient and less wasteful than the current system of flood irrigation. As a result of this drip system, fertilizer-use efficiency is improved and crop yield, though never decreased, is sometimes increased in some crops. (MA)

  5. SDI versus MESA Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is known that irrigation application method can impact crop water use and water use efficiency, but the mechanisms involved are incompletely understood, particularly in terms of the water and energy balances during the growing season from pre-irrigation through planting, early growth and yield de...

  6. IRRIGATION SYSTEM COMPONENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The common components of a irrigation system are defined in terms of the diversion, delivery, distribution and drainage subsystems. Irrigation systems can be defined on at least three different levels: project, farm and field. Each level will have the same basic set of components regardless of sca...

  7. Arsenic Contamination in Food-chain: Transfer of Arsenic into Food Materials through Groundwater Irrigation

    PubMed Central

    Joardar, J.C.; Parvin, S.; Correll, Ray; Naidu, Ravi

    2006-01-01

    Arsenic contamination in groundwater in Bangladesh has become an additional concern vis-à-vis its use for irrigation purposes. Even if arsenic-safe drinking-water is assured, the question of irrigating soils with arsenic-laden groundwater will continue for years to come. Immediate attention should be given to assess the possibility of accumulating arsenic in soils through irrigation-water and its subsequent entry into the food-chain through various food crops and fodders. With this possibility in mind, arsenic content of 2,500 water, soil and vegetable samples from arsenic-affected and arsenic-unaffected areas were analyzed during 1999–2004. Other sources of foods and fodders were also analyzed. Irrigating a rice field with groundwater containing 0.55 mg/L of arsenic with a water requirement of 1,000 mm results in an estimated addition of 5.5 kg of arsenic per ha per annum. Concentration of arsenic as high as 80 mg per kg of soil was found in an area receiving arsenic-contaminated irrigation. A comparison of results from affected and unaffected areas revealed that some commonly-grown vegetables, which would usually be suitable as good sources of nourishment, accumulate substantially-elevated amounts of arsenic. For example, more than 150 mg/kg of arsenic has been found to be accumulated in arum (kochu) vegetable. Implications of arsenic ingested in vegetables and other food materials are discussed in the paper. PMID:17366772

  8. Capital requirements for the transportation of energy materials: 1979 arc estimates

    SciTech Connect

    Not Available

    1980-08-29

    Summaries of transportation investment requirements through 1990 are given for the low, medium and high scenarios. Total investment requirements for the three modes and the three energy commodities can accumulate to a $46.3 to $47.0 billion range depending on the scenario. The high price of oil, following the evidence of the last year, is projected to hold demand for oil below the recent past. Despite the overall decrease in traffic some investment in crude oil and LPG pipelines is necessary to reach new sources of supply. Although natural gas production and consumption is projected to decline through 1990, new investments in carrying capacity also are required due to locational shifts in supply. The Alaska Natural Gas Transportation System is the dominant investment for energy transportation in the next ten years. This year's report focuses attention on waterborne coal transportation to the northeast states in keeping with a return to significant coal consumption projected for this area. A resumption of such shipments will require a completely new fleet. The investment estimates given in this report identify capital required to transport projected energy supplies to market. The requirement is strategic in the sense that other reasonable alternatives do not exist or that a shared load of new growth can be expected. Not analyzed or forecasted are investments in transportation facilities made in response to local conditions. The total investment figures, therefore, represent a minimum necessary capital improvement to respond to changes in interregional supply conditions.

  9. Root canal irrigants

    PubMed Central

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ‘root canal irrigants’ and ‘endodontic irrigants.’ The reference lists of each article were manually checked for additional articles of relevance. PMID:21217955

  10. Preliminary estimate of environmental flow requirements of the Rusape River, Zimbabwe

    NASA Astrophysics Data System (ADS)

    Love, Faith; Madamombe, Elisha; Marshall, Brian; Kaseke, Evans

    Environmental flow requirements for the Rusape River, a tributary of the Save River, in Zimbabwe, were estimated using a rapid results approach. Thirty years of hydrological data with daily time steps from gauging stations upstream and downstream of the Rusape Dam were analysed using DRIFT Software. The dam appeared to have caused an increase in intra-annual and inter-annual flood events downstream compared to upstream, including significant dry season releases, while inter-annual floods were larger. The water releases from the dam differ from the natural flow in both volume and frequency, especially in the dry season and may have had a negative impact on the local ecosystem and subsistence farmers. The building block method (BMM) was applied, using the hydrological analyses performed, in order to estimate environmental flow requirements, which are presented in mean monthly flows. The flow regime that is recommended for the Rusape River should reduce or reverse these impacts, whilst ensuring sufficient water resources are released for economic needs. The EFR proposed can be achieved within mean monthly flows observed. However, it should be stressed that the EFR proposed have been developed from a rapid method, and are only a first estimate of the EFR for the Rusape River. This study represents a step in developing a management plan for the Save Basin, shared between Zimbabwe and Mozambique.

  11. Effect of reference ET method on irrigation scheduling model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A commonly used method of scheduling irrigations involves maintaining a soil-water balance and estimating a daily soil-water deficit. The water balance accounts for water moving into the soil (as irrigation or rainfall) and out (as crop evapotranspiration or runoff). A critical component, evapotra...

  12. The Current State of Predicting Furrow Irrigation Erosion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There continues to be a need to predict furrow irrigation erosion to estimate on- and off-site impacts of irrigation management. The objective of this paper is to review the current state of furrow erosion prediction technology considering four models: SISL, WEPP, WinSRFR and APEX. SISL is an empiri...

  13. Grower demand for sensor-controlled irrigation

    NASA Astrophysics Data System (ADS)

    Lichtenberg, Erik; Majsztrik, John; Saavoss, Monica

    2015-01-01

    Water scarcity is likely to increase in the coming years, making improvements in irrigation efficiency increasingly important. An emerging technology that promises to increase irrigation efficiency substantially is a wireless irrigation sensor network that uploads sensor data into irrigation management software, creating an integrated system that allows real-time monitoring and control of moisture status that has been shown in experimental settings to reduce irrigation costs, lower plant loss rates, shorten production times, decrease pesticide application, and increase yield, quality, and profit. We use an original survey to investigate likely initial acceptance, ceiling adoption rates, and profitability of this new sensor network technology in the nursery and greenhouse industry. We find that adoption rates for a base system and demand for expansion components are decreasing in price, as expected. The price elasticity of the probability of adoption suggests that sensor networks are likely to diffuse at a rate somewhat greater than that of drip irrigation. Adoption rates for a base system and demand for expansion components are increasing in specialization in ornamental production: growers earning greater shares of revenue from greenhouse and nursery operations are willing to pay more for a base system and are willing to purchase larger numbers of expansion components at any given price. We estimate that growers who are willing to purchase a sensor network expect investment in this technology to generate significant profit, consistent with findings from experimental studies.

  14. Estimating sugarcane water requirements for biofuel feedstock production in Maui, Hawaii using satellite imagery

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Anderson, R. G.; Wang, D.

    2011-12-01

    Water availability is one of the limiting factors for sustainable production of biofuel crops. A common method for determining crop water requirement is to multiply daily potential evapotranspiration (ETo) calculated from meteorological parameters by a crop coefficient (Kc) to obtain actual crop evapotranspiration (ETc). Generic Kc values are available for many crop types but not for sugarcane in Maui, Hawaii, which grows on a relatively unstudied biennial cycle. In this study, an algorithm is being developed to estimate sugarcane Kc using normalized difference vegetation index (NDVI) derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery. A series of ASTER NDVI maps were used to depict canopy development over time or fractional canopy cover (fc) which was measured with a handheld multispectral camera in the fields during satellite overpass days. Canopy cover was correlated with NDVI values. Then the NDVI based canopy cover was used to estimate Kc curves for sugarcane plants. The remotely estimated Kc and ETc values were compared and validated with ground-truth ETc measurements. The approach is a promising tool for large scale estimation of evapotranspiration of sugarcane or other biofuel crops.

  15. Participatory approach: from problem identification to setting strategies for increased productivity and sustainability in small scale irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Habtu, Solomon; Ludi, Eva; Jamin, Jean Yves; Oates, Naomi; Fissahaye Yohannes, Degol

    2014-05-01

    Practicing various innovations pertinent to irrigated farming at local field scale is instrumental to increase productivity and yield for small holder farmers in Africa. However the translation of innovations from local scale to the scale of a jointly operated irrigation scheme is far from trivial. It requires insight on the drivers for adoption of local innovations within the wider farmer communities. Participatory methods are expected to improve not only the acceptance of locally developed innovations within the wider farmer communities, but to allow also an estimation to which extend changes will occur within the entire irrigation scheme. On such a base, more realistic scenarios of future water productivity within an irrigation scheme, which is operated by small holder farmers, can be estimated. Initial participatory problem and innovation appraisal was conducted in Gumselassa small scale irrigation scheme, Ethiopia, from Feb 27 to March 3, 2012 as part of the EAU4FOOD project funded by EC. The objective was to identify and appraise problems which hinder sustainable water management to enhance production and productivity and to identify future research strategies. Workshops were conducted both at local (Community of Practices) and regional (Learning Practice Alliance) level. At local levels, intensive collaboration with farmers using participatory methods produced problem trees and a "Photo Safari" documented a range of problems that negatively impact on productive irrigated farming. A range of participatory methods were also used to identify local innovations. At regional level a Learning Platform was established that includes a wide range of stakeholders (technical experts from various government ministries, policy makers, farmers, extension agents, researchers). This stakeholder group did a range of exercise as well to identify major problems related to irrigated smallholder farming and already identified innovations. Both groups identified similar problems

  16. Parameter Estimation of Ion Current Formulations Requires Hybrid Optimization Approach to Be Both Accurate and Reliable

    PubMed Central

    Loewe, Axel; Wilhelms, Mathias; Schmid, Jochen; Krause, Mathias J.; Fischer, Fathima; Thomas, Dierk; Scholz, Eberhard P.; Dössel, Olaf; Seemann, Gunnar

    2016-01-01

    Computational models of cardiac electrophysiology provided insights into arrhythmogenesis and paved the way toward tailored therapies in the last years. To fully leverage in silico models in future research, these models need to be adapted to reflect pathologies, genetic alterations, or pharmacological effects, however. A common approach is to leave the structure of established models unaltered and estimate the values of a set of parameters. Today’s high-throughput patch clamp data acquisition methods require robust, unsupervised algorithms that estimate parameters both accurately and reliably. In this work, two classes of optimization approaches are evaluated: gradient-based trust-region-reflective and derivative-free particle swarm algorithms. Using synthetic input data and different ion current formulations from the Courtemanche et al. electrophysiological model of human atrial myocytes, we show that neither of the two schemes alone succeeds to meet all requirements. Sequential combination of the two algorithms did improve the performance to some extent but not satisfactorily. Thus, we propose a novel hybrid approach coupling the two algorithms in each iteration. This hybrid approach yielded very accurate estimates with minimal dependency on the initial guess using synthetic input data for which a ground truth parameter set exists. When applied to measured data, the hybrid approach yielded the best fit, again with minimal variation. Using the proposed algorithm, a single run is sufficient to estimate the parameters. The degree of superiority over the other investigated algorithms in terms of accuracy and robustness depended on the type of current. In contrast to the non-hybrid approaches, the proposed method proved to be optimal for data of arbitrary signal to noise ratio. The hybrid algorithm proposed in this work provides an important tool to integrate experimental data into computational models both accurately and robustly allowing to assess the often non

  17. Evaluation of alternative methods for estimating reference evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evapotranspiration is an important component in water-balance and irrigation scheduling models. While the FAO-56 Penman-Monteith method has become the de facto standard for estimating reference evapotranspiration (ETo), it is a complex method requiring several weather parameters. Required weather ...

  18. Toxic Release Inventory reporting requirement: Estimating volatile organic compound releases from industrial wastewater treatment facilities

    SciTech Connect

    Hall, F.E. Jr.

    1997-12-31

    In production/maintenance processes at the Oklahoma City Air Logistics Center, industrial wastewater streams are generated which contain organic compounds. These wastewaters are collected and treated in a variety of ways. Some of these collection and treatment steps result in the release of volatile organic compounds (VOC) from the wastewater to the ambient air. This paper provides a discussion of the potential VOC emission sources and presents estimates of emissions for an Industrial Wastewater Treatment Plant (IWTP). As regulatory reporting requirements become increasingly more stringent, Air Force installations are being required to quantify and report VOC releases to the environment. The computer software described in this paper was used to identify and quantify VOC discharges to the environment. The magnitude of VOC emissions depends greatly on many factors such as the physical properties of the pollutants, the temperature of the wastewater, and the design of the individual collection and treatment process units. IWTP VOC releases can be estimated using a computer model designed by the Environmental Protection Agency. The Surface Impoundment Model System (SIMS) model utilizes equipment information to predict air emissions discharged from each individual process unit. SIMS utilizes mass transfer expressions, process unit information, in addition to chemical/physical property data for the interested chemicals. By inputting process conditions and constraints, SIMS determines the effluent concentrations along with the air emissions discharged from each individual process unit. The software is user-friendly with the capable of estimating effluent concentration and ambient air releases. The SIMS software was used by Tinker AFB chemical engineers to predict VOC releases to satisfy the Toxic Release Inventory reporting requirements.

  19. A multisector analysis of urban irrigation and water savings potential

    NASA Astrophysics Data System (ADS)

    Bijoor, N.; Kim, H.; Famiglietti, J. S.

    2014-12-01

    Urban irrigation strains limited water supplies in semi-arid areas such as Orange County, CA, yet the quantity and controlling factors of urban irrigation are not well understood. The goals of this research are to (1) quantify and compare landscape irrigation applied by residential and commercial sectors in various retail agencies at a parcel scale (2) determine over- and under-irrigation compared to theoretical need (3) determine the climatic and socioeconomic controls on landscape irrigation. A research partnership was established between six water retail agencies in Orange County, CA representing a wide range of climatic and economic conditions. These agencies contributed between 3 and 13 years of water use data on a monthly/bimonthly basis. Irrigation depth (mm) was estimated using the "minimum month method," and landscape evapotranspiration was calculated using the Hargreaves equation for 122,345 parcels. Multiple regressions of water use were conducted with climatic and socioeconomic variables as possible explanatory variables. Single family residences accounted for the majority of urban water use. Findings from 112,192 single family residences (SFRs) show that total and indoor water use declined, though irrigation did not significantly change. Average irrigation for SFRs was 94 L/day, and a large proportion (42%) of irrigation was applied in excess to landscapes. Air temperature was found to be the primary driver of irrigation. We mapped over-irrigation relative to plant water demand to highlight areas that can be targeted for water conservation efforts. We also show the water savings that would be gained by improving the efficiency of irrigation systems. The information gained in this study would be useful for developing water use efficiency policies and/or educational programs to promote sustainable irrigation practices at the individual parcel scale.

  20. Estimating potential evapotranspiration with improved radiation estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potential evapotranspiration (PET) is of great importance to estimation of surface energy budget and water balance calculation. The accurate estimation of PET will facilitate efficient irrigation scheduling, drainage design, and other agricultural and meteorological applications. However, accuracy o...

  1. Space transfer vehicle concepts and requirements. Volume 3: Program cost estimates

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Space Transfer Vehicle (STV) Concepts and Requirements Study has been an eighteen-month study effort to develop and analyze concepts for a family of vehicles to evolve from an initial STV system into a Lunar Transportation System (LTS) for use with the Heavy Lift Launch Vehicle (HLLV). The study defined vehicle configurations, facility concepts, and ground and flight operations concepts. This volume reports the program cost estimates results for this portion of the study. The STV Reference Concept described within this document provides a complete LTS system that performs both cargo and piloted Lunar missions.

  2. 25 CFR 171.220 - What must I do to my farm unit to receive irrigation service?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What must I do to my farm unit to receive irrigation... WATER IRRIGATION OPERATION AND MAINTENANCE Irrigation Service § 171.220 What must I do to my farm unit to receive irrigation service? You must meet the following requirements for us to provide service:...

  3. 25 CFR 171.220 - What must I do to my farm unit to receive irrigation service?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false What must I do to my farm unit to receive irrigation... WATER IRRIGATION OPERATION AND MAINTENANCE Irrigation Service § 171.220 What must I do to my farm unit to receive irrigation service? You must meet the following requirements for us to provide service:...

  4. 25 CFR 171.220 - What must I do to my farm unit to receive irrigation service?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true What must I do to my farm unit to receive irrigation... WATER IRRIGATION OPERATION AND MAINTENANCE Irrigation Service § 171.220 What must I do to my farm unit to receive irrigation service? You must meet the following requirements for us to provide service:...

  5. 25 CFR 171.220 - What must I do to my farm unit to receive irrigation service?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false What must I do to my farm unit to receive irrigation... WATER IRRIGATION OPERATION AND MAINTENANCE Irrigation Service § 171.220 What must I do to my farm unit to receive irrigation service? You must meet the following requirements for us to provide service:...

  6. 25 CFR 171.220 - What must I do to my farm unit to receive irrigation service?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What must I do to my farm unit to receive irrigation... WATER IRRIGATION OPERATION AND MAINTENANCE Irrigation Service § 171.220 What must I do to my farm unit to receive irrigation service? You must meet the following requirements for us to provide service:...

  7. Comparison of optimal irrigation scheduling and groundwater recharge at representative sites in the North China Plain

    NASA Astrophysics Data System (ADS)

    Ma, Ying

    2014-05-01

    The North China Plain (NCP) is an important food production area in China, facing an increasing water shortage and overexploitation of groundwater. It is critical to optimize the irrigation scheduling and accurately estimate groundwater recharge for saving water and increasing crop water use efficiency. However, the water cycle and crop responses to irrigation are quite various in different areas, because of the spatial variation of climatic, soil, water table and other management practices in the NCP. In this study, three representative sites (LC site in the piedmont plain, TZ site in the northern alluvial and lacustrine plain, YC site in the southern alluvial and lacustrine plain) were selected to compare the optimal irrigation scheduling and corresponding groundwater recharge under different hydrological years for winter wheat-summer maize double cropping system. At each site, a physically based agro-hydrological model (SWAP) was calibrated using field data of soil moisture. Then, scenarios under different irrigation time and amount were simulated. Results showed that the optimal irrigation scheduling and corresponding groundwater recharge were significant different between the three representative sites. The mean water table depth at the LC (33.0 m), YC (10.3 m), and TZ site (2.5 m) caused great different time lags of infiltrated water and groundwater contribution to evapotranspiration. Then, the most irrigation amount was required for the TZ site but the least requirement for the YC site at each hydrologic year. As most clay contents in the deep soils at the LC site increased tortuosity and limited water movement, which resulted in lower rates of recharge compared to more sandy soils at the other two sites. Averagely, using the optimal irrigation scheduling could save 2.04×109 m3 irrigation water and reduce about 84.3% groundwater over-exploitation in winter wheat growth period in the NCP. Therefore, comparison of the simulation results among the three

  8. Mapping irrigation potential from renewable groundwater in Africa - a quantitative hydrological approach

    NASA Astrophysics Data System (ADS)

    Altchenko, Y.; Villholth, K. G.

    2015-02-01

    Groundwater provides an important buffer to climate variability in Africa. Yet, groundwater irrigation contributes only a relatively small share of cultivated land, approximately 1% (about 2 × 106 hectares) as compared to 14% in Asia. While groundwater is over-exploited for irrigation in many parts in Asia, previous assessments indicate an underutilized potential in parts of Africa. As opposed to previous country-based estimates, this paper derives a continent-wide, distributed (0.5° spatial resolution) map of groundwater irrigation potential, indicated in terms of fractions of cropland potentially irrigable with renewable groundwater. The method builds on an annual groundwater balance approach using 41 years of hydrological data, allocating only that fraction of groundwater recharge that is in excess after satisfying other present human needs and environmental requirements, while disregarding socio-economic and physical constraints in access to the resource. Due to high uncertainty of groundwater environmental needs, three scenarios, leaving 30, 50 and 70% of recharge for the environment, were implemented. Current dominating crops and cropping rotations and associated irrigation requirements in a zonal approach were applied in order to convert recharge excess to potential irrigated cropland. Results show an inhomogeneously distributed groundwater irrigation potential across the continent, even within individual countries, mainly reflecting recharge patterns and presence or absence of cultivated cropland. Results further show that average annual renewable groundwater availability for irrigation ranges from 692 to 1644 km3 depending on scenario. The total area of cropland irrigable with renewable groundwater ranges from 44.6 to 105.3 × 106 ha, corresponding to 20.5 to 48.6% of the cropland over the continent. In particular, significant potential exists in the semi-arid Sahel and eastern African regions which could support poverty alleviation if developed

  9. 76 FR 23321 - New Sweden Irrigation District, ID; Notice of Preliminary Permit Application Accepted for Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ... Energy Regulatory Commission New Sweden Irrigation District, ID; Notice of Preliminary Permit Application..., 2011, New Sweden Irrigation District filed an application for a preliminary permit, pursuant to section.... The estimated annual generation of the New Sweden Irrigation Project would be 5.6...

  10. Competing Conservation Objectives for Predators and Prey: Estimating Killer Whale Prey Requirements for Chinook Salmon

    PubMed Central

    Williams, Rob; Krkošek, Martin; Ashe, Erin; Branch, Trevor A.; Clark, Steve; Hammond, Philip S.; Hoyt, Erich; Noren, Dawn P.; Rosen, David; Winship, Arliss

    2011-01-01

    Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada–US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict

  11. Competing conservation objectives for predators and prey: estimating killer whale prey requirements for Chinook salmon.

    PubMed

    Williams, Rob; Krkošek, Martin; Ashe, Erin; Branch, Trevor A; Clark, Steve; Hammond, Philip S; Hoyt, Erich; Noren, Dawn P; Rosen, David; Winship, Arliss

    2011-01-01

    Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada-US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict

  12. Monitoring of flood irrigation for the characterization of irrigation practices of grassland fields in the Crau region (South of France)

    NASA Astrophysics Data System (ADS)

    Alkassem Alosman, Mohamed; Ruy, Stéphane; Olioso, Albert; Flamain, Fabrice

    2015-04-01

    Surface irrigation (flooding and furrow) is the main irrigation technic in the world. This irrigation system is known as having poor water efficiency and that results in very large water losses through drainage and runoff out the field. Although these unused water amounts can generate positive externalities (wetlands and groundwater recharge), a decreased of water volume used in surface irrigation is sought in a context of limited water resource. In the Crau area (South of France), more than 12,500 ha of grassland are irrigated by flooding. There, at the regional scale, it is estimated that the water volumes brought into the field are very high; and ranges from 15,000; up to 20,000 m3.h-1.year-1; more than 78% of these amounts recharges the Crau aquifer (Saos, 2006). However, the actual volumes which are injected to the plot surface (the " irrigation dose ") are insufficiently known, because of the diversity of encountered agricultural practices and fields topography. For better characterizing these practices, a campaign of irrigation monitoring has been carried out during an irrigation season (March to September 2014) on a set of representative plots of soil variability, practices, and different stages of hay grow. Each grassland field has been also characterized from a topographical and pedological view point. A mobile device for measurements (soil moisture and water level probes, photographic monitoring, soil sampling, .. ) was deployed for each irrigation. A total of 35 irrigation events were followed. The data obtained allow describing accurately and quantitatively the variability in encountered irrigation practices. Combined with a flood irrigation model (Model CALHY, Bader et al., 2010, Hydrol. Sci. J., 55, 177-191), these data will be used to calculate the water balance at the field scale: amounts of injected, infiltrated and lost water by runoff or drainage. They will also offer different ways for optimizing the irrigation efficiency.

  13. Comparative study of irrigation water use and groundwater recharge under various irrigation schemes in an agricultural region, central Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2016-04-01

    The risk of rice production has increased notably due to climate change in Taiwan. To respond to growing agricultural water shortage without affecting normal food production in the future, the application of water-saving irrigation will be a substantial resolution. However, the adoption of water-saving irrigation may result in the reducing of groundwater recharge because continuous flooding in the paddy fields could be regarded as an important source for groundwater recharge. The aim of this study was to evaluate the irrigation water-saving benefit and groundwater recharge deficit when adopting the System of Rice Intensification, known as SRI methodology, in the Choushui River alluvial fan (the largest groundwater pumping and the most important rice-cropping region in central Taiwan). The three-dimensional finite element groundwater model, FEMWATER, was applied to simulate the infiltration process and groundwater recharge under SRI methodology and traditional irrigation schemes including continuous irrigation, and rotational irrigation in two rice-crop periods with hydro-climatic data of 2013. The irrigation water use was then calculated by water balance. The results showed that groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reduced 3.6% and 1.6% in the first crop period, and reduced 3.2% and 1.6% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. However, the SRI methodology achieved notably water-saving benefit compared to the disadvantage of reducing the groundwater recharge amount. The field irrigation requirement amount of SRI methodology was significantly lower than those of traditional irrigation schemes, saving 37% and 20% of irrigation water in the first crop period, and saving 53% and 35% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. Therefore, the amount of groundwater pumping for

  14. Advances in sprinkler irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sprinkler irrigation is being increasingly adopted in the US and worldwide because it offers increased crop water productivity over what is possible with gravity irrigation. Most sprinkler irrigation is by center pivot, which is presently used on about 50 and 80 percent of land irrigated in the US a...

  15. Preliminary estimates of galactic cosmic ray shielding requirements for manned interplanetary missions

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.; Wilson, John W.; Nealy, John E.

    1988-01-01

    Estimates of radiation risk to the blood forming organs from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different constituents per layer. Calculated galactic cosmic ray doses and dose equivalents behind various thicknesses of aluminum and water shielding are presented for solar maximum and solar minimum periods. Estimates of risk to the blood forming organs are made using 5 cm depth dose/dose equivalent values for water. These results indicate that at least 5 g/sq cm (5 cm) of water of 6.5 g/sq cm (2.4 cm) of aluminum shield is required to reduce annual exposure below the current recommended limit of 50 rem. Because of the large uncertainties in fragmentation parameters, and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as 70 percent. Therefore, more detailed analyses with improved inputs could indicate the need for additional shielding.

  16. Improving Soil Moisture and Evapotranspiration Estimation by Data Assimilation and Remote Sensing Data over Irrigated Cropland in the Northern China Plain

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Chen, H.

    2014-12-01

    Land surface model is considered to be a powerful tool to estimate continuous soil water content and surface fluxes. However, simulation error tends to accumulate in the process of model simulation due to the inevitable uncertainties of forcing data and intrinsic model errors. Data assimilation technique considered the uncertainty of the model, update model states during the simulation period, and therefore improve the accuracy of soil water content and surface fluxes estimation. In this study, an Ensemble Kalman Filter (EnKF) technique was coupled to a Hydrologically-Enhanced Land Process (HELP) model to update model states including soil water content and surface temperature. The remotely sensed latent heat flux (LE) estimated by Surface Energy Balance System (SEBS) was used as the observation value in the data assimilation system to update the model states such as soil water contents and surface temperatures, etc.The model was validated by the observation data in 2006 at Shandong Weishan eco-hydrological station, where the open-loop estimation without state updating was treated as the benchmark run. Results showed that the root mean square error (rmse) of soil water content reduced by 30%-50% compared to the benchmark run, while the surface fluxes also had significant improvement to different extents, among which the rmse of LE estimation from wheat season and maize season reduced by 33% and 44%, respectively. These results demonstrated that the application of data assimilation technique can substantially improve estimation of land surface energy fluxes and soil water states. It is suggested that data assimilation system had great potential to be used in land surface models in agriculture and water management.

  17. Irrigation on Topographic Maps.

    ERIC Educational Resources Information Center

    Raitz, Karl B.

    1979-01-01

    Describes how study of irrigation practices on topographic maps can help students in introductory high school and college geography courses understand man and land relationships to geography. (Author/DB)

  18. Ground-water use, locations of production wells, and areas irrigated using ground water in 1998, middle Humboldt River basin, north-central Nevada

    USGS Publications Warehouse

    Plume, Russell W.

    2003-01-01

    In 1998, ground water was being pumped from about 420 production wells in the middle Humboldt River Basin for a variety of uses. Principal uses were for agriculture, industry, mining, municipal, and power plant purposes. This report presents a compilation of the number and types of production wells, areas irrigated by ground water, and ground-water use in 14 hydrographic areas of the middle Humboldt River Basin in 1998. Annual pumping records for production wells usually are reported to the Nevada Division of Water Resources. However, operators of irrigation wells are not consistently required to report annual pumpage. Daily power-consumption and pump-discharge rates measured at 20 wells during the 1998 irrigation season and total power use at each well were used to estimate the amount of water, in feet of depth, applied to 20 alfalfa fields. These fields include about 10 percent of the total area, 36,700 acres, irrigated with ground water in the middle Humboldt River Basin. In 1998 an average of 2.0 feet of water was applied to 14 fields irrigated using center-pivot sprinkler systems, and an average of 2.6 feet of water was applied to 6 fields irrigated using wheel-line sprinkler systems. A similar approach was used to estimate the amount of water pumped at three wells using pumps powered by diesel engines. The two fields served by these three wells received 3.9 feet of water by flood irrigation during the 1998 irrigation season. The amount of water applied to the fields irrigated by center-pivot and wheel-line irrigation systems during the 1998 irrigation season was less than what would have been applied during a typical irrigation season because late winter and spring precipitation exceeded long-term monthly averages by as much as four times. As a result, the health of crops was affected by over-saturated soils, and most irrigation wells were only used sporadically in the first part of the irrigation season. Power consumption at 19 of the 20 wells in the 1994

  19. Irrigated Agriculture, Saudi Arabia

    NASA Technical Reports Server (NTRS)

    1990-01-01

    In Saudi Arabia, center-pivot, swing-arm irrigated agriculture complexes such as the one imaged at Jabal Tuwayq (20.5N, 45.0 E) extract deep fossil water reserves to achieve food crop production self sufficiency in this desert environment. The significance of the Saudi expanded irrigated agriculture is that the depletion of this finite water resource is a short term solution to a long term need that will still exist when the water has been extracted.

  20. Capital requirements for the transportation of energy materials: 1979 ARC estimates. Draft final report

    SciTech Connect

    Not Available

    1980-08-13

    This report contains TERA's estimates of capital requirements to transport natural gas, crude oil, petroleum products, and coal in the United States by 1990. The low, medium, and high world-oil-price scenarios from the EIA's Mid-range Energy Forecasting System (MEFS), as used in the 1979 Annual Report to Congress (ARC), were provided as a basis for the analysis and represent three alternative futures. TERA's approach varies by energy commodity to make best use of the information and analytical tools available. Summaries of transportation investment requirements through 1990 are given. Total investment requirements for three modes (pipelines, rails, waterways and the three energy commodities can accumulate to a $49.9 to $50.9 billion range depending on the scenario. The scenarios are distinguished primarily by the world price of oil which, given deregulation of domestic oil prices, affects US oil prices even more profoundly than in the past. The high price of oil, following the evidence of the last year, is projected to hold demand for oil below the recent past.

  1. Evapotranspiration-based irrigation scheduling of lettuce and broccoli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation of crop evapotranspiration supports efficient irrigation water management, which in turn supports water conservation, mitigation of groundwater depletion/degradation, energy savings, and crop quality maintenance. Past research in California has revealed strong relationships between fract...

  2. Irrigation timing and volume affects growth of container grown maples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Container nursery production requires large inputs of water and nutrients but frequently irrigation inputs exceed plant demand and lack application precision or are not applied at optimal times for plant production. The results from this research can assist producers in developing irrigation manage...

  3. SPRINKLER IRRIGATION FOR THE REMOVAL OF VOCS FROM GROUNDWATER

    EPA Science Inventory

    Sprinkler irrigation is a common farming practice in those states where the semi arid climate and lack of sufficient rainfall during critical growing periods necessitate the requirement for supplemental water. The source of most irrigation water is groundwater which can be contam...

  4. Integrated management of water resources demand and supply in irrigated agriculture from plot to regional scale

    NASA Astrophysics Data System (ADS)

    Schütze, Niels; Wagner, Michael

    2016-05-01

    Growing water scarcity in agriculture is an increasing problem in future in many regions of the world. Recent trends of weather extremes in Saxony, Germany also enhance drought risks for agricultural production. In addition, signals of longer and more intense drought conditions during the vegetation period can be found in future regional climate scenarios for Saxony. However, those climate predictions are associated with high uncertainty and therefore, e.g. stochastic methods are required to analyze the impact of changing climate patterns on future crop water requirements and water availability. For assessing irrigation as a measure to increase agricultural water security a generalized stochastic approach for a spatial distributed estimation of future irrigation water demand is proposed, which ensures safe yields and a high water productivity at the same time. The developed concept of stochastic crop water production functions (SCWPF) can serve as a central decision support tool for both, (i) a cost benefit analysis of farm irrigation modernization on a local scale and (ii) a regional water demand management using a multi-scale approach for modeling and implementation. The new approach is applied using the example of a case study in Saxony, which is dealing with the sustainable management of future irrigation water demands and its implementation.

  5. Earth observation products for operational irrigation management: the PLEIADeS project

    NASA Astrophysics Data System (ADS)

    D'Urso, G.; Vuolo, F.; Richter, K.; Calera Belmonte, A.; Osann, M. A.

    2009-09-01

    In the context of a sustainable agriculture, a controlled and efficient irrigation management is required to avoid negative effects of the increasing water scarcity, especially in arid and semi-arid regions. Within this background, the project 'Participatory multi-Level EO-assisted tools for Irrigation water management and Agricultural Decision-Support' (PLEIADeS: http://www.pleiades.es) addressed the efficient and sustainable use of water for food production in water-scarce environments. Economical, environmental, technical, social and political dimensions are considered by means of a synergy of leading-edge technologies and participatory approaches. Project partners, represented by a set of nine pilot case studies, include a broad range of conditions characteristic for the European, Southern Mediterranean and American regions. PLEIADeS aimed at improving the performance of irrigation schemes by means of a range of measures, made possible through wide space-time coverage of Earth observation (E.O.) data and interactive networking capabilities of Information and Communication Technologies (ICT). Algorithms for a number of basic products to estimate Irrigation Water Requirements (IWR) in an operational context are defined. In this study, the pilot zone at the Nurra site in Sardinia, Italy, is chosen to test, validate and apply these methodologies.

  6. Estimating pollutant removal requirements for landfills in the UK: II. Model development.

    PubMed

    Hall, D H; Drury, D; Gronow, J R; Rosevear, A; Pollard, S J T; Smith, R

    2006-12-01

    A modelling methodology using a leachate source term has been produced for estimating the timescales for achieving environmental equilibrium status for landfilled waste. Results are reported as the period of active management required for modelled scenarios of non-flushed and flushed sites for a range of pre-filling treatments. The base scenario against which results were evaluated was raw municipal solid waste (MSW) for which only cadmium failed to reach equilibrium. Flushed raw MSW met our criteria for stabilisation with active leachate management for 40 years, subject to each of the leachate species being present at or below their average UK concentrations. Stable non-reactive wastes, meeting EU waste acceptance criteria, fared badly in the non-flushed scenario, with only two species stabilising after a management period within 1000 years and the majority requiring > 2000 years of active leachate management. The flushing scenarios showed only a marginal improvement, with arsenic still persisting beyond 2000 years management even with an additional 500 mm y(-1) of infiltration. The stabilisation time for mechanically sorted organic residues (without flushing) was high, and even with flushing, arsenic and chromium appeared to remain a problem. Two mechanical biological treatment (MBT) scenarios were examined, with medium and high intensity composting. Both were subjected to the non-flushing and flushing scenarios. The non-flushing case of both options fell short of the basic requirements of achieving equilibrium within decades. The intense composting option with minimal flushing appeared to create a scenario where equilibrium could be achieved. For incinerator bottom ash (raw and subjected to various treatments), antimony, copper, chloride and sulphate were the main controls on achieving equilibrium, irrespective of treatment type. Flushing at higher flushing rates (500 mm y(-1)) failed to demonstrate a significant reduction in the management period required. PMID

  7. EURRECA-Estimating vitamin D requirements for deriving dietary reference values.

    PubMed

    Cashman, Kevin D; Kiely, Mairead

    2013-01-01

    The time course of the EURRECA from 2008 to 2012, overlapped considerably with the timeframe of the process undertaken by the North American Institute of Medicine (IOM) to revise dietary reference intakes for vitamin D and calcium (published November 2010). Therefore the aims of the vitamin D-related activities in EURRECA were formulated to address knowledge requirements that would complement the activities undertaken by the IOM and provide additional resources for risk assessors and risk management agencies charged with the task of setting dietary reference values for vitamin D. A total of three systematic reviews were carried out. The first, which pre-dated the IOM review process, identified and evaluated existing and novel biomarkers of vitamin D status and confirmed that circulating 25-hydroxyvitamin D (25(OH)D) concentrations is a robust and reliable marker of vitamin D status. The second systematic review conducted a meta-analysis of the dose-response of serum 25(OH)D to vitamin D intake from randomized controlled trials (RCT) among adults to explore the most appropriate model of the vitamin D intake-serum 25(OH)D) relationship to estimate requirements. The third review also carried out a meta-analysis to evaluate evidence of efficacy from RCT using foods fortified with vitamin D, and found they increased circulating 25(OH)D concentrations in a dose-dependent manner but identified a need for stronger data on the efficacy of vitamin D-fortified food on deficiency prevention and potential health outcomes, including adverse effects. Finally, narrative reviews provided estimates of the prevalence of inadequate intakes of vitamin D in adults and children from international dietary surveys, as well as a compilation of research requirements for vitamin D to inform current and future assessments of vitamin D requirements. [Supplementary materials are available for this article. Go to the publisher's onilne edition of Critical Reviews in Food Science and Nutrion for

  8. Irrigation in a changing world: a global systems analysis perspective

    NASA Astrophysics Data System (ADS)

    Doell, P.

    2003-04-01

    The global issues of water security and food security are closely linked. Sustainable plant production requires a sustained provisioning of water, either in the form of "green" or of "blue" water (as introduced by Malin Falkenmark in 1993). Green water is defined as the fraction of water that is evapotranspirated, i.e. the water supply for all non-irrigated vegetation. Blue water refers to the water flows in groundwater and surface water. It represents the water that can be withdrawn, e.g. for irrigation. In areas without enough green water in the soil to achieve satisfactory crop growth, crops can be irrigated with blue water. The distinction between green and blue water helps to understand the linkages between rainfall, soil, land productivity and water availability for irrigation and other human uses. Today, about 67% of the current global water withdrawals and about 87% of the consumptive water use (withdrawal minus return flow) is for irrigation purposes. Irrigated land comprises less than one-fifth of all cropped area but produces about two-fifth of the world's cereals. Due to the high and reliable productivity of irrigated land, an extension of irrigation appears to be an appropriate strategy to feed the world's growing population However, will there be enough water available for the necessary extension? To assess this question, both water availability and demand must be analyzed. At the global scale, such an assessment is supported by the global model of water resources and use model WaterGAP 2, which, with a spatial resolution of 0.5 degrees, computes both water resources and water use by irrigation, livestock, households, manufacturing and thermal power plants. WaterGAP is applied to derive scenarios that show the impact of climate change as well as demographic, economic and technological changes. The Global Irrigation Model of WaterGAP computes, for example, the impact of climate change on irrigation requirements on net irrigation requirements. This is

  9. Estimation of crop water requirements: extending the one-step approach to dual crop coefficients

    NASA Astrophysics Data System (ADS)

    Lhomme, J. P.; Boudhina, N.; Masmoudi, M. M.; Chehbouni, A.

    2015-07-01

    Crop water requirements are commonly estimated with the FAO-56 methodology based upon a two-step approach: first a reference evapotranspiration (ET0) is calculated from weather variables with the Penman-Monteith equation, then ET0 is multiplied by a tabulated crop-specific coefficient (Kc) to determine the water requirement (ETc) of a given crop under standard conditions. This method has been challenged to the benefit of a one-step approach, where crop evapotranspiration is directly calculated from a Penman-Monteith equation, its surface resistance replacing the crop coefficient. Whereas the transformation of the two-step approach into a one-step approach has been well documented when a single crop coefficient (Kc) is used, the case of dual crop coefficients (Kcb for the crop and Ke for the soil) has not been treated yet. The present paper examines this specific case. Using a full two-layer model as a reference, it is shown that the FAO-56 dual crop coefficient approach can be translated into a one-step approach based upon a modified combination equation. This equation has the basic form of the Penman-Monteith equation but its surface resistance is calculated as the parallel sum of a foliage resistance (replacing Kcb) and a soil surface resistance (replacing Ke). We also show that the foliage resistance, which depends on leaf stomatal resistance and leaf area, can be inferred from the basal crop coefficient (Kcb) in a way similar to the Matt-Shuttleworth method.

  10. A new remote sensing procedure for the estimation of crop water requirements

    NASA Astrophysics Data System (ADS)

    Spiliotopoulos, M.; Loukas, A.; Mylopoulos, N.

    2015-06-01

    The objective of this work is the development of a new approach for the estimation of water requirements for the most important crops located at Karla Watershed, central Greece. Satellite-based energy balance for mapping evapotranspiration with internalized calibration (METRIC) was used as a basis for the derivation of actual evapotranspiration (ET) and crop coefficient (ETrF) values from Landsat ETM+ imagery. MODIS imagery has been also used, and a spatial downscaling procedure is followed between the two sensors for the derivation of a new NDVI product with a spatial resolution of 30 m x 30 m. GER 1500 spectro-radiometric measurements are additionally conducted during 2012 growing season. Cotton, alfalfa, corn and sugar beets fields are utilized, based on land use maps derived from previous Landsat 7 ETM+ images. A filtering process is then applied to derive NDVI values after acquiring Landsat ETM+ based reflectance values from the GER 1500 device. ETrF vs NDVI relationships are produced and then applied to the previous satellite based downscaled product in order to finally derive a 30 m x 30 m daily ETrF map for the study area. CropWat model (FAO) is then applied, taking as an input the new crop coefficient values with a spatial resolution of 30 m x 30 m available for every crop. CropWat finally returns daily crop water requirements (mm) for every crop and the results are analyzed and discussed.

  11. Comparison of site-specific and conventional uniform irrigation management on potatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-Specific Irrigation Management (SSIM) can be defined as irrigation management (depth, timing) based on crop need to defined sub-areas of a field referred to as management zones. Implementation of SSIM will require additional irrigation system hardware, labor and information on soil and/or plant...

  12. Crop water stress indices correlated with soil water storage: Implications for variable rate irrigation management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water sensing methods are now coming to be used for irrigation scheduling of whole fields. However, newly introduced variable rate irrigation (VRI) systems require information about soil water content in many areas of a field, each called an irrigation management zone. Commonly available soil w...

  13. Simulation of freezing and thawing soilsin Inner Mongolia Hetao irrigation district, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inner Mongolia Hetao Irrigation District, in north of China, is typical of seasonal frozen soil areas in the region. Irrigation in autumn is required to leach soil salt and to provide a reserve of soil water for the next year’s crop. However, improper autumn irrigation results in the secondary salin...

  14. 25 CFR 162.611 - Payment of fees and drainage and irrigation charges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Payment of fees and drainage and irrigation charges. 162... AND PERMITS Non-Agricultural Leases § 162.611 Payment of fees and drainage and irrigation charges. (a) Any lease covering lands within an irrigation project or drainage district shall require the lessee...

  15. Observation and Modelling of Soil Water Content Towards Improved Performance Indicators of Large Irrigation Schemes

    NASA Astrophysics Data System (ADS)

    Labbassi, Kamal; Akdim, Nadia; Alfieri, Silvia Maria; Menenti, Massimo

    2014-05-01

    Irrigation performance may be evaluated for different objectives such as equity, adequacy, or effectiveness. We are using two performance indicators: IP2 measures the consistency of the allocation of the irrigation water with gross Crop Water requirements, while IP3 measures the effectiveness of irrigation by evaluating the increase in crop transpiration between the case of no irrigation and the case of different levels of irrigation. To evaluate IP3 we need to calculate the soil water balance for the two cases. We have developed a system based on the hydrological model SWAP (Soil Water atmosphere Plant) to calculate spatial and temporal patterns of crop transpiration T(x, y, t) and of the vertical distribution of soil water content θ(x, y, z, t). On one hand, in the absence of ground measurement of soil water content to validate and evaluate the precision of the estimated one, a possibility would be to use satellite retrievals of top soil water content, such as the data to be provided by SMAP. On the other hand, to calculate IP3 we need root zone rather than top soil water content. In principle, we could use the model SWAP to establish a relationship between the top soil and root zone water content. Such relationship could be a simple empirical one or a data assimilation procedure. In our study area (Doukkala- Morocco) we have assessed the consistency of the water allocation with the actual irrigated area and crop water requirements (CWR) by using a combination of multispectral satellite image time series (i,e RapidEye (REIS), SPOT4 (HRVIR1) and Landsat 8 (OLI) images acquired during the 2012/2013 agricultural season). To obtain IP2 (x, y, t) we need to determine ETc (x, y, t). We have applied two (semi)empirical approaches: the first one is the Kc-NDVI method, based on the correlation between the Near Difference Vegetation Index (NDVI) and the value of crop coefficient (kc); the second one is the analytical approach based on the direct application of Penman

  16. A review of groundwater recharge under irrigated agriculture in Australia

    NASA Astrophysics Data System (ADS)

    Riasat, Ali; Mallants, Dirk; Walker, Glen; Silberstein, Richard

    2014-05-01

    Quantification of recharge under irrigated agriculture is one of the most important but difficult tasks. It is the least understood component in groundwater studies because of its large variability in space and time and the difficulty of direct measurement. Better management of groundwater resources is only possible if we can accurately determine all fluxes going into and out of a groundwater system. One of the major challenges facing irrigated agriculture in Australia, and the world, is to reduce uncertainty in estimating or measuring the recharge flux. Reducing uncertainty in groundwater recharge under irrigated agriculture is a pre-requisite for effective, efficient and sustainable groundwater resource management especially in dry areas where groundwater usage is often the key to economic development. An accurate quantification of groundwater recharge under irrigated systems is also crucial because of its potential impacts on soil profile salinity, groundwater levels and groundwater quality. This paper aims to identify the main recharge control parameters thorough a review of past field and modelling recharge studies in Australia. We find that the main recharge control parameters under irrigated agriculture are soil type, irrigation management, watertable depth, land cover or plant water uptake, soil surface conditions, and soil, irrigation water and groundwater chemistry. The most commonly used recharge estimation approaches include chloride mass balance, water budget equation, lysimeters, Darcy's law and numerical models. Main sources and magnitude of uncertainty in recharge estimates associated with these approaches are discussed.

  17. A global map of irrigated agriculture in dry areas.

    NASA Astrophysics Data System (ADS)

    Rowhani, P.; Linderman, M. A.

    2014-12-01

    With changing socio-economic environments and population growth, it is estimated that agricultural production levels need to double by 2050. One way to achieve this may be through agricultural expansion into drier regions, which cover about 41% of earth's land area. Currently, about 70% of freshwater withdrawals are used for irrigation, which in turn produces about 40% of global food. However, little is known about the global area under irrigated agriculture in these water-stressed, arid regions which host about 2 billion people. Here we estimate the global area under irrigation in the arid and hyperarid regions. To this end, we analyse the temporal signature of the Enhanced Vegetation Index (EVI) that was derived from the ~500m BRDF-adjusted reflectance data provided by the MODIS sensor since February 2000. This method does not rely on any external data sources and it allows to explore the temporal evolution of irrigation practices. Additionally, compared to other irrigation maps, our dataset can be quickly updated annually to provide the latest estimations. Initial results show that by using a combination of simple metrics quantifying each pixel's phenology we are able to clearly identify irrigated areas in these dry regions. Our results will be compared to existing global irrigation datasets as well as global land cover maps.

  18. Impact evaluation of the irrigation management reform in northern China

    NASA Astrophysics Data System (ADS)

    Huang, Qiuqiong

    2014-05-01

    The paper evaluates the reform in the irrigation sector in northern China, in particular, the transfer of irrigation management to water user associations or contractors from the village committee. With a set of panel data collected in randomly selected villages in northern China, a fixed effects model at the canal level with instrumental variable estimation is used to control for unobservable heterogeneity and endogeneity problem. The results show that WUAs have increased maintenance expenditures, the timeliness of water deliveries, the percent of irrigated area and the rates of fee collection. There are also improvements in irrigation systems managed by contractors but with magnitudes smaller than in the case of WUAs. WUAs or contracting, however, have limited impacts on water use and crop production. Discussions on reasons for the findings of limited impacts offer some suggestions for the next steps of the irrigation reform and call for continued research efforts to collect more data for further impact evaluations.

  19. Micro irrigation of tropical fruit crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In most tropical regions, tropical fruits are grown either in wet-and-dry climates characterized by erratic rainfall patterns and prolonged dry periods or in fertile but semiarid lands under irrigation. Little is known about water requirements of tropical crops grown in the tropics. This book chapt...

  20. Automatic restart of complex irrigation systems

    SciTech Connect

    Werner, H.D.; Alcock, R.; DeBoer, D.W.; Olson, D.I. . Dept. of Agricultural Engineering)

    1992-05-01

    Automatic restart of irrigation systems under load management has the potential to maximize pumping time during off-peak hours. Existing automation technology ranges from time delay relays to more sophisticated control using computers together with weather data to optimize irrigation practices. Centrifugal pumps and water hammer concerns prevent automatic restart of common but often complex irrigation systems in South Dakota. The irrigator must manually prime the pump and control water hammer during pipeline pressurization. Methods to prime centrifugal pumps and control water hammer facilitate automatic restart after load management is released. Seven priming methods and three water hammer control methods were investigated. A sump pump and small vacuum pump were used to test two automatic prime and restart systems in the laboratory. A variable frequency phase converter was also used to automatically control water hammer during pipeline pressurization. Economical methods to safely prime and restart centrifugal pumps were discussed. The water hammer control methods safely pressurize the pipeline but require a higher initial investment. The automatic restart systems can be used to safely restart centrifugal pumps and control water hammer after load management is released. Based upon laboratory research and a technical review of available restart components, a computer software program was developed. The program assists customers in evaluating various restart options for automatic restarting of electric irrigation pumps. For further information on the software program, contact the South Dakota State University, Department of Agricultural Engineering.

  1. Potential for Photovoltaic Solar Installation in Non-Irrigated Corners of Center Pivot Irrigation Fields in the State of Colorado

    SciTech Connect

    Roberts, B.

    2011-07-01

    The State of Colorado expressed an interest in assessing the potential for photovoltaic (PV) solar installations on non-irrigated corners of center-pivot irrigation (CPI) fields throughout the state. Using aerial imagery and irrigated land data available from the Colorado Water Conservation Board, an assessment of potentially suitable sites was produced. Productivity estimates were calculated from that assessment. The total area of non-irrigated corners of CPI fields in Colorado was estimated to be 314,674 acres, which could yield 223,418 acres of installed PV panels assuming 71% coverage in triangular plots. The total potential annual electricity production for the state was estimated to be 56,821 gigawatt hours (GWH), with an average of 1.3 GWH per available plot.

  2. ENERGY BALANCE ESTIMATION OF EVAPOTRANSPIRATION FOR WHEAT GROWN UNDER VARIABLE MANAGEMENT PRACTICES IN CENTRAL ARIZONA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimation and monitoring the spatial distribution of evapotranspiration (ET) over irrigated crops is becoming increasingly important for managing crop water requirements under water scarce conditions. The usual approaches for estimating ET, however, do not provide plot-specific data but instead pro...

  3. Calcium requirement: new estimations for men and women by cross-sectional statistical analyses of metabolic calcium balance data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To provide new estimates of the average Ca requirement for men and women, we determined the dietary Ca intake required to maintain neutral Ca balance. Ca balance data (Ca intake - [fecal Ca + urinary Ca]) were collected from 154 subjects (females: n=73, weight=77.1±18.5 kg, age=47.0±18.5 y [range: 2...

  4. MANPOWER REQUIREMENTS AND DEMAND IN AGRICULTURE BY REGIONS AND NATIONALLY, WITH ESTIMATION OF VOCATIONAL TRAINING AND EDUCATIONAL NEEDS AND PRODUCTIVITY.

    ERIC Educational Resources Information Center

    ARCUS, PETER; HEADY, EARL O.

    THE PURPOSE OF THIS STUDY IS TO ESTIMATE THE MANPOWER REQUIREMENTS FOR THE NATION FOR 144 REGIONS THE TYPES OF SKILLS AND WORK ABILITIES REQUIRED BY AGRICULTURE IN THE NEXT 15 YEARS, AND THE TYPES AND AMOUNTS OF EDUCATION NEEDED. THE QUANTITATIVE ANALYSIS IS BEING MADE BY METHODS APPROPRIATE TO THE PHASES OF THE STUDY--(1) INTERRELATIONS AMONG…

  5. Non-sustainable groundwater sustaining irrigation - a global assessment

    NASA Astrophysics Data System (ADS)

    Wada, Y.; van Beek, L. P. H.; Bierkens, M. F. P.

    2012-04-01

    Irrigated crops play a vital role in securing global food production. It is estimated that 17% of agricultural lands are irrigated, yet they account for 40% of the global food production, sustaining the livelihood of billions of people (Abdullah, 2006). At the same time, water used by irrigated crops (i.e., crop water demand) and irrigation water demand are responsible for about 70% of the global water withdrawal and account for about 90% of the global water consumption, i.e. water withdrawal minus return flow respectively. Water demand for irrigated crops can be met by three different sources: 1) green water, being water from local precipitation that is temporarily stored in the soil, 2) blue water, being surface freshwater available in rivers, lakes, reservoirs and wetlands, and renewable groundwater, and 3) non-renewable or non-sustainable groundwater and non-local water resources. Here, we quantify globally the amount of non-renewable groundwater abstraction to sustain current irrigation practice. We use the global hydrological model PCR-GLOBWB to simulate gross crop water demand for irrigated crops and available blue and green water to meet this demand. We downscale country statistics of groundwater abstraction by considering the part of net total water demand that cannot be met by surface freshwater. We subsequently confront these with simulated groundwater recharge including return flow from irrigation to estimate non-renewable groundwater abstraction. Results show that non-renewable groundwater abstraction contributes approximately 20% to the global gross irrigation water demand for the year 2000. The contribution of non-renewable groundwater abstraction to irrigation is largest in India (68 km3 yr-1) followed by Pakistan (35 km3/yr), USA (30 km3/yr), Iran (20 km3/yr), China (20 km3/yr), Mexico (10 km3/yr) and Saudi Arabia (10 km3/yr). Results also show that globally this contribution more than tripled from 75 to 234 km3/yr over the period 1960-2000. These

  6. Evaluation of a method estimating real-time individual lysine requirements in two lines of growing-finishing pigs.

    PubMed

    Cloutier, L; Pomar, C; Létourneau Montminy, M P; Bernier, J F; Pomar, J

    2015-04-01

    The implementation of precision feeding in growing-finishing facilities requires accurate estimates of the animals' nutrient requirements. The objectives of the current study was to validate a method for estimating the real-time individual standardized ileal digestible (SID) lysine (Lys) requirements of growing-finishing pigs and the ability of this method to estimate the Lys requirements of pigs with different feed intake and growth patterns. Seventy-five pigs from a terminal cross and 72 pigs from a maternal cross were used in two 28-day experimental phases beginning at 25.8 (±2.5) and 73.3 (±5.2) kg BW, respectively. Treatments were randomly assigned to pigs within each experimental phase according to a 2×4 factorial design in which the two genetic lines and four dietary SID Lys levels (70%, 85%, 100% and 115% of the requirements estimated by the factorial method developed for precision feeding) were the main factors. Individual pigs' Lys requirements were estimated daily using a factorial approach based on their feed intake, BW and weight gain patterns. From 25 to 50 kg BW, this method slightly underestimated the pigs' SID Lys requirements, given that maximum protein deposition and weight gain were achieved at 115% of SID Lys requirements. However, the best gain-to-feed ratio (G : F) was obtained at a level of 85% or more of the estimated Lys requirement. From 70 to 100 kg, the method adequately estimated the pigs' individual requirements, given that maximum performance was achieved at 100% of Lys requirements. Terminal line pigs ate more (P=0.04) during the first experimental phase and tended to eat more (P=0.10) during the second phase than the maternal line pigs but both genetic lines had similar ADG and protein deposition rates during the two phases. The factorial method used in this study to estimate individual daily SID Lys requirements was able to accommodate the small genetic differences in feed intake, and it was concluded that this method can be

  7. Assessment of radar resolution requirements for soil moisture estimation from simulated satellite imagery. [Kansas

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T. (Principal Investigator); Dobson, M. C.; Moezzi, S.

    1982-01-01

    Radar simulations were performed at five-day intervals over a twenty-day period and used to estimate soil moisture from a generalized algorithm requiring only received power and the mean elevation of a test site near Lawrence, Kansas. The results demonstrate that the soil moisture of about 90% of the 20-m by 20-m pixel elements can be predicted with an accuracy of + or - 20% of field capacity within relatively flat agricultural portions of the test site. Radar resolutions of 93 m by 100 m with 23 looks or coarser gave the best results, largely because of the effects of signal fading. For the distribution of land cover categories, soils, and elevation in the test site, very coarse radar resolutions of 1 km by 1 km and 2.6 km by 3.1 km gave the best results for wet moisture conditions while a finer resolution of 93 m by 100 m was found to yield superior results for dry to moist soil conditions.

  8. Electrofishing effort required to estimate biotic condition in Southern Idaho Rivers

    USGS Publications Warehouse

    Maret, T.R.; Ott, D.S.; Herlihy, A.T.

    2007-01-01

    An important issue surrounding biomonitoring in large rivers is the minimum sampling effort required to collect an adequate number of fish for accurate and precise determinations of biotic condition. During the summer of 2002, we sampled 15 randomly selected large-river sites in southern Idaho to evaluate the effects of sampling effort on an index of biotic integrity (IBI). Boat electrofishing was used to collect sample populations of fish in river reaches representing 40 and 100 times the mean channel width (MCW; wetted channel) at base flow. Minimum sampling effort was assessed by comparing the relation between reach length sampled and change in IBI score. Thirty-two species of fish in the families Catostomidae, Centrarchidae, Cottidae, Cyprinidae, Ictaluridae, Percidae, and Salmonidae were collected. Of these, 12 alien species were collected at 80% (12 of 15) of the sample sites; alien species represented about 38% of all species (N = 32) collected during the study. A total of 60% (9 of 15) of the sample sites had poor IBI scores. A minimum reach length of about 36 times MCW was determined to be sufficient for collecting an adequate number of fish for estimating biotic condition based on an IBI score. For most sites, this equates to collecting 275 fish at a site. Results may be applicable to other semiarid, fifth-order through seventh-order rivers sampled during summer low-flow conditions. ?? Copyright by the American Fisheries Society 2007.

  9. Assessing the changes of groundwater recharge / irrigation water use between SRI and traditional irrigation schemes in Central Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2015-04-01

    To respond to agricultural water shortage impacted by climate change without affecting rice yield in the future, the application of water-saving irrigation, such as SRI methodology, is considered to be adopted in rice-cultivation in Taiwan. However, the flooded paddy fields could be considered as an important source of groundwater recharge in Central Taiwan. The water-saving benefit of this new methodology and its impact on the reducing of groundwater recharge should be integrally assessed in this area. The objective of this study was to evaluate the changes of groundwater recharge/ irrigation water use between the SRI and traditional irrigation schemes (continuous irrigation, rotational irrigation). An experimental paddy field located in the proximal area of the Choushui River alluvial fan (the largest groundwater pumping region in Taiwan) was chosen as the study area. The 3-D finite element groundwater model (FEMWATER) with the variable boundary condition analog functions, was applied in simulating groundwater recharge process and amount under traditional irrigation schemes and SRI methodology. The use of effective rainfall was taken into account or not in different simulation scenarios for each irrigation scheme. The simulation results showed that there were no significant variations of infiltration rate in the use of effective rainfall or not, but the low soil moisture setting in deep soil layers resulted in higher infiltration rate. Taking the use of effective rainfall into account, the average infiltration rate for continuous irrigation, rotational irrigation, and SRI methodology in the first crop season of 2013 were 4.04 mm/day, 4.00 mm/day and 3.92 mm/day, respectively. The groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reducing 4% and 2% compared with continuous irrigation and rotational irrigation, respectively. The field irrigation requirement amount of SRI methodology was significantly

  10. Irrigation Management in the Texas High Plains: Present Status, Challenges, and Opportunities (Invited)

    NASA Astrophysics Data System (ADS)

    Gowda, P. H.

    2013-12-01

    Evapotranspiration (ET) is an essential component of the water balance and a major consumptive use of irrigation water and precipitation on cropland. Any attempt to improve water use efficiency must be based on reliable estimates of ET for irrigation scheduling purposes. In the Texas High Plains, irrigation scheduling is implemented using lysimeter-based crop coefficients and reference ET data from the Texas High Plains ET Network. This presentation will discuss the current state of irrigation management in the Texas High Plains, knowledge gaps, ongoing developments, and role of remote sensing based regional ET mapping algorithms with respect to irrigated agriculture.

  11. Strategy of Irrigation Branch in Russia

    NASA Astrophysics Data System (ADS)

    Zeyliger, A.; Ermolaeva, O.

    2012-04-01

    At this moment, at the starting time of the program on restoration of a large irrigation in Russia till 2020, the scientific and technical community of irrigation branch does not have clear vision on how to promote a development of irrigated agriculture and without repeating of mistakes having a place in the past. In many respects absence of a vision is connected to serious backlog of a scientific and technical and informational and technological level of development of domestic irrigation branch from advanced one. Namely such level of development is necessary for the resolving of new problems in new conditions of managing, and also for adequate answers to new challenges from climate and degradation of ground & water resources, as well as a rigorous requirement from an environment. In such important situation for irrigation branch when it is necessary quickly generate a scientific and technical politics for the current decade for maintenance of translation of irrigated agriculture in the Russian Federation on a new highly effective level of development, in our opinion, it is required to carry out open discussion of needs and requirements as well as a research for a adequate solutions. From political point of view a framework organized in FP6 DESIRE 037046 project is an example of good practice that can serve as methodical approach how to organize and develop such processes. From technical point of view a technology of operational management of irrigation at large scale presents a prospective alternative to the current type of management based on planning. From point of view ICT operational management demands creation of a new platform for the professional environment of activity. This platform should allow to perceive processes in real time, at their partial predictability on signals of a straight line and a feedback, within the framework of variability of decision making scenarious, at high resolution and the big ex-awning of sensor controls and the gauges

  12. Application of remote sensing techniques for identification of irrigated crop lands in Arizona

    NASA Technical Reports Server (NTRS)

    Billings, H. A.

    1981-01-01

    Satellite imagery was used in a project developed to demonstrate remote sensing methods of determining irrigated acreage in Arizona. The Maricopa water district, west of Phoenix, was chosen as the test area. Band rationing and unsupervised categorization were used to perform the inventory. For both techniques the irrigation district boundaries and section lines were digitized and calculated and displayed by section. Both estimation techniques were quite accurate in estimating irrigated acreage in the 1979 growing season.

  13. Impact of reclaimed water irrigation on soil health in urban green areas.

    PubMed

    Chen, Weiping; Lu, Sidan; Pan, Neng; Wang, Yanchun; Wu, Laosheng

    2015-01-01

    Rapid increase of reclaimed water irrigation in urban green areas requires investigating its impact on soil health conditions. In this research, field study was conducted in 7 parks in Beijing with different histories of reclaimed water irrigation. Twenty soil attributes were analyzed to evaluate the effects of reclaimed water irrigation on the soil health conditions. Results showed that soil nutrient conditions were ameliorated by reclaimed water irrigation, as indicated by the increase of soil organic matter content (SOM), total nitrogen (TN), and available phosphorus (AP). No soil salinization but a slight soil alkalization was observed under reclaimed water irrigation. Accumulation of heavy metals in soil was insignificant. It was also observed that reclaimed water irrigation could significantly improve the soil microorganism activities. Overall, the soil health conditions were improved with reclaimed water irrigation, and the improvement increased when the reclaimed water irrigation period became longer. PMID:25150469

  14. Ensuring equal opportunity sprinkler irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Equal opportunity for plants to sprinkler irrigation water must be carefully considered by crop producers, irrigation consultants, and the industry that supplies the irrigation equipment. Equal opportunity can be negated by improper marketing, design, and installation, as well as through improper f...

  15. Planning for an Irrigation System.

    ERIC Educational Resources Information Center

    Turner, J. Howard; Anderson, Carl L.

    The publication, with the aid of tables and colored illustrations and diagrams, presents information to help the farmer who is considering the installation of an irrigation system determine whether or not to irrigate, the type of system to use, and the irrigation cost and return on investment. Information is presented on the increase in yield to…

  16. Uncertainty in future irrigation water demand and risk of crop failure for maize in Europe

    NASA Astrophysics Data System (ADS)

    Webber, Heidi; Gaiser, Thomas; Oomen, Roelof; Teixeira, Edmar; Zhao, Gang; Wallach, Daniel; Zimmermann, Andrea; Ewert, Frank

    2016-07-01

    While crop models are widely used to assess the change in crop productivity with climate change, their skill in assessing irrigation water demand or the risk of crop failure in large area impact assessments is relatively unknown. The objective of this study is to investigate which aspects of modeling crop water use (reference crop evapotranspiration (ET0), soil water extraction, soil evaporation, soil water balance and root growth) contributes most to the variability in estimates of maize crop water use and the risk of crop failure, and demonstrate the resulting uncertainty in a climate change impact study for Europe. The SIMPLACE crop modeling framework was used to couple the LINTUL5 crop model in factorial combinations of 2–3 different approaches for simulating the 5 aspects of crop water use, resulting in 51 modeling approaches. Using experiments in France and New Zeland, analysis of total sensitivity revealed that ET0 explained the most variability in both irrigated maize water use and rainfed grain yield levels, with soil evaporation also imporatant in the French experiment. In the European impact study, net irrigation requirement differed by 36% between the Penman and Hargreaves ET0 methods in the baseline period. Average EU grain yields were similar between models, but differences approached 1–2 tonnes in parts of France and Southern Europe. EU wide esimates of crop failure in the historical period ranged between 5.4 years for Priestley–Taylor to every 7.9 years for the Penman ET0 methods. While the uncertainty in absolute values between models was significant, estimates of relative changes were similar between models, confirming the utility of crop models in assessing climate change impacts. If ET0 estimates in crop models can be improved, through the use of appropriate methods, uncertainty in irrigation water demand as well as in yield estimates under drought can be reduced.

  17. Modeling of basin-wide water management for dry-season paddy irrigation with large reservoirs in the Mekong River Basin

    NASA Astrophysics Data System (ADS)

    Kudo, R.; Masumoto, T.; Horikawa, N.; Yoshida, T.

    2012-12-01

    . Irrigation and crop patterns are set as agricultural conditions in each mesh, and then irrigation water and actual evapotranspiration can be estimated according to crop stage and soil moisture. We also modeled water management of 160 reservoirs (10 large reservoirs and 150 medium reservoirs) and water allocation process of 10 large irrigated areas in the basin. The results obtained in this study are as follows: 1) The reservoir operation model reproduced water management such as impoundment of flood discharge during rainy seasons and release of irrigation water controlled by water requirement in downstream irrigation area during dry seasons. 2) The paddy water use and the water allocation models estimated water withdrawals at diversion weirs and water supply in paddy fields depending on water demands in large irrigation areas. 3) Based on the difference in water use patterns between rainy and dry seasons, the cropping model represented the actual conditions of rice planting pattern in both seasons. These results show that the interaction among the sub-models (reservoir operation, paddy water use, water allocation and so on) enables this hydrological model to represent the detailed processes of paddy water use and to evaluate the interaction between hydrological cycle and agricultural activities through anthropogenic water management for paddy irrigation.

  18. Texas Irrigation Situation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The irrigation situation in Texas is an interaction between hydrology and water policies. In 2012, according to National Agricultural Statistical Service (NASS) four High Plains counties, Gainesville, Yoakum, Terry and Cochran, accounted for approximately 60% of the 150,000 acres of peanut productio...

  19. EROSION: IRRIGATION-INDUCED

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlling erosion on and soil loss from irrigated lands is critical to sustain agricultural production. Protecting and stabilizing the soil surface will minimize sediment detachment. Slowing or reducing overland flow will minimize sediment transport. Reducing or managing runoff is the key to co...

  20. Erosion: Irrigation-induced

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil can be eroded by sprinkler or surface irrigation. Once sprinkler droplet kinetic energy detaches soil, overland flow transports the sediment downslope and off-site. Protecting the soil surface, increasing sprinkler wetted diameters, and tilling to increase infiltration and thereby lessen overla...

  1. The Arkansas Irrigation Scheduler

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the U.S. Mid-South, annual rainfall is generally sufficient for limited crop production, but periods of drought during the growing season make irrigation essential for optimum yields. However, factors such as cloudy weather, rainfall, and temperature swings caused by the movement of weather front...

  2. Deterioration Prediction Model of Irrigation Facilities by Markov Chain Model

    NASA Astrophysics Data System (ADS)

    Mori, Takehisa; Nishino, Noriyasu; Fujiwara, Tetsuro

    "Stock Management" launched in all over Japan is an activity to use irrigation facilities effectively and to reduce life cycle costs of theirs. Deterioration prediction of the irrigation facility condition is a vital process for the study of maintenance measures and the estimation of maintenance cost. It is important issue to establish the prediction technique with higher accuracy. Thereupon, we established a deterioration prediction model by a statistical method "Markov chain", and analyzed a function diagnosis data of irrigation facilities. As a result, we clarified the deterioration characteristics into each structure type and facilities.

  3. Empirical evidence for a recent slowdown in irrigation-induced cooling

    SciTech Connect

    Bonfils, C; Lobell, D

    2007-01-19

    Understanding the influence of past land use changes on climate is needed to improve regional projections of future climate change and inform debates about the tradeoffs associated with land use decisions. The effects of rapid expansion of irrigated area in the 20th century has remained unclear relative to other land use changes, such as urbanization, that affected a similar total land area. Using spatial and temporal variations in temperature and irrigation extent observed in California, we show that irrigation expansion has had a large cooling effect on summertime average daily daytime temperatures (-0.15 to -0.25 C.decade{sup -1}), which corresponds to a cooling estimated at -2.0 - -3.3 C since the introduction of irrigation practice. Irrigation has negligible effects on nighttime temperatures, leading to a net cooling effect of irrigation on climate (-0.06 to -0.19 C.decade{sup -1}). Stabilization of irrigated area has occurred in California since 1980 and is expected in the near future for most irrigated regions. The suppression of past human-induced greenhouse warming by increased irrigation is therefore likely to slow in the future, and a potential decrease in irrigation may even contribute to a more rapid warming. Changes in irrigation alone are not expected to influence broadscale temperatures, but they may introduce large uncertainties in climate projections for irrigated agricultural regions, which provide roughly 40% of global food production.

  4. A comparison of groundwater recharge estimation methods in a semi-arid, coastal avocado and citrus orchard (Ventura County, California)

    NASA Astrophysics Data System (ADS)

    Grismer, Mark E.; Bachman, S.; Powers, T.

    2000-10-01

    We assess the relative merits of application of the most commonly used field methods (soil-water balance (SWB), chloride mass balance (CMB) and soil moisture monitoring (NP)) to determine recharge rates in micro-irrigated and non-irrigated areas of a semi-arid coastal orchard located in a relatively complex geological environment.Application of the CMB method to estimate recharge rates was difficult owing to the unusually high, variable soil-water chloride concentrations. In addition, contrary to that expected, the chloride concentration distribution at depths below the root zone in the non-irrigated soil profiles was greater than that in the irrigated profiles. The CMB method severely underestimated recharge rates in the non-irrigated areas when compared with the other methods, although the CMB method estimated recharge rates for the irrigated areas, that were similar to those from the other methods, ranging from 42 to 141 mm/year.The SWB method, constructed for a 15-year period, provided insight into the recharge process being driven by winter rains rather than summer irrigation and indicated an average rate of 75 mm/year and 164 mm/year for the 1984 - 98 and 1996 - 98 periods, respectively. Assuming similar soil-water holding capacity, these recharge rates applied to both irrigated and non-irrigated areas. Use of the long period of record was important because it encompassed both drought and heavy rainfall years. Successful application of the SWB method, however, required considerable additional field measurements of orchard ETc, soil-water holding capacity and estimation of rainfall interception - runoff losses.Continuous soil moisture monitoring (NP) was necessary to identify both daily and seasonal seepage processes to corroborate the other recharge estimates. Measured recharge rates during the 1996 - 1998 period in both the orchards and non-irrigated site averaged 180 mm/year. The pattern of soil profile drying during the summer irrigation season, followed

  5. Prophylactic peri-operative local antibiotic irrigation.

    PubMed

    Whiteside, L A

    2016-01-01

    An extensive review of the spinal and arthroplasty literature was undertaken to evaluate the effectiveness of local antibiotic irrigation during surgery. The efficacy of antibiotic irrigation for the prevention of acute post-operative infection after total joint arthroplasty was evaluated retrospectively in 2293 arthroplasties (1990 patients) between January 2004 and December 2013. The mean follow-up was 73 months (20 to 139). One surgeon performed all the procedures with minimal post-operative infection. The intra-operative protocol included an irrigation solution of normal saline with vancomycin 1000 mg/l and polymyxin 250,000 units/l at the rate of 2 l per hour. No patient required re-admission for primary infection or further antibiotic treatment. Two morbidly obese patients (two total hip arthroplasties) developed subcutaneous fat necrosis requiring debridement and one was revised because the deep capsular sutures were contaminated by the draining subcutaneous haematoma. One patient who had undergone total knee arthroplasty had unrecognised damage to the lateral superior geniculate artery and developed a haematoma that became infected secondarily four months after the surgery and underwent revision. The use of antibiotic irrigation during arthroplasty surgery has been highly effective for the prevention of infection in the author's practice. However, it should be understood that any routine prophylactic use of antibiotics may result in resistant organisms, and the wise stewardship of the use of antibiotics is an important part of surgical practice. PMID:26733636

  6. Estimating the Reliability of Dynamic Variables Requiring Rater Judgment: A Generalizability Paradigm.

    ERIC Educational Resources Information Center

    Webber, Larry; And Others

    Generalizability theory, which subsumes classical measurement theory as a special case, provides a general model for estimating the reliability of observational rating data by estimating the variance components of the measurement design. Research data from the "Heart Smart" health intervention program were analyzed as a heuristic tool. Systolic…

  7. From rainfed agriculture to stress-avoidance irrigation: II. Sustainability, crop yield, and profitability

    NASA Astrophysics Data System (ADS)

    Vico, Giulia; Porporato, Amilcare

    2011-02-01

    The optimality of irrigation strategies may be sought with respect to a number of criteria, including water requirements, crop yield, and profitability. To explore the suitability of different demand-based irrigation strategies, we link the probabilistic description of irrigation requirements under stochastic hydro-climatic conditions, provided in a companion paper [Vico G, Porporato A. From rainfed agriculture to stress-avoidance irrigation: I. A generalized irrigation scheme with stochastic soil moisture. Adv Water Resour 2011;34(2):263-71], to crop-yield and economic analyses. Water requirements, application efficiency, and investment costs of different irrigation methods, such as surface, sprinkler and drip irrigation systems, are described via a unified conceptual and theoretical approach, which includes rainfed agriculture and stress-avoidance irrigation as extreme cases. This allows us to analyze irrigation strategies with respect to sustainability, productivity, and economic return, using the same framework, and quantify them as a function of climate, crop, and soil parameters. We apply our results to corn ( Zea mays), a food staple and biofuel source, which is currently mainly irrigated through surface systems. As our analysis shows, micro-irrigation maximizes water productivity, but more traditional solutions may be more profitable at least in some contexts.

  8. Simulated Impacts of Climate Change on Water Use and Yield of Irrigated Sugarcane in South Africa

    NASA Technical Reports Server (NTRS)

    Jones, M.R; Singels, A.; Ruane, A. C.

    2015-01-01

    Reliable predictions of climate change impacts on water use, irrigation requirements and yields of irrigated sugarcane in South Africa (a water-scarce country) are necessary to plan adaptation strategies. Although previous work has been done in this regard, methodologies and results vary considerably. The objectives were (1) to estimate likely impacts of climate change on sugarcane yields, water use and irrigation demand at three irrigated sugarcane production sites in South Africa (Malelane, Pongola and La Mercy) for current (1980-2010) and future (2070-2100) climate scenarios, using an approach based on the Agricultural Model Inter-comparison and Improvement Project (AgMIP) protocols; and (2) to assess the suitability of this methodology for investigating climate change impacts on sugarcane production. Future climate datasets were generated using the Delta downscaling method and three Global Circulation Models (GCMs) assuming atmospheric CO2 concentration [CO2] of 734 ppm(A2 emissions scenario). Yield and water use were simulated using the DSSAT-Canegro v4.5 model. Irrigated cane yields are expected to increase at all three sites (between 11 and 14%), primarily due to increased interception of radiation as a result of accelerated canopy development. Evapotranspiration and irrigation requirements increased by 11% due to increased canopy cover and evaporative demand. Sucrose yields are expected to decline because of increased consumption of photo-assimilate for structural growth and maintenance respiration. Crop responses in canopy development and yield formation differed markedly between the crop cycles investigated. Possible agronomic implications of these results include reduced weed control costs due to shortened periods of partial canopy, a need for improved efficiency of irrigation to counter increased demands, and adjustments to ripening and harvest practices to counter decreased cane quality and optimize productivity. Although the Delta climate data

  9. Estimation of yield and water requirements of maize crops combining high spatial and temporal resolution images with a simple crop model, in the perspective of the Sentinel-2 mission

    NASA Astrophysics Data System (ADS)

    Battude, Marjorie; Bitar, Ahmad Al; Brut, Aurore; Cros, Jérôme; Dejoux, Jean-François; Huc, Mireille; Marais Sicre, Claire; Tallec, Tiphaine; Demarez, Valérie

    2016-04-01

    Water resources are under increasing pressure as a result of global change and of a raising competition among the different users (agriculture, industry, urban). It is therefore important to develop tools able to estimate accurately crop water requirements in order to optimize irrigation while maintaining acceptable production. In this context, remote sensing is a valuable tool to monitor vegetation development and water demand. This work aims at developing a robust and generic methodology mainly based on high resolution remote sensing data to provide accurate estimates of maize yield and water needs at the watershed scale. Evapotranspiration (ETR) and dry aboveground biomass (DAM) of maize crops were modeled using time series of GAI images used to drive a simple agro-meteorological crop model (SAFYE, Duchemin et al., 2005). This model is based on a leaf partitioning function (Maas, 1993) for the simulation of crop biomass and on the FAO-56 methodology for the ETR simulation. The model also contains a module to simulate irrigation. This study takes advantage of the SPOT4 and SPOT5 Take5 experiments initiated by CNES (http://www.cesbio.ups-tlse.fr/multitemp/). They provide optical images over the watershed from February to May 2013 and from April to August 2015 respectively, with a temporal and spatial resolution similar to future images from the Sentinel-2 and VENμS missions. This dataset was completed with LandSat8 and Deimos1 images in order to cover the whole growing season while reducing the gaps in remote sensing time series. Radiometric, geometric and atmospheric corrections were achieved by the THEIA land data center, and the KALIDEOS processing chain. The temporal dynamics of the green area index (GAI) plays a key role in soil-plant-atmosphere interactions and in biomass accumulation process. Consistent seasonal dynamics of the remotely sensed GAI was estimated by applying a radiative transfer model based on artificial neural networks (BVNET, Baret

  10. Number of trials required to estimate a free-energy difference, using fluctuation relations.

    PubMed

    Yunger Halpern, Nicole; Jarzynski, Christopher

    2016-05-01

    The difference ΔF between free energies has applications in biology, chemistry, and pharmacology. The value of ΔF can be estimated from experiments or simulations, via fluctuation theorems developed in statistical mechanics. Calculating the error in a ΔF estimate is difficult. Worse, atypical trials dominate estimates. How many trials one should perform was estimated roughly by Jarzynski [Phys. Rev. E 73, 046105 (2006)PLEEE81539-375510.1103/PhysRevE.73.046105]. We enhance the approximation with the following information-theoretic strategies. We quantify "dominance" with a tolerance parameter chosen by the experimenter or simulator. We bound the number of trials one should expect to perform, using the order-∞ Rényi entropy. The bound can be estimated if one implements the "good practice" of bidirectionality, known to improve estimates of ΔF. Estimating ΔF from this number of trials leads to an error that we bound approximately. Numerical experiments on a weakly interacting dilute classical gas support our analytical calculations. PMID:27300866

  11. Number of trials required to estimate a free-energy difference, using fluctuation relations

    NASA Astrophysics Data System (ADS)

    Yunger Halpern, Nicole; Jarzynski, Christopher

    2016-05-01

    The difference Δ F between free energies has applications in biology, chemistry, and pharmacology. The value of Δ F can be estimated from experiments or simulations, via fluctuation theorems developed in statistical mechanics. Calculating the error in a Δ F estimate is difficult. Worse, atypical trials dominate estimates. How many trials one should perform was estimated roughly by Jarzynski [Phys. Rev. E 73, 046105 (2006), 10.1103/PhysRevE.73.046105]. We enhance the approximation with the following information-theoretic strategies. We quantify "dominance" with a tolerance parameter chosen by the experimenter or simulator. We bound the number of trials one should expect to perform, using the order-∞ Rényi entropy. The bound can be estimated if one implements the "good practice" of bidirectionality, known to improve estimates of Δ F . Estimating Δ F from this number of trials leads to an error that we bound approximately. Numerical experiments on a weakly interacting dilute classical gas support our analytical calculations.

  12. Study of the hydrological functionning of the irrigated crops in the southern mediterranean basin

    NASA Astrophysics Data System (ADS)

    Khabba, Said; Jarlan, Lionel; Er-Raki, Salah; Le Page, Michel; Merlin, Olivier; Ezzahar, Jamal; Kharrou, Mohamed H.

    2015-04-01

    the physically based SVATs such as ISBA provide good estimates of surface fluxes over all sites once a proper calibration is carried out. However, they required several input parameters that are not routinely available at the appropriate spatial scale. For operational purposes, simpler approaches such as the FAO-56 and the TSEB models showed a good estimate of ET at field scale. Also, the FAO-56 approach was adapted to use a satellite-based vegetation index. It was calibrated and validated on the Haouz plain, for the main crops (wheat, olive and citrus). Its implementation was validated using a Landsat TM image time series and also using low resolution images. The results showed that despite the simplicity of the model, spatial estimates of ET were reasonable. This model was converted in software for Satellite Monitoring of Irrigation. However, the FAO-56 method combined with solar remote sensing data alone was not sufficient to accurately estimate water consumption, especially when soil evaporation and stress under full vegetation cover conditions occurred. In this regard, we directly assimilated snapshot evaporation data that could be obtained through the resolution of a simple energy budget forced by TIR observations. These preliminary results showed a clear improvement of the seasonal ET estimates.

  13. Practical salinity management for leachate irrigation to poplar trees.

    PubMed

    Smesrud, Jason K; Duvendack, George D; Obereiner, James M; Jordahl, James L; Madison, Mark F

    2012-01-01

    Landfill leachate can be beneficially reused for irrigation of fiber crops with appropriate attention to nutrient and salinity management. The Riverbend Landfill in Western Oregon has been effectively practicing irrigation of landfill leachate to poplar trees since 1993. Over that time, the site has been adaptively managed to control salinity impacts to the tree crop while beneficially utilizing the applied water and nutrients during each growing season. Representative leachate irrigation water has ranged in concentration of total dissolved solids from 777 to 6,940 mg/L, chloride from 180 to 1,760 mg/L and boron from 3.2 to 7.3 mg/L. Annual leachate irrigation applications have also ranged between 102 and 812 mm/yr. Important conclusions from this site have included: 1) Appropriate tree clone selection and tree stand spacing, thinning, and harvest rotations are critical to maintaining a productive tree stand that is resilient and resistant to salt stress. The most effective combinations have included clones DN-34, OP-367, 184-411, 49-177, and 15-29 planted at spacing of 3.7-m x 1.8-m to 3.7-m x 3.7-m; 2) Leaf tissue boron levels are closely correlated to soil boron levels and can be managed with leaching. When leaf tissue boron levels exceed 200 to 250 mg/kg, signs of salt stress may emerge and should be monitored closely; 3) Salinity from leachate irrigation can be managed to sustain a healthy tree crop by controlling mass loading rates and providing appropriate irrigation blending if necessary. Providing freshwater irrigation following each leachate irrigation and targeting freshwater irrigation as 30 percent of total irrigation water applied has successfully controlled salt impacts to vegetation; and 4) Drip irrigation generally requires more careful attention to long-term soil salinity management than spray irrigation. Moving drip irrigation tubes periodically to prevent the formation of highly saline zones within the soil profile is important. In this paper, a

  14. Asian irrigation, African rain: Remote impacts of irrigation

    NASA Astrophysics Data System (ADS)

    Vrese, Philipp; Hagemann, Stefan; Claussen, Martin

    2016-04-01

    Irrigation is not only vital for global food security but also constitutes an anthropogenic land use change, known to have strong effects on local hydrological and energy cycles. Using the Max Planck Institute for Meteorology's Earth System Model, we show that related impacts are not confined regionally but that possibly as much as 40% of the present-day precipitation in some of the arid regions in Eastern Africa are related to irrigation-based agriculture in Asia. Irrigation in South Asia also substantially influences the climate throughout Southeast Asia and China via the advection of water vapor and by altering the Asian monsoon. The simulated impact of irrigation on remote regions is sensitive to the magnitude of the irrigation-induced moisture flux. Therefore, it is likely that a future extension or decline of irrigated areas due to increasing food demand or declining fresh water resources will also affect precipitation and temperatures in remote regions.

  15. Agricultural irrigated land-use inventory for Jackson, Calhoun, and Gadsden Counties in Florida, and Houston County in Alabama, 2014

    USGS Publications Warehouse

    Marella, Richard L.; Dixon, Joann F.

    2015-01-01

    The irrigated acreage estimated for Jackson County in 2014 (31,608) is about 47 percent higher than the 2012 estimated acreage published by the USDA (21,508 acres). The estimates of irrigated acreage field verified during 2014 for Calhoun and Gadsden Counties are also higher than those published by the USDA for 2012 (86 percent and 71 percent, respectively). In Calhoun County the USDA reported 1,647 irrigated acres while the current study estimated 3,060 acres, and in Gadsden County the USDA reported 2,650 acres while the current study estimated 4,547 acres. For Houston County the USDA-reported value of 9,138 acres in 2012 was 13 percent below the 10,333 acres field verified in the current study. Differences between the USDA 2012 values and 2014 field verified estimates in these two datasets may occur because (1) irrigated acreage for some specific crops increased or decreased substantially during the 2-year interval due to commodity prices or economic changes, (2) irrigated acreage calculated for the current study may be estimated high because irrigation was assumed if an irrigation system was present and therefore the acreage was counted as irrigated, when in fact that may not have been the case as some farmers may not have used their irrigation systems during this growing period even if they had a crop in the field, or (3) the amount of irrigated acreages published by the USDA for selected crops may be underestimated in some cases.

  16. Producer gas from citrus wood fuels irrigation power unit

    SciTech Connect

    Churchill, D.B.; Hedden, S.L.; Whitney, J.D.; Shaw, L.N.

    1985-01-01

    A 90-hp diesel engine operating a citrus irrigation system was converted to run on a dual-fuel mixture utilizing producer gas from citrus wood chips as the main fuel source. A chip feeder mechanism, gasifier, filter system and control unit were designed to meet typical irrigation power requirements. Blighted, unproductive and dead trees removed near the irrigation site were used for chipping. Data on chip moisture content, fuel analysis, drying rate and fuel/tree weight are presented but labour and equipment costs were not determined. 14 references.

  17. Physically-based Methods for the Estimation of Crop Water Requirements from E.O. Optical Data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The estimation of evapotranspiration (ET) represent the basic information for the evaluation of crop water requirements. A widely used method to compute ET is based on the so-called "crop coefficient" (Kc), defined as the ratio of total evapotranspiration by reference evapotranspiration ET0. The val...

  18. Reported energy intake by weight status, day and estimated energy requirement among adults: NHANES 2003-2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To describe energy intake reporting by gender, weight status, and interview sequence and to compare reported intakes to the Estimated Energy Requirement at different levels of physical activity. Methods: Energy intake was self-reported by 24-hour recall on two occasions (day 1 and day 2)...

  19. Drip irrigation management in different chufa planting strategies: yield and irrigation water use efficiency

    NASA Astrophysics Data System (ADS)

    Pascual-Seva, Nuria; San Bautista, Alberto; López-Galarza, Salvador; Maroto, José Vicente; Pascual, Bernardo

    2013-04-01

    In a study presented in the EGU assembly 2012, it was analysed how yield and irrigation water use efficiency (IWUE) in chufa (Cyperus esculentus L. var. sativus), crop, were affected by planting strategy (ridges and flat raised beds, with two and three plant rows along them) and irrigation system [furrow (FI) and drip irrigation (DI)]. Each irrigation session started when the Volumetric Soil Water Content (VSWC) in ridges dropped to 80% of field capacity; beds were irrigated simultaneously with ridges and with the same irrigation duration. R produced lower yield than the two types of beds, and yields in DI were higher than those FI. Ridges led to the highest IWUE with DI, and to the lowest with FI. Then, it was decided to analyse, in DI, how yield and IWUE responded to start each irrigation session when the VSWC in the central point of different planting strategies [ridges (R), and flat raised beds with two (b) and three (B) plant rows along them] dropped to 80% of field capacity. In R and b, plants were irrigated by a single dripline per plant row, while in B two irrigation layouts were assayed: a single dripline per plant row (B3) and two driplines per bed (B2), placing each dripline between two planting rows. Irrigation session stop was also automated as a function of the VSWC. Results show that yield was affected (P˜0.01) by planting strategy; the greatest yield was obtained in b (2.4 kgm-2), differing (P˜0.05) from that obtained in R (2.1 kgm-2), with intermediate yields in B2 (2.3 kgm-2) and B3 (2.3 kgm-2). Yield was not affected (P˜0.05) by the utilisation of two or three driplines in B. Considerably less irrigation water was applied (IWA) in R (376 mm) than in B3 (465 mm), B2 (475 mm) and b (502 mm). This automatic irrigation management, as a function of the VSWC in each planting strategy, lead to adjust the IWA to the plant water requirements, which were similar in all three flat raised beds, since they correspond to the same planting density, that was

  20. Phenotypic performance of timothy accessions under irrigated and non-irrigated conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Timothy (Phleum pratense L.) is one of the most winter hardy cool-season perennial grasses, used for forage production. However, its lack of tolerance to water stress requires supplemental irrigation for successful production in more arid areas of the world. A set of 112 timothy accessions and six...

  1. Sample Size Requirements for Estimation of Item Parameters in the Multidimensional Graded Response Model

    PubMed Central

    Jiang, Shengyu; Wang, Chun; Weiss, David J

    2016-01-01

    Likert types of rating scales in which a respondent chooses a response from an ordered set of response options are used to measure a wide variety of psychological, educational, and medical outcome variables. The most appropriate item response theory model for analyzing and scoring these instruments when they provide scores on multiple scales is the multidimensional graded response model (MGRM) A simulation study was conducted to investigate the variables that might affect item parameter recovery for the MGRM. Data were generated based on different sample sizes, test lengths, and scale intercorrelations. Parameter estimates were obtained through the flexMIRT software. The quality of parameter recovery was assessed by the correlation between true and estimated parameters as well as bias and root-mean-square-error. Results indicated that for the vast majority of cases studied a sample size of N = 500 provided accurate parameter estimates, except for tests with 240 items when 1000 examinees were necessary to obtain accurate parameter estimates. Increasing sample size beyond N = 1000 did not increase the accuracy of MGRM parameter estimates. PMID:26903916

  2. Comparative anti-microbial efficacy of Azadirachta indica irrigant with standard endodontic irrigants: A preliminary study

    PubMed Central

    Dutta, Arindam; Kundabala, Mala

    2014-01-01

    Objective: The anti-microbial efficacy of 2.5% sodium hypochlorite (SHC) and 0.2% chlorhexidine gluconate were compared with an experimental irrigant formulated from the Neem tree, Azadirachta indica A. Juss. Materials and Methods: A sample of 36 single rooted anterior teeth with periapical radiolucency and absence of response to vitality tests that required root canal treatment were selected for this study. The test irrigants and their combinations were assigned to five different groups and saline served as the control. Access cavities were prepared using an aseptic technique and samples collected for both anaerobic culture and Gram stained smears, followed by irrigation and sample collection again. The number of organisms were expressed in colony forming units/ml after 72 h of incubation; the smears were analyzed for their microbial loads and tissue clearance and assessed as per defined criteria. Results: Our results found the maximum reduction in microbial loads, when analyzed by culture method, with a combination of SHC and the experimental neem irrigant. Maximum tissue clearance on the Gram Stained smears was also found with the same combination. Conclusion: Neem irrigant has anti-microbial efficacy and can be considered for endodontic use. PMID:24778508

  3. A global dataset of the extent of irrigated land from 1900 to 2005

    NASA Astrophysics Data System (ADS)

    Siebert, S.; Kummu, M.; Porkka, M.; Döll, P.; Ramankutty, N.; Scanlon, B. R.

    2014-12-01

    Irrigation intensifies land use by increasing crop yield but also impacts water resources. It affects water and energy balances and consequently the microclimate in irrigated regions. Therefore, knowledge of the extent of irrigated land is important for hydrological and crop modelling, global change research, and assessments of resource use and management. Information on the historical evolution of irrigated lands is limited. The new global Historical Irrigation Dataset (HID) provides estimates of the temporal development of the area equipped for irrigation (AEI) between 1900 and 2005 at 5 arc-minute resolution. We collected subnational irrigation statistics from various sources and found that the global extent of AEI increased from 63 million ha (Mha) in 1900 to 112 Mha in 1950 and 306 Mha in 2005. We developed eight gridded versions of time series of AEI by combining subnational irrigation statistics with different data sets on the historical extent of cropland and pasture. Different rules were applied to maximize consistency of the gridded products to subnational irrigation statistics or to historical cropland and pasture data sets. The HID reflects very well the spatial patterns of irrigated land in the western United States as shown on historical maps. Mean aridity on irrigated land increased and river discharge decreased from 1900-1950 whereas aridity decreased from 1950-2005. The dataset and its documentation are made available in an open data repository at https://mygeohub.org/publications/8 (doi:10.13019/M2MW2G).

  4. Groundwater Depletion versus Soil Salinization in Irrigated Agriculture in Semiarid Southern High Plains, Texas

    NASA Astrophysics Data System (ADS)

    Reedy, R. C.; Gates, J. B.; Scanlon, B. R.

    2008-12-01

    Because irrigated agriculture is the primary consumer of global freshwater resources, there is increased emphasis on using more water conservative irrigation application techniques to reduce depletion of water resources while maintaining crop productivity. The objective of this study was to evaluate the impacts of land use change from natural or rainfed agricultural ecosystems to irrigated agricultural ecosystems on water resources and soil salinity using data from the southern High Plains (SHP, 75,000 km2) in Texas, USA as an example. Approximately 11% of the land surface is irrigated with groundwater from the Ogallala (High Plains) Aquifer. Boreholes were drilled beneath irrigated cropland (13 boreholes) and beneath rainfed cropland (19 boreholes) and native vegetation (3 boreholes) to provide baseline control. Unsaturated zone soil samples were analyzed for water content, matric potential, and water-extractable chloride, bromide, sulfate, and nitrate concentrations. Increased drainage beneath irrigated sites displaced pre-existing salt bulges downward to 5 m in fine-grained soils and to greater than profile depths in coarser soils (4 - 17 m). Most irrigated profiles showed salt bulges which are attributed to deficit irrigation. Large inventories of nitrate and high correlations with chloride indicate overapplication of fertilizers and leaching below the root zone. Estimated drainage rates beneath irrigated sites are similar to the range of drainage/recharge rates beneath rainfed agriculture. These results emphasize the potential for soil salinization with deficit irrigation when the irrigation water quality is poor and precipitation is insufficient to flush accumulating salts.

  5. Estimated quantitative amino acid requirements for Florida pompano reared in low-salinity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As with most marine carnivores, Florida pompano require relatively high crude protein diets to obtain optimal growth. Precision formulations to match the dietary indispensable amino acid (IAA) pattern to a species’ requirements can be used to lower the overall dietary protein. However IAA requirem...

  6. Water savings potentials of irrigation systems: dynamic global simulation

    NASA Astrophysics Data System (ADS)

    Jägermeyr, J.; Gerten, D.; Heinke, J.; Schaphoff, S.; Kummu, M.; Lucht, W.

    2015-04-01

    Global agricultural production is heavily sustained by irrigation, but irrigation system efficiencies are often surprisingly low. However, our knowledge of irrigation efficiencies is mostly confined to rough indicative estimates for countries or regions that do not account for spatio-temporal heterogeneity due to climate and other biophysical dependencies. To allow for refined estimates of global agricultural water use, and of water saving and water productivity potentials constrained by biophysical processes and also non-trivial downstream effects, we incorporated a dynamic representation of the three major irrigation systems (surface, sprinkler, and drip) into a process-based bio- and agrosphere model, LPJmL. Based on this enhanced model we provide a gridded worldmap of dynamically retrieved irrigation efficiencies reflecting differences in system types, crop types, climatic and hydrologic conditions, and overall crop management. We find pronounced regional patterns in beneficial irrigation efficiency (a refined irrigation efficiency indicator accounting for crop-productive water consumption only), due to differences in these features, with lowest values (< 30%) in South Asia and Sub-Saharan Africa and highest values (> 60%) in Europe and North America. We arrive at an estimate of global irrigation water withdrawal of 2396 km3 (2004-2009 average); irrigation water consumption is calculated to be 1212 km3, of which 511 km3 are non-beneficially consumed, i.e. lost through evaporation, interception, and conveyance. Replacing surface systems by sprinkler or drip systems could, on average across the world's river basins, reduce the non-beneficial consumption at river basin level by 54 and 76%, respectively, while maintaining the current level of crop yields. Accordingly, crop water productivity would increase by 9 and 15%, respectively, and by much more in specific regions such as in the Indus basin. This study significantly advances the global quantification of

  7. Changes in whole grain polyphenols and antioxidant activity of six sorghum genotypes under different irrigation treatments.

    PubMed

    Wu, Gangcheng; Johnson, Stuart K; Bornman, Janet F; Bennett, Sarita J; Fang, Zhongxiang

    2017-01-01

    Sorghum grain containing elevated polyphenolic antioxidant content may provide foods with benefits to human health. A study was undertaken to determine the potential role of irrigation on the content of polyphenols and antioxidant levels in sorghum grain. Bound, free and total polyphenols were investigated in six diverse sorghum genotypes grown under either full irrigation or a deficit irrigation regime. Results showed genotype, irrigation and their interaction had a significant effect on polyphenols and antioxidant activity (P⩽0.05). The deficit irrigation treatment significantly increased polyphenol content and antioxidant activity compared to the full irrigation treatment. Of the six genotypes Shawaya black short 1 and IS1311C (brown) showed the highest polyphenols levels and antioxidant activity. Therefore, both irrigation treatments and genotype need to be considered by sorghum breeders and farmers during sorghum production to produce grain with the required levels of polyphenolics and antioxidant activity for targeted end-use. PMID:27507466

  8. EVALUATION OF SAMPLING FREQUENCIES REQUIRED TO ESTIMATE NUTRIENT AND SUSPENDED SEDIMENT LOADS IN LARGE RIVERS

    EPA Science Inventory

    Nutrients and suspended sediments in streams and large rivers are two major issues facing state and federal agencies. Accurate estimates of nutrient and sediment loads are needed to assess a variety of important water-quality issues including total maximum daily loads, aquatic ec...

  9. A Method to Estimate the Number of House Officers Required in Teaching Hospitals.

    ERIC Educational Resources Information Center

    Chan, Linda S.; Bernstein, Sol

    1980-01-01

    A method of estimating the number of house officers needed for direct patient care in teaching hospitals is discussed. An application of the proposed method is illustrated for 11 clinical services at the Los Angeles County-University of Southern California Medical Center. (Author/MLW)

  10. Development of Procedures for Generating Alternative Allied Health Manpower Requirements and Supply Estimates.

    ERIC Educational Resources Information Center

    Applied Management Sciences, Inc., Silver Spring, MD.

    This report presents results of a project to assess the adequacy of existing data sources on the supply of 21 allied health occupations in order to develop improved data collection strategies and improved procedures for estimation of manpower needs. Following an introduction, chapter 2 provides a discussion of the general phases of the project and…

  11. Sampling and Calibration Requirements for Soil Property Estimation Using Reflectance Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optical diffuse reflectance sensing is a potential approach for rapid and reliable on-site estimation of soil properties. One issue with this sensing approach is whether additional calibration is necessary when the sensor is applied under conditions (e.g., soil types or ambient conditions) different...

  12. SAMPLING AND CALIBRATION REQUIREMENTS FOR SOIL PROPERTY ESTIMATION USING NIR SPECTROSCOPY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil physical and chemical properties are important in crop production since they control the availability of plant water and nutrients. Optical diffuse reflectance sensing is a potential approach for rapid and reliable on-site estimation of soil properties. One issue with this sensing approach is w...

  13. Potential conservation opportunities from the use of improved irrigation scheduling in the Pacific Northwest region

    SciTech Connect

    Harrer, B J; Lezberg, A J

    1985-03-01

    This report documents research to identify the potential energy savings and the costs per kWh saved from using systematic rather than traditional irrigation scheduling to reduce water usage in the irrigated agricultural sector of the Pacific Northwest. This research is part of an overall project aimed at developing a computer model and data base that will allow for estimation of the potential energy savings and cost effectiveness of a number of conservation technologies that are available for use in irrigated agriculture.

  14. Enhancing TIR image resolution via bayesian smoothing for IRRISAT irrigation management project

    NASA Astrophysics Data System (ADS)

    Addesso, Paolo; Capodici, Fulvio; D'Urso, Guido; Longo, Maurizio; Maltese, Antonino; Montone, Rita; Restaino, Rocco; Vivone, Gemine

    2013-10-01

    Accurate estimation of physical quantities depends on the availability of High Resolution (HR) observations of the Earth surface. However, due to the unavoidable tradeoff between spatial and time resolution, the acquisition instants of HR data hardly coincides with those required by the estimation algorithms. A possible solution consists in constructing a synthetic HR observation at a given time k by exploiting Low Resolution (LR) and HR data acquired at different instants. In this work we recast this issue as a smoothing problem, thus focusing on cases in which observations acquired both before and after time k are available. The proposed approach is validated on a region of interest for the IRRISAT irrigation management project in which the surface thermal inertia estimation, requiring multiple HR images at specific instants, constitute a key step.

  15. Coolidge solar powered irrigation pumping project

    NASA Technical Reports Server (NTRS)

    Larson, D. L.

    1980-01-01

    A 150 kW solar thermal electric power plant which includes over 2100 square meters of parabolic trough type collectors and an organic Rankine cycle turbine engine was constructed on an irrigated farm. The plant is interconnected with the electrical utility grid. Operation is providing an evaluation of equipment performance and operating and maintenance requirements as well as the desirability of an on farm location.

  16. Influence of time scale wind speed data on sustainability analysis for irrigating greenhouse crops

    NASA Astrophysics Data System (ADS)

    Díaz Méndez, Rodrigo; García Llaneza, Joaquín; Peillón, Manuel; Perdigones, Alicia; Sanchez, Raul; Tarquis, Ana M.; Garcia, Jose Luis

    2014-05-01

    Appropriate water supply at crop/farm level, with suitable costs, is becoming more and more important. Energy management is closely related to water supply in this context, being wind energy one of the options to be considered, using wind pumps for irrigation water supply. Therefore, it is important to characterize the wind speed frequency distribution to study the technical feasibility to use its energy for irrigation management purpose. The general objective of this present research is to analyze the impact of time scale recorded wind speed data in the sustainability for tomato (Solanum lycopersicum L.) grown under greenhouse at Cuban conditions using drip irrigation system. For this porpoise, a daily estimation balance between water needs and water availability was used to evaluate the feasibility of the most economic windmill irrigation system. Several factors were included: wind velocity (W, m/s) in function of the time scale averaged, flow supplied by the wind pump as a function of the elevation height (H, m) and daily greenhouse evapotranspiration. Monthly volumes of water required for irrigation (Dr, m3/ha) and in the water tank (Vd, m3), as well as the monthly irrigable area (Ar, ha), were estimated by cumulative deficit water budgeting taking in account these factors. Three-hourly wind velocity (W3h, m/s) data from 1992 till 2008 was available for this study. The original data was grouped in six and twelve hourly data (W6h and W12h respectively) as well as daily data (W24h). For each time scale the daily estimation balance was applied. A comparison of the results points out a need for at least three-hourly data to be used mainly in the months in which mean wind speed are close or below the pumps threshold speed to start-up functioning. References Manuel Esteban Peillon Mesa, Ana Maria Tarquis Alfonso, José Luis García Fernández, and Raúl Sánchez Calvo. The use of wind pumps for irrigating greenhouse tomato crops: a case study in Cuba. Geophysical

  17. Irrigation Capacity Impact on limited irrigation management and cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation capacity in corn production is an increasingly important issue in the semi-arid Great Plains as irrigation well outputs decrease to the point where fully meeting crop water needs is not possible. Strategies need to be developed that will maximize yields under reduced water application amo...

  18. Irrigation capacity impact on limited irrigation management and cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation capacity in corn production is an increasingly important issue in the semi-arid Great Plains as irrigation well outputs decrease to the point where fully meeting crop water needs is not possible. Strategies need to be developed that will maximize yields under reduced water application amo...

  19. Integrating multiple irrigation technologies for overall improvement in irrigation.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are many tools, techniques, and/or schemes to assist producers in irrigation water management and specifically in irrigation scheduling. This paper will highlight several of those but emphasize that several methods should be used simultaneously as an improved or advanced procedure to avoid bia...

  20. Shadow Radiation Shield Required Thickness Estimation for Space Nuclear Power Units

    NASA Astrophysics Data System (ADS)

    Voevodina, E. V.; Martishin, V. M.; Ivanovsky, V. A.; Prasolova, N. O.

    The paper concerns theoretical possibility of visiting orbital transport vehicles based on nuclear power unit and electric propulsion system on the Earth's orbit by astronauts to maintain work with payload from the perspective of radiation safety. There has been done estimation of possible time of the crew's staying in the area of payload of orbital transport vehicles for different reactor powers, which is a consistent part of nuclear power unit.

  1. Biology, population structure, and estimated forage requirements of lake trout in Lake Michigan

    USGS Publications Warehouse

    Eck, Gary W.; Wells, LaRue

    1983-01-01

    Data collected during successive years (1971-79) of sampling lake trout (Salvelinus namaycush) in Lake Michigan were used to develop statistics on lake trout growth, maturity, and mortality, and to quantify seasonal lake trout food and food availability. These statistics were then combined with data on lake trout year-class strengths and age-specific food conversion efficiencies to compute production and forage fish consumption by lake trout in Lake Michigan during the 1979 growing season (i.e., 15 May-1 December). An estimated standing stock of 1,486 metric tons (t) at the beginning of the growing season produced an estimated 1,129 t of fish flesh during the period. The lake trout consumed an estimated 3,037 t of forage fish, to which alewives (Alosa pseudoharengus) contributed about 71%, rainbow smelt (Osmerus mordax) 18%, and slimy sculpins (Cottus cognatus) 11%. Seasonal changes in bathymetric distributions of lake trout with respect to those of forage fish of a suitable size for prey were major determinants of the size and species compositions of fish in the seasonal diet of lake trout.

  2. Estimating resting energy expenditure in patients requiring nutritional support: a survey of dietetic practice.

    PubMed

    Green, A J; Smith, P; Whelan, K

    2008-01-01

    Estimation of resting energy expenditure (REE) involves predicting basal metabolic rate (BMR) plus adjustment for metabolic stress. The aim of this study was to investigate the methods used to estimate REE and to identify the impact of the patient's clinical condition and the dietitians' work profile on the stress factor assigned. A random sample of 115 dietitians from the United Kingdom with an interest in nutritional support completed a postal questionnaire regarding the estimation of REE for 37 clinical conditions. The Schofield equation was used by the majority (99%) of dietitians to calculate BMR; however, the stress factors assigned varied considerably with coefficients of variation ranging from 18.5 (cancer with cachexia) to 133.9 (HIV). Dietitians specializing in gastroenterology assigned a higher stress factor to decompensated liver disease than those not specializing in gastroenterology (19.3 vs 10.7, P=0.004). The results of this investigation strongly suggest that there is wide inconsistency in the assignment of stress factors within specific conditions and gives rise to concern over the potential consequences in terms of under- or overfeeding that may ensue. PMID:17311053

  3. MEG Connectivity and Power Detections with Minimum Norm Estimates Require Different Regularization Parameters

    PubMed Central

    Hincapié, Ana-Sofía; Kujala, Jan; Mattout, Jérémie; Daligault, Sebastien; Delpuech, Claude; Mery, Domingo; Cosmelli, Diego; Jerbi, Karim

    2016-01-01

    Minimum Norm Estimation (MNE) is an inverse solution method widely used to reconstruct the source time series that underlie magnetoencephalography (MEG) data. MNE addresses the ill-posed nature of MEG source estimation through regularization (e.g., Tikhonov regularization). Selecting the best regularization parameter is a critical step. Generally, once set, it is common practice to keep the same coefficient throughout a study. However, it is yet to be known whether the optimal lambda for spectral power analysis of MEG source data coincides with the optimal regularization for source-level oscillatory coupling analysis. We addressed this question via extensive Monte-Carlo simulations of MEG data, where we generated 21,600 configurations of pairs of coupled sources with varying sizes, signal-to-noise ratio (SNR), and coupling strengths. Then, we searched for the Tikhonov regularization coefficients (lambda) that maximize detection performance for (a) power and (b) coherence. For coherence, the optimal lambda was two orders of magnitude smaller than the best lambda for power. Moreover, we found that the spatial extent of the interacting sources and SNR, but not the extent of coupling, were the main parameters affecting the best choice for lambda. Our findings suggest using less regularization when measuring oscillatory coupling compared to power estimation. PMID:27092179

  4. MEG Connectivity and Power Detections with Minimum Norm Estimates Require Different Regularization Parameters.

    PubMed

    Hincapié, Ana-Sofía; Kujala, Jan; Mattout, Jérémie; Daligault, Sebastien; Delpuech, Claude; Mery, Domingo; Cosmelli, Diego; Jerbi, Karim

    2016-01-01

    Minimum Norm Estimation (MNE) is an inverse solution method widely used to reconstruct the source time series that underlie magnetoencephalography (MEG) data. MNE addresses the ill-posed nature of MEG source estimation through regularization (e.g., Tikhonov regularization). Selecting the best regularization parameter is a critical step. Generally, once set, it is common practice to keep the same coefficient throughout a study. However, it is yet to be known whether the optimal lambda for spectral power analysis of MEG source data coincides with the optimal regularization for source-level oscillatory coupling analysis. We addressed this question via extensive Monte-Carlo simulations of MEG data, where we generated 21,600 configurations of pairs of coupled sources with varying sizes, signal-to-noise ratio (SNR), and coupling strengths. Then, we searched for the Tikhonov regularization coefficients (lambda) that maximize detection performance for (a) power and (b) coherence. For coherence, the optimal lambda was two orders of magnitude smaller than the best lambda for power. Moreover, we found that the spatial extent of the interacting sources and SNR, but not the extent of coupling, were the main parameters affecting the best choice for lambda. Our findings suggest using less regularization when measuring oscillatory coupling compared to power estimation. PMID:27092179

  5. Irrigation with desalinated water: A step toward increasing water saving and crop yields

    NASA Astrophysics Data System (ADS)

    Silber, Avner; Israeli, Yair; Elingold, Idan; Levi, Menashe; Levkovitch, Irit; Russo, David; Assouline, Shmuel

    2015-01-01

    We examined the impact of two different approaches to managing irrigation water salinity: salt leaching from the field ("conventional" management) and water desalination before field application ("alternative" management). Freshwater commonly used for irrigation (FW) and desalinated water (DS) were applied to the high-water-demanding crop banana at four different rates. Both irrigation rate and water salinity significantly affected yield. DS application consistently produced higher yields than FW, independently of irrigation rate. The highest yield for FW-irrigation was achieved with the highest irrigation rate, whereas the same yield was obtained in the case of DS-irrigation with practically half the amount of water. Yield decreased with FW-irrigation, even when the water salinity, ECi, was lower than the limit considered safe for soil and crops. Irrigating with FW provided a massive amount of salt which accumulated in the rhizosphere, inducing increased osmotic potential of the soil solution and impairing plant water uptake. Furthermore, applying the "conventional" management, a significant amount of salt is leached from the rhizosphere, accumulating in deeper soil layers, and eventually reaching groundwater reservoirs, thus contributing to the deterioration of both soil and water quality. Removal of salt excess from the water before it reaches the field by means of DS-irrigation may save significant amounts of irrigation water by reducing the salt leaching requirements while increasing yield and improving fruit quality, and decreasing salt load in the groundwater.

  6. Subsurface drip irrigation in different planting spacing of sugarcane

    NASA Astrophysics Data System (ADS)

    Pires, R. C. M.; Barbosa, E. A. A.; Arruda, F. B.; Silva, T. J. A.; Sakai, E.; Landell, M. G. A.

    2012-04-01

    The use of subsurface drip irrigation (SDI) in sugarcane cultivation is an interesting cultural practice to improve production and allow cultivation in marginal lands due to water deficits conditions. The SDI provides better water use efficiency, due to the water and nutrients application in root zone plants. However, it is important to investigate the long-term effect of irrigation in the yield and technological quality in different ecological condition cultivation. Thus, the aim of this work was to evaluate the effect of SDI in sugarcane cultivated in different planting spacings on technological quality, yield and theoretical recoverable sugar during four cycles of sugarcane cultivation. The experiment was carried out at Colorado Mill, Guaíra, São Paulo State in Brazil, in a clay soil. The experiment was installed in randomized blocks, with six replications. The treatments were three different planting spacings (S1 - 1.5 m between rows; S2 - 1.8 m between rows and S3 - planting in double line of 0.5 m x 1.3 m between planting rows) which were subdivided in irrigated and non-irrigated plots. In S1 and S2 treatments were installed one drip line in each plant row and in treatment S3 one drip line was installed between the rows with smaller spacing (0.5 m). The RB855536 genotype was used and the planting date occurred in May, 25th 2005. The analyzed parameters were: percentage of soluble solids (brix), percent apparent sucrose juice (Pol), total recoverable sugar (ATR), yield and theoretically recoverable sugar (RTR). Four years of yield (plant cane and first, second and third ratoon) were analyzed. Data were submitted to variance analysis and the averages compared by Duncan test at 5% probability. Two months before the first harvest a yield estimate was realized. According to the observed results the irrigated plants provided increase of about 20 % compared to non irrigated plants. However there was a great tipping of plants specially in irrigated plots. The

  7. Preserving the world second largest hypersaline lake under future irrigation and climate change.

    PubMed

    Shadkam, Somayeh; Ludwig, Fulco; van Vliet, Michelle T H; Pastor, Amandine; Kabat, Pavel

    2016-07-15

    Iran Urmia Lake, the world second largest hypersaline lake, has been largely desiccated over the last two decades resulting in socio-environmental consequences similar or even larger than the Aral Sea disaster. To rescue the lake a new water management plan has been proposed, a rapid 40% decline in irrigation water use replacing a former plan which intended to develop reservoirs and irrigation. However, none of these water management plans, which have large socio-economic impacts, have been assessed under future changes in climate and water availability. By adapting a method of environmental flow requirements (EFRs) for hypersaline lakes, we estimated annually 3.7·10(9)m(3) water is needed to preserve Urmia Lake. Then, the Variable Infiltration Capacity (VIC) hydrological model was forced with bias-corrected climate model outputs for both the lowest (RCP2.6) and highest (RCP8.5) greenhouse-gas concentration scenarios to estimate future water availability and impacts of water management strategies. Results showed a 10% decline in future water availability in the basin under RCP2.6 and 27% under RCP8.5. Our results showed that if future climate change is highly limited (RCP2.6) inflow can be just enough to meet the EFRs by implementing the reduction irrigation plan. However, under more rapid climate change scenario (RCP8.5) reducing irrigation water use will not be enough to save the lake and more drastic measures are needed. Our results showed that future water management plans are not robust under climate change in this region. Therefore, an integrated approach of future land-water use planning and climate change adaptation is therefore needed to improve future water security and to reduce the desiccating of this hypersaline lake. PMID:27070383

  8. Preserving the World Second Largest Hypersaline Lake under Future Irrigation and Climate Change

    NASA Astrophysics Data System (ADS)

    Shadkam, Somayeh; Ludwig, Fulco; van Vliet, Michelle; Pastor, Amandine; Kabat, Pavel

    2016-04-01

    Urmia Lake, the world second largest hypersaline lake, has been largely desiccated over the last two decades resulting in socio-environmental consequences similar or even larger than the Aral Sea disaster. To rescue the lake a new water management plan has been proposed, a rapid 40% decline in irrigation water use replacing a former plan which intended to develop reservoirs and irrigation. However, none of these water management plans, which have large socio-economic impacts, have been assessed under future changes in climate and water availability. By adapting a method of environmental flow requirements (EFRs) for hypersaline lakes, we estimated annually 3.9•109 m3 water is needed to preserve Urmia Lake. Then, the Variable Infiltration Capacity (VIC) hydrological model was forced with bias-corrected climate model outputs for both the lowest (RCP2.6) and highest (RCP8.5) greenhouse-gas concentration scenarios to estimate future water availability and impacts of water management strategies. Results showed a 10% decline in future water availability in the basin under RCP2.6 and 27% under RCP8.5. Our results showed that if future climate change is highly limited (RCP2.6) inflow can be just enough to meet the EFRs by implementing the reduction irrigation plan. However, under more rapid climate change scenario (RCP8.5) reducing irrigation water use will not be enough to save the lake and more drastic measures are needed. Our results showed that future water management plans are not robust under climate change in this region. Therefore, an integrated approach of future land-water use planning and climate change adaptation is therefore needed to improve future water security and to reduce the desiccating of this hypersaline lake.

  9. Modern Endodontic Principles Part 4: Irrigation.

    PubMed

    Darcey, James; Jawad, Sarra; Taylor, Carly; Roudsari, Reza Vahid; Hunter, Mark

    2016-01-01

    The complex anatomy of the tooth limits the ability to eradicate pathogens by mechanical means alone. Irrigation is the key to solving this problem. This paper highlights the importance of irrigation, the key irrigants available and methods of improving the performance of irrigants within the canal. CPD/CLINICAL RELEVANCE: To provide advice on which irrigants to use, how to use them effectively and safely and what to do if irrigants are extruded beyond the apex. PMID:27024899

  10. A comparison of methods to estimate nutritional requirements from experimental data.

    PubMed

    Pesti, G M; Vedenov, D; Cason, J A; Billard, L

    2009-01-01

    1. Research papers use a variety of methods for evaluating experiments designed to determine nutritional requirements of poultry. Growth trials result in a set of ordered pairs of data. Often, point-by-point comparisons are made between treatments using analysis of variance. This approach ignores that response variables (body weight, feed efficiency, bone ash, etc.) are continuous rather than discrete. Point-by-point analyses harvest much less than the total amount of information from the data. Regression models are more effective at gleaning information from data, but the concept of "requirements" is poorly defined by many regression models. 2. Response data from a study of the lysine requirements of young broilers was used to compare methods of determining requirements. In this study, multiple range tests were compared with quadratic polynomials (QP), broken line models with linear (BLL) or quadratic (BLQ) ascending portions, the saturation kinetics model (SK) a logistic model (LM) and a compartmental (CM) model. 3. The sum of total residuals squared was used to compare the models. The SK and LM were the best fit models, followed by the CM, BLL, BLQ, and QP models. A plot of the residuals versus nutrient intake showed clearly that the BLQ and SK models fitted the data best in the important region where the ascending portion meets the plateau. 4. The BLQ model clearly defines the technical concept of nutritional requirements as typically defined by nutritionists. However, the SK, LM and CM models better depict the relationship typically defined by economists as the "law of diminishing marginal productivity". The SK model was used to demonstrate how the law of diminishing marginal productivity can be applied to poultry nutrition, and how the "most economical feeding level" may replace the concept of "requirements". PMID:19234926

  11. On farm evaluation of the effect of low cost drip irrigation on water and crop productivity compared to conventional surface irrigation system

    NASA Astrophysics Data System (ADS)

    Maisiri, N.; Senzanje, A.; Rockstrom, J.; Twomlow, S. J.

    This on-farm research study was carried out at Zholube irrigation scheme in a semi-arid agro tropical climate of Zimbabwe to determine how low cost drip irrigation technologies compare with conventional surface irrigation systems in terms of water and crop productivity. A total of nine farmers who were practicing surface irrigation were chosen to participate in the study. The vegetable English giant rape ( Brassica napus) was grown under the two irrigation systems with three fertilizer treatments in each system: ordinary granular fertilizer, liquid fertilizer (fertigation) and the last treatment with no fertilizer. These trials were replicated three times in a randomized block design. Biometric parameters of leaf area index (LAI) and fresh weight of the produce, water use efficiency (WUE) were used to compare the performance of the two irrigation systems. A water balance of the inflows and outflows was kept for analysis of WUE. The economic profitability and the operation, maintenance and management requirements of the different systems were also evaluated. There was no significant difference in vegetable yield between the irrigation systems at 8.5 ton/ha for drip compared to 7.8 ton/ha in surface irrigation. There were significant increases in yields due to use of fertilizers. Drip irrigation used about 35% of the water used by the surface irrigation systems thus giving much higher water use efficiencies. The leaf area indices were comparable in both systems with the same fertilizer treatment ranging between 0.05 for surface without fertilizer to 6.8 for low cost drip with fertigation. Low cost drip systems did not reflect any labour saving especially when manually lifting the water into the drum compared to the use of siphons in surface irrigation systems. The gross margin level for surface irrigation was lower than for low cost drip irrigation but the gross margin to total variable cost ratio was higher in surface irrigation systems, which meant that surface

  12. COLT: seasonal prediction of crop irrigation needs

    NASA Astrophysics Data System (ADS)

    Villani, Giulia; Spisni, Andrea; Mariani, Maria Cristina; Pratizzoli, William; Pavan, Valentina; Tomei, Fausto; Botarelli, Lucio; Marletto, Vittorio

    2013-04-01

    from the ARPA-SIMC web site. Since 2010 forecasts of the crops water irrigation requirements have been computed and compared with the simulated data at the end of the summer with good results. The COLT scheme is able to predict the very large interannual variability of the seasonal crop water needs: in 2010 the summer was rather wet and COLT predicted about 500 Mm3, while in 2011 the median forecast was 850 Mm3, a value considered as normal. The summer of 2012 was exceptionally dry, thus the median COLT forecast was 1077 Mm3, while the value computed with observed summer data reached 1340 Mm3 (+24%). The COLT scheme was also tested in a study area located near Ravenna (570 ha), where actual crop irrigation volumes are measured. The median forecasted irrigation (0.50 Mm3) resulted 14% higher than the observed value for 2011 (0.44 Mm3), mainly due to errors in classification of non irrigated crops as irrigated, and possibly to the water table not being accounted for in the model. COLT looks like a promising approach for assessing, planning and managing water resources in agriculture, and for mitigating the impacts of intense climate anomalies in the agricultural sector.

  13. Estimating Sugarcane Water Requirements for Biofuel Feedstock Production in Maui, Hawaii Using Satellite Imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water availability is one of the limiting factors for sustainable production of biofuel crops. A common method for determining crop water requirement is to multiply daily potential evapotranspiration (ETo) calculated from meteorological parameters by a crop coefficient (Kc) to obtain actual crop eva...

  14. Are There Infinite Irrigation Trees?

    NASA Astrophysics Data System (ADS)

    Bernot, M.; Caselles, V.; Morel, J. M.

    2006-08-01

    In many natural or artificial flow systems, a fluid flow network succeeds in irrigating every point of a volume from a source. Examples are the blood vessels, the bronchial tree and many irrigation and draining systems. Such systems have raised recently a lot of interest and some attempts have been made to formalize their description, as a finite tree of tubes, and their scaling laws [25], [26]. In contrast, several mathematical models [5], [22], [10], propose an idealization of these irrigation trees, where a countable set of tubes irrigates any point of a volume with positive Lebesgue measure. There is no geometric obstruction to this infinitesimal model and general existence and structure theorems have been proved. As we show, there may instead be an energetic obstruction. Under Poiseuille law R(s) = s -2 for the resistance of tubes with section s, the dissipated power of a volume irrigating tree cannot be finite. In other terms, infinite irrigation trees seem to be impossible from the fluid mechanics viewpoint. This also implies that the usual principle analysis performed for the biological models needs not to impose a minimal size for the tubes of an irrigating tree; the existence of the minimal size can be proven from the only two obvious conditions for such irrigation trees, namely the Kirchhoff and Poiseuille laws.

  15. Evapotranspiration of deficit irrigated sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deficit irrigation is used commonly in regions with reduced or limited irrigation capacity to increase water use efficiency (WUE). This research measured sorghum (Sorghum bicolor L. Moench) water use (ET) and yield so WUE could be determined. Two precision weighing lysimeters were used to accurate...

  16. Water balance and flow rate discharge on a receiving water body: Application to the B-XII Irrigation District in Spain

    NASA Astrophysics Data System (ADS)

    Moyano, Maria C.; Tornos, Lucia; Juana, Luis

    2015-08-01

    The quantification of the main water balance components becomes necessary to diminish the pollutants load from drainage, and its harmful effect on the environment, aggravated within a context of increasing water scarcity. As a first approach to the hydrological study of the 15,000 ha B-XII Irrigation District in Spain, a conceptual lumped model entitled WATEN has been developed, aiming to calculate the monthly flow rate discharge to the Guadalquivir River over the period 2002-2012. The model requires as inputs, irrigation, precipitation and potential crop evapotranspiration. Main model parameters are the total and readily available moisture in the soil, the effective rainfall and the irrigation efficiency. Energy consumption for drainage discharge was used for calibration. Both classical optimization and a robust approach based on Monte Carlo were performed. In order to diminish computational requirements, Monte Carlo was not haphazardly applied, but conducted on a similar manner to genetic algorithms, entitled Parameters Estimation on Driven Trials (PEDT). The model attained an average Nash-Sutcliffe coefficient e2 ≅ 0.90 between observed and estimated drainage discharge. It was detected a significant crop evapotranspiration reduction compared to potential values. The volume of water discharged to the river might be sufficient for leaching irrigation water salts.

  17. The metabolic power requirements of flight and estimations of flight muscle efficiency in the cockatiel (Nymphicus hollandicus).

    PubMed

    Morris, Charlotte R; Nelson, Frank E; Askew, Graham N

    2010-08-15

    Little is known about how in vivo muscle efficiency, that is the ratio of mechanical and metabolic power, is affected by changes in locomotory tasks. One of the main problems with determining in vivo muscle efficiency is the large number of muscles generally used to produce mechanical power. Animal flight provides a unique model for determining muscle efficiency because only one muscle, the pectoralis muscle, produces nearly all of the mechanical power required for flight. In order to estimate in vivo flight muscle efficiency, we measured the metabolic cost of flight across a range of flight speeds (6-13 m s(-1)) using masked respirometry in the cockatiel (Nymphicus hollandicus) and compared it with measurements of mechanical power determined in the same wind tunnel. Similar to measurements of the mechanical power-speed relationship, the metabolic power-speed relationship had a U-shape, with a minimum at 10 m s(-1). Although the mechanical and metabolic power-speed relationships had similar minimum power speeds, the metabolic power requirements are not a simple multiple of the mechanical power requirements across a range of flight speeds. The pectoralis muscle efficiency (estimated from mechanical and metabolic power, basal metabolism and an assumed value for the 'postural costs' of flight) increased with flight speed and ranged from 6.9% to 11.2%. However, it is probable that previous estimates of the postural costs of flight have been too low and that the pectoralis muscle efficiency is higher. PMID:20675549

  18. A conditional likelihood is required to estimate the selection coefficient in ancient DNA

    PubMed Central

    Valleriani, Angelo

    2016-01-01

    Time-series of allele frequencies are a useful and unique set of data to determine the strength of natural selection on the background of genetic drift. Technically, the selection coefficient is estimated by means of a likelihood function built under the hypothesis that the available trajectory spans a sufficiently large portion of the fitness landscape. Especially for ancient DNA, however, often only one single such trajectories is available and the coverage of the fitness landscape is very limited. In fact, one single trajectory is more representative of a process conditioned both in the initial and in the final condition than of a process free to visit the available fitness landscape. Based on two models of population genetics, here we show how to build a likelihood function for the selection coefficient that takes the statistical peculiarity of single trajectories into account. We show that this conditional likelihood delivers a precise estimate of the selection coefficient also when allele frequencies are close to fixation whereas the unconditioned likelihood fails. Finally, we discuss the fact that the traditional, unconditioned likelihood always delivers an answer, which is often unfalsifiable and appears reasonable also when it is not correct. PMID:27527811

  19. Irrigation efficiency and production energy efficiency of traditional and modern farms in the Al-Hassa Oasis, Saudi Arabia

    SciTech Connect

    Al-Taher, A.A.

    1987-01-01

    The Al-Hassa Oasis is located in eastern Saudi Arabia. The dry tropical climate requires irrigation throughout the year for agricultural crop production, which currently faces the following problems: declining groundwater tables, scarcity of surface water, high soil salinity in substantial parts of the districts serviced by the irrigation authority, low efficiency of irrigation water use in fields, rising costs for production inputs, and declining crop yields. The objectives of this research are to assess field irrigation efficiency under traditional, intermediate, and modern irrigation methods, to calculate energy efficiency under transitional, intermediate, and modern soil management practices, and to determine the relationship between irrigation efficiency and production energy efficiency within the current agricultural scenario of the Oasis. Analyses regarding the relationship between (1) food energy output and irrigation energy input, non-irrigation energy input and irrigation efficiency, (2) irrigation efficiency and total cultural energy input, (3) irrigation efficiency and irrigation energy input, (4) food energy output and cultural energy input, and (5) production energy efficiency and irrigation efficiency under tomatoes, cucumber, potatoes, other vegetables, alfalfa, wheat, dates, and rice indicate that the effect varies from one crop to another.

  20. Irrigation Depletions 1928-1989 : 1990 Level of Irrigation, Snake Yakima and Deschutes River Basins.

    SciTech Connect

    United States. Bonneville Power Administation; A.G. Crook Company

    1993-07-01

    The vast amount of irrigation in relation to the available water and extensive system of reservoirs located in the Snake River Basin above Brownlee reservoir precludes this area from using methods such as Blaney-Criddle for estimating irrigation depletions. Also the hydrology, irrigation growth patterns, and water supply problems are unique and complex. Therefore regulation studies were utilized to reflect the net effect on streamflow of the changes in irrigated acreage in terms of corresponding changes in storage regulation and in the amount of water depleted and diverted from and returned to the river system. The regulation study for 1990 conditions was conducted by the Idaho Department of Water Resources. The end product of the basin simulation is 61 years of regulated flows at various points in the river system that are based on 1990 conditions. Data used by the Idaho Department of Water Resources is presented in this section and includes natural gains to the river system and diversions from the river system based on a 1990 level of development and operation criteria. Additional information can be obtained for an Idaho Department of Water Resources Open-File Report ``Stream Flows in the Snake River Basin 1989 Conditions of Use and Management`` dated June 1991. Similar considerations apply to the Yakima and Deschutes river basins.

  1. Irrigation of human prepared root canal – ex vivo based computational fluid dynamics analysis

    PubMed Central

    Šnjarić, Damir; Čarija, Zoran; Braut, Alen; Halaji, Adelaida; Kovačević, Maja; Kuiš, Davor

    2012-01-01

    Aim To analyze the influence of the needle type, insertion depth, and irrigant flow rate on irrigant flow pattern, flow velocity, and apical pressure by ex-vivo based endodontic irrigation computational fluid dynamics (CFD) analysis. Methods Human upper canine root canal was prepared using rotary files. Contrast fluid was introduced in the root canal and scanned by computed tomography (CT) providing a three-dimensional object that was exported to the computer-assisted design (CAD) software. Two probe points were established in the apical portion of the root canal model for flow velocity and pressure measurement. Three different CAD models of 27G irrigation needles (closed-end side-vented, notched open-end, and bevel open-end) were created and placed at 25, 50, 75, and 95% of the working length (WL). Flow rates of 0.05, 0.1, 0.2, 0.3, and 0.4 mL/s were simulated. A total of 60 irrigation simulations were performed by CFD fluid flow solver. Results Closed-end side-vented needle required insertion depth closer to WL, regarding efficient irrigant replacement, compared to open-end irrigation needle types, which besides increased velocity produced increased irrigant apical pressure. For all irrigation needle types and needle insertion depths, the increase of flow rate was followed by an increased irrigant apical pressure. Conclusions The human root canal shape obtained by CT is applicable in the CFD analysis of endodontic irrigation. All the analyzed values –irrigant flow pattern, velocity, and pressure – were influenced by irrigation needle type, as well as needle insertion depth and irrigant flow rate. PMID:23100209

  2. Irrigants in non-surgical endodontic treatment.

    PubMed

    Regan, John D; Fleury, Alex A P

    2006-01-01

    This paper highlights that one of the main goals of root canal treatment is the elimination of microorganisms from the contaminated root canal system. Instrumentation alone will not allow for adequate debridement and disinfection of the complex and diverse root canal system. Chemomechanical debridement is required. The importance of the use of irrigants during non-surgical root canal treatment has frequently been neglected both during instruction of dental students and later in the clinical practice of endodontics. The article highlights 'shape, clean and fill' vs. 'clean, shape and fill' to enable chemomechanical debridement. Our protocol advises mechanical debridement and copious irrigation for a minimum of twenty minutes with 2.5% to 6% solutions of sodium hypochlorite, followed by a rinse with a 17% solution of ethylenediaminetetraacetic acid and a final rinse with 2% chlorhexidine. The canals are dried with high volume aspirators and sterile paper points. PMID:16989370

  3. Irrigation water demand: A meta-analysis of price elasticities

    NASA Astrophysics Data System (ADS)

    Scheierling, Susanne M.; Loomis, John B.; Young, Robert A.

    2006-01-01

    Metaregression models are estimated to investigate sources of variation in empirical estimates of the price elasticity of irrigation water demand. Elasticity estimates are drawn from 24 studies reported in the United States since 1963, including mathematical programming, field experiments, and econometric studies. The mean price elasticity is 0.48. Long-run elasticities, those that are most useful for policy purposes, are likely larger than the mean estimate. Empirical results suggest that estimates may be more elastic if they are derived from mathematical programming or econometric studies and calculated at a higher irrigation water price. Less elastic estimates are found to be derived from models based on field experiments and in the presence of high-valued crops.

  4. Seasonal simulation of water, salinity and nitrate dynamics under drip irrigated mandarin (Citrus reticulata) and assessing management options for drainage and nitrate leaching

    NASA Astrophysics Data System (ADS)

    Phogat, V.; Skewes, M. A.; Cox, J. W.; Sanderson, G.; Alam, J.; Šimůnek, J.

    2014-05-01

    Estimation of all water fluxes temporally and spatially within and out of the crop root zone, and evaluation of issues like salinity and nutrient leaching, are necessary to fully appraise the efficiency of irrigation systems. Simulation models can be used to investigate these issues over several seasons when the cost of long term monitoring is prohibitive. Model results can be used to advise growers if improvements are required to various aspects of irrigation system operations. In this study, HYDRUS-2D was used to evaluate data measured during one season in a young mandarin (Citrus reticulata) orchard, irrigated with an intensive surface drip fertigation system. Water contents, salinities, and nitrate concentrations measured weekly in the field were compared with model predictions. The temporal mean absolute error (MAE) values between weekly measured and simulated water contents ranged from 0.01 to 0.04 cm3 cm-3. However, modelling error (MAE) was slightly larger at 10 cm depth (0.04 cm3 cm-3), as compared to greater depths (0.02-0.03 cm3 cm-3). Similarly, the errors were larger in the surface soil layer (25 cm depth) for nitrate-nitrogen, NO3--N (1.52 mmol(c) L-1), as compared to greater depths. The spatial and temporal soil solution salinity (ECsw) and NO3--N data showed accumulation of salts and nitrate within the soil up until day 150 of the simulation (December, 2006), followed by leaching due to high precipitation and over irrigation at later times. Only 49% of applied water was used by the mandarin trees, while 33.5% was leached. On the other hand, the simulation revealed that a significant amount of applied nitrogen (85%) was taken up by the mandarin trees, and the remaining 15% was leached. The results indicate that the irrigation and fertigation schedule needs modifying as there was overwatering from December onwards. Different permutations and combinations of irrigation and fertigation scheduling were evaluated to optimise the water and nitrogen uptake

  5. Two-source energy balance model estimates of evapotranspiration using component and composite surface temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The two-source energy balance model (TSEB) can estimate evaporation (E), transpiration (T), and evapotranspiration (ET) of vegetated surfaces, which has important applications in water resources management for irrigated crops. The TSEB requires soil (TS) and canopy (TC) surface temperatures to solv...

  6. Estimating minimum environmental flow requirements for well-mixed estuaries in Spain

    NASA Astrophysics Data System (ADS)

    Peñas, Francisco J.; Juanes, José A.; Galván, Cristina; Medina, Raúl; Castanedo, Sonia; Álvarez, César; Bárcena, Javier F.

    2013-12-01

    Following the principles of the European Water Framework Directive, the current Spanish water management legislation requires the definition of the environmental flow regimes for all water bodies, including estuaries. The scientific community has tried to answer the question of how much freshwater an estuary needs since the mid-1970s, resulting in the development of several methodologies and approaches in different parts of the world. However the ability to reproduce most of these approaches is difficult due to the scarcity of required data and also to the differences between the studied estuaries. In this paper, we present a methodology to calculate environmental flow regimes in well-mixed estuaries based on the numerical modelling of salinity and which takes into account the seasonal climatic and hydrologic pattern of the catchment. The approach follows three sequential steps: 1) Definition of reference conditions based on the unaltered salinity patterns and zoning of the estuary, 2) definition of salinity thresholds and 3) calculation of the minimum flows required to satisfy these thresholds. The application of the methodology to five estuaries on the northern coast of Spain has highlighted the importance of considering the hydrological variability and the division of the estuary into homogeneous zones. Moreover, the studies carried out demonstrate the ineffectiveness of river specific methodologies when used to define environmental flow regimes in several estuaries and periods, and the need to apply specific methodologies. The methodology is based on the principles defined by other already tested approaches, but its greatest advantage lies in the ability to be applied to large scales, when physical and biological data is scarce.

  7. Estimation of the lead thickness required to shield scattered radiation from synchrotron radiation experiments

    NASA Astrophysics Data System (ADS)

    Wroblewski, Thomas

    2015-03-01

    In the enclosure of synchrotron radiation experiments using a monochromatic beam, secondary radiation arises from two effects, namely fluorescence and scattering. While fluorescence can be regarded as isotropic, the angular dependence of Compton scattering has to be taken into account if the shielding shall not become unreasonably thick. The scope of this paper is to clarify how the different factors starting from the spectral properties of the source and the attenuation coefficient of the shielding, over the spectral and angular distribution of the scattered radiation and the geometry of the experiment influence the thickness of lead required to keep the dose rate outside the enclosure below the desired threshold.

  8. A Method for Precision Closed-Loop Irrigation Using a Modified PID Control Algorithm

    NASA Astrophysics Data System (ADS)

    Goodchild, Martin; Kühn, Karl; Jenkins, Malcolm; Burek, Kazimierz; Dutton, Andrew

    2016-04-01

    The benefits of closed-loop irrigation control have been demonstrated in grower trials which show the potential for improved crop yields and resource usage. Managing water use by controlling irrigation in response to soil moisture changes to meet crop water demands is a popular approach but requires knowledge of closed-loop control practice. In theory, to obtain precise closed-loop control of a system it is necessary to characterise every component in the control loop to derive the appropriate controller parameters, i.e. proportional, integral & derivative (PID) parameters in a classic PID controller. In practice this is often difficult to achieve. Empirical methods are employed to estimate the PID parameters by observing how the system performs under open-loop conditions. In this paper we present a modified PID controller, with a constrained integral function, that delivers excellent regulation of soil moisture by supplying the appropriate amount of water to meet the needs of the plant during the diurnal cycle. Furthermore, the modified PID controller responds quickly to changes in environmental conditions, including rainfall events which can result in: controller windup, under-watering and plant stress conditions. The experimental work successfully demonstrates the functionality of a constrained integral PID controller that delivers robust and precise irrigation control. Coir substrate strawberry growing trial data is also presented illustrating soil moisture control and the ability to match water deliver to solar radiation.

  9. Integrating Field Spectra and Worldview-2 Data for Grapevine Productivity in Different Irrigation Treatments

    NASA Astrophysics Data System (ADS)

    Maimaitiyiming, M.; Bozzolo, A.; Wulamu, A.; Wilkins, J. L.

    2015-12-01

    Precision farming requires high spectral, spatial and temporal resolution remote sensing data to detect plant physiological changes. The higher spatial resolution is particularly as important as the spectral resolution for crop monitoring. It is important to develop data integration techniques between field or airborne hyperspectral data with spaceborne broad band multispectral images for plant productivity monitoring. To investigate varying rootstock and irrigation interactions, different irrigation treatments are implemented in a vineyard experimental site either i) unirrigated ii) full replacement of evapotranspiration (ET) iii) irrigated at 50 % of the potential ET. In summer 2014, we collected leaf and canopy spectra of the vineyard using field spectroscopy along with other plant physiological and nutritional variables. In this contribution, we integrate the field spectra and the spectral wavelengths of WorldView-2 to develop a predictive model for plant productivity,i.e., fruit quality and yield. First, we upscale field and canopy spectra to WorldView-2 spectral bands using radiative transfer simulations (e.g., MODTRAN). Then we develop remote sensing techniques to quantify plant productivity in different scenarios water stress by identifying the most effective and sensitive wavelengths, and indices that are capable of early detection of plant health and estimation of crop nutrient status. Finally we present predictive models developed from partial least square regression (PLSR) for plant productivity using spectral wavelengths and indices derived from integrated field and satellite remote sensing data.

  10. [Estimating the impacts of future climate change on water requirement and water deficit of winter wheat in Henan Province, China].

    PubMed

    Ji, Xing-jie; Cheng, Lin; Fang, Wen-song

    2015-09-01

    Based on the analysis of water requirement and water deficit during development stage of winter wheat in recent 30 years (1981-2010) in Henan Province, the effective precipitation was calculated using the U.S. Department of Agriculture Soil Conservation method, the water requirement (ETC) was estimated by using FAO Penman-Monteith equation and crop coefficient method recommended by FAO, combined with the climate change scenario A2 (concentration on the economic envelopment) and B2 ( concentration on the sustainable development) of Special Report on Emissions Scenarios (SRES) , the spatial and temporal characteristics of impacts of future climate change on effective precipitation, water requirement and water deficit of winter wheat were estimated. The climatic impact factors of ETc and WD also were analyzed. The results showed that under A2 and B2 scenarios, there would be a significant increase in anomaly percentage of effective precipitation, water requirement and water deficit of winter wheat during the whole growing period compared with the average value from 1981 to 2010. Effective precipitation increased the most in 2030s under A2 and B2 scenarios by 33.5% and 39.2%, respectively. Water requirement increased the most in 2010s under A2 and B2 scenarios by 22.5% and 17.5%, respectively, and showed a significant downward trend with time. Water deficit increased the most under A2 scenario in 2010s by 23.6% and under B2 scenario in 2020s by 13.0%. Partial correlation analysis indicated that solar radiation was the main cause for the variation of ETc and WD in future under A2 and B2 scenarios. The spatial distributions of effective precipitation, water requirement and water deficit of winter wheat during the whole growing period were spatially heterogeneous because of the difference in geographical and climatic environments. A possible tendency of water resource deficiency may exist in Henan Province in the future. PMID:26785550

  11. E.O.-based estimation of transpiration and crop water requirements for vineyards: a case study in southern Italy

    NASA Astrophysics Data System (ADS)

    D'Urso, Guido; Maltese, Antonino; Palladino, Mario

    2014-10-01

    An efficient use of water for irrigation is a challenging task. From an agronomical point of view, it requires establishing the optimal amount of water to be supplied, at the correct time, based on phenological phase and water stress spatial distribution. Indeed, the knowledge of the actual water stress is essential for agronomic decisions, vineyards need to be managed to maintain a moderate water stress, thus allowing to optimize berries quality and quantity. Methods for quickly quantifying where, when and in what extent, vines begin to experience water stress are beneficial. Traditional point based methodologies, such those based on Scholander pressure chamber, even if well established are time expensive and do not give a comprehensive picture of the vineyard water deficit. Earth Observation (E.O.) based methodologies promise to achieve a synoptic overview of the water stress. Some E.O. data, indeed, sense the territory in the thermal part of the spectrum and, as it is well recognized, leaf radiometric temperature is related to the plant water status. However, current satellite sensors have not detailed enough spatial resolution to detect pure canopy pixels; thus, the pixel radiometric temperature characterizes the whole soil-vegetation system, and in variable proportions. On the other hand, due to limits in the actual crop dusters, there is no need to characterize the water stress distribution at plant scale, and a coarser spatial characterization would be sufficient. The research aims to assess to what extent: 1) E.O. based canopy radiometric temperature can be used, straightforwardly, to detected plant water status; 2) E.O. based canopy transpiration, would be more suitable (or not) to describe the spatial variability in plant water stress. To these aims: 1) radiometric canopy temperature measured in situ, and derived from a two-source energy balance model applied on airborne data, were compared with in situ leaf water potential from freshly cut leaves; 2) two

  12. The hidden regional costs of improving irrigation efficiency: a case study from India

    NASA Astrophysics Data System (ADS)

    Grogan, D. S.; Frolking, S. E.; Lammers, R. B.; Wisser, D.; Proussevitch, A. A.; Glidden, S.

    2013-12-01

    Indian agriculture depends heavily on groundwater pumping. These water withdrawals are not all consumed directly by the crops they irrigate; estimated irrigation inefficiencies indicate that two thirds of irrigation water withdrawals in India are 'lost'. Withdrawals lost through leaky canals and flood irrigation systems become runoff and re-enter the surface water system. This mechanism causes irrigation inefficiencies to re-distribute water across basins, and can significantly alter the amount of surface water available both locally and downstream. In this study we used a gridded water balance model to track the path of groundwater from its pumping location, through irrigation systems, and to its downstream consumption or discharge from river mouths. We find that nearly half of all groundwater pumped at rates higher than recharge are re-used downstream. Furthermore, increasing the efficiency of irrigation systems has the potential to decrease surface water levels downstream. We used the water balance model to simulate scenarios of increased irrigation efficiency and find that doubling efficiency does not reduce India's dependence on pumping deep groundwater by half as would be expected from standard measures of irrigation efficiency, but rather by only 38%. Increasing irrigation efficiency to 100% (i.e., no irrigation water losses) causes a decrease in modeled river discharge in both the Indus and the Ganges. The water balance model can also simulate scenarios in which groundwater pumping is limited to recharge rates. In this case, increasing irrigation efficiency to 100% results in a decrease in available surface water across large regions of eastern India, revealing the region's dependence on surface water that was originally sourced from deep groundwater pumping upstream. These results have two important implications. First, they raise questions about the strategy of increasing irrigation efficiency as a strategy for reducing water stress. Second, they show

  13. Estimation of distance error by fuzzy set theory required for strength determination of HDR 192Ir brachytherapy sources

    PubMed Central

    Kumar, Sudhir; Datta, D.; Sharma, S. D.; Chourasiya, G.; Babu, D. A. R.; Sharma, D. N.

    2014-01-01

    Verification of the strength of high dose rate (HDR) 192Ir brachytherapy sources on receipt from the vendor is an important component of institutional quality assurance program. Either reference air-kerma rate (RAKR) or air-kerma strength (AKS) is the recommended quantity to specify the strength of gamma-emitting brachytherapy sources. The use of Farmer-type cylindrical ionization chamber of sensitive volume 0.6 cm3 is one of the recommended methods for measuring RAKR of HDR 192Ir brachytherapy sources. While using the cylindrical chamber method, it is required to determine the positioning error of the ionization chamber with respect to the source which is called the distance error. An attempt has been made to apply the fuzzy set theory to estimate the subjective uncertainty associated with the distance error. A simplified approach of applying this fuzzy set theory has been proposed in the quantification of uncertainty associated with the distance error. In order to express the uncertainty in the framework of fuzzy sets, the uncertainty index was estimated and was found to be within 2.5%, which further indicates that the possibility of error in measuring such distance may be of this order. It is observed that the relative distance li estimated by analytical method and fuzzy set theoretic approach are consistent with each other. The crisp values of li estimated using analytical method lie within the bounds computed using fuzzy set theory. This indicates that li values estimated using analytical methods are within 2.5% uncertainty. This value of uncertainty in distance measurement should be incorporated in the uncertainty budget, while estimating the expanded uncertainty in HDR 192Ir source strength measurement. PMID:24872605

  14. Quantifying and mapping China's crop yield gains from sustainable and unsustainable irrigation water use

    NASA Astrophysics Data System (ADS)

    Grogan, D. S.; Zhang, F.; Glidden, S.; Wisser, D.; Proussevitch, A. A.; Li, C.; Lammers, R. B.; Frolking, S.

    2012-12-01

    About 40 - 50% of China's cropland is irrigated. We used the DNDC model to predict crop yield for ~17 crop types involved in ~28 cropping systems across China, under zero and full irrigation for each county for 1981-2000. We estimate that yield increases due to irrigation range from 0 - 100%, depending on water deficits arising from local climate and weather conditions and crop types. We used gridded water balance simulations with the UNH WBM driven by MERRA weather reconstructions for 1981-2000 to compute demand for irrigation water, and the capacity of various sources to supply that demand in each grid cell. We estimate that approximately 15% - 20% of the water needed to fulfill the country's irrigation water demand must come from unsustainable sources such as fossil groundwater. Yields using only the sustainable irrigation water capacity are calculated by weighing the DNDC zero and full irrigation yields based on the water availability results of WBM for each grid cell. Restricting irrigation water use to only sustainable sources results in a national crop yield decrease of ~20%. Irrigation water demand, unsustainable water use, and crop yield gains due to irrigation all have significant spatial variation across China. These spatial variations show that irrigation water use - sustainable and unsustainable - results in significant crop yield gains in some regions, and little to no crop yield gains in other regions. Unsustainable water use for irrigation is concentrated in the highly populated and agriculturally valuable North China Plain region, particularly Hebei, Shandong and Henan Provinces. While current plans for the South-North Water Transfer could mitigate some of the water deficit we do not expect the projected transfers to adequately supply this region with sufficient water resources to supply both the people and crops sustainably.

  15. Amelioration of the irrigated lands of the Vakhsh valley

    NASA Astrophysics Data System (ADS)

    Ikromov, Islomkul; Mirzoev, Mm

    2015-04-01

    In the agro-industrial country like Tajikistan, the efficient use of irrigation of arable land is important because it contributes to the solution of the State Program of the Food independence of the country, by increasing the yield of agricultural production per unit of irrigated area. The irrigated area in the Republic of Tajikistan as of 1.01.2014g. equal to about 750 thousand. ha, per capita, on average, less than 0.10 hectares. and its share in relation to agricultural land is only 10.5%. However, more than 90% of crop production are grown on these lands. Given the demographic growth of the population of the republic specific area of irrigated land from year to year is becoming less and less of that call into question the successful solution of the above program. Therefore, in our view, to ensure food independence of the country in addition to the development of land from the reserve, should focus on the amelioration of existing irrigated areas, improve the culture of land and water, on modernization of reclamation systems contribute to a high degree of adaptability based on a high degree of water metering, water distribution, water and resource conservation, the use of the latest technology and irrigation techniques. Condition of the soil is their estimated figures is mainly determined by its productivity. It is determined by the degree of salinity of soils, the depth of the groundwater level and salinity, erosion and on stony ground. Vakhsh valley in Tajikistan is one of the main oases, ensuring production of agricultural products but, in recent years due to a number of man-made reasons: Adherence crop irrigation, low technical condition of irrigation systems and as a consequence their efficiency and utilization of irrigation water and farming, inoperable drainage system, or lack of them all, the virtual absence of vodouchёta on the field, no use of it modern technology and irrigation techniques, etc., the level of both fresh and saline groundwater rose

  16. Virtual Sensors for Designing Irrigation Controllers in Greenhouses

    PubMed Central

    Sánchez, Jorge Antonio; Rodríguez, Francisco; Guzmán, José Luis; Arahal, Manuel R

    2012-01-01

    Monitoring the greenhouse transpiration for control purposes is currently a difficult task. The absence of affordable sensors that provide continuous transpiration measurements motivates the use of estimators. In the case of tomato crops, the availability of estimators allows the design of automatic fertirrigation (irrigation + fertilization) schemes in greenhouses, minimizing the dispensed water while fulfilling crop needs. This paper shows how system identification techniques can be applied to obtain nonlinear virtual sensors for estimating transpiration. The greenhouse used for this study is equipped with a microlysimeter, which allows one to continuously sample the transpiration values. While the microlysimeter is an advantageous piece of equipment for research, it is also expensive and requires maintenance. This paper presents the design and development of a virtual sensor to model the crop transpiration, hence avoiding the use of this kind of expensive sensor. The resulting virtual sensor is obtained by dynamical system identification techniques based on regressors taken from variables typically found in a greenhouse, such as global radiation and vapor pressure deficit. The virtual sensor is thus based on empirical data. In this paper, some effort has been made to eliminate some problems associated with grey-box models: advance phenomenon and overestimation. The results are tested with real data and compared with other approaches. Better results are obtained with the use of nonlinear Black-box virtual sensors. This sensor is based on global radiation and vapor pressure deficit (VPD) measurements. Predictive results for the three models are developed for comparative purposes. PMID:23202208

  17. Virtual sensors for designing irrigation controllers in greenhouses.

    PubMed

    Sánchez, Jorge Antonio; Rodríguez, Francisco; Guzmán, José Luis; Arahal, Manuel R

    2012-01-01

    Monitoring the greenhouse transpiration for control purposes is currently a difficult task. The absence of affordable sensors that provide continuous transpiration measurements motivates the use of estimators. In the case of tomato crops, the availability of estimators allows the design of automatic fertirrigation (irrigation + fertilization) schemes in greenhouses, minimizing the dispensed water while fulfilling crop needs. This paper shows how system identification techniques can be applied to obtain nonlinear virtual sensors for estimating transpiration. The greenhouse used for this study is equipped with a microlysimeter, which allows one to continuously sample the transpiration values. While the microlysimeter is an advantageous piece of equipment for research, it is also expensive and requires maintenance. This paper presents the design and development of a virtual sensor to model the crop transpiration, hence avoiding the use of this kind of expensive sensor. The resulting virtual sensor is obtained by dynamical system identification techniques based on regressors taken from variables typically found in a greenhouse, such as global radiation and vapor pressure deficit. The virtual sensor is thus based on empirical data. In this paper, some effort has been made to eliminate some problems associated with grey-box models: advance phenomenon and overestimation. The results are tested with real data and compared with other approaches. Better results are obtained with the use of nonlinear Black-box virtual sensors. This sensor is based on global radiation and vapor pressure deficit (VPD) measurements. Predictive results for the three models are developed for comparative purposes. PMID:23202208

  18. Distillation irrigation: a low-energy process for coupling water purification and drip irrigation

    USGS Publications Warehouse

    Constantz, J.

    1989-01-01

    A method is proposed for combining solar distillation and drip irrigation to simultaneously desalinize water and apply this water to row crops. In this paper, the basic method is illustrated by a simple device constructed primarily of sheets of plastic, which uses solar energy to distill impaired water and apply the distillate to a widely spaced row crop. To predict the performance of the proposed device, an empirical equation for distillate production, dp, is developed from reported solar still production rates, and a modified Jensen-Haise equation is used to calculate the potential evapotranspiration, et, for a row crop. Monthly values for et and dp are calculated by using a generalized row crop at five locations in the Western United States. Calculated et values range from 1 to 22 cm month-1 and calculated dp values range from 2 to 11 cm month-1, depending on the location, the month, and the crop average. When the sum of dp plus precipitation, dp + P, is compared to et for the case of 50% distillation irrigation system coverage, the results indicate that the crop's et is matched by dp + P, at the cooler locations only. However, when the system coverage is increased to 66%, the crop's et is matched by dp + P even at the hottest location. Potential advantages of distillation irrigation include the ability: (a) to convert impaired water resources to water containing no salts or sediments; and (b) to efficiently and automatically irrigate crops at a rate that is controlled primarily by radiation intensities. The anticipated disadvantages of distillation irrigation include: (a) the high costs of a system, due to the large amounts of sheeting required, the short lifetime of the sheeting, and the physically cumbersome nature of a system; (b) the need for a widely spaced crop to reduce shading of the system by the crop; and (c) the production of a concentrated brine or precipitate, requiring proper off-site disposal. ?? 1989.

  19. Nonuniform and Unsteady Solute Transport in Furrow Irrigation II. Description of Field Experiments and Calibration of Infiltration and Roughness Coefficients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field tests were conducted to obtain irrigation evaluation and solute transport data that were used to calibrate and validate an advection-dispersion model for furrow irrigation. Empirical infiltration equation and roughness parameters were estimated from the field data. These estimates were used a...

  20. Drip irrigation research update at NPRL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drip irrigation research has been conducted since 1998 at NPRL. Systems include deep subsurface drip irrigation (SSDI), surface drip irrigation (SDI), and shallow subsurface drip irrigation (S3DI). Results have shown that SDI and S3DI are more economical to install than SSDI. SDI systems have more r...

  1. Bridging dry spells for maize cropping through supplemental irrigation in the Central Rift Valley of Ethiopia

    NASA Astrophysics Data System (ADS)

    Muluneh Bitew, Alemayehu; Keesstra, Saskia; Stroosnijder, Leo

    2015-04-01

    Maize yield in the Central Rift Valley of Ethiopia (CRV) suffers from dry spells at sensitive growth stages. Risk of crop failure makes farmers reluctant to invest in fertilizer. This makes the CRV food insecure. There are farms with well-maintained terraces and Rain Water Harvesting (RWH) systems using concrete farms ponds. We tested the hypothesis that in these farms supplemental irrigation with simultaneous crop intensification might boost production of a small maize area sufficient to improve food security. Intensification includes a higher plant density of a hybrid variety under optimum fertilization. First we assessed the probability of occurrence of dry spells. Then we estimated the availability of sufficient runoff in the ponds in dry years. During 2012 (dry) and 2013 (wet) on-farm field research was conducted with 10 combinations of supplemental irrigation and plant density. The simplest was rainfed farming with 30,000 plants ha-1. The most advanced was no water stress and 75,000 plants ha-1. Finally we compared our on-farm yield with that of neighbouring farmers. Because 2013 was a wet year no irrigation was needed. Our long term daily rainfall (1970-2011) analysis proves the occurrence of dry spells during the onset of the maize (Belg months March and April). In March there is hardly enough water in the ponds. So, we advise later sowing. Starting from April available water (runoff from a 2.2 ha catchment) matches crop water requirement (for 0.5 ha maize). Significant differences between grain and total biomass yield were observed between rainfed and other irrigation levels. However, since the largest difference is only 12%, the investment in irrigation non-critical drought years is not worth the effort. There was also a limited effect (18-22%) of increasing plant density. So, we advise not to use more than 45,000 plants ha-1. The grain yield and total biomass difference between farmers own practice and our on-farm research was 101% and 84% respectively

  2. Remote sensing technologies applied to the irrigation water management on a golf course

    NASA Astrophysics Data System (ADS)

    Pedras, Celestina; Lança, Rui; Martins, Fernando; Soares, Cristina; Guerrero, Carlos; Paixão, Helena

    2015-04-01

    An adequate irrigation water management in a golf course is a complex task that depends upon climate (multiple microclimates) and land cover (where crops differ in morphology, physiology, plant density, sensitivity to water stress, etc.). These factors change both in time and space on a landscape. A direct measurement provides localized values of the evapotranspiration and climate conditions. Therefore this is not a practical or economical methodology for large-scale use due to spatial and temporal variability of vegetation, soils, and irrigation management strategies. Remote sensing technology combines large scale with ground measurement of vegetation indexes. These indexes are mathematical combinations of different spectral bands mostly in the visible and near infrared regions of the electromagnetic spectrum. They represent the measures of vegetation activity that vary not only with the seasonal variability of green foliage, but also across space, thus they are suitable for detecting spatial landscape variability. The spectral vegetation indexes may enhance irrigation management through the information contained in spectral reflectance data. This study was carried out on the 18th fairway of the Royal Golf Course, Vale do Lobo, Portugal, and it aims to establish the relationship between direct measurements and vegetation indexes. For that it is required (1) to characterize the soil and climatic conditions, (2) to assessment of the irrigation system, (3) to estimate the evapotranspiration (4) and to calculate the vegetation indices. The vegetation indices were determined with basis on spectral bands red, green and blue, RGB, and near Infrared, NIR, obtained from the analysis of images acquired from a unpiloted aerial vehicle, UAV, platform. The measurements of reference evapotranspiration (ETo) were obtained from two meteorological stations located in the study area. The landscape evapotranspiration, ETL, was determined in the fairway with multiple microclimates

  3. Estimation of the standardized ileal digestible lysine requirement for primiparous pregnant sows.

    PubMed

    Shi, M; Shi, C X; Li, Y K; Li, D F; Wang, F L

    2016-04-01

    This experiment was conducted to determine the optimal standardized ileal digestible lysine (SID Lys) level in diets fed to primiparous sows during gestation. A total of 150 (Landrace × Large White) crossbred gilts (weighing 149.9 ± 3.1 kg) were fed gestation diets (12.55 MJ of ME/kg) containing SID Lys levels of 0.43, 0.52, 0.60, 0.70 or 0.80% respectively. Gilts were fed 2.0 kg/day from day 1 to 80 and 3.0 kg/day from day 80 to 110 of gestation respectively. Gilts were allocated to treatments based on their body weight on the day of breeding. Weight gain from day 80 to 110 increased with increasing dietary SID Lys levels (p = 0.044). Fitted broken-line (p = 0.031) and quadratic plot (p = 0.047) analysis of body weight gain indicated that the optimal SID Lys level for primiparous sows was 0.70 and 0.69% respectively. During gestation, neither backfat thickness nor loin eye area was affected by dietary SID Lys level. Increasing dietary Lys had no effect on the litter size at birth or pigs born alive per litter. Litter weight at birth was not affected by dietary SID Lys level. The litter weight variation at birth quadratically decreased with increasing dietary SID Lys (p = 0.021) and was minimized at 0.70% dietary SID Lys. Gilts fed the 0.70% SID Lys diet had the highest dry matter (p = 0.031) and protein (p = 0.044) content in colostrum. On day 110 of gestation, gilts fed the 0.70% SID Lys diet tended to have the highest serum prolactin (p = 0.085) and serum insulin (p = 0.074) levels. The data demonstrate that the optimal dietary SID Lys was 0.70% for pregnant gilts, which is similar to the recommendation of 0.69% that was estimated by the NRC (2012). PMID:26174182

  4. Estimates of power requirements for a Manned Mars Rover powered by a nuclear reactor

    NASA Technical Reports Server (NTRS)

    Morley, Nicholas J.; El-Genk, Mohamed S.; Cataldo, Robert; Bloomfield, Harvey

    1991-01-01

    This paper assesses the power requirement for a Manned Mars Rover vehicle. Auxiliary power needs are fulfilled using a hybrid solar photovoltaic/regenerative fuel cell system, while the primary power needs are meet using an SP-100 type reactor. The primary electric power needs, which include 30-kW(e) net user power, depend on the reactor thermal power and the efficiency of the power conversion system. Results show that an SP-100 type reactor coupled to a Free Piston Stirling Engine yields the lowest total vehicle mass and lowest specific mass for the power system. The second lowest mass was for a SP-100 reactor coupled to a Closed Brayton Cycle using He/Xe as the working fluid. The specific mass of the nuclear reactor power system, including a man-rated radiation shield, ranged from 150-kg/kW(e) to 190-kg/KW(e) and the total mass of the Rover vehicle varied depend upon the cruising speed.

  5. Estimates of power requirements for a Manned Mars Rover powered by a nuclear reactor

    NASA Astrophysics Data System (ADS)

    Morley, Nicholas J.; El-Genk, Mohamed S.; Cataldo, Robert; Bloomfield, Harvey

    This paper assesses the power requirement for a Manned Mars Rover vehicle. Auxiliary power needs are fulfilled using a hybrid solar photovoltaic/regenerative fuel cell system, while the primary power needs are meet using an SP-100 type reactor. The primary electric power needs, which include 30-kW(e) net user power, depend on the reactor thermal power and the efficiency of the power conversion system. Results show that an SP-100 type reactor coupled to a Free Piston Stirling Engine yields the lowest total vehicle mass and lowest specific mass for the power system. The second lowest mass was for a SP-100 reactor coupled to a Closed Brayton Cycle using He/Xe as the working fluid. The specific mass of the nuclear reactor power system, including a man-rated radiation shield, ranged from 150-kg/kW(e) to 190-kg/KW(e) and the total mass of the Rover vehicle varied depend upon the cruising speed.

  6. Estimates of power requirements for a manned Mars rover powered by a nuclear reactor

    NASA Astrophysics Data System (ADS)

    Morley, Nicholas J.; El-Genk, Mohamed S.; Cataldo, Robert; Bloomfield, Harvey

    1991-01-01

    This paper assesses the power requirement for a Manned Mars Rover vehicle. Auxiliary power needs are fulfilled using a hybrid solar photovoltaic/regenerative fuel cell system, while the primary power needs are met using an SP-100 type reactor. The primary electric power needs, which include 30-kWe net user power, depend on the reactor thermal power and the efficiency of the power conversion system. Results show that an SP-100 type reactor coupled to a Free Piston Stirling Engine (FPSE) yields the lowest total vehicle mass and lowest specific mass for the power system. The second lowest mass was for a SP-100 reactor coupled to a Closed Brayton Cycle (CBC) using He/Xe as the working fluid. The specific mass of the nuclear reactor power systrem, including a man-rated radiation shield, ranged from 150-kg/kWe to 190-kg/kWe and the total mass of the Rover vehicle varied depend upon the cruising speed.

  7. Agricultural irrigated land-use inventory for Osceola County, Florida, October 2013-April 2014

    USGS Publications Warehouse

    Marella, Richard L.; Dixon, Joann F.

    2014-01-01

    A detailed inventory of irrigated crop acreage is not available at the level of resolution needed to increase the accuracy of current water-use estimates or to project future water demands in many Florida counties. This report provides a detailed digital map and summary of irrigated areas within Osceola County for the agricultural growing period October 2013–April 2014. The irrigated areas were first delineated using land-use data and satellite imagery and then field verified between February and April 2014. Selected attribute data were collected for the irrigated areas, including crop type, primary water source, and type of irrigation system. Results indicate that an estimated 27,450 acres were irrigated during the study period. This includes 4,370 acres of vegetables, 10,970 acres of orchard crops, 1,620 acres of field crops, and 10,490 acres of ornamentals and grasses. Specifically, irrigated acreage included citrus (10,860 acres), sod (5,640 acres), pasture (4,580 acres), and potatoes (3,320 acres). Overall, groundwater was used to irrigate 18,350 acres (67 percent of the total acreage), and surface water was used to irrigate the remaining 9,100 acres (33 percent). Microirrigation systems accounted for 45 percent of the total acreage irrigated, flood systems 30 percent, and sprinkler systems the remaining 25 percent. An accurate, detailed, spatially referenced, and field-verified inventory of irrigated crop acreage can be used to assist resource managers making current and future county-level water-use estimates in Osceola County.

  8. 76 FR 20971 - Turlock Irrigation District and Modesto Irrigation District; Notice of Intent To File License...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-14

    ... Energy Regulatory Commission Turlock Irrigation District and Modesto Irrigation District; Notice of..., 2011. d. Submitted By: Turlock Irrigation District and Modesto Irrigation District. e. Name of Project... Regulatory Affairs, Turlock Irrigation District, P.O. Box 949, Turlock, California 95381, 209-883-8241...

  9. 77 FR 4291 - Turlock Irrigation District; Modesto Irrigation District; Notice of Proposed Restricted Service...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-27

    ... Energy Regulatory Commission Turlock Irrigation District; Modesto Irrigation District; Notice of Proposed... any Order issuing a license. Turlock Irrigation District and Modesto Irrigation District, as the..., Turlock Irrigation District, P.O. Box 949, Turlock, CA 95381. Greg Dias or Representative,...

  10. 21 CFR 876.5220 - Colonic irrigation system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., including colon cleansing routinely for general well being. (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of completion of a PDP is required to be filed with the Food and Drug... irrigation system shall have an approved PMA in effect before being placed in commercial distribution....

  11. Long-term climate sensitivity of an integrated water supply system: The role of irrigation.

    PubMed

    Guyennon, Nicolas; Romano, Emanuele; Portoghese, Ivan

    2016-09-15

    The assessment of the impact of long-term climate variability on water supply systems depends not only on possible variations of the resources availability, but also on the variation of the demand. In this framework, a robust estimation of direct (climate induced) and indirect (anthropogenically induced) effects of climate change is mandatory to design mitigation measures, especially in those regions of the planet where the groundwater equilibrium is strongly perturbed by exploitations for irrigation purposes. The main goal of this contribution is to propose a comprehensive model that integrates distributed crop water requirements with surface and groundwater mass balance, able to consider management rules of the water supply system. The proposed overall model, implemented, calibrated and validated for the case study of the Fortore water supply system (Apulia region, South Italy), permits to simulate the conjunctive use of the water from a surface artificial reservoir and from groundwater. The relative contributions of groundwater recharges and withdrawals to the aquifer stress have been evaluated under different climate perturbations, with emphasis on irrigation practices. Results point out that irrigated agriculture primarily affects groundwater discharge, indicating that ecosystem services connected to river base flow are particularly exposed to climate variation in irrigated areas. Moreover, findings show that the recharge both to surface and to groundwater is mainly affected by drier climate conditions, while hotter conditions have a major impact on the water demand. The non-linearity arising from combined drier and hotter conditions may exacerbate the aquifer stress by exposing it to massive sea-water intrusion. PMID:27161129

  12. Intelligent irrigation performance: evaluation and quantifying its ability for conserving water in arid region

    NASA Astrophysics Data System (ADS)

    Al-Ghobari, Hussein M.; Mohammad, Fawzi S.

    2011-12-01

    controlling irrigation water and has been proven to be a good mean to determine the water requirements for crops and to schedule irrigation automatically.

  13. An applied simulation model for estimating the supply of and requirements for registered nurses based on population health needs.

    PubMed

    Tomblin Murphy, Gail; MacKenzie, Adrian; Alder, Robert; Birch, Stephen; Kephart, George; O'Brien-Pallas, Linda

    2009-11-01

    Aging populations, limited budgets, changing public expectations, new technologies, and the emergence of new diseases create challenges for health care systems as ways to meet needs and protect, promote, and restore health are considered. Traditional planning methods for the professionals required to provide these services have given little consideration to changes in the needs of the populations they serve or to changes in the amount/types of services offered and the way they are delivered. In the absence of dynamic planning models that simulate alternative policies and test policy mixes for their relative effectiveness, planners have tended to rely on projecting prevailing or arbitrarily determined target provider-population ratios. A simulation model has been developed that addresses each of these shortcomings by simultaneously estimating the supply of and requirements for registered nurses based on the identification and interaction of the determinants. The model's use is illustrated using data for Nova Scotia, Canada. PMID:20164064

  14. Chlorhexidine as a canal irrigant: a review.

    PubMed

    Ryan, Steven

    2010-06-01

    The use of an irrigant during root canal therapy is an important factor in the cleaning and disinfecting of the root canal system. While sodium hypochlorite has been used for decades as a primary irrigant, other irrigants have been investigated as alternatives. This article reviews chlorhexidine as a canal irrigant, explores its different properties, and provides the dental practitioner with information to help make a more informed decision when choosing an irrigant. PMID:20583503

  15. Irrigation scheduling using remote sensing data assimilation approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Linked remote sensing and crop growth models have enhanced our ability to understand soil water balance in irrigated agriculture. However, limited efforts have been made to adopt data assimilation methodologies in these linked models that use stochastic parameter estimation with genetic algorithm (G...

  16. Using the soil water balance to analyze the deep percolation losses and the irrigation adequacy of irrigated citrus crops (Haouz plain, Morocco)

    NASA Astrophysics Data System (ADS)

    Nassah, Houda; Fakir, Younes; Er-raki, Salah; Khabba, Said; Merlin, Olivier; Mougenot, Bernard

    2016-04-01

    In the semi-arid Haouz plain, located in central Morocco, agriculture consumes about 85% of the available water resources. Therefore, the management of irrigation water is important to avoid the water loss by soil evaporation and by deep percolation (DP) below the plant root zone. Estimating the irrigation water demand has been investigated by many studies in the Haouz plain, but DP losses beneath the irrigated areas have not been quantified yet. In this context, the objectives of the persent work are threefold :1) to evaluate DP over irrigated citrus orchard under drip and flood irrigation systems using the soil water balance equation; 2) to compare the obtained results to direct measurements of DP by a "flux-meter"; and 3) to optimize the irrigation rates that avoid excessive DP losses and water stress. The results showed that the weekly DP losses vary in average from 15 mm/week to more than 40 mm/week depending to the amount of water supply. The irrigation systems have also an important impact on DP losses evaluated to 38 % in drip irrigation and 12% in flood irrigation. Additionally the density of canopy influences the DP percentage inducing a difference of 10% between the denser citrus site and the sparse one. The comparison of DP losses calculated by soil water balance with those measured by a flux-meter installed beneath the root zone show that the first method gives higher values than the second does. Finally we evaluated the adequacy of the water supply for the crop needs based on two performance indices: depleted fraction (DF) and relative evapotranspiration (RET), showing that the drip irrigation has respond to the culture demands with an excessive quantity of irrigation, unlike to the flood one.

  17. Local Irrigation Management Institutions Mediate Changes Driven by External Policy and Market Pressures in Nepal and Thailand

    NASA Astrophysics Data System (ADS)

    Bastakoti, Ram C.; Shivakoti, Ganesh P.; Lebel, Louis

    2010-09-01

    This article assesses the role of local institutions in managing irrigation water use. Fifty irrigation systems in each country were studied in Nepal and Thailand to compare the influence of local institutions on performance of irrigation systems amid changes in external policy and market pressures. Nepal’s new irrigation policy after the re-instatement of multiparty democracy in 1990 emphasized participatory irrigation management transferring the management responsibility from state authorities to water users. The water user associations of traditional farmer-managed irrigation systems were formally recognized by requiring registration with related state authorities. In Thailand also government policies encouraged people’s participation in irrigation management. Today water users are directly involved in management of even some large irrigation systems at the level of tertiary canals. Traditional communal irrigation systems in northern Thailand received support for system infrastructure improvement but have faced increased interference from government. In Thailand market development supported diversification in farming practices resulting in increased areas under high water-demanding commercial crops in the dry season. In contrast, the command areas of most irrigation systems in Nepal include cereal-based subsistence farming with only one-third having commercial farming. Cropping intensities are higher in Nepal than in Thailand reflecting, in part, differences in availability of land and management. In both countries local institutions play an important role in maintaining the performance of irrigation systems as external drivers and local contexts change. Local institutions have provided alternative options for irrigation water use by mediating external pressures.

  18. Daily irrigation attenuates xylem abscisic acid concentration and increases leaf water potential of Pelargonium × hortorum compared with infrequent irrigation.

    PubMed

    Boyle, Richard K A; McAinsh, Martin; Dodd, Ian C

    2016-09-01

    The physiological response of plants to different irrigation frequencies may affect plant growth and water use efficiency (WUE; defined as shoot biomass/cumulative irrigation). Glasshouse-grown, containerized Pelargonium × hortorum BullsEye plants were irrigated either daily at 100% of plant evapotranspiration (ET) (well-watered; WW), or at 50% ET applied either daily [frequent deficit irrigation (FDI)] or cumulatively every 4 days [infrequent deficit irrigation (IDI)], for 24 days. Both FDI and IDI applied the same irrigation volume. Xylem sap was collected from the leaves, and stomatal conductance (gs ) and leaf water potential (Ψleaf ) measured every 2 days. As soil moisture decreased, gs decreased similarly under both FDI and IDI throughout the experiment. Ψleaf was maintained under IDI and increased under FDI. Leaf xylem abscisic acid (ABA) concentrations ([X-ABA]leaf ) increased as soil moisture decreased under both IDI and FDI, and was strongly correlated with decreased gs , but [X-ABA]leaf was attenuated under FDI throughout the experiment (at the same level of soil moisture as IDI plants). These physiological changes corresponded with differences in plant production. Both FDI and IDI decreased growth compared with WW plants, and by the end of the experiment, FDI plants also had a greater shoot fresh weight (18%) than IDI plants. Although both IDI and FDI had higher WUE than WW plants during the first 10 days of the experiment (when biomass did not differ between treatments), the deficit irrigation treatments had lower WUE than WW plants in the latter stages when growth was limited. Thus, ABA-induced stomatal closure may not always translate to increased WUE (at the whole plant level) if vegetative growth shows a similar sensitivity to soil drying, and growers must adapt their irrigation scheduling according to crop requirements. PMID:26910008

  19. Characterisation of areas under irrigated agriculture: mapping and water use

    NASA Astrophysics Data System (ADS)

    Peña Arancibia, Jorge; McVicar, Tim R.; Guerschman, Juan P.; Li, Lingtao T.

    2014-05-01

    The evolution of remote sensing and classification methods has enabled effective mapping, monitoring and management of irrigated agriculture. A random forest classification was implemented using learning samples inferred from Landsat TM/ETM data and monthly time-series of remotely-sensed observations from the MODerate resolution Imaging Spectroradiometer (MODIS). The covariates included in the method characterised: (i) the vegetation phenology via the recurrent and persistent fractions of photosynthetically active radiation (fPARrecandfPARper, respectively); (ii) vegetation water use via estimates of actual evapotranspiration (AET), rainfall (P) and the difference between AET and P . Maps of irrigated areas under different climates and cropping conditions were produced for the whole Murray-Darling Basin (Australia) for the years 2004 to 2010 with 0.96 observed agreement in terms of the Kappa Index (were a value of 1 indicates perfect agreement). An independent comparison of yearly irrigated area estimates and corresponding water use showed a linear relationship with good agreement (R2 >0.7) against available yearly metered water withdrawals and estimates of agricultural yields. A sequential covariate optimisation suggested that the most important predictors included the emergence-senescence period (as determined by the fPARrec and corresponding rates of change) and the AET surplus over P during this period. The latter can be important when determining more opportunistic irrigation practices due to unreliable water supply in areas with otherwise high annual rainfall. The procedure can be implemented to map irrigated areas at the global scale: the MODIS time-series used in the classification methodology are available globally since February 2000 and so are the Landsat archives which can be used to infer learning samples and irrigation practices elsewhere.

  20. Supplemental irrigation potential and impact on downstream flow of Karkheh River basin in Iran

    NASA Astrophysics Data System (ADS)

    Hessari, Behzad; Bruggeman, Adriana; Akhoond-Ali, Ali Mohammad; Oweis, Theib; Abbasi, Fariborz

    2016-05-01

    Supplemental irrigation of rainfed winter crops improves and stabilises crop yield and water productivity. Although yield increases by supplemental irrigation are well established at the field level, its potential extent and impact on water resources at the basin level are less researched. This work presents a Geographic Information Systems (GIS)-based methodology for identifying areas that are potentially suitable for supplemental irrigation and a computer routine for allocating streamflow for supplemental irrigation in different sub-basins. A case study is presented for the 42 908 km2 upper Karkheh River basin (KRB) in Iran, which has 15 840 km2 of rainfed crop areas. Rainfed crop areas within 1 km from the streams, with slope classes 0-5, 0-8, 0-12, and 0-20 %, were assumed to be suitable for supplemental irrigation. Four streamflow conditions (normal, normal with environmental flow requirements, drought and drought with environmental flow) were considered for the allocation of water resources. Thirty-seven percent (5801 km2) of the rainfed croplands had slopes less than 5 %; 61 % (3559 km2) of this land was suitable for supplemental irrigation, but only 22 % (1278 km2) could be served with irrigation in both autumn (75 mm) and spring (100 mm), under normal flow conditions. If irrigation would be allocated to all suitable land with slopes up to 20 %, 2057 km2 could be irrigated. This would reduce the average annual outflow of the upper KRB by 9 %. If environmental flow requirements are considered, a maximum (0-20 % slopes) of 1444 km2 could receive supplemental irrigation. Under drought conditions a maximum of 1013 km2 could be irrigated, while the outflow would again be reduced by 9 %. Thus, the withdrawal of streamflow for supplemental irrigation has relatively little effect on the outflow of the upper KRB. However, if the main policy goal would be to improve rainfed areas throughout the upper KRB, options for storing surface water need to be developed.

  1. Effects of irrigation practices on water use in the groundwater management districts within the Kansas high plains, 1991-2003

    USGS Publications Warehouse

    Perry, Charles A.

    2006-01-01

    estimator of irrigation water use incorporated total acres irrigated and annual average or March-October regional precipitation. A conclusion that can be drawn from the trend analyses described in this report is that, although irrigation water use for all GMDs showed no statistically significant trend, an apparent increased efficiency of center pivots irrigation systems with drop nozzles has allowed more water-intensive crops to be grown on more irrigated acres.

  2. 78 FR 3892 - Turlock Irrigation District and Modesto Irrigation District; Notice Clarifying Party Status

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Turlock Irrigation District and Modesto Irrigation District; Notice Clarifying Party Status On January 9, 2013, the Modesto Irrigation District (Modesto) filed a motion...

  3. Numerical investigation of root canal irrigation adopting innovative needles with dimple and protrusion.

    PubMed

    Li, Ping; Zhang, Di; Xie, Yonghui; Lan, Jibing

    2013-01-01

    As important passive flow control methods, dimples and protrusions have been successfully implemented via geometric modifications to manipulate flow fields to get a desired flow parameters enhancement. In this research, two novel needles were proposed based on a prototype by means of the dimple and protrusion, and flow patterns within a root canal during final irrigation with these needles were numerically investigated. The calculation cases consistent with the clinically realistic irrigant flow rates, which are 0.02, 0.16 and 0.26 mL s(-1) are marked as case A, B and C, respectively. The characteristic parameters to estimate irrigation efficiency, such as shearing effect, mean apical pressure, irrigation replacement and fluid agitation, were compared and the optimal geometry in every calculation case was obtained. As shown from the results, flow rates and needle geometries were the causes of irrigation parameters variations. The sum of shear stress, irrigation replacement and fluid agitation were equal in the low flow rate case A, however, the needle with a protrusion on its tip had advantages in the three irrigation characteristic parameters above in calculation case B, and the needle with a dimple on its tip had advantages in calculation case C. Furthermore, the needles proposed did not give rise to the risk of irrigant extrusion. These needles can be better choices at larger flow rates. Therefore, needle geometry optimizations utilizing passive flow control methods are worthy to be investigated in the root canal irrigation enhancement. PMID:23957591

  4. Ecohydrology of agroecosystems: quantitative approaches towards sustainable irrigation.

    PubMed

    Vico, Giulia; Porporato, Amilcare

    2015-02-01

    Irrigation represents one of the main strategies to enhance and stabilize agricultural productivity, by mitigating the effects of rainfall vagaries. In the face of the projected growth in population and in biofuel demands, as well as shifts in climate and dietary habits, a more sustainable management of water resources in agroecosystems is needed. The field of ecohydrology, traditionally focusing on natural ecosystems, has the potential to offer the necessary quantitative tools to assess and compare agricultural enterprises across climates, soil types, crops, and irrigation strategies, accounting for the unpredictability of the hydro-climatic forcing. Here, agricultural sustainability and productivity are assessed with reference to water productivity (defined as the ratio between yield and total supplied water), yields, water requirements, and their variability-a crucial element for food security and resource allocation planning. These synthetic indicators are quantified by means of a probabilistic description of the soil water balance and crop development. The model results allow the interpretation of patterns of water productivity observed in Zea mays (maize) and Triticum aestivum (wheat), grown under a variety of soils, climates, and irrigation strategies. Employing the same modeling framework, the impact of rainfall pattern and irrigation strategy on yield and water requirements is further explored. The obtained standard deviations of yield and water requirements suggest the existence of a nonlinear tradeoff between yield stabilization and variability of water requirements, which in turn is strongly impacted by irrigation strategy. Moreover, intermediate rainfall amounts are associated to the highest variability in yields and irrigation requirements, although allowing the maximum water productivity. The existence of these tradeoffs between productivity, reliability, and sustainability poses a problem for water management, in particular in mesic climates. PMID

  5. Weighing Lysimeters for Developing Crop Coefficients and Efficient Irrigation Practices for Vegetable Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large weighing lysimeters are expensive but invaluable tools for measuring crop evapotranspiration and developing crop coefficients for horticultural crops. Crop coefficients are used by both growers and researchers to estimate crop water use and accurately schedule irrigations. Two lysimeters of ...

  6. Pervaporative irrigation: a flow rate driven by environmental conditions

    NASA Astrophysics Data System (ADS)

    Todman, L. C.; Mougros, C.; Ireson, A. M.; Butler, A. P.; Templeton, M. R.

    2012-04-01

    Pervaporative irrigation allows in-situ treatment of low quality water (e.g. saline water) whilst simultaneously distributing water throughout the soil. The system is also low energy, requiring only that a positive head of water is maintained in a supply tank. To irrigate using this method a pervaporative polymer membrane is formed into a pipe, buried in the soil and filled with water. Water is transported across the membrane by the process of pervaporation whilst the transport of contaminants is retarded, thus reducing the risk of soil degradation due to the use of low water quality. Uniquely these systems also inherently provide a feedback mechanism by which crops can affect the irrigation rate. Such a system has significant possibilities to provide an irrigation pipe from which water is only applied when required, hence reducing the volume of water used. However such systems are currently not fully understood and, to be implemented effectively, the behaviour of the membrane in different environmental conditions must be quantified. From experimental results this work has identified the significance of vapour flows in predicting the flux from the irrigation system in dry soils. In a 15cm layer of sand, the presence of a desiccant above the soil doubled the flux from the pipe, but more than 70% of this mass was adsorbed by the desiccant. Experiments also show that the flux into typical top soil was greater than into sand because of the greater capacity of the top soil for water adsorption. This adsorption maintained a lower humidity in the soil, hence providing a larger gradient across the irrigation membrane and inducing a higher flux. Although there is some evidence that seeds can absorb water from vapour flows the possibility that plants also do this has not yet been explored. This technology provides future opportunities to explore the interaction of plants both with vapour flows, and with a system where the irrigation rate is influenced by the crop uptake and

  7. Sustaining Irrigated Agriculture in Arid Areas: Lessons Learned in the San Joaquin Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The conventional wisdom is that drainage is required to sustain irrigation in arid and semiarid areas. However, disposal of saline drainage water is a problem throughout the world that is challenging the sustainability of irrigated agriculture. The presence of elements besides salt in the drainage w...

  8. Alfalfa production with subsurface drip irrigation in the Central Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigated alfalfa production is gaining interest because of the growing number of dairies in the semi-arid U.S. Central Great Plains and its longstanding superior profitability compared to other alternative crops grown in the region. Irrigation requirements for alfalfa are great because of alfalfa's...

  9. Developing a hybrid solar/wind powered irrigation system for crops in the Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some small scale irrigation systems (< 2 ha) powered by wind or solar do not require subsidies, but this paper discusses ways to achieve an economical renewable energy powered center pivot irrigation system for crops in the Great Plains. By adding a solar-photovoltaic (PV) array together with a wind...

  10. Assessing spatial variation of corn response to irrigation using a bayesian semiparametric model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial irrigation of agricultural crops using site-specific variable-rate irrigation (VRI) systems is beginning to have wide-spread acceptance. However, optimizing the management of these VRI systems to conserve natural resources and increase profitability requires an understanding of the spatial ...

  11. CANOPY RESISTANCE AS AFFECTED BY SOIL AND WEATHER FACTORS IN POTATO IRRIGATION SCHEDULING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irrigation requires a method of quantifying the crop water status or root zone depletion of water. A direct measure of canopy resistance has the potential of being used as a crop water status indicator for irrigation management. Canopy resistance as affected by soil and weather factors has been us...

  12. Improving evapotranspiration simulations in the CERES-Maize model under limited irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustaining irrigated agriculture with limited water supplies may require management such as limited or deficit irrigation, where the goal is to maximize crop yield per unit of water consumed. Field trials of corn and sunflower have been conducted near Greeley, CO since 2008, with varying levels of ...

  13. A global data set of the extent of irrigated land from 1900 to 2005

    NASA Astrophysics Data System (ADS)

    Siebert, S.; Kummu, M.; Porkka, M.; Döll, P.; Ramankutty, N.; Scanlon, B. R.

    2015-03-01

    Irrigation intensifies land use by increasing crop yield but also impacts water resources. It affects water and energy balances and consequently the microclimate in irrigated regions. Therefore, knowledge of the extent of irrigated land is important for hydrological and crop modelling, global change research, and assessments of resource use and management. Information on the historical evolution of irrigated lands is limited. The new global historical irrigation data set (HID) provides estimates of the temporal development of the area equipped for irrigation (AEI) between 1900 and 2005 at 5 arcmin resolution. We collected sub-national irrigation statistics from various sources and found that the global extent of AEI increased from 63 million ha (Mha) in 1900 to 111 Mha in 1950 and 306 Mha in 2005. We developed eight gridded versions of time series of AEI by combining sub-national irrigation statistics with different data sets on the historical extent of cropland and pasture. Different rules were applied to maximize consistency of the gridded products to sub-national irrigation statistics or to historical cropland and pasture data sets. The HID reflects very well the spatial patterns of irrigated land as shown on historical maps for the western United States (around year 1900) and on a global map (around year 1960). Mean aridity on irrigated land increased and mean natural river discharge on irrigated land decreased from 1900 to 1950 whereas aridity decreased and river discharge remained approximately constant from 1950 to 2005. The data set and its documentation are made available in an open-data repository at https://mygeohub.org/publications/8 (doi:10.13019/M20599).

  14. Apical Extrusion of Debris and Irrigants Using Different Irrigation Needles.

    PubMed

    Silva, Paula Barcellos; Krolow, Angélica Mohnsam; Pilownic, Katerine Jahnecke; Casarin, Renata Picanço; Lima, Regina Karla Pontes; Leonardo, Renato de Toledo; Pappen, Fernanda Geraldo

    2016-04-01

    This study evaluated the influence of irrigation tip, root canal curvature and final apical diameter on periapical debris and irrigant extrusion during root canal instrumentation. After being classified as mildly or moderately curved, the mesiobuccal root canals of 90 human molars were instrumented. The teeth were allocated into three groups according to the used needle type: a flat open-end needle (Group 1), a side-vented needle (Group 2) or a double side-vented needle (Group 3). The amount of extruded material after instrumentation was calculated for each group. The differences in irrigant and debris extrusion between the experimental groups were analyzed with the Mann-Whitney U test. Irrigation tips and final instrument diameter differences were analyzed with the Kruskal-Wallis test. Multiple groups were compared using the Mann-Whitney U-test with a Bonferroni correction at α=0.05. The amount of extruded material from the double side-vented needle was significantly less than the open-ended flat needle (p=0.008), but there was no difference compared to the side-vented needle (p=0.929). The results showed no effect of root curvature and final apical diameter on the amount of irrigant and debris extrusion (p>0.05). The double side-vented needles generated the least material extrusion to the periapical tissues. Irrigation needle type had the greatest influence on periapical irrigant and debris extrusion and the double side-vented needles may be safely used during endodontic therapy. PMID:27058383

  15. Monitoring irrigation water consumption using high resolution NDVI image time series (Sentinel-2 like). Calibration and validation in the Kairouan plain (Tunisia)

    NASA Astrophysics Data System (ADS)

    Saadi, Sameh; Simonneaux, Vincent; Boulet, Gilles; Mougenot, Bernard; Zribi, Mehrez; Lili Chabaane, Zohra

    2015-04-01

    Water scarcity is one of the main factors limiting agricultural development in semi-arid areas. It is thus of major importance to design tools allowing a better management of this resource. Remote sensing has long been used for computing evapotranspiration estimates, which is an input for crop water balance monitoring. Up to now, only medium and low resolution data (e.g. MODIS) are available on regular basis to monitor cultivated areas. However, the increasing availability of high resolution high repetitivity VIS-NIR remote sensing, like the forthcoming Sentinel-2 mission to be lunched in 2015, offers unprecedented opportunity to improve this monitoring. In this study, regional crops water consumption was estimated with the SAMIR software (Satellite of Monitoring Irrigation) using the FAO-56 dual crop coefficient water balance model fed with high resolution NDVI image time series providing estimates of both the actual basal crop coefficient (Kcb) and the vegetation fraction cover. The model includes a soil water model, requiring the knowledge of soil water holding capacity, maximum rooting depth, and water inputs. As irrigations are usually not known on large areas, they are simulated based on rules reproducing the farmer practices. The main objective of this work is to assess the operationality and accuracy of SAMIR at plot and perimeter scales, when several land use types (winter cereals, summer vegetables…), irrigation and agricultural practices are intertwined in a given landscape, including complex canopies such as sparse orchards. Meteorological ground stations were used to compute the reference evapotranspiration and get the rainfall depths. Two time series of ten and fourteen high-resolution SPOT5 have been acquired for the 2008-2009 and 2012-2013 hydrological years over an irrigated area in central Tunisia. They span the various successive crop seasons. The images were radiometrically corrected, first, using the SMAC6s Algorithm, second, using invariant

  16. Assessing future drought impacts on yields based on historical irrigation reaction to drought for four major crops in Kansas.

    PubMed

    Zhang, Tianyi; Lin, Xiaomao

    2016-04-15

    Evaluation of how historical irrigation reactions can adapt to future drought is indispensable to irrigation policy, however, such reactions are poorly quantified. In this paper, county-level irrigation data for maize, soybean, grain sorghum, and wheat crops in Kansas were compiled. Statistical models were developed to quantify changes of irrigation and yields in response to drought for each crop. These were then used to evaluate the ability of current irrigation to cope with future drought impacts on each crop based on an ensemble Palmer Drought Severity Index (PDSI) prediction under the Representative Concentration Pathways 4.5 scenario. Results indicate that irrigation in response to drought varies by crop; approximately 10 to 13% additional irrigation was applied when PDSI was reduced by one unit for maize, soybean, and grain sorghum. However, the irrigation reaction for wheat exhibits a large uncertainty, indicating a weaker irrigation reaction. Analysis of future climate conditions indicates that maize, soybean, and grain sorghum yields would decrease 2.2-12.4% at the state level despite additional irrigation application induced by drought (which was expected to increase 5.1-19.0%), suggesting that future drought will exceed the range that historical irrigation reactions can adapt to. In contrast, a lower reduction (-0.99 to -0.63%) was estimated for wheat yields because wetter climate was projected in the central section of the study area. Expanding wheat areas may be helpful in avoiding future drought risks for Kansas agriculture. PMID:26851757

  17. Forecast of irrigation water demand considering multiple factors

    NASA Astrophysics Data System (ADS)

    Wang, X.; Lei, X.; Guo, X.; You, J.; Wang, H.

    2015-05-01

    Many factors influence irrigation water requirement on the basin scale, which make it difficult to obtain comprehensive data. Despite the advantage of less needing historical data, the prediction precision of traditional trend prediction methods is hard to guarantee. For water scarce basins, the artificial influence on irrigation requirement should be thought of as important impact factors. In this paper, the PCA (principal component analysis) method is used to identify the main influencing factors, such as precipitation, irrigation area, water saving technology and so on. Based on that, an irrigation water demand prediction model considering multiple factors is developed for water shortage regions. The method is applied in the Haihe River basin as an example. The study results show that the irrigation water demand forecasting method considering multiple factors in this paper can achieve higher modelling accuracy, compared with the traditional trend prediction method and the method that does not consider the human influence. In view of the small average relative error, 1.32%, it has good values for application.

  18. Economics of wind energy use for irrigation in India.

    PubMed

    Tewari, S K

    1978-11-01

    The production of energy from windmills designed specifically to operate in the low wind velocities that usually prevail in India during the main irrigation season is estimated to be reasonably economical for irrigating small farms from open wells. The economics would improve if irrigation was practiced all year round, even in the hot summer season. The calculations made here are expected to be valid for the windier 10 percent of the locations identified from available wind speed records. Other, windier locations are expected to be identified when more wind speed data are collected in the future. Governmental policies along lines similar to those for rural electrification may be needed to support research and development efforts to optimize the designs of windmills and to promote their use in rural areas. PMID:17813470

  19. Quantification of deep percolation from two flood-irrigated alfalfa field, Roswell Basin, New Mexico

    USGS Publications Warehouse

    Roark, D. Michael; Healy, D.F.

    1998-01-01

    For many years water management in the Roswell ground-water basin (Roswell Basin) and other declared basins in New Mexico has been the responsibility of the State of New Mexico. One of the water management issues requiring better quantification is the amount of deep percolation from applied irrigation water. Two adjacent fields, planted in alfalfa, were studied to determine deep percolation by the water-budget, volumetric-moisture, and chloride mass-balance methods. Components of the water-budget method were measured, in study plots called borders, for both fields during the 1996 irrigation season. The amount of irrigation water applied in the west border was 95.8 centimeters and in the east border was 169.8 centimeters. The total amount of precipitation that fell during the irrigation season was 21.9 centimeters. The increase in soil-moisture storage from the beginning to the end of the irrigation season was 3.2 centimeters in the west border and 8.8 centimeters in the east border. Evapotranspiration, as estimated by the Bowen ratio energy balance technique, in the west border was 97.8 centimeters and in the east border was 101.0 centimeters. Deep percolation determined using the water-budget method was 16.4 centimeters in the west border and 81.6 centimeters in the east border. An average deep percolation of 22.3 centimeters in the west border and 31.6 centimeters in the east border was determined using the volumetric-moisture method. The chloride mass-balance method determined the multiyear deep percolation to be 15.0 centimeters in the west border and 38.0 centimeters in the east border. Large differences in the amount of deep percolation between the two borders calculated by the water-budget method are due to differences in the amount of water that was applied to each border. More water was required to flood the east border because of the greater permeability of the soils in that field and the smaller rate at which water could be applied.

  20. Estimating water and nitrate leaching in tree crops using inverse modelled plant and soil hydraulic properties

    NASA Astrophysics Data System (ADS)

    Couvreur, Valentin; Kandelous, Maziar; Mairesse, Harmony; Baram, Shahar; Moradi, Ahmad; Pope, Katrin; Hopmans, Jan

    2015-04-01

    Groundwater quality is specifically vulnerable in irrigated agricultural lands in California and many other (semi-)arid regions of the world. The routine application of nitrogen fertilizers with irrigation water in California is likely responsible for the high nitrate concentrations in groundwater, underlying much of its main agricultural areas. To optimize irrigation/fertigation practices, it is essential that irrigation and fertilizers are applied at the optimal concentration, place, and time to ensure maximum root uptake and minimize leaching losses to the groundwater. The applied irrigation water and dissolved fertilizer, root nitrate and water uptake interact with soil and root properties in a complex manner that cannot easily be resolved. It is therefore that coupled experimental-modelling studies are required to allow for unravelling of the relevant complexities that result from typical variations of crop properties, soil texture and layering across farmer-managed fields. A combined field monitoring and modelling approach was developed to quantify from simple measurements the leaching of water and nitrate below the root zone. The monitored state variables are soil water content within the root zone, soil matric potential below the root zone, and nitrate concentration in the soil solution. Plant and soil properties of incremented complexity are optimized with the software HYDRUS in an inverse modelling scheme, which allows estimating leaching under constraint of hydraulic principles. Questions of optimal irrigation and fertilization timing can then be addressed using predictive results and global optimization algorithms.

  1. Determining Environmental Impacts of Large Scale Irrigation in Turkey

    NASA Astrophysics Data System (ADS)

    Simpson, K.; Douglas, E. M.; Limbrunner, J. F.; Ozertan, G.

    2010-12-01

    In 1989, the Turkish government launched their most comprehensive regional development plan in history entitled the Southeastern Anatolia Project (SAP) which focuses on improving the quality of life and income level within the most underdeveloped region in Turkey. This project aims to integrate sustainable human development through agriculture, industry, transportation, education, health and rural and urban infrastructure building. In May 2008, a new action plan was announced for the region which includes the designation of almost 800,000 hectares of previously unirrigated land to be open for irrigation within the next five years. If not done in a sustainable manner, such a large-scale irrigation project could cause severe environmental impacts. The first objective of our research is to use computer simulations to reproduce the observed environmental impacts of irrigated agriculture in this arid region, primarily by simulating the effects of soil salinization. The second objective of our research is to estimate soil salinization that could result from expanded irrigation and suggest sustainable strategies for the newly irrigated land in Turkey in order to minimize these environmental impacts.

  2. Effects of Changes in Irrigation Practices and Aquifer Development on Groundwater Discharge to the Jobos Bay National Estuarine Research Reserve near Salinas, Puerto Rico

    USGS Publications Warehouse

    Kuniansky, Eve L.; Rodriguez, Jose M.

    2010-01-01

    Since 1990, about 75 acres of black mangroves have died in the Jobos Bay National Estuarine Research Reserve near Salinas, Puerto Rico. Although many factors can contribute to the mortality of mangroves, changes in irrigation practices, rainfall, and water use resulted in as much as 25 feet of drawdown in the potentiometric surface of the aquifer in the vicinity of the reserve between 1986 and 2002. To clarify the issue, the U.S. Geological Survey, in cooperation with the Puerto Rico Department of Natural and Environmental Resources, conducted a study to ascertain how aquifer development and changes in irrigation practices have affected groundwater levels and groundwater flow to the Mar Negro area of the reserve. Changes in groundwater flow to the mangrove swamp and bay from 1986 to 2004 were estimated in this study by developing and calibrating a numerical groundwater flow model. The transient simulations indicate that prior to 1994, high irrigation return flows more than offset the effect of reduced groundwater withdrawals. In this case, the simulated discharge to the coast in the modeled area was 19 million gallons per day. From 1994 through 2004, furrow irrigation was completely replaced by micro-drip irrigation, thus eliminating return flows and the simulated average coastal discharge was 7 million gallons per day, a reduction of 63 percent. The simulated average groundwater discharge to the coastal mangrove swamps in the reserve from 1986 to 1993 was 2 million gallons per day, compared to an average simulated discharge of 0.2 million gallons per day from 1994 to 2004. The average annual rainfall for each of these periods was 38 inches. The groundwater discharge to the coastal mangrove swamps in the Jobos Bay National Estuarine Research Reserve was estimated at about 0.5 million gallons per day for 2003-2004 because of higher than average annual rainfall during these 2 years. The groundwater flow model was used to test five alternatives for increasing

  3. Estimation of spatial distribution of heavy metals in groundwater using interpolation methods and multivariate statistical techniques; its suitability for drinking and irrigation purposes in the Middle Black Sea Region of Turkey.

    PubMed

    Arslan, Hakan; Ayyildiz Turan, Nazlı

    2015-08-01

    Monitoring of heavy metal concentrations in groundwater potentially used for drinking and irrigation is very important. This study collected groundwater samples from 78 wells in July 2012 and analyzed them for 17 heavy metals (Pb, Zn, Cr, Mn, Fe, Cu, Cd, Co, Ni, Al, As, Mo, Se, B, Ti, V, Ba). Spatial distributions of these elements were identified using three different interpolation methods [inverse distance weighing (IDW), radial basis function (RBF), and ordinary kriging (OK)]. Root mean squared error (RMSE) and mean absolute error (MAE) for cross validation were used to select the best interpolation methods for each parameter. Multivariate statistical analysis [cluster analysis (CA) and factor analysis (FA)] were used to identify similarities among sampling sites and the contribution of variables to groundwater pollution. Fe and Mn levels exceeded World Health Organization (WHO) recommended limits for drinking water in almost all of the study area, and some locations had Fe and Mn levels that exceeded Food and Agriculture Organization (FAO) guidelines for drip irrigation systems. Al, As, and Cd levels also exceeded WHO guidelines for drinking water. Cluster analysis classified groundwater in the study area into three groups, and factor analysis identified five factors that explained 73.39% of the total variation in groundwater, which are as follows: factor 1: Se, Ti, Cr, Mo; factor 2: Ni, Mn, Co, Ba; factor 3: Pb, Cd; factor 4: B, V, Fe, Cu; and factor 5: AS, Zn. As a result of this study, it could be said that interpolation methods and multivariate statistical techniques gave very useful results for the determination of the source. PMID:26202813

  4. Key aspects in representing the impact of irrigation on hydrology and climate

    NASA Astrophysics Data System (ADS)

    de Vrese, Philipp; Hagemann, Stefan

    2015-04-01

    The hydrological cycle is a key component in the climate system and its alteration presents a critical anthropogenic influence on climate change. The amount of solar radiation absorbed by water vapor within the atmosphere makes it the most important greenhouse gas. Furthermore strong positive climate feedbacks are presumed in connection with atmospheric water vapor; increasing temperatures could increase the global water vapor concentration by increasing the water vapor pressure at saturation. This in turn increases the amount of absorbed solar radiation and thus temperatures. It is often assumed that on the global scale the atmospheric input of water vapor attributed to irrigation is negligible in comparison to the naturally occurring water vapor. On the regional scale however many studies showed that irrigation has a strong impact on climate which will very likely increase in the future due to increasing demands and changing climate conditions. Furthermore it is plausible that the estimated impact of irrigation is not only depending on the scope (regional vs. global) but also on the design of a given study. Thus the key concern of this study was not only to estimate the impact of irrigation on a global scale, but rather to evaluate the importance of the way irrigation is represented in a model. On one hand, the effect of the representation of different irrigation characteristics was investigated e.g. the extent to which irrigation was applied to the vegetated/ non-vegetated part of a grid box. On the other hand it was investigated, whether the scheme used to couple the two model components plays an important role for the impact of irrigation on climate. For the investigation, several 20-year-AMIP-type experiments were conducted using the Max Planck Institute for Meteorology's earth system model, i.e. the general circulation ECHAM6 coupled to a version of the land-surface model JSBACH, which had been modified to represent irrigated areas. It was found that

  5. 25 CFR 134.1 - Partial reimbursement of irrigation charges; 5 percent per annum of cost of system, June 30, 1920.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... provisions of law requiring reimbursement of the cost of such system and to which land, water for irrigation... land to which water for irrigation purposes can be delivered on that date; and on November 15 of each... water for irrigation purposes can be delivered from the system on that date. Provision is contained...

  6. 25 CFR 134.1 - Partial reimbursement of irrigation charges; 5 percent per annum of cost of system, June 30, 1920.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... provisions of law requiring reimbursement of the cost of such system and to which land, water for irrigation... land to which water for irrigation purposes can be delivered on that date; and on November 15 of each... water for irrigation purposes can be delivered from the system on that date. Provision is contained...

  7. 25 CFR 134.1 - Partial reimbursement of irrigation charges; 5 percent per annum of cost of system, June 30, 1920.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... provisions of law requiring reimbursement of the cost of such system and to which land, water for irrigation... land to which water for irrigation purposes can be delivered on that date; and on November 15 of each... water for irrigation purposes can be delivered from the system on that date. Provision is contained...

  8. Alternating irrigation water quality as a method to control solute concentrations and mass fluxes below irrigated fields: A numerical study

    NASA Astrophysics Data System (ADS)

    Russo, David

    2016-05-01

    The aim of the present numerical study was to extend the data-driven protocol for the control of soil salinity, to control chloride and nitrate concentrations and mass fluxes below agricultural fields irrigated with treated waste water (TWW). The protocol is based on alternating irrigation water quality between TWW and desalinized water (DSW), guided by solute concentrations at soil depth, zs. Two different schemes, the first requires measurements of soil solution concentrations of chloride and nitrate at zs, while, the second scheme requires only measurements of soil solution EC at zs, were investigated. For this purpose, 3-D numerical simulations of flow and transport were performed for variably saturated, spatially heterogeneous, flow domains located at two different field sites. The sites differ in crop type, irrigation method, and in their lithology; these differences, in turn, considerably affect the performance of the proposed schemes, expressed in terms of their ability to reduce solute concentrations that drained below the root zone. Results of the analyses suggest that the proposed data-driven schemes allow the use of low-quality water for irrigation, while minimizing the consumption of high-quality water to a level, which, for given climate, soil, crop, irrigation method, and water quality, may be determined by the allowable nitrate and chloride concentrations in the groundwater. The results of the present study indicate that with respect to the diminution of groundwater contamination by chloride and nitrate, the more data demanding, first scheme is superior the second scheme.

  9. Mapping irrigated areas in Afghanistan over the past decade using MODIS NDVI

    USGS Publications Warehouse

    Pervez, Md Shahriar; Budde, Michael; Rowland, James

    2014-01-01

    the severe drought conditions in those years, whereas 2009, 2012 and 2013 registered the largest irrigated area (~ 2.5 million hectares) due to record snowpack and snowmelt in the region. The model holds promise the ability to provide near-real-time (by the end of the growing seasons) estimates of irrigated area, which are beneficial for food security monitoring as well as subsequent decision making for the country. While the model is developed for Afghanistan, it can be adopted with appropriate adjustments in the derived threshold values to map irrigated areas elsewhere.

  10. Remote-Sensing-Based Evaluation of Relative Consumptive Use Between Flood- and Drip-Irrigated Fields

    NASA Astrophysics Data System (ADS)

    Martinez Baquero, G. F.; Jordan, D. L.; Whittaker, A. T.; Allen, R. G.

    2013-12-01

    Governments and water authorities are compelled to evaluate the impacts of agricultural irrigation on economic development and sustainability as water supply shortages continue to increase in many communities. One of the strategies commonly used to reduce such impacts is the conversion of traditional irrigation methods towards more water-efficient practices. As part of a larger effort by the New Mexico Interstate Stream Commission to understand the environmental and economic impact of converting from flood irrigation to drip irrigation, this study evaluates the water-saving effectiveness of drip irrigation in Deming, New Mexico, using a remote-sensing-based technique combined with ground data collection. The remote-sensing-based technique used relative temperature differences as a proxy for water use to show relative differences in crop consumptive use between flood- and drip-irrigated fields. Temperature analysis showed that, on average, drip-irrigated fields were cooler than flood-irrigated fields, indicating higher water use. The higher consumption of water by drip-irrigated fields was supported by a determination of evapotranspiration (ET) from all fields using the METRIC Landsat-based surface energy balance model. METRIC analysis yielded higher instantaneous ET for drip-irrigated fields when compared to flood-irrigated fields and confirmed that drip-irrigated fields consumed more water than flood-irrigated fields planted with the same crop. More water use generally results in more biomass and hence higher crop yield, and this too was confirmed by greater relative Normalized Difference Vegetation Index for the drip irrigated fields. Results from this study confirm previous estimates regarding the impacts of increased efficiency of drip irrigation on higher water consumption in the area (Ward and Pulido-Velazquez, 2008). The higher water consumption occurs with drip because, with the limited water supplies and regulated maximum limits on pumping amounts, the

  11. Irrigation with treated wastewater: effects on soil, lettuce (Lactuca sativa L.) crop and dynamics of microorganisms.

    PubMed

    Mañas, Pilar; Castro, Elena; de Las Heras, Jorge

    2009-10-01

    The aim of this study was to evaluate the applicability of treated wastewater for horticultural crops, assess the effects of continuous use of treated water on soil and crops, and analyse the physical, chemical and biological effects of irrigation with recycled water. Two lettuce plots watered with drinking water and treated wastewater were monitored over a three year period. Nutrients, heavy metal and the dynamics of pathogen and indicator microorganism content in soil and foliar tissues were analysed. Wastewater irrigation had a high influence on soil parameters: organic matter, N, P, Ca, Al, Fe, Pb and Zn. Indicator and pathogenic microorganisms were detected in soil and plants grown in the wastewater-irrigated plot, and persisted in the soil for 27 days during the study under humid conditions. N, P, Pb and Al content were significantly higher in plant tissues of wastewater-irrigated plots than in the control after 3 years of irrigation. Harvest was significantly higher in the wastewater-irrigated plot. Wastewater can be a resource for agricultural irrigation. In any case, the possible heavy metal accumulation in soils and presence of pathogenic organisms require careful management of this alternative resource: use of a drip irrigation system, previous wastewater disinfection and a limited irrigation period are recommended. PMID:19847714

  12. Global effect of irrigation and its impact on the onset of the Indian summer monsoon

    NASA Astrophysics Data System (ADS)

    Guimberteau, Matthieu; Laval, Katia; Perrier, Alain; Polcher, Jan

    2012-09-01

    In a context of increased demand for food and of climate change, the water consumptions associated with the agricultural practice of irrigation focuses attention. In order to analyze the global influence of irrigation on the water cycle, the land surface model ORCHIDEE is coupled to the GCM LMDZ to simulate the impact of irrigation on climate. A 30-year simulation which takes into account irrigation is compared with a simulation which does not. Differences are usually not significant on average over all land surfaces but hydrological variables are significantly affected by irrigation over some of the main irrigated river basins. Significant impacts over the Mississippi river basin are shown to be contrasted between eastern and western regions. An increase in summer precipitation is simulated over the arid western region in association with enhanced evapotranspiration whereas a decrease in precipitation occurs over the wet eastern part of the basin. Over the Indian peninsula where irrigation is high during winter and spring, a delay of 6 days is found for the mean monsoon onset date when irrigation is activated, leading to a significant decrease in precipitation during May to July. Moreover, the higher decrease occurs in June when the water requirements by crops are maximum, exacerbating water scarcity in this region. A significant cooling of the land surfaces occurs during the period of high irrigation leading to a decrease of the land-sea heat contrast in June, which delays the monsoon onset.

  13. Effect of Intraoperative Corneal Stromal Pocket Irrigation in Small Incision Lenticule Extraction

    PubMed Central

    Liu, Yu-Chi; Jayasinghe, Lasitha; Ang, Heng Pei; Lwin, Nyein Chan; Yam, Gary Hin Fai; Mehta, Jodhbir S.

    2015-01-01

    This study aimed at evaluating the effect of intraoperative corneal pocket irrigation in small incision lenticule extraction (SMILE) and compares it to that in femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Sixteen rabbit eyes underwent a SMILE procedure, with 8 eyes having corneal pocket irrigation, while the other 8 eyes were without irrigation. Another 16 eyes underwent a FS-LASIK procedure for comparison, with 8 eyes having flap irrigation, while the other 8 eyes were without irrigation. The results showed that the changes in the total corneal thickness, anterior and posterior lamellar thickness, measured by the anterior segment optical coherence tomography, were comparable between the SMILE with and without irrigation groups, suggesting that the irrigation did not lead to significant changes in the corneal thickness. However, at postoperative 8 hours, in vivo confocal microscopy showed that the interface reflectivity in the SMILE with irrigation group was significantly higher than that in other three groups. The presence of interface fluid was further confirmed by the identification of fluid pockets with undulated collagen shown on histological section in the post-SMILE with irrigation eyes. Our findings might contribute to the occurrence of post-SMILE delayed immediate visual quality recovery and further clinical study is required. PMID:26273659

  14. Effect of Intraoperative Corneal Stromal Pocket Irrigation in Small Incision Lenticule Extraction.

    PubMed

    Liu, Yu-Chi; Jayasinghe, Lasitha; Ang, Heng Pei; Lwin, Nyein Chan; Yam, Gary Hin Fai; Mehta, Jodhbir S

    2015-01-01

    This study aimed at evaluating the effect of intraoperative corneal pocket irrigation in small incision lenticule extraction (SMILE) and compares it to that in femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Sixteen rabbit eyes underwent a SMILE procedure, with 8 eyes having corneal pocket irrigation, while the other 8 eyes were without irrigation. Another 16 eyes underwent a FS-LASIK procedure for comparison, with 8 eyes having flap irrigation, while the other 8 eyes were without irrigation. The results showed that the changes in the total corneal thickness, anterior and posterior lamellar thickness, measured by the anterior segment optical coherence tomography, were comparable between the SMILE with and without irrigation groups, suggesting that the irrigation did not lead to significant changes in the corneal thickness. However, at postoperative 8 hours, in vivo confocal microscopy showed that the interface reflectivity in the SMILE with irrigation group was significantly higher than that in other three groups. The presence of interface fluid was further confirmed by the identification of fluid pockets with undulated collagen shown on histological section in the post-SMILE with irrigation eyes. Our findings might contribute to the occurrence of post-SMILE delayed immediate visual quality recovery and further clinical study is required. PMID:26273659

  15. Influence of deficit irrigation strategies on fatty acid and tocopherol concentration of almond (Prunus dulcis).

    PubMed

    Zhu, Ying; Taylor, Cathy; Sommer, Karl; Wilkinson, Kerry; Wirthensohn, Michelle

    2015-04-15

    The effects of deficit irrigation on almond fatty acid and tocopherol levels were studied in a field trial. Mature almond trees were subjected to three levels of deficit irrigation (85%, 70% and 55% of potential crop evapotranspiration (ETo), as well as control (100% ETo) and over-irrigation (120% ETo) treatments. Two deficit irrigation strategies were employed: regulated deficit irrigation (RDI) and sustained deficit irrigation (SDI). Moderate deficit irrigation (85% RDI and 85% SDI) had no detrimental impact on almond kernel lipid content, but severe and extreme deficiencies (70% and 55%) influenced lipid content. Unsaturated fatty acid (USFA) and saturated fatty acid (SFA) contents fluctuated under these treatments, the oleic/linoleic ratio increased under moderate water deficiency, but decreased under severe and extreme water deficiency. Almond tocopherols concentration was relatively stable under deficit irrigation. The variation between years indicated climate has an effect on almond fruit development. In conclusion it is feasible to irrigate almond trees using less water than the normal requirement, without significant loss of kernel quality. PMID:25466095

  16. Relation between irrigation engineering and bilharziasis*

    PubMed Central

    Lanoix, Joseph N.

    1958-01-01

    The author discusses the relation between irrigation systems and the transmission of bilharziasis, with special reference to the important part the irrigation engineer can play in checking the spread of the disease. He points out that, in the past, there has been little co-operation between health departments and public works agencies in respect of the setting-up of irrigation systems, and stresses the advantages to be gained from an active collaboration between malacologists, epidemiologists and irrigation engineers at the planning stage of irrigation schemes. The author also puts forward some suggestions for research on irrigation-system design and outlines the role of WHO in bilharziasis control. PMID:13573123

  17. Requirements for zero energy balance of nonlactating, pregnant dairy cows fed fresh autumn pasture are greater than currently estimated.

    PubMed

    Mandok, K S; Kay, J K; Greenwood, S L; Edwards, G R; Roche, J R

    2013-06-01

    Fifty-three nonlactating, pregnant Holstein-Friesian and Holstein-Friesian × Jersey cross dairy cows were grouped into 4 cohorts (n=15, 12, 13, and 13) and offered 1 of 3 allowances of fresh, cut pasture indoors for 38 ± 2 d (mean ± SD). Cows were released onto a bare paddock after their meal until the following morning. Animals were blocked by age (6 ± 2 yr), day of gestation (208 ± 17 d), and body weight (BW; 526 ± 55 kg). The 3 pasture allowances [low: 7.5 kg of dry matter (DM), medium: 10.1 kg of DM, or high: 12.4 kg of DM/cow per day] were offered in individual stalls to determine the estimated DM and metabolizable energy (ME) intake required for zero energy balance. Individual cow DM intake was determined daily and body condition score was assessed once per week. Cow BW was recorded once per week in cohorts 1 and 2, and 3 times per week in cohorts 3 and 4. Low, medium, and high allowance treatments consumed 7.5, 9.4, and 10.6 kg of DM/cow per day [standard error of the difference (SED)=0.26 kg of DM], and BW gain, including the conceptus, was 0.2, 0.6, and 0.9 kg/cow per day (SED=0.12 kg), respectively. The ME content of the pasture was estimated from in vitro true digestibility and by near infrared spectroscopy. Total ME requirements for maintenance, pregnancy, and limited activity were 1.07 MJ of ME/kg of measured metabolic BW per day. This is more than 45% greater than current recommendations. Differences may be due to an underestimation of ME requirements for maintenance or pregnancy, an overestimation of diet metabolizability, or a combination of these. Further research is necessary to determine the reasons for the greater ME requirements measured in the present study, but the results are important for on-farm decisions regarding feed allocation for nonlactating, pregnant dairy cows. PMID:23522671

  18. Productivity of irrigation technologies in the White Volta basin

    NASA Astrophysics Data System (ADS)

    Ofosu, E. A.; van der Zaag, P.; van de Giesen, N. C.; Odai, S. N.

    Parts of the White Volta basin in northern Ghana and southern Burkina Faso have witnessed a spectacular rise of irrigated agriculture since about 2000, largely without government support, and seems to have been triggered by a strong and growing demand for vegetables, notably tomatoes in the urban centres of southern Ghana. It is interesting to note the variety of different irrigation technologies that individual and groups of smallholder farmers adopted, adapted and implemented. Some technologies are well-known, such as those associated with conventional sources of water like small and large reservoirs; others have been rarely described in literature, such as temporal shallow wells and alluvial dugouts. This paper describes and characterises these different irrigation technologies and conducts a comparative analysis of their productivities, in terms of crop yield, water use and financial returns. The study was conducted in three neighbouring and transboundary watersheds (Anayari, Atankwidi and Yarigatanga) located in the Upper East Region of Ghana and southern Burkina Faso. For the study, 90 tomato farmers with different irrigation technologies were surveyed during one crop season (2007/2008). The results show that adequate fertilizer application is the major contributor to irrigation productivity. Technologies characterised by relatively small farm sizes are better managed by the surveyed farmers because they are able to provide adequate water and crop nutrients thus resulting in higher productivity, and high profit margins. Apart from technologies that depend on reservoirs, all other technologies surveyed in the paper are farmer driven and required no government support. This ongoing type of endogenous irrigation development provides a strong backing that the way forward in sub-Saharan Africa is for governments to create policies that facilitate poor farmers becoming irrigation entrepreneurs. Such policies should aim to enhance the reliability of markets (both

  19. Radiological Evaluation of Penetration of the Irrigant according to Three Endodontic Irrigation Techniques

    PubMed Central

    Benkiran, Imane; El Ouazzani, Amal

    2016-01-01

    Introduction. This experimental study is to compare radiographs based on the penetration depth of the irrigant following three final irrigation techniques. Material and Method. A sample of sixty teeth with single roots were prepared with stainless steel K files followed by mechanized Ni-Ti files iRace® under irrigation with 2.5% sodium hypochlorite. Radiopaque solution was utilized to measure the penetration depth of the irrigant. Three irrigation techniques were performed during this study: (i) passive irrigation, (ii) manually activated irrigation, and (iii) passive irrigation with an endodontic needle CANAL CLEAN®. Radiographs were performed to measure the length of irrigant penetration in each technique. Results. In comparison, passive irrigation with a conventional syringe showed infiltration of the irrigant by an average of 0.682 ± 0.105, whereas the manually activated irrigation technique indicated an average of 0.876 ± 0.066 infiltration. Irrigation with an endodontic syringe showed an average infiltration of 0.910 ± 0.043. The results revealed highly significant difference between the three irrigation techniques (α = 5%). Conclusion. Adding manual activation to the irrigant improved the result by 20%. This study indicates that passive irrigation with an endodontic needle has proved to be the most effective irrigation technique of the canal system. PMID:27433162

  20. Simulation of groundwater flow and effects of groundwater irrigation on stream base flow in the Elkhorn and Loup River Basins, Nebraska, 1895-2055-Phase Two

    USGS Publications Warehouse

    Stanton, Jennifer S.; Peterson, Steven M.; Fienen, Michael N.

    2010-01-01

    Regional groundwater-flow simulations for a 30,000-square-mile area of the High Plains aquifer, referred to collectively as the Elkhorn-Loup Model, were developed to predict the effects of groundwater irrigation on stream base flow in the Elkhorn and Loup River Basins, Nebraska. Simulations described the stream-aquifer system from predevelopment through 2005 [including predevelopment (pre-1895), early development (1895-1940), and historical development (1940 through 2005) conditions] and future hypothetical development conditions (2006 through 2033 or 2055). Predicted changes to stream base flow that resulted from simulated changes to groundwater irrigation will aid development of long-term strategies for management of hydrologically connected water supplies. The predevelopment through 2005 simulation was calibrated using an automated parameter-estimation method to optimize the fit to pre-1940 groundwater levels and base flows, 1945 through 2005 decadal groundwater-level changes, and 1940 through 2005 base flows. The calibration results of the pre-1940 period indicated that 81 percent of the simulated groundwater levels were within 30 feet of the measured water levels. The results did not indicate large areas of simulated groundwater levels that were biased too high or too low, indicating that the simulation generally captures the regional trends. Calibration results using 1945 through 2005 decadal groundwater-level changes indicated that a majority of the simulated groundwater-level changes were within 5 feet of the changes calculated from measured groundwater levels. Simulated groundwater-level rises generally were smaller than measured rises near surface-water irrigation districts. Simulated groundwater-level declines were larger than measured declines in several parts of the study area having large amounts of irrigated crops. Base-flow trends and volumes generally were reproduced by the simulation at most sites. Exceptions include downward trends of simulated