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Andre Peters - One of the best experts on this subject based on the ideXlab platform.
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large zero tension plate Lysimeters for soil water and solute collection in undisturbed soils
Hydrology and Earth System Sciences, 2009Co-Authors: Andre Peters, Wolfgang DurnerAbstract:Abstract. Water collection from undisturbed unsaturated soils to estimate in situ water and solute fluxes in the field is a challenge, in particular if soils are heterogeneous. Large sampling devices are required if preferential flow paths are present. We present a modular plate system that allows installation of large zero-tension lysimeter plates under undisturbed soils in the field. To investigate the influence of the lysimeter on the water flow field in the soil, a numerical 2-D simulation study was conducted for homogeneous soils with uni- and bimodal pore-size distributions and stochastic Miller-Miller heterogeneity. The collection efficiency was found to be highly dependent on the hydraulic functions, infiltration rate, and lysimeter size, and was furthermore affected by the degree of heterogeneity. In homogeneous soils with high saturated conductivities the devices perform poorly and even large Lysimeters (width 250 cm) can be bypassed by the soil water. Heterogeneities of soil hydraulic properties result into a network of flow channels that enhance the sampling efficiency of the lysimeter plates. Solute breakthrough into zero-tension lysimeter occurs slightly retarded as compared to the free soil, but concentrations in the collected water are similar to the mean flux concentration in the undisturbed soil. To validate the results from the numerical study, a dual tracer study with seven Lysimeters of 1.25×1.25 m area was conducted in the field. Three Lysimeters were installed underneath a 1.2 m filling of contaminated silty sand, the others deeper in the undisturbed soil. The Lysimeters directly underneath the filled soil material collected water with a collection efficiency of 45%. The deeper Lysimeters did not collect any water. The arrival of the tracers showed that almost all collected water came from preferential flow paths.
Wolfgang Durner - One of the best experts on this subject based on the ideXlab platform.
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large zero tension plate Lysimeters for soil water and solute collection in undisturbed soils
Hydrology and Earth System Sciences, 2009Co-Authors: Andre Peters, Wolfgang DurnerAbstract:Abstract. Water collection from undisturbed unsaturated soils to estimate in situ water and solute fluxes in the field is a challenge, in particular if soils are heterogeneous. Large sampling devices are required if preferential flow paths are present. We present a modular plate system that allows installation of large zero-tension lysimeter plates under undisturbed soils in the field. To investigate the influence of the lysimeter on the water flow field in the soil, a numerical 2-D simulation study was conducted for homogeneous soils with uni- and bimodal pore-size distributions and stochastic Miller-Miller heterogeneity. The collection efficiency was found to be highly dependent on the hydraulic functions, infiltration rate, and lysimeter size, and was furthermore affected by the degree of heterogeneity. In homogeneous soils with high saturated conductivities the devices perform poorly and even large Lysimeters (width 250 cm) can be bypassed by the soil water. Heterogeneities of soil hydraulic properties result into a network of flow channels that enhance the sampling efficiency of the lysimeter plates. Solute breakthrough into zero-tension lysimeter occurs slightly retarded as compared to the free soil, but concentrations in the collected water are similar to the mean flux concentration in the undisturbed soil. To validate the results from the numerical study, a dual tracer study with seven Lysimeters of 1.25×1.25 m area was conducted in the field. Three Lysimeters were installed underneath a 1.2 m filling of contaminated silty sand, the others deeper in the undisturbed soil. The Lysimeters directly underneath the filled soil material collected water with a collection efficiency of 45%. The deeper Lysimeters did not collect any water. The arrival of the tracers showed that almost all collected water came from preferential flow paths.
Dragutin Petosic - One of the best experts on this subject based on the ideXlab platform.
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experimental and mathematical modeling of water regime and nitrate dynamics on zero tension plate Lysimeters in soil influenced by high groundwater table
Nutrient Cycling in Agroecosystems, 2013Co-Authors: Vilim Filipovic, Radka Kodesova, Dragutin PetosicAbstract:Unlike laboratory experiments, which are mostly performed under controlled conditions, lysimeter experiments generally simulate actual field conditions. This paper focuses on an efficiency of the zero tension plate Lysimeters, which were implanted in silty-clay soils influenced by a high groundwater table. Measurements and following numerical simulations using the HYDRUS-2D model were performed separately for each of 4 years (2007–2010) to assess water flow and nitrate fluxes (applied as NPK or UREA fertilizer). Low efficiency of Lysimeters during the vegetation period was mostly caused by high plant water demand and possible water diversion to the sides when the groundwater table was low. The HYDRUS-2D model was able in some degree to reproduce observed water and nitrate outflows. The water outflow through the lysimeter occurred when the groundwater table was high and greater rainfall events occurred. Water and solute diverged from the plate towards the dryer surrounding soil when groundwater table was low. Pressure head, water velocity and nitrate concentration distributions simulated around the lysimeter plate illustrated that the lysimeter plate had a significant impact on the water regime and nitrate behavior within the soil profile. The lysimeter plate also acted as a barrier for water flow and solute transport also.
Terry A. Howell - One of the best experts on this subject based on the ideXlab platform.
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the bushland weighing Lysimeters a quarter century of crop et investigations to advance sustainable irrigation
Transactions of the ASABE, 2016Co-Authors: Steven R. Evett, Terry A. Howell, A. D. Schneider, D. A. Dusek, Karen S. Copeland, David Brauer, Judy A Tolk, Gary W Marek, Thomas M Marek, Prasanna H GowdaAbstract:In 1987-1989, the first irrigated crops were grown on the four large, precision weighing Lysimeters at the USDA-ARS Conservation and Production Research Laboratory at Bushland, Texas, on the Southern High Plains (SHP). Thus began >25-years of full- and deficit-irrigated crop growth, energy and water balance, evapotranspiration (ET), yield, and water use efficiency (WUE) studies of major SHP crops, including alfalfa, corn and sorghum for both grain and forage, cotton, soybean, sunflower, and winter wheat. Alfalfa studies supported development of the ASCE Standardized Reference ET methodology. The lysimeter effort, led by Terry Howell, Sr., co-designed with Lynne Ebling and Thomas Marek and constructed by Arland Schneider, eventually grew to include a separate lysimeter to study short grass ET, again for the ASCE standard, and a 48-lysimeter facility to study soil type effects on crop water uptake, ET, and WUE using monoliths of four soils typical of SHP irrigated soils. The large Lysimeters were managed to be representative of sprinkler-irrigated fields so as to develop crop coefficients used for irrigation scheduling by clients of ET networks developed by Texas A&M AgriLife in collaboration with the USDA-ARS. In addition, the Lysimeters were used to test and further develop several technologies important to irrigation science, including soil water sensors, eddy covariance and Bowen ratio systems, scintillometers, thermal remote sensing based ET models, and hydrologic and crop simulation models. With the installation of subsurface drip irrigation systems on two of the lysimeter fields in 2013, the Bushland Lysimeters are entering a new phase of advanced irrigation method and management studies.
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the bushland weighing Lysimeters a quarter century of crop et investigations to advance sustainable irrigation
2015 ASABE IA Irrigation Symposium: Emerging Technologies for Sustainable Irrigation - A Tribute to the Career of Terry Howell Sr. Conference Proceedi, 2015Co-Authors: Steven R. Evett, Terry A. Howell, A. D. Schneider, D. A. Dusek, Karen S. Copeland, David Brauer, Judy A Tolk, Gary W Marek, Thomas M Marek, Prasanna H GowdaAbstract:Abstract. In 1987-1989, the first irrigated crops were grown on the four large, precision weighing Lysimeters at the USDA-ARS Laboratory at Bushland, Texas, on the Southern High Plains (SHP). Thus began >25-years of full- and deficit-irrigated crop growth, energy and water balance, evapotranspiration (ET), yield and water use efficiency (WUE) studies of major SHP crops, including alfalfa, corn and sorghum for both grain and forage, cotton, soybean, sunflower and winter wheat. Alfalfa studies supported development of the ASCE Standardized Reference ET methodology. The lysimeter effort, led by Terry Howell, Sr., co-designed with Lynne Ebling and Thomas Marek and constructed by Arland Schneider, eventually grew to include a separate lysimeter to study short grass ET, again for the ASCE standard, and a 48-lysimeter facility to study soil type effects on crop water uptake, ET and WUE using monoliths of four soils typical of SHP irrigated soils. The large Lysimeters were managed to be representative of sprinkler-irrigated fields so as to develop crop coefficients used for irrigation scheduling by clients of ET networks developed by Texas A&M AgriLife in collaboration with ARS. In addition, the Lysimeters were used to test and further develop several technologies important to irrigation science, including soil water sensors, eddy covariance and Bowen ratio systems, scintillometers, thermal remote sensing based ET models, and hydrologic and crop simulation models. With the installation of subsurface drip irrigation systems on two of the lysimeter fields in 2013, the Bushland Lysimeters are entering a new phase of advanced irrigation method and management studies.
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Weighing Lysimeters for the Determination of Crop Water Requirements and Crop Coefficients
Applied Engineering in Agriculture, 2006Co-Authors: Thomas H. Marek, Terry A. Howell, A. D. Schneider, G. Piccinni, M. Jett, D. DusekAbstract:Weighing Lysimeters are accurate instruments to measure crop evapotranspiration. Three weighing Lysimeters, consisting of undisturbed 1.5- ×2.0-m surface area by 2.5-m depth cores of soil, were constructed and installed at the Texas Agricultural Experiment Station in Uvalde, Texas. Two Lysimeters, each weighing approximately 14 Mg, were located beneath a linear irrigation sprinkler system and used in the field production of several crops commonly grown in the area. The third lysimeter was constructed and is used to measure reference ET from a well-watered, grass (ETos) located adjacent to the field Lysimeters. Design construction, installation, engineering details and other considerations to ensure acceptable performance of the Lysimeters are discussed. The lysimeter facility was developed to accurately assess crop water requirements of vegetables as well as other field crops grown in the Winter Garden region of Texas. Preliminary detection capability of the scale system is also reported.
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ASIMPLIFIED WEIGHING LYSIMETER FOR MONOLITHIC OR RECONSTRUCTED SOILS
Applied Engineering in Agriculture, 1998Co-Authors: A. D. Schneider, Terry A. Howell, Steven R. Evett, A. T. A. Moustafa, W. Abou-zeidAbstract:A simplified weighing lysimeter applicable to both monolithic and reconstructed soils was developed and tested in two Lysimeters installed at Ismailia, Egypt and one installed at Bushland, Texas, USA. A monolithic lysimeter was used to measure reference grass evapotranspiration (ET) at Bushland because the dense subsoil and calcic horizon of the clay loam soil cannot be reconstructed. The desert sand at Ismailia allowed the use of reconstructed soils for measuring reference ET of alfalfa and ET of field crops. The main lysimeter components are the concrete foundation, deck scale, soil tank and enclosure consisting of a base, a tank and a top. The steel soil tank and enclosure are shop-fabricated, and the scale is commercially available. Field construction consists mainly of excavation, collection of the soil monolith, if needed, and installation of the concrete foundation. Field calibration of the Bushland lysimeter over a 214-mm (8.43 in.) ET range resulted in sy/x = 0.1 mm (0.004 in.) and r2 = 0.9999. Similar calibration of one of the Ismailia Lysimeters over an 80-mm (3.2-in.) ET range resulted in sy/x = 0.02 mm (0.0008 in.) and r2 = 0.9999. In initial tests, the Kimberly-Penman equation overestimated grass reference ET, and the Penman-Monteith equation slightly underestimated grass reference ET for the Bushland environment. Hourly grass ET measured with the Bushland lysimeter agreed closely with hourly grass ET calculated by the 1963 Penman equation.
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Calibration and Scale Performance of Bushland Weighing Lysimeters
Transactions of the ASABE, 1995Co-Authors: Terry A. Howell, A. D. Schneider, D. A. Dusek, Thomas H. Marek, Jean L. SteinerAbstract:Weighing lysimetry is the primary method to directly measure evapotranspiration, and the scale performance of weighing Lysimeters is often affected by wind loading. This study was conducted to calibrate the weighing Lysimeters at Bushland, Texas, and to determine the effects of wind on the measurement accuracy of the lysimeter scales. Applied mass amounts equivalent to 150% of the lysimeter range were applied, and lysimeter scale calibrations were determined. Wind influences were measured by covering the Lysimeters with a rubber sheet to minimize evaporation during an extended period. The Lysimeters were sensitive to mass changes as small as 0.05 mm (450 g), highly linear with less than 1% total error over the 250-mm range (2.25 Mg), insensitive to load distribution on the lysimeter surface, and sensitive to surface pressures created by wind loading. The effects of wind can be minimized with data smoothing but not eliminated. The USDA-ARS weighing Lysimeters at Bushland, Texas, have evapotranspiration measurement accuracy necessary to determine evapotranspiration rates as small as 0.05 to 0.1 mm/h over time periods of 30-min or greater.
Vilim Filipovic - One of the best experts on this subject based on the ideXlab platform.
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experimental and mathematical modeling of water regime and nitrate dynamics on zero tension plate Lysimeters in soil influenced by high groundwater table
Nutrient Cycling in Agroecosystems, 2013Co-Authors: Vilim Filipovic, Radka Kodesova, Dragutin PetosicAbstract:Unlike laboratory experiments, which are mostly performed under controlled conditions, lysimeter experiments generally simulate actual field conditions. This paper focuses on an efficiency of the zero tension plate Lysimeters, which were implanted in silty-clay soils influenced by a high groundwater table. Measurements and following numerical simulations using the HYDRUS-2D model were performed separately for each of 4 years (2007–2010) to assess water flow and nitrate fluxes (applied as NPK or UREA fertilizer). Low efficiency of Lysimeters during the vegetation period was mostly caused by high plant water demand and possible water diversion to the sides when the groundwater table was low. The HYDRUS-2D model was able in some degree to reproduce observed water and nitrate outflows. The water outflow through the lysimeter occurred when the groundwater table was high and greater rainfall events occurred. Water and solute diverged from the plate towards the dryer surrounding soil when groundwater table was low. Pressure head, water velocity and nitrate concentration distributions simulated around the lysimeter plate illustrated that the lysimeter plate had a significant impact on the water regime and nitrate behavior within the soil profile. The lysimeter plate also acted as a barrier for water flow and solute transport also.
