Assessment of plant available soil water on producer fields in western Kansas (original) (raw)
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Agricultural Water Management, 2019
The increasing pressure on water resources in Nebraska-US and other agricultural areas requires the implementation of innovative tools and solutions for the governance of water resources and the analysis of water use efficiency. In this vein, this paper presents the application of a remote sensing based soil water balance for the study of water use in agricultural areas. The specific objectives were the identification of the temporal and spatial behavior of the irrigation water use based on the quantification of the water use deviation (irrigation water applied minus irrigation water requirements), as the main indicator and the comparative analysis of the irrigation productivity (crop yield under irrigated field minus crop yield under rainfed condition per volume of water applied by irrigation), WP i , water productivity (harvestable grain per total volume of water applied considering precipitation plus irrigation), WP, and finally water productivity based on evapotranspiration (harvested grain per total volume of water evapotranspired), WP ET , in the various management zones analyzed. Additionally, we examined the impact of soil types, local weather and irrigation system (center pivot and furrow irrigation) on these indicators. The study was carried out in three Natural Resources District (Tri-Basin, Central Platte and Lower Niobrara) across Central Nebraska for the period 2004-2012 and comprised over 2000 irrigated corn fields per year. Crop water requirements were estimated using the reflectance-based crop coefficient approach developed in previous research (see Campos et al., 2017) and the field data were reported for each field monitored through cropland data layer by National Agricultural Statistics Service of USDA. The difference between modeled irrigation water requirements and field level irrigation application was significant (p < 0.001) being the water use deviation in generally positive (over irrigation). These results were consistently higher for furrow irrigated fields during the whole analyzed period, reaching up to three times more water applied compared to the required amount. This was expected as surface irrigation systems typically require a higher application depth. This trend changed for the central pivot irrigated fields depending on the climatic conditions, especially in dry years. The analysis of the water use deviation with respect to soil types and weather conditions revealed that the water use deviation is not justified by the biophysical conditions alone. The estimated values of WP and WP i for furrow system was lower compared to center pivot in both NRD's reaching the maximum value of 1.37 kg m-3 and 3.06 kg m-3 for WP and WP i in Tri-basin respectively for center pivot. In general, the results suggested potential to improve water management in these NRDs in Central Nebraska and reduce pumping potentially saving groundwater resources for drought years and other uses monitoring soil type, weather data and switching to sprinklers system.
Water Application and Irrigation Efficiencies in Selected Fields in the Arkansas River Valley (CO)
2005
During the 2004 growing season (May 20 - August 20), irrigation activi- ties were monitored along the 160-mile stretch between Fowler and Holly in Colo- rado's Lower Arkansas Valley. Fifteen fields were monitored to evaluate ongoing wa- ter use practices with an eye toward potential improvement. Ten of the monitored fields were surface irrigated, two by center pivot sprinkler systems and two by sub- surface drip irrigation systems. Where possible, measurements of total irrigation wa- ter inflow and outflow were made. Infiltration tests were conducted, and water was sampled for salinity, phosphate, and nitrate concentrations. To carry out these activi- ties, flumes (Cutthroat and Parshall), existent flow-meters (for sprinkler and drip sys- tems), GPS units, conductimeters, and pressure transducers (water level sensors) were employed. As more than one growing season is required to establish an accurate baseline and understanding of the region's water use practices, the results...
Soil water recharge in a semi-arid temperate climate of the Central U.S. Great Plains
Agricultural Water Management, 2010
The amount of soil water at the beginning of the growing season has a large impact on crop yields in rainfed agriculture, especially in semi-arid regions and in years with below-average rainfall in more humid climates. Robust algorithms are needed to estimate soil water storage before planting to aid crop management decisions. The main objectives of this paper are to investigate soil water recharge during the non-growing season (October 20 to May 1) in a semi-arid, temperate ecosystem in southcentral Nebraska (USA) and to evaluate empirical models to estimate soil water content at the beginning of the summer-crop growing season. A database of soil water content measurements collected over 5 years at nine locations in south-central Nebraska was used to estimate available water-holding limits in the soil profile and to determine the change in available soil water during the non-growing season.
Open Journal of Soil Science, 2020
Crop production in the Texas High Plains is shifting from irrigated to dryland due to the increase of the depth to the water table from the Ogallala aquifer in regions where the saturated thickness of 9 m, the minimum to sustain irrigation, has been reached. Our objective was to use the mechanistic model ENWATBAL to evaluate the daily and annual water balance for three scenarios of rainfall in this region, a dry (189 mm), an average (449 mm) and a wet (669 mm) year. These three scenarios were applied to two major soil series of this region, Pullman and Amarillo. In all simulations, we used hourly input weather data for a location near Lubbock, Texas and used measured soil hydraulic properties to simulate the water balance for each soil series and the three rainfall scenarios. Results showed that in years with average and wet rain, storage of rainfall occurred in the Pullman but not in in the Amarillo soil series. However, storage of water could be enhanced by combining furrow dikes with minimum tillage along with crop covers that provide a surface residue. The implications of our results for dryland crop production in the semiarid climate of the THP suggest that for years with average and wetter rainfall soils in the Pullman series could store water that would be available for crop use. However, this was not the case for the Amarillo soil series and these soils represent a higher risk for dryland crop production.
Technical Note: Development of Water Usage Coefficients for a Fully Watered Tallgrass Prairie
Transactions of the ASABE, 2008
An irrigation study was conducted from 1991 to 2000 at the Konza Prairie Biological Station (KPBS) Long-Term Ecological Research (LTER) site, near Manhattan, Kansas, to provide a better understanding of how the prairie ecosystem uses and dispenses water over the growing season. The irrigation transect was established on an annually burned portion of the 3,500 ha preserve of native tallgrass prairie in 1991. Irrigation transects created a water gradient over the topographically distinct upland and lowland areas of the experimental site. In order to calculate the plant water coefficient (crop coefficient) for the prairie ecosystem, the site was instrumented to measure soil moisture in 1994, and a water balance was performed at the fully watered locations on the irrigation transect to calculate actual evapotranspiration (ET c). These values, along with reference evapotranspiration (ET r) data calculated using the modified Penman equation, were used to determine the plant water usage coefficient based on the following relationship: ET c = ET r × K c × K sm , where K c is the plant water usage coefficient, and K sm is the soil moisture coefficient. For fully watered sites, the plant water usage coefficient is the ratio of ET c /ET r , since K sm = 1.0 because of ample water. Results indicated maximum plant water usage coefficients of 1.32 in the fully watered locations, similar in magnitude to the crop coefficients of warm-season agricultural crops (ET r is alfalfa based). Over the season (June 1 to September 30), tallgrass water usage was below the reference crop water use, with an average growing season coefficient of 0.90.
Fuel and Energy Abstracts, 2011
Modification of land cover systems is being studied in subsurface drained Iowa croplands due to their potential benefits in increasing soil water and nitrogen depletion thus reducing drainage and NO 3 -N loss in the spring period. The objective of this study was to evaluate the impacts of modified land covers on soil water dynamics. In each individual year, modified land covers including winter rye-corn (rC), winter rye-soybean (rS), kura clover as a living mulch for corn (kC), and perennial forage (PF), as well as conventional corn (C) and soybean (S), were grown in subsurface drained plots in north-central Iowa. Results showed that subsurface drainage was not reduced under modified land covers in comparison to conventional corn and soybean. Soil water storage (SWS) was significantly reduced by PF treatments during the whole growing seasons and by kC during May through July when compared to the cropping system with corn or soybean only (p < 0.05). Treatments of rC and rS typically maintained higher SWS than C and S, respectively, during the 3 years of this study. In the spring during a 10-15-day period when the rainfall was minimal, SWS in plots with rye, kura clover, and forage decreased at a significantly higher rate than the C and S plots which were bare. Estimated evapotranspiration (ET) during this period was significantly higher in rS, kC, and PF treatments than C and S. The results of this study suggested that significantly higher ET and similar drainage for modified land covers may increase water infiltration, which would be expected to reduce surface runoff thus to decrease stream flow. Because subsurface drainage reduction was not seen in this study, impact of modified land covers on NO 3 -N loss needs further investigation.
Agricultural Water Management, 2018
Considering ground water pumping restrictions and unpredictable amount of water available for irrigation from year to year, Nebraska Panhandle producers are facing a challenge to reduce their irrigation water usage and practice deficit irrigation. Among irrigated crops in the region, dry bean (a major cash crop and critical to crop rotation systems) has relatively low water use and is capable to withstand periods of stress. Consequently, two experiments within six consecutive growing seasons (2010-2015) were conducted to determine the impacts of multiple irrigation scenarios (full irrigation, deficit irrigation, and rainfed) and two soil surface conditions (bare soil versus crop residue) on dry bean production, irrigation water use efficiency, and temporal soil water dynamic within the crop root zone. Dry bean yield ranged from 0.41 to 4.07 Mg ha −1 during the six years of the study (2010-2015). The results (2012-2015) indicated that reducing irrigation water by 25% on average increased irrigation water use efficiency (I WUE) by 26% and only caused 6% yield reduction in relative to the full irrigation treatment scenario. However, applying only 50% crop evapotranspiration requirement (ETc) resulted in significant yield reduction (30% reduction on average) in 5 out of 6 years compared to the full irrigation treatment (p < 0.05). Our results indicate that temporal in-season rainfall and ETc demand variabilities along with the per-season soil water content status should be carefully analyzed in order to target the appropriate growth stage(s) for more severe deficit irrigation scenarios. When pre and early season rainfall was abundant deficit irrigation treatments imposed before flowering outperformed treatments targeting after flowering. However, under normal and dry conditions yield decline was more pronounced due to severe early season (before flowering) water stress compared to late season (after flowering) water stress. In two of three years plots with bare soil significantly (p < 0.05) outyielded plots covered with residue. Average yield across irrigation treatments was 14% lower for plots with residue cover (average yield: 2.15 Mg ha −1) compared to bare soil plots (average yield: 2.51 Mg ha −1). Overall, the dynamic of soil water content within root zone and I WUE in plots covered with residue was similar to that in bare soil plots across irrigation treatments throughout the growing seasons.