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Reports

Water Management

Statistical and spectral approaches to automate hot and cold pixel selection for surface energy balance based evapotranspiration mapping   A novel statistical-spectral methodology for the selection of hot and cold end member pixels is developed to make the application of single source energy balance models more robust, and successfully applied. Results indicated that the proposed methodology performed better than existing methods.   

Optimal irrigation based on ET estimates for new stress tolerant corn hybrids in Texas High Plains   Increasing irrigation beyond 75% of evapotranspiration or increasing plant density in excess of 30,000 per acre did not increase corn silage yields.   

Yield and water use of stay green and senescent varieties of sorghum grown in four soils under limited irrigation   Under extreme water and heat stress that occurred in 2011, a stay green variety of sorghum produced significantly larger grain yields due to a larger number of seeds per square meter.   

BIOTIC irrigation method for controlled deficit irrigation on cotton.   In a production setting, continuous canopy temperature provided a potentially useful validation of the accuracy of ET estimates that might help to manage deficit irrigation.  

Can Deficit Irrigation Scheduling Be Improved for as Little as $5.00?   Stress Degree Hour (SDH) irrigation scheduling more closely approximates scheduling by Crop Water Stress Index (CWSI) than does the Stress Time (ST) irrigation scheduling approach.  

Irrigation Systems

Completion of Identification of Water-Use Efficient Peanut Genotypes, and Estimated of Effects of Reduced Water Usage and Potential of Improved Water Use Efficiency in Peanut   Analysis of the U.S. peanut minicore collection identified accessions with significantly greater tolerance to drought and heat stress than possessed by check varieties. Runner accessions with yields >25% higher than checks were identified, as well as accessions with improved harvest indices. Economic analysis demonstrated that it is possible to grow peanut profitably under reduced irrigation using current varieties; however, varieties developed for improved profitability under reduced irrigation are needed.   

Field Scale Subsurface Drip Irrigation Interval Effects on Cotton Production   A three-year study showed subsurface drip irrigation (SDI) at 7-day intervals did not reduce cotton lint yields compared to 0.25- and 2-day applications. Longer SDI intervals could simplify irrigation systems thereby lowering initial cost without causing production problems.  

Cross Cutting Soil Water Sensing System   A waveguide-on-access-tube (WOAT) system for measuring soil water content and bulk electrical conductivity to user-chosen depths in 0.2-m increments using time domain reflectometry (TDR) was invented, tested in the laboratory and field with positive results, and a patent application submitted.  

Performance evaluation of pressure regulated in-canopy center pivot nozzle packages   Pressure regulators selected from older center pivot nozzle packages at third and last spans performed well under test conditions. The pressure regulators for an entire system were also tested; a number of regulators located near the pivot point were not functioning properly.   

Sensors to improve irrigation system technology and water use efficiency   A reliable and economical wireless infrared thermometer can be developed from off-the-shelf components. Normalized vegetative indices calculated from wireless multi-band prototypes were useful in distinguishing between soil and vegetation which will aid in irrigation automation.  

Economics

Impacts of the Ethanol Industry on the Southern Ogallala Region   Ethanol plants in the Southern Ogallala generate considerable economic activity in local economies. Comparison of socioeconomic benefits for the production of ethanol versus irrigated crop production using equivalent water resources indicates that ethanol production generates much larger employment.  

Economic and Policy Implications of Underground Water Use in the Southern Ogallala Region-FY07 (Objectives EAI 1.3.d).   Some form of long term water use restriction is necessary in order to achieve meaningful water savings. Adoption of improved biotechnology or irrigation technology without restrictions will not save water. Temporary restrictions have little impact in the long run and should not be pursued.  

Economic and Policy Implications of Groundwater   A two-year study on groundwater utilization in Southern Ogallala Aquifer indicates that without policy intervention, the regional average level of saturated thickness would decrease more than 50% and most irrigated cropland would be converted to dryland by the end of the 60-year planning horizon.   

CAFO and Processing Industry

Freshwater Usage and Wastewater Utilization at Texas High Plains Open Corral Dairies   A two-year study of water usage at a Texas High Plains dary has found that on average, total water use was 234 L hd-1 d-1, while average drinking water consumption was 76 L hd-1 d-1. Of the total used, 27% was reused for crop production. This data provides guidance for water planning authorities.  

Water Use by Western Kansas Dairies   Among eight dairies located in western Kansas, freshwater usage was 35% less in those using a drylot system compared to freestalls.   

Numerical Simulation of the Air-Mist Spray Chilling of Beef Carcasses for Conservation of Water Usage   Spray impaction higher than 95% occur when spraying droplets larger than 0.040 mm from a distance of 0.15 m or larger than 0.060 mm from a distance of 0.3 m. Cooling enhancement 5 times that of air occurs for droplets between 0.010 and 0.020 mm.  

Production Systems

Spatial Interpolation of Daily Evapotranspiration (ET) Data in the Texas High Plains   Commonly used interpolation (inverse weighted, spline, and kriging) methods and one new method (machine learning with optimization algorithm(s)) were evaluated for mapping reference ET in the Texas High Plains. Thin-plate spline models increased accuracy of the daily ET maps.  

Perennial grasses for the Texas South Plains   Alamo switchgrass yielded most among 13 grasses, then WWB Dahl and Caucasian old world bluestem. Low irrigation (4.3 inches annually) yielded 15 to 75% above dryland, but 8.7 inches of irrigation per year had minimal impact on further increases.  

Quantifying impacts of limited irrigation on soil carbon sequestration in no-till systems   Application of irrigation water increased soil organic carbon (C) concentration in the top 4 inches of soil at Garden City, KS, but not at Tribune, KS. Irrigation had, however, no effects on soil C fluxes in the short term.   

Growing forage sorghum during fallow of WSF rotation for increased cropping intensity   Wheat-Sorghum-Fallow (WSF) rotation stores fallow precipitation as soil water to increase yield, but precipitation was crucial to establishment and growth of dryland forage planted during fallow to intensify the WSF rotation by using spring runoff.  

Perennial Grasses for the Texas South Plains: Species Productivity and Irrigation Response   Alamo switchgrass yielded most among 13 grasses, then WWB Dahl and Caucasian old world bluestem. Low irrigation (4.3 inches annually) yielded 15 to 75% above dryland, but 8.7 inches of irrigation per year had minimal impact on further increases in forage yields.  

Hydrology/Climatology

Regional Climate Forecast   Coupled groundwater, economic and crop models have been developed for studies in the Ogallala Aquifer. The data for these studies have been gathered and stored in GIS data models. Results illustrate crop choices, changes in groundwater elevation, and total revenue.  

Assessing Impact of Climate Variability and Climate Change on Crop Production in Ogallala Aquifer Region.   Ogallala region will experience warmer temperatures and temporal shifting of precipitation patterns. In future climates, productivity of grain sorghum will decrease, while winter wheat will increase. Crop management decisions and genetic advancements can minimize yield losses.  

Evaluating 90-day Forecasts for Cropping Strategies   If accurate 90-day forecasts can be developed, then we posses the management knowledge to position crops to reduce the impacts of crop stress on yields.   

Understanding Climate Variability for Improving Management Decisions   Region would experience 4-6 C increase in the maximum temperature and highly variable rainfall. Variations in minimum temperatures would be more profound with an average increase of 5-7 C. A sharp decline in grain sorghum production; however, wheat showed a significant increase in yield.   

Modeling Aquifer Recharge   During 2006-2008, we monitored the water budget in ten playas on the Texas High Plains. Seepage rates ranged from 1 to 20 mm/d and varied significantly between locations and inundation events. Playas surrounded by cropland drained an average of four times faster than playas in native grassland.   

Education Training

Evaluating Alternative Meteorological Data Sources for Potential Use in Irrigation Management   Carefully selected alternative data sources can complement agricultural weather station networks, provided data and siting biases can be addressed adequately through calibration and associated data techniques. Machine learning methods can be helpful in filling spatial data gaps.  

Educational video and slide show content addition to OAP and TXHPET Web sites   A two-year project to develop educational digital media addressing Ogallala water use issues for Texas High Plains agricultural producers has demonstrated that online outlets are an effective means for dissemination.   

Cotton irrigation for sustainable production in a thermally limited region   Irrigation of 5 to 7 inches, depending on rainfall, produced 2.5 bales of cotton in Southwestern Kansas. Factors limiting cotton are total growing degree days and hail storms.   

Field Evaluation of Center Pivot Nozzle Package Application Intensity   A tipping bucket rain gauge was added to the data collection set during linear and center pivot uniformity evaluations. The collected data are consistent with industry ranges of application rates for particular nozzles and configurations.  

Training, user feedback, testing, economic impact, and revisions of the Crop Water Allocator and Crop Yield Predictor models   These models are useful and user-friendly irrigation resource management planning tools. Impact of the products can be maximized by incorporating user feedback, expanding the regional applicability, and supporting adoption through promotion, training and technical support.   

Last Modified: 04/22/2012