Limited Irrigation management
Corn: Corn is the dominant irrigated crop in western Kansas. With declining water levels in the Ogallala aquifer the number of low capacity wells is increasing. Many of the low capacity wells cannot supply peak irrigation water needs for corn during the summer and must rely on soil water reserves to mitigate the crop from water stress especially during the critical reproductive growth stages. Limited irrigation management strategies e.g., growth stage based irrigation timing, no-till management, residue management, pre-irrigation, herbicide use and crop rotations e.t.c., can help stabilize yields and improve crop quality and enhance profitability for producers with low capacity wells. Emerging transgenic drought tolerant (DT) corn technologies could offer opportunities to sustain irrigated corn production especially during moderate drought years. However, more research is still needed to understand and quantify growth, development, and response to water of transgenic DT corn in semi-arid environments. The objectives are to: 1) compare differences in yield, yield components and water productivity of DT corn with a transgenic trait with a check hybrid under different irrigation timings and well capacities, 2) compare net returns from DT corn with a transgenic trait and a check hybrid to determine an optimum irrigation management strategy and 3) compare physiological responses to limited water between DT corn with transgenic traits and a check corn hybrid.
Forage Sorghum and triticale: A significant proportion of forages produced in the Central Great Plains are produced under irrigation. Reduced well capacities coupled with frequent droughts have made it difficult for forage producers to meet demand from the region’s beef cattle industry. While grains can be brought in from other states within U.S. Grain belt, forages have to be produced locally due to their low bulk density and expensive transportation costs. This project will develop integrated limited irrigation management strategies for forage sorghum and triticale production with limited water. The objectives are to: 1) compare yield and forage quality of BMR and non-BMR forage sorghum varieties under limited irrigation management, and 2) compare yield and forage quality of different varieties of triticale under limited irrigation and also develop production functions for the selected forages for the Central Plains region.
Canola: Canola has received considerable attention as an alternative to wheat in the crop rotation. Winter canola is an excellent option for the Central High Plains region due to: 1) uses water during the winter, 2) lower water requirement compared with corn, and 3) greater market value per unit of yield produced due to its multiple uses (biodiesel, oil, feed, etc.). There are also benefits to including canola into the rotation such as improvements in pest management, weed control and soil physical properties. Maximizing the benefits of this crop will require a better understanding of how to produce canola with limited water. This study will generate information on canola response to water, crop coefficients, physiological and phenological indicators of growth and development under limited water. The objectives are to: 1) evaluate water productivity and yield stability of canola genotypes (open pollinated varieties –OPVs-, and hybrids) under different irrigation levels (0%, 25%, 50%, 75%, and 100% of ET), 2) evaluate the effect of irrigation termination during the season on yield and quality, and 3) develop a model for simulating canola yield under varying water levels to facilitate economic analysis for canola production under limited irrigation.
Precision irrigation technologies
Integrated Sensor-Based Water Management for Corn: Timing of limited irrigation events is critical. Traditionally timing of irrigation events has been based on the producer’s perceptions of plant water needs. However, as well capacities dwindle, precision irrigation management will be critical. Basing irrigation management decisions on integrated monitoring of the soil-plant-atmosphere system can minimize the uncertainty in irrigation scheduling that mighty result from using only one type of feedback. This approach is expected to enhance the producer’s confidence in using sensor-based water management technologies to minimize crop water stress especially at critical growth stages. The project goal is to develop best management practices for using integrated soil water sensors, plant canopy temperature sensors, and weather-based approaches for improving irrigation scheduling. The objectives are to: 1) compare grain yield, crop water use (ETc), and water productivity for drought and conventional corn hybrids irrigated using different sensor technologies and feedback combinations, and variable rate irrigation technology and 2) develop baselines for using canopy temperature sensors.
Coordinated water and nutrient management
Conserving productivity of our land resources is critical for sustainable agricultural production. Monitoring variables such as electro conductivity (EC) in the vadose zone could allow us to optimize limited irrigation water management especially in semi-arid environments where precipitation might not be sufficient to provide adequate leaching of salts out of the root zone. In addition, low well capacities might not provide sufficient water to provide a leaching fraction. The objective of this project will be to use EC in conjunction with soil water measurements to optimize irrigation water management for corn and other crops.
Agro-hydrological modeling of crop response to limited water
Dynamic crop simulation models such as those found in the Decision Support System for Agrotechnology Transfer-Cropping Systems Model (DSSAT-CSM) can play a role in assessing costs and benefits of alternative irrigation management strategies. Modeling of limited irrigation can allow for comparison of alternative irrigation management strategies in a much more efficient way in terms of time and cost compared to a field experiment in some situations. The goal of this project is to evaluate the ability of the DSSAT-CSM to reproduce yield, ET and biomass from a long term (10 year) limited irrigation cropping system study. The objectives are to: 1) compare simulated and measured yields and ET of corn, grain sorghum, and wheat under different irrigation water levels, 2) apply the calibrated model to evaluate the costs and benefits of different irrigation timing and amount management strategies.