Project Number: 5402-13000-007-00
Project Type: Appropriated

Start Date: Feb 14, 2012
End Date: Feb 13, 2017

Objective:
1. Quantify crop physiological and yield response to water stress at different growth stages. 2. Develop real-time crop coefficients based on canopy temperature and reflectance for irrigation scheduling. 3. Determine and quantify and understand the causes of variability in crop water productivity to improve yield predictions and decision making. 4. Determine the dissipation and movement of herbicides applied to soil under deficit irrigation.

Approach:
Irrigated agriculture plays a critical role in meeting global food needs. Declining irrigation water supplies threaten the sustainability of irrigated agricultural production in the Great Plains, the U.S. and worldwide. Projected increases in temperature, evaporation, and drought frequency with climate change magnify this concern. The aim of this research is to provide fundamental information and tools to optimize crop production with deficit irrigation and sustain irrigated agriculture under limited water supply. Deficit irrigation supplies less water than crops need to maximize yields, with the goal to increase net returns per unit of water. However, mechanisms of crop response and water savings under deficit irrigation remain poorly understood. We will determine the effect of timing and severity of deficit irrigation on evapotranspiration, crop physiological response, and crop productivity using corn and sunflower as models. With this information, we will develop recommendations on how to time irrigations to maximize crop yield per unit water consumed and allocate limited irrigation on a farm. We will also develop a method to schedule deficit irrigation using measurements of crop ground cover and canopy temperature. As part of a multi-location project, we will develop methods to apply experimental results like ours throughout the western U.S. and areas of the world facing similar threats. We also will ensure that weeds will not hinder deficit irrigation success by determining the herbicide efficacy and environmental impacts in these systems.