Year3: Irrigating the Soil to Maximize the Crop # An Approach for Wheat to Efficient and Environmentally Sustainable Irrigation Water Management in Kentucky

The importance of irrigation and related research has been pointed out in the original proposal. Here we i) provide the objectives, ii) describe progress and iii) explain our plans for year 3. The purpose of this project is to develop a strategy for deriving a map of functional soil water characteristics based on easily obtainable land surface observations. The objectives are • to derive a field-scale characterization of soil hydraulic properties for better irrigation management, • to implement this information and sporadic soil and crop measurements into a computer model for describing the annual water status in different zones across the field while taking into account crop growth, and • to evaluate different sources of land surface remotely sensed information as a basis for upscaling detailed information and knowledge to improve irrigation management at a regional scale. In spring of 2016, a major step was the installation of a wireless sensor network for measuring soil water status at 48 locations and three depths in the main experimental field at Hillview Farms (Trevor Gilkey, Princeton). Moreover, soil nitrogen, wheat NDVI, and leaf area index were measured as well as different satellite remote sensing images. Soil core samples were taken for soil hydraulic property measurements. One key observation was that in clayey zones of the field, we do not get sufficient quantities of water into the ground once the soil has become too dry at the surface. Consistent with the farmer’s observations, surface runoff is occurring under both natural rainfall as well as irrigation in the clayey zones of the field. Our attempts in year 3 will be based on developing an irrigation strategy to overcome this problem. One potential solution to this problem may be to reduce the rate and increase the frequency of irrigation runs. We will also continue to collect soil core samples to measure soil water storage properties and water permeability of the soil under different moisture conditions. These measurements are relevant for the computer simulations (objective 2). We ask for support at a total amount of $12,085 (= 25% of project total in year 3).