Deficit Irrigation of Row Crops Provides Drought Mitigation, Environmental Protection, and Optimized Yield in Humid Regions

In the Southeastern United States, irrigated agriculture has grown by 60% or 4.2 million acres over the last 20 years due to droughts and the need for row crop producers to insure high yield against the high cost of production. The rapid growth of irrigation in conjunction with population growth in the southeast has led to water conflicts during drought periods. Deficit irrigation of row crops is an effective way to mitigate drought in humid regions by applying less water to the majority of irrigated acres in the Southeastern US. The purpose of this project is to promote deficit irrigation for humid regions as a means to apply less water for drought mitigation, to optimize yield by better utilization of rainfall, and to improve the sustainability of row crop production. Deficit irrigation in humid regions means not supplying the crop with all the water it could use and not keeping the soil-water profile at field capacity, a condition known as full irrigation. Deficit irrigation makes use of rainfall while full irrigation does not. This is because in a full irrigation scenario, there is no or little storage capacity remaining in the soil and additional rainfall could saturate the soil, leach fertilizer, and/or run-off the soil surface. Five tasks will be undertaken to advance this goal: (1) finalize the strategy for deficit irrigation of cotton in variable water holding capacity soils; (2) start a deficit irrigation demonstration for soybeans similar to the cotton irrigation demonstration that tests three start times and three irrigation rates; (3) work with producers to implement deficit irrigation strategies; (4) calculate and compare indicators of environmental sustainability from data collected at the research station and on-farm sites; (5) extend project results via fact-sheets, websites, producer workshops/regional meetings, field days and on-farm demonstration sites.