The Emerging Imperative to Improve Crop Water Productivity: U.S. Southern High Plains As a Case Study.

In the U.S. there is growing demand for water as the supply diminishes; it is uncertain how irrigated agriculture will fare under these circumstances. The USDA-ERS noted in 2007 that irrigated crops accounted for 55% of U.S. production from 7.5% of the crop acreage. The Southern High Plains is one example where water supply is diminishing and this situation is creating an environment where crop water productivity must improve if farms and communities are to survive in the future. The Ogallala Aquifer supplies water for a significant portion of U.S. irrigated crop production. It has been recognized for several decades that the withdrawal rates from the Ogallala Aquifer greatly exceed recharge for much of the Southern High Plains. Changes in hydrology and water policies are setting limits on the amount of water that farmers can use to irrigate their fields. For example, the High Plains Underground Water District No. 1 is imposing production limits that will limit irrigation to an allotment of 380 mm of water per acre. Thus, the crop water productivity will have to increase to sustain current levels of farm income.  Strategic decisions regarding on-farm resources that improve the integration of dryland and deficit irrigation techniques will be key elements in achieving the goal of increasing crop water productivity and sustaining farm incomes with declining irrigation water availability.