Project Number: 6209-13000-013-06
Project Type: Specific Cooperative Agreement

Start Date: Sep 15, 2005
End Date: Sep 14, 2010

Objective:
1) Determine the optimum and additional profitable seasonal irrigation water volumes for five regional seasonal crops (corn, cotton, grain sorghum, soybeans, and sunflower) and soils as affected by precipitation pattern and evaporative demand, within the constraints of expected irrigation capacities (flow rate per unit land area) using models and validation from fields research. 2) Evaluate the effect of differing irrigation supply constraints (hydrologic and institutional under both single-season and multi-season strategies). 3) Development and measurement of soil-and/or plant-based indicators of crop water status for scheduling irrigation. 4) Evaluation of the potential to improve determination of yield sensitivity factors to water deficits for grain crops and cotton incorporating yield component responses. 5) Recommend procedures and strategies to achieve the greatest likelihood of successful deficit irrigation applications in this region.

Approach:
Existing models and irrigated crop simulations (Enwatbal, KSU irrigation capacity simulations, and KSU Crop Water Allocator) will be used to determine the optimum irrigation amount for five summer crops (corn, cotton, grain sorghum, soybeans, and sunflower). Field research from recent, ongoing or new replicated field studies will be used to validate and calibrate the existing results. The effectiveness and sensitivity of various deficit irrigation management strategies to various irrigation supply constraints will be determined. Both hydrologic constraints (declining flow rates, etc.) and institutional constraints (limits on seasonal pumping volumes) will be examined. Several advanced soil-or plant-based indicators that may have merit in scheduling deficit irrigations will be considered and tested in field plots. A concept of clumping will be considered as a management strategy. Existing datasets will be used to determine sensitivity of various yield components to water deficits. Promising strategies will be thoroughly examined before being released for public use.