|King, Bradley - Brad|
Submitted to: United States Committee on Irrigation and Drainage Conference
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2006
Publication Date: 10/1/2006
Citation: King, B., Stark, J., Love, S., McIntosh, C. 2006. Drought risk management for irrigated potato production in Idaho. In: Proceedings of the U.S. Society for Irrigation and Drainage Professionals Water Management Conference. Ground Water and Surface Water Under Stress: Competition, Interaction, Solutions, October 25-28, 2006, Boise, Idaho. p. 321-330.
Interpretive Summary: Irrigation is required for the profitable production of commercial potatoes in Idaho. However, periodic drought is a fact of life, and can force producers to adopt sub-optimal irrigation practices due to restrictions on water availability which greatly increases financial risk. Drought management planning is necessary to minimize financial loss that can result from water supply shortages. An approach for estimating the risk of a water shortage and associated potential severity on an irrigation district basis was developed to assist producers with drought management planning. The approach requires a minimum amount of hydrologic information and incorporates an irrigation district’s water rights into the estimates using historical water allocation and use data. Relative drought tolerances of six commercial potato varieties were evaluated under four different water restrictive irrigation management schemes. The results highlight how different potato varieties respond to reduced water application. An economic analysis of yields for each potato variety under each irrigation management scheme demonstrates the potential financial impact variety selection can have under drought conditions. These results show that choosing appropriate potato varieties and irrigation management strategies can substantially reduce risk of economic loss during drought.
Technical Abstract: Streamflow in much of the western United States originates as snowfall that has accumulated in the mountains during the winter and early spring. During periods of drought, the water supply for a large portion of irrigated cropland in Idaho is at risk of depletion before the growing season ends. In the case of irrigated potato production, early depletion or limited availability of irrigation water can result in substantial financial loss to a producer due to reduced yield and quality and difficulty in harvesting, handling and storing the raw product. Basin wide estimates of available water supply are provided by Federal and State agencies, however, a given producer’s irrigation water supply can be vastly different due to water rights based on the Doctrine of Prior Appropriation, which allocates water according to a priority date. To minimize financial risk under drought conditions, potato producers need realistic estimates of available water supply well in advance of the growing season and crop management guidelines for economical potato production under limited water supply. To address this need, a suite of decision support materials was developed to assist producers with drought risk management planning. The decision support materials include risk assessment of an irrigation water supply shortage on an irrigation district basis that is updated monthly, January through April, potato variety drought tolerance comparisons, guidelines for irrigation and nitrogen management with limited water supply, and economic comparisons of water management strategies. These decision support materials are disseminated through a website.