How do I make the most of limited water? A systematic approach to improvements in efficiency.
(A09-hsiao436441-oral)
Authors:
T. Hsiao* - Univ. of California, Davis
Abstract:
Effective management of scarce water resources requires a systems approach. Starting at the source of water, a cascade of events leads to the final consumption of the water in the production of crops. These events are mostly sequential, with each process step in the sequence having its own efficiency of output per unit of input. Using the simple sequence of conveyance of water from a reservoir to a farm and the application of the water to the crop, it will be shown that the overall efficiency of delivering water from the reservoir to the root zone of the crop is the product of the efficiency of each sequential step. That is, efficiencies of individual process steps are multiplicative in determining the overall efficiency. Thus, improvement in any one of the steps has equal effect in improving the overall efficiency, and the overall improvement is more than the sum of the individual improvements. This approach will be extended to include the subsequent steps of consumptive water use by crop fields leading to the final
product--harvested yield. Important factors considered will include choice of crops, agronomic
practices such as plant density and nutritional status, and irrigation scheduling with emphasis on timing in relation to crop growth stage. Selected cropping systems will be examined and illustrated with sample data. How this principle may aid in deciding which of the efficiency steps in the overall sequence to spend money for improvement will be discussed.
Speaker Information: Theodore C. Hsiao, Univ. of California, Davis, Dept. of Land, Air & Water Resources Universi, Davis, CA 95616; Phone: 530-752-0691; E-mail: [email protected]
Session Information: Monday, November 3, 2003, 3:10 PM-5:15 PM Presentation Start: 4:15 PM
Keywords: water use efficiency; water productivity; crop water use; more crop per drop
