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The irrigation scheduling problem and evapotranspiration uncertainty
Author(s) -
Rhenals Alonso E.,
Bras Rafael L.
Publication year - 1981
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr017i005p01328
Subject(s) - evapotranspiration , irrigation scheduling , irrigation , water resources , agricultural engineering , environmental science , deficit irrigation , irrigation management , water resource management , low flow irrigation systems , farm water , agriculture , water conservation , computer science , hydrology (agriculture) , soil water , engineering , soil science , agronomy , ecology , geotechnical engineering , biology
Scheduling and determining of irrigation water applications are important considerations given limited water resources and increasing concern about agricultural productivity. Past literature has repeatedly been concerned with the influence of the variability of actual evapotranspiration on crop irrigation needs. This work investigates the above issue. A model, based on stochastic dynamic programing, is formulated to maximize net benefits from a crop facing uncertain, correlated evapotranspiration demands. Weekly irrigation decisions are made after observing current soil moisture and available irrigation water, as well as potential evapotranspiration in the past week. The model is similar to the traditional reservoir control algorithms popular in the surface water literature. A case study example indicates that although the model formulation is useful and feasible, the effect of uncertain evapotranspiration on irrigation performance measures is apparently minimal. This work should be of interest to researchers of agricultural management and to those studying the applications and use of operation research techniques in water resources. Computer programs utilized in this paper are available from the authors.