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Intraseasonal water allocation in deficit irrigation
Author(s) -
Bras Rafael L.,
Cordova Jose R.
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/wr017i004p00866
Subject(s) - evapotranspiration , water content , irrigation , deficit irrigation , conditional expectation , environmental science , mathematics , hydrology (agriculture) , irrigation management , statistics , agronomy , geotechnical engineering , biology , ecology , engineering
This paper is concerned with the optimal temporal allocation of irrigation water, taking into consideration the intraseasonal stochastic variation of the crop water requirements and the dynamics of the soil moisture depletion process. Expressions for the soil moisture transition probabilities over a given time period and the first two moments of associated actual evapotranspiration are derived analytically. The conditional probabilities of soil moisture and associated actual evapotranspiration are used within a stochastic dynamic programing (DP) algorithm with rewards being a function of cost and crop yield. The DP algorithm is used to determine optimal control policies at each irrigation decision point, conditional on the state of the system (soil moisture content). Both mean and variance of net benefits are computed. Analytic results are corroborated with a case study example.