OPTIMAL SCHEDULING OF IRRIGATION

Abstract

Irrigation is artificial application of water to soil for purpose of crop production. For obtaining the potential crop yield, the applied irrigation must, be adequate to elimi- nate the water stress in the root zone and also must meet the leaching requirement to keep the soil salinity below the tol- erance level of crop. However the total irrigation water that a project can supply is always limited. This inevitably leads to a certain loss of crop yield due to water tress and/or ex-cessive soil salinity. Our aim today is to make the best use of the available water to increase agriculture production per unit volume of water per unit area of crop land per unit time. This can be accomplished by an optimal scheduling of irriga-tion with an objective of minimizing the loss of yield on acc-ount of water stress and salinity. In the present study a mathematical model to simulate water balance and salt accumulation in the root zone has been presented. The model is capable of providing the estimate of the crop yield for a given irrigation schedule. This model has been linked to a non-linear optimization programme to ob-- tain the optimal irrigation schedules to minimize the loss of crop yield due to soil water stress and soil salinity. The model can also be employed to arrive at the crop response func- tions.