231-Irrigation Water Management Using a Dynamic Crop Growth Model.

Abstract

There has been a considerable increase in the irrigated agricultural areas all over the world in the last few decades. The major reason for such an increase can be attributed to growing demand for food by the increasing population. However, this has created a competing environment for water, which is a scarce resource but essential for agricultural production. Hence better water management practices are warranted. It follows that new scientific techniques in agriculture and in irrigation management is to be introduced. Irrigation scheduling under water deficit situation is the challenge before the scientists and engineers. It is known that the sensitivity of any crop to water deficit is not uniform throughout its growth, and therefore it is difficult to take a decision by the irrigation manager on how to distribute the deficit along the intra-seasonal periods of a crop. The practice so far has been either to uniformly distribute the deficit throughout the crop growth or to decrease the cropped area so that full irrigation can be provided. This study proposes the use of ORYZA 2000: lowland rice crop growth simulation model in conjunction with an optimization model to effectively schedule the irrigation releases froni the reservoir in order to achieve minimum reduction in crop yield due to the water stress and also maximise the water use efficiency (crop per drop). The iht.,,i.ated ORYZA 2000: rice crop growth model with an optimization framework for operating a reservoir that irrigates multiple crops in a command area, which aim to minimize the yield reduction due to water deficit for the crop. The model is demonstrated using a case study—Chittar river basin irrigation system, Tamilnadu, India.