Abstract:
Sri Lanka is a tropical country with two major cultivation seasons, called Yala and Maha. Rice is the major staple food grows under different climate and environmental conditions. Crop models have been found to be very good methods for testing different decision making process and management option in crop cultivation. Agricultural Production Systems Simulator (APSIM) is a best crop model used in present day in several cropping systems. Study was done in Kadaweramulla area of the Kurunegala district
and APSIM crop model was used to evaluate paddy yield under different
water management methods (irrigation only, rainfall only and irrigation+rainfall conditions) to identify water stress condition for paddy cultivation. The crop model used for simulate rice yield under number of dates irrigation supply for each farmer and graphical show yield variation
and simulated water content in management methods. According
the root zone under different water to the results of different water
management options, the simulated yield was higher under the
irrigation+rainfall option compared to other two options because of less
water stress conditions. According to simulate data after increasing number of irrigation days supply for paddy field, soil moisture less fields paddy yields continuously increase and after some point yield try to decrease. Soil moisture condition high paddy fields can see opposite results. Those two
phenomena mainly happened due to water stress condition in the paddy
fields. Soil water content in the root zone is varied in whole life cycle of the rice plant according to the simulation results.
