Use of agrometrological data to calculate irrigation requirement

Abstract

IRRI-CLAC is a software developed by the Central Laboratory for Agricultural Climate (CLAC) aiming at calculating either daily irrigation requirement or irrigation scheduling for a given growing season. The software is divided into three major screens. The first Screen deals with the crop groups that include vegetables, fruits, field crops and greenhouses. Each group include a list of crops belonging to it. Knowing the plant age, or planting date, the program picks a crop coefficient (Kc) and root depth as a function of plant age. The second screen is related to the location and includes the farm area and the nearest weather station to calculate the potential evapotranspiration (ETo) utilizing one of ten different equation according to the availability of weather parameters. It also includes an options to select soil type select soil field capacity and permanent wilting point. The program then calculates the maximum amount of water that could be given to fill the soil down to a given root depth. The program can estimate the frequency and amount of water should be given to a certain crop at a certain location according to plant soil and crop age; i.e. how much and how often to irrigate. The last section is related to the irrigation system type, efficiency and discharge per unit length as well as distance between laterals. This section allows the program to estimate the duration of irrigation, i.e. how long to irrigate.