MODEL TO ESTIMATE IRRIGATED CROP YIELD USING SEQUENTIAL WATER BALANCE: PRESENTATION AND APPLICATION

Abstract

The use of computers resources for planning rational water use in irrigated systems is even more frequent in the modern technical agriculture. Due to the constant improvements of those resources, it is important to update the developed softwares, specifically in the irrigation area, by incorporating the most recent technologies developed in this segment. The objective of this work was to elaborate an easy to handle computation tool, which allows freedom to act in relation to the used criteria in irrigated farming, and show an application example. The model was developed to help decisions taking about the irrigation management level to be adopted, based on a rainfall forecast simulated on a historically sequence and the maximum crop yield expected for a specific irrigation moment. As input data, the software need (i) regional climatic parameters, (ii) characteristics of irrigated crop, (iii) soil properties and (iv) water management adopted. Based on available data, user can choose among several methods of calculate the potential evapotranspiration. By running the program with data from Piracicaba - SP region, where there is not a significant water deficit along the year, no difference was shown among the different irrigation moments, but it is to suppose that in dryer regions the contrast among them will be more significantly. The developed tool can be useful for the user because it is flexible regarding to the different climatic regions of the country.