Analisis Kebutuhan Irigasi Padi Berdasarkan Metode KP-01 dan CROPWAT 8

Abstract

There are two different methods for determining irrigation water requirement for paddy, KP-01 and CROPWAT 8, by using climate data. The object of this research was irrigation water requirement. The purpose of this research was to analyse paddy irrigation requirement based on KP-01 method and CROPWAT 8. Those methods have different criterias to determine irrigation water requirement. That can be shown from parameters used such as reference crop evapotranspiration (ETo), effective rainfall, land preparation, crop coefficient and physical soil data. According to the two methods, the average ETo value in KP-01 method was higher than in Penman-Monteith method (CROPWAT 8), 123.61%. Ratio of effective rainfall percentage KP-01 to CROPWAT 8 was 42.91%. Water requirement for land preparation using CROPWAT 8 was calculated from the water requirement during scheduling pre puddling and puddling, while KP-01 used a method developed by Van de Goor and Zijlstra. Water requirement for land preparation using CROPWAT 8 method was larger than KP-01. Paddy irrigation water requirement from CROPWAT 8 calculation was generally lower than that of KP-01, because the effective rainfall (in CROPWAT 8) have fulfilled crop water requirement.