Spatial and temporal variability of irrigation requirement play an important role in crop growth and yield in agricultural systems. Due to erratic rainfall, irrigation water management are critical for sugar cane cultivation, a raw material for sugar production. But irrigation requirement depends on the soil type, climatic condition, and topography and in this regard, there is a limitation in the Arjo-Dedessa sugar factory and the surrounding. The objective of this study was to estimate the variability of sugar cane's irrigation requirement and prepare the spatial map for the Arjo-Dedessa sugar factory and the surrounding area, for an effective agricultural water management. Arc GIS, CROPWAT, and XLSTAT were the materials used. The irrigation water requirement was calculated by using CROPWAT 8.0. For mapping, a linear regression equation was developed between observed data and the station's location. The inverse distance weight map reveals that the irrigation water requirement was in the range of 464.34 ml - 961.57 ml depth of water spatially. It was high in the Northern and low in the Western and Eastern part of the study area. There is more than 50% irrigation water requirement depth difference between Anger and Arjo areas because of the climate variability and altitudinal difference. At high elevation areas, irrigation requirement is relatively low due to high amount of rainfall. The temporal variation of the crop irrigation requirement reveals that it does not require irrigation during May, June, July, August, and September in all parts of the study area.

Keywords: Irrigation, Mapping, ml, Sugarcane, Water depth