Estimating crop yields and production by integrating the FAO Crop specificWater Balance model with real-time satellite data and ground-based ancillary data

An operational crop yield model was developed by introducing realtime satel lite imagery into a Geographical Information System (GIS) and the Crop Spec ific Water Balance (CSWB) model of the Food and Agriculture Organization (F AO). Input databases were developed with three different resolutions; agro- ecological zone (AEZ) polygons, 7.6 km and 1.1 km pixels; from archived sat ellite data commonly used by Early Warning Systems (EWS) to simulate maize yield and production in Kenya from 1989 to 1997. Simulated production resul ts from the GIS-based CSWB model were compared to historical maize producti on reports from two Government of Kenya (GoK) agencies. The coefficients of determination (r(2)) between the model and GoK district reports ranged fro m 0.86 to 0.89. The results indicated the 7.6 km pixel-by-pixel analysis wa s the most favorable method due to the Rainfall Estimate (RFE) input data h aving the same resolution. The GIS-based CSWB model developed by this study could also be easily expanded for use in other countries, extended for oth er crops, and improved in the future as satellite technologies improve.