Abstract:
Gadaref State is one of the major areas that depend on rain-fed agriculture. The main objective of the study was to employ Budget Program to determine the size of rainfall catchments area required to improve Sorghum crop yield in the rain-fed areas of Gadaref, Sudan using water balance (BUDGET) to postulate crop plantation on the computer via exploiting records of the climatologically data of the area for a period of 30 years (1980 - 2009) in addition to the soil and crop data. Evapotranspiration for the crop has been calculated using ETo program. Penman Montieth (FAO) equation, and RAINBO program was used to calculate the probability of rains using the normal distribution. The years were classified according to rain quantities to very wet, wet, normal, dry and very dry years. The monthly rain, minimum and maximum temperature, evaporation, mean wind speed and the mean sun rays were the climatologically data used. The study compared estimated productivity to the actual one and provided the shortage in water quantity for the blank (water stress) and surface runoff and by using these values to calculate the percentage of water catchments areas to the cultivated areas. By using the probability 67% and efficiency factor range between 0.5 to 0.75 as recommended by FAO, the percentage was 3.16:1 to 2.12:1 to each efficiency factor, respectively. And when the efficiency coefficient calculated from the rain quality and evaporation for each year the efficiency factor was found to be 0.74 and C:CA percentage was 2.18:1. By using the probability 67% and the medium value for the water stress the percentage C:CA was 3.8:1. The reservoir capacity is 927 m3/fed.
