Rainfall probability analysis for crop planning in Bilaspur region of Chhattisgarh plain

Probability analysis of rainfall offers a better scope for predicting the minimum assured rainfall to help in crop planning in rainfed regions. An attempt has been made to evaluate rainfall distribution patterns i.e. weekly, seasonal and annual rainfall, based on 12 years (2001–2012) data of Bilaspur, Chhattisgarh in the year of 2014 at BRSM College of Agricultural Engineering and Technology, Indira Gandhi Krishi Vishva Vidylay, Mungeli, Chhattisgarh. Expected weekly, monthly, seasonal, and annual rainfall values at different probability levels were determined by using Weibull's formula. The analysis showed that at 75% probability level the highest rainfall 39.7 mm received by 28th week and lowest rainfall of 39^th week i.e. 0.0 mm was considered. The expected rainfall amount at 75% probability is more than 200 mm in the months of July and August. In cropping season analysis of rainfall at various probability levels, it was found that the values of rainfall reduced with increase in the probability level. The highest rainfall received at 75% probability levels during kharif season was 784.0 mm which contributed as the 65% of average annual rainfall. The values of annual rainfall were estimated 974.0, 1008.7, 1027.7, 1047.9, 1093.3, 1146.9, 1212.5, 1297.0, 1416.3 and 1620.0 mm at 90, 80, 75, 70, 60, 50, 40, 30, 20 and 10% probability level, respectively. At 70% probability enough rainfall is available for growing high value fruit crops although supplemental irrigation is required for kharif crops.