Analysis of Rainfall Probabilities for Strategic Crop Planning in Raipur District of Chhattisgarh State

Abstract

Rainfall data of recent forty three years (1971-2013) of Labhandi station, Indira Gandhi Krishi Vishwavidhyalaya Raipur, Chhattisgarh was analysed with the method of incomplete gamma probability. The data revealed that the average rainfall of labhandi station is 1202 mm spread over 61 rainy days. Out of this 1055, 68, 53 and 27 mm received from south west monsoon (June-September), north east (October-December), summer (March-May) and winter season (January -February) respectively. Probability for receiving more than 100 mm of rainfall can be expected only at 25% probability level and that too in four weeks which is leading to the interpretation that rainfed rice production is a challenging task in this region. it has been found that at 75 per cent assured probability level rainfall of more than 200 mms can be expected only in July and August months and this rainfall is hardly sufficient for meeting the water requirement in upland situations. However at 50 per cent probability which is equivalent to average condition, cultivation of rice is possible under well water management conditions. On seasonal basis rainfall at assured probability level of 75% is not sufficient as the quantity is 795 mm rainfall in south-western monsoon season.