Analysis of Rainfall Characteristics for Crop Planning in North and South Saurashtra Region of Gujarat

Abstract

Knowledge of the sequences of dry and wet spells as well as onset and withdrawal of monsoon season is necessary for successful planning and management of agricultural ecosystem. In this study, 21-year (1997-2017) rainfall data of the North and South Saurashtra region of Gujarat were analysed to understand and quantify the South-west monsoon characteristics. Analysis of the results revealed that the onset and withdrawal of rainy season occurred during the 26th Standard Meteorological Week (SMW) and 40th SMW, respectively, in the North and South Saurashtra region. The length of the rainy season was 15 weeks for South Saurashtra and 14.5 weeks for North Saurashtra region. The South - and North-Saurashtra region received 96.7 % and 95.1 % of the mean annual rainfall, respectively, during the monsoon season. The initial probability of the wet weeks (25th - 34th SMW) and the conditional probability of wet week, followed by another wet week in the Saurashtra region varied from 47.6 % to 66.7 %, and 20.0 % to 64.3 %, respectively. Results indicated that the land preparation and sowing of kharif crops should be undertaken during the 24th to 26th SMW. The sowing of dryland crops in rabi season may be completed between 40th and 41st SMW, as remaining weeks have less probability of getting sufficient rainfall.