An attempt has been made to study the variability and trends of annual and seasonal rainfall for the period of 38 years (1973-2010) for all seven tehsils of Jhalawar district of Rajasthan. The mean annual rainfall of the district was found to 910 mm with standard deviation 218 mm and coefficient of variation 24 per cent. Annual rainfall varied from about 831 mm in Khanpur to more than 1022 mm in the Pirawa tehsil of the district. The annual rainfall showed declined trend (-0.23 to -17.41 mm/year) in all seven tehsils of the district. The negative trends at Pirawa (17.407 mm/year), Manoharthana (11.595 mm/year) and Aklera (5.789 mm/year) are statistically significant at less than 0.001, 0.05 and 0.05 levels, respectively. During the study period maximum dry period was recorded during postmonsoon and winter. Also, for the entire 38 years period maximum dry months were recorded during December till April. August was normal month for about 87 per cent followed by July and June for about 84 per cent and 66 per cent respectively. It was evident that the onset of south-west (SW) monsoon took place in the month of June and chances
of drought occurrence during kharif season were very low. Hence, SW monsoon rainfall is found ideal for raising kharif crops like soybeans, urd, moong, jowar, maize, tomato, brinjal, chilli, okra, kharif onion, amaranth, rainfed green gram, red gram, castor, etc in the district.
Coefficient of variation, MK-trend test, Precipitation concentration index, Rainfall variability, Senâ€™s slope
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