Vol. 10 No. 2
Study of rainfall variability for efficient crop planning - a case study
Author(s): M. Ghosh, B. C. Patra and D. Mazumdar
Abstract: Daily rainfall data of 12 years (1981-1992) recorded at Regional Research Sub-station, Bidhan Chandra Krishi Viswavidyalaya, Raghunathpur (23036’N, 86042’E, 169 m), Purulia, West Bengal, India were analysed for determining annual, seasonal, monthly and weekly rainfall averages of the region, which were compared with corresponding values of the current period of 5 years (2003-2007). Mean annual rainfall was 1156.0 mm, of which July recorded highest rainfall (313.3 mm) and January lowest rainfall (1.8 mm). Mean rainfall for pre-kharif, kharif and rabi season were 106.6 mm (9.22%), 1010.7 mm (87.43%) and 38.7 mm (3.35%), respectively. The changes in rainfall pattern between two periods of 1981-1992 and 2003-2007 were very little during pre kharif (-1.7%) and kharif (+1.0%) seasons, but moderate during rabi season (-22.7%). Mean week of onset and withdrawal of south-west monsoon were 24th (11-17 June) standard meteorological week (SMW) and 40th SMW (1-7 October) and average length of rainy season was 18 weeks (126 days) with a variation between 15 and 24 weeks. Mid season drought was likely to occur during 33rd-34th SMW and terminal droughts during 37-40th SMWs at <10 and 10-25% probability levels, respectively. Rice was the main crop in the region during kharif season along with maize and arhar in some areas, while short duration pulses, oilseeds and wheat could be grown with residual soil moisture and live-saving irrigations during rabi season....
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