National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
For adopting a particular cropping plan, the time of onset of monsoon is the most important single parameter but it has not been considered in most of the studies conducted for crop planning under rainfed regions. Rainfall data of Bhilwara district in Rajasthan state for a period of 57 years were analysed from two approaches viz.; ‘Meteorological’ approach and ‘Onset of monsoon’ approach. The ‘Meteorological’ approach is a conventional approach wherein the information for crop growth period is assumed based on normal week of onset of monsoon and also provides a single set of information which leads to a single set of cropping plan irrespective of time of onset of monsoon. On the contrary in the ‘Onset of monsoon’ approach, the rainfall data are arranged by considering onset of monsoon as datum and also grouped for different weeks of onset of monsoon. The results reveal considerable difference in rainfall characteristics with respect to length of growing period, water surplus/ deficit and probability of intervening dry spells due to these approaches. The ‘Onset of monsoon’ approach is more rational as it precisely describes the actual crop environment and provides information for varying onsets of monsoon as compared to ‘Meteorological’ approach. The results of water balance study reveals an increase of water deficit due to early and delay in onset (31st SMW) as compared to normal onset of monsoon (27th SMW), whereas an decrease of 50.2 per cent in water surplus and a decrease of 55.8 per cent in water surplus was recorded due to late and early onset of monsoon as compared to normal onset of monsoon. The correlation studies also reveal that onset of monsoon is inversely correlated (-0.91) with duration of rainy season while positively correlated (0.83) with water deficit. Thus, the ‘onset of monsoon’ approach should be considered for crop planning under rainfed regions to harness more profit per unit of rainfall.
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