Analysis of drought and dependable rainfall of Palamau region of Jharkhand for better crop planning

Daily rainfall data of fifty years (1958–2007) recorded at Zonal Research Station, Chianki were analyzed to study the drought characteristics and dependable rainfall of Palamau region of Jharkhand which is typical in climatic variability. The result clearly indicated that rainfall has been drastically reduced during last ten years where as, the frequency of drought years has been increased during last twenty years. There is also increase in total number of drought months and the drought frequency during September month which has increased by 250% in last 25 years in comparison to previous 25 years. This is a remarkable change because rainfed crops remain in flowering to grain formation stage and crops are adversely affected resulting in poor yield. The decrease in dependable annual rainfall has also been noticed during last twenty years. The seasonal dependable rainfall has also decreased in recent years. The sizable amount of dependable rainfall in the monsoon months i.e. June, July, August and September are crucial from agricultural point of view and has decreased during last ten years which may adversely affect crop yield. It has also been observed that monthly dependable rainfall of July and August in terms of amount has also been shifted. The dependable rainfall of October month also decreased during last ten years. Therefore, timely sowing of rabi crops is being affected, and without supplemental irrigation sowing has become difficult. Therefore, essentially, there is a need to harvest the surplus water during south west monsoon for life saving or supplemental irrigation and re-scheduling the sowing time and also to adopt new cropping system such as short duration Pigeonpea – chickpea, short duration rice – chickpea, maize/sorghum/finger millet – chickpea, castor/cotton (unirrigated) etc which may be viable options in place of existing cropping system (rice-wheat, rice-fallow, etc.) of this region.