Management of drought in sali rice under increasing rainfall variability in the North Bank Plains Zone of Assam, North East India

摘要

The intermittent dry spells during growing season of winter or sali rice, cultivated in NBPZ of Assam located in the foothills of Eastern Himalayan region, is a major weather risk causing widespread damage to the crop. Herein, variability of rainfall in Lakhimpur district situated in NBPZ was studied. A significant decreasing trend of annual and seasonal rainfall was observed. Significant decrease in monsoon rainfall and increase in monthly rainfall variability clearly explains the recent rainfall fluctuations with increasing frequency of intermittent dry spells and flash floods. A participatory evaluation trial was conducted in Chamua village of Lakhimpur district having different land situations to identify climate resilient technologies to cope with seasonal drought in sali rice. High-yielding short-duration varieties, viz., Dishang, Luit, Lachit and Kolong, and medium-duration varieties, viz., Basundhara, Mohan, Mulagabhoru and TTB-404 performed consistently better than the long-duration HYV or the traditional varieties under upland and medium land situations, respectively. Though the effect of dry spells on long-duration varieties cultivated on low lands was least, yield of these varieties reduced up to 43.07% when sowing was delayed beyond 23rd of June. Performance of the delayed sown varieties was further declined, when exposed to dry spells at later growth stages. However, adverse impact of dry spells can be managed effectively by replacing farmers' varieties with short and medium-duration high-yielding varieties in upland and medium lands, respectively, and manipulating sowing time of long-duration varieties for low lands.