Subhendu Bikash Goswami,Er. Soumen Saha, Bidhan Chandra Agriculture University, AICRP on Water Management, sbg_bckv05@rediffmail.com
ABSTRACT
With the background of an alarming draw down of ground water table 3-12 m bgl or more during summer, farm-level interventions on water delivery, allotment, method of application and crop selection were made at deep tube-well commands (40 ha) in the lower Indo-Gangetic plains of West Bengal, India for 10 years during 1999 - 2009. On-farm adaptive research revealed that in summer paddy spout-wise alternate wetting and drying (AWD) at 1-3 days after disappearance of ponded water saved 25-40 % of irrigation water over continuous submergence (5+2 cm). Conveyance efficiency was remarkably improved up to 95% by using polythene delivery pipes in rice as well as non-rice crops. Water distribution efficiency was improved by furrow irrigation, raised bed furrow water application in non-rice crops. Inclusion of vegetables in rice based crop sequences increased the water productivity by 2-3 times as compared to other non-rice crop sequences. In terms of benefit-cost ratio, winter rice-tomato sequence recorded the highest value followed by winter ricecabbage-summer rice sequence. Inclusion of summer rice increased precious irrigation water expenditure and water cost many folds in the tube well commands.
Key words: Crop water productivity, Tube-well commands, Rice based crop sequences,