Crop water productivity of crop sequences involving rice (Oryza sativa), jute (Corchorus species) and vegetables in deep and shallow tube-well commands of lower Gangetic plains region

Eight rice (Oryza sativa L.)-based crop sequences were evaluated during 1999–2000 and 2000–2001 for their land and water productivity in tube-well commands of Lower Gangetic Plains Region. On rice-equivalent yield basis autumn rice-cabbage (Brassica oleracea L. convar. capitata (L.) Alef. var. capitate]-summer rice (24.6 tonnes/ha) or cauliflower [B. oleracea convar. botrytis (L.) Alef. var. botrytis L.]-pointed gourd (Trichosanthes dioca Rox b.)(23.4 tonnes/ha) crop sequences recorded significantly higher land productivity (LP) than other crop sequences like winter rice-wheat (Triticum aestivum L. emend. Fiori & Paol.)-jute (Corchorus sp.) (10.3 tonnes/ha) and winter rice-summer rice (11.7 tonnes/ha). Farm-level water productivity (WP) was computed on the basis of reference crop evapotranspiration (WP_ET) and water supply to fields (WP_WS). Winter vegetables recorded higher WP_ET (kg/m³) than summer-growing crop. The WP on the basis of ET was for cabbage 23.0, cauliflower 20.7, potato 18.8, tomato (Lycopersecon esculentum Miller nom. cons.)14.3, rice 1.6, wheat 2.1, sesame (Sesamum indicum L.) 0.4, jute 0.7 and pointed gourd 2.5 kg/m³. The WP values in terms of water supply (WP_Ws) was 30–50% lower than potential WP_ET. The WP in economic term (Rs/m³) was also high in vegetables (Rs 24.6–31.5) and its inclusion in rice-based crop sequence increased the water productivity by 2–3 times compared to other non-vegetable-based sequences. Irrigation water charge for crop production was 4–6 times higher under private owned shallow tube-well run by diesel than the government owned deep tube-well. In ST well commands water cost (WC) for cultivation was much higher in winter rice-summer rice or autumn rice-cabbage-summer rice sequences (Rs 8–13 thousand/ha) than autumn rice-tomato or other sequences. Inclusion of summer rice in the rice-rice system increased the WC for produce (Rs 57.7–71.8 q) in tubewell-irrigated ecosystem.