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Intensive tillage-based conventional cotton-wheat system (CWS) entails high production costs and has low crop and water productivity thereby threatening its sustainability in the north-western India. Conservation agriculture (CA) based management practices such as conservation tillage, permanent raised beds and relay planting have the potential to improve sustainability, profitability, and water use efficiency in CWS. A two-year (2013–2015) field experiment was conducted to evaluate CA based management practices such as zero tillage (ZT), permanent beds, relay seeding (RS) of wheat, seeding configuration, and integration of mungbean (MB) in terms of crop productivity, input use efficiency (water and energy) and profitability in the CWS system. Treatments included; permanent narrow (67.5 cm, PNB) and broad (102 cm, PBB) raised beds with cotton planted in the centre of beds, ZT narrow flats (67.5 cm, ZTNF) and broad flats (102 cm, ZTBF), and PBB with cotton planted on one side of bed and intercropped with MB (PBBc + MB) or no MB (PBBc). In the above treatments, wheat was relay seeded in standing cotton after second picking. In addition, conventional till (CT) CWS on flats was included as control treatment. PBBc + MB produced 37% and 10% higher system productivity (2 yrs’ mean) over CT and PBB, respectively. Relay seeded wheat on PBB produced 50% higher yield and required 40% less irrigation water compared to CT wheat in both the years. Mean system irrigation water productivity (WP I ) was 131% higher with PBBc + MB compared with CT. The energy input was 61% higher in CT compared to PBB but energy output was 21% higher with PBB than with CT. PBB and PBBc + MB recorded 52–54% higher energy productivity and 64–69% higher net returns compared to CT. In conclusion, PBB and PBBc + MB were the best options for sustainable CWS under similar soil and climatic conditions in India. [ABSTRACT FROM AUTHOR]

In intensive rice–wheat systems of north-west (NW) India, surface retention of rice residues in wheat has been recommended instead of burning. Optimum nitrogen (N) management for zero till (ZT) wheat sown into rice residues may to differ from that of conventional practice ( in-situ burning of residues followed by intensive tillage prior to sowing). Therefore, we conducted several on-farm and on-station field experiments in 2007–2008 to 2012–2013 to evaluate N management practices for ZT wheat sown into rice residues using the Happy Seeder. The optimum N rate for wheat planted into rice residues in fields with no or only a short history of rice residue retention was 120 kg N ha −1 , the current recommendation for conventional practice. Short-term (up to 20 d) soil N mineralization was lower in undisturbed soil than disturbed soil, while the total amount of N mineralization was similar after 40 d, suggesting that over the crop season, total soil N mineralization may be similar in tilled and non-tilled soil. Ammonia volatilization loss from urea broadcast over the residue covered surface, followed by irrigation, was low (<2 kg ha −1 ) regardless of time of urea application. Band placement of 20% of the fertilizer N as diammonium phosphate at seeding, and topdressing of the remaining 80% as urea in two equal doses before first and second irrigations produced higher grain yield and N use efficiency than other treatments. However, surface residue retention reduces the rate of soil drying and in some situations this delays the time of the second irrigation and thus N fertilizer application beyond the optimum time. Therefore, the effect of banding various proportions of the urea N between the rows at sowing was investigated. The results showed that, on a loam soil, up to 75% of the recommended N fertilizer can be applied at sowing, 24 kg N ha −1 as DAP with the seed and 66 kg N ha −1 as urea drilled between every second wheat row, without loss of yield. In conclusion, a better applied N management strategy for ZT wheat than currently practiced is drilling of 24 kg N ha −1 as diammonimum phosphate into the soil at seeding followed by two top-dressings of 48 kg N ha −1 each just prior to first and second irrigations. [ABSTRACT FROM AUTHOR]