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Conventional tillage practices in rice–wheat cropping systems of the Indo-Gangetic Plains are not only energy-intensive but also release large quantities of greenhouse gases (GHGs) resulting in calls for more sustainable tillage practices. To assess total energy use, energy-use efficiency, GHG emissions and total global warming potential, three reduced tillage rice–wheat systems were compared to standard conventional practice. Dry direct-seeded rice, unpuddled transplanted rice and puddled transplanted rice were paired with zero tillage wheat systems for two years in 84 on-farm trials in two Terai districts of Nepal, and compared to the puddled transplanted rice-conventional tillage wheat. In both districts, the total energy use was lower (p < 0.05) by 17–18% in dry direct-seeded rice and 15–17% in unpuddled transpanted rice than in puddled transplanted rice, and lower by 12.5–19% in zero tillage wheat than in conventional tillage. In both crops, the total global warming potential was lower for reduced tillage practices compared with the conventional counterparts. Higher energy-use efficiency with lower global warming potential could be a resilient and risk minimization strategy for crops in the rice–wheat systems established with reduced tillage under both irrigated and rainfed environments. To offer the most promising incentive for a transition from conventional to reduced tillage practices, availability and optimum use of herbicides, easy access to planting machines, and availability of skilled service providers are necessary. [ABSTRACT FROM AUTHOR]

An on-farm research was conducted at Gouripur upazila under Mymensingh district of Bangladesh during aman and boro season in 2013-14 to evaluate the performance of unpuddled rice cultivation. The rice var. Hybrid Krishan2 in aman and BRRI dhan28 in boro season were transplanted by two tillage practices viz., conventional tillage (CT) and strip tillage (ST) and two levels of crop residue i.e, no residue (R0) and 50% residue (R50). The experiment was designed in a randomized complete block design with four replications. ST yielded higher grains in aman season (5.67 t ha-1) and also in boro season (4.70 t ha-1) which were 9 and 13% higher compared to CT. Higher grain yield in ST leading to 26% higher BCR in aman and 23% higher in boro compared to CT. Retention of 50% residue increased by 5% yield in aman and by 4% yield in boro compared to no residue which contributed to 9% higher BCR in both aman and boro. ST combine with 50% residue retention yielded the highest grain yield in both of aman (5.97 t ha-1) and boro season (4.81t ha-1) which attributed to obtain the highest BCR in aman (3.08) and boro (2.78).

The field experiment was conducted at Agricultural College and Research Institute, Madurai, Tamil Nadu, during Kharif, 2017 to study the physiological and economic analysis of rice grown under unpuddled condition. The treatments comprised of two date of sowing (first and second fortnight of July) and two establishment methods with different varieties (Direct sowing and Unpuddled Transplanted Rice (UPTR) of CO 51, MDU 5 and ADT 48 rice varieties). The experiment was laid out in split plot design with three replications. The results revealed that direct sowing of CO 51 had superior physiological indices like LAI, CGR and RGR at panicle initiation, flowering and harvest stages than the other varieties and net return and benefit cost ratio were also achieved highly in this method of cultivation on sowing at first fortnight of July. While, the lower net return was obtained from ADT 48 under UPTR cultivation. This study clearly indicated that delay of water released from the dam up to July second fortnight, CO 51 and MDU 5 rice variety under direct sowing condition gives the better result than other varieties. [ABSTRACT FROM AUTHOR]

Wetland rice ( Oryza sativa L.) production contributes 55% of agricultural greenhouse gas (GHG) emissions in the world. Hence any new technology with the potential to reduce the GHG emissions of wetland rice could make a significant contribution to total global warming mitigation by agriculture. We applied a streamlined life cycle assessment to the effect of a novel unpuddled transplanting of rice and of increased crop residue retention on GHG emissions from rice fields in the Eastern Gangetic Plains. We compared them with the conventional puddling of soils and current residue retention for transplanting. The GHG emissions from one tonne of rice production for the following four cropping practices were studied: a) conventional puddled transplanting with low residue retention (CTLR); b) conventional puddled transplanting with high residue retention (CTHR); c) unpuddled transplanting following strip tillage with low residue retention (UTLR) and; d) unpuddled transplanting with high residue retention (UTHR). The emissions recorded on-farm and emissions related to pre-farm activities were converted to CO 2 -eq using Global Warming Potential (GWP) values of GHGs for 20-, 100- and 500-year time horizons. The GHG emissions of 1 tonne of rice varied from 1.11 to 1.57 tonne CO 2 -eq in the 100-year horizon. For all four treatments, soil methane (CH 4 ) was the predominant GHG emitted (comprising 60–67% of the total) followed by emission from on-farm machinery use. The UTLR was the most effective GHG mitigation option (it avoided 29%, 16% and 6% of the total GHG emissions in comparison with CTHR, CTLR and UTHR, respectively) in wetland rice production. The novel minimum tillage establishment approach for rice involving strip tillage followed by UT has potential to increase global warming mitigation of wetland rice in the Eastern Gangetic Plains, but further research is needed to assess the role of increased residue retention. [ABSTRACT FROM AUTHOR]