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Conventional tillage (CT) degrades soil and environmental quality in many major cropping systems. Conservation agriculture, like reduced tillage, can play an important role in maintaining soil organic carbon (SOC) storage and in minimizing greenhouse gas (GHG) emissions from crop fields. An experiment was conducted at the Bangladesh Agricultural Research Institute (BARI), Gazipur to evaluate GHG emission, global warming potential (GWP), GHG intensity and net SOC variations in rice-mustard-rice cropping systems under CT and strip tillage (ST). The emissions of nitrous oxide (N2O) and carbon dioxide (CO2) varied significantly because of CT and ST tillage practices. The ST reduced 24–47% methane (CH4) emission factor, 20–32% CH4 flux, 32–46% GHG intensity and 31–47% GWP than CT practice. In mustard crop, ST reduced 55–61% of GHG intensity and 52–58% of GWP compared to CT. There was about 33% increase in N2O emission and 24% augmentation of soil respiratory CO2 with ST compared to CT. About 8% absorption of net ecosystem CO2, 9–11% of net SOC and 10% of rice equivalent yields increased in ST compared to CT. It is concluded that ST can minimize soil C loss, improve net ecosystem CO2 absorption, and reduce GHG intensity, GWP under rice-mustard-rice systems in Asian countries. [ABSTRACT FROM AUTHOR]

We review the recent development of Conservation Agriculture (CA) for rice-based smallholder farms in the Eastern Gangetic Plain (EGP) and the underpinning research on agronomy, weed control, soil properties and greenhouse gas emissions being tested to accelerate its adoption in Bangladesh. The studies are based mostly on minimum soil disturbance planting in strip planting (SP) mode, using the Versatile Multi-crop Planter (VMP), powered by a two-wheel tractor (2WT). One-pass SP with the VMP decreased fuel costs for crop establishment by up to 85% and labour requirements by up to 50%. We developed strip-based non-puddled rice (Oryza sativa) transplanting (NPT) in minimally-disturbed soil and found that rice grain yield increased (by up to 12%) in longer-term practice of CA. On farms, 75% of NPT crops increased gross margin. For non-rice crops, relative yield increases ranged from 28% for lentil (Lens culinaris) to 6% for wheat (Triticum aestivum) on farms that adopted CA planting. Equivalent profit increases were from 47% for lentil to 560% for mustard (Brassica juncea). Moreover, VMP and CA adopting farms saved 34% of labour costs and lowered total cost by up to 10% for production of lentil, mustard, maize (Zea mays) and wheat. Effective weed control was obtained from the use of a range of pre-emergent and post-emergence herbicides and retention of increased crop residue. In summary, a substantial body of research has demonstrated the benefits of CA and mechanized planting for cost savings, yield increases in many cases, increased profit in most cases and substantial labour saving. Improvement in soil quality has been demonstrated in long-term experiments together with reduced greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

This study was conducted to know cropping cycles required to improve OM status in soil and to investigate the effects of medium-term tillage practices on soil properties and crop yields in Grey Terrace soil of Bangladesh under wheat-mungbean-T. aman cropping system. Four different tillage practices, namely, zero tillage (ZT), minimum tillage (MT), conventional tillage (CT), and deep tillage (DT), were studied in a randomized complete block (RCB) design with four replications. Tillage practices showed positive effects on soil properties and crop yields. After four cropping cycles, the highest OM accumulation, the maximum root mass density (0-15 cm soil depth), and the improved physical and chemical properties were recorded in the conservational tillage practices. Bulk and particle densities were decreased due to tillage practices, having the highest reduction of these properties and the highest increase of porosity and field capacity in zero tillage. The highest total N, P, K, and S in their available forms were recorded in zero tillage. All tillage practices showed similar yield after four years of cropping cycles. Therefore, we conclude that zero tillage with 20% residue retention was found to be suitable for soil health and achieving optimum yield under the cropping system in Grey Terrace soil (Aeric Albaquept).