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Introduction: Conservation agriculture (CA) is gaining attention in the South Asia as an environmentally benign and sustainable food production system. The knowledge of the soil bacterial community composition along with other soil properties is essential for evaluating the CA-based management practices for achieving the soil environment sustainability and climate resilience in the ricewheat-greengram system. The long-term effects of CA-based tillage-cum-crop establishment (TCE) methods on earthworm population, soil parameters as well as microbial diversity have not been well studied. Methods: Seven treatments (or scenarios) were laid down with the various tillage (wet, dry, or zero-tillage), establishment method (direct-or drill-seeding or transplantation) and residue management practices (mixed with the soil or kept on the soil surface). The soil samples were collected after 7 years of experimentation and analyzed for the soil quality and bacterial diversity to examine the effect of tillage-cum-crop establishment methods. Results and Discussion: Earthworm population (3.6 times), soil organic carbon (11.94%), macro (NPK) (14.50-23.57%) and micronutrients (Mn, and Cu) (13.25 and 29.57%) contents were appreciably higher under CA-based TCE methods than tillage-intensive farming practices. Significantly higher number of OTUs (1,192 ± 50) and Chao1 (1415.65 ± 14.34) values were observed in partial CAbased production system (p = 0.05). Forty-two (42) bacterial phyla were identified across the scenarios, and Proteobacteria, Actinobacteria, and Firmicutes were the most dominant in all the scenarios. The CA-based scenarios harbor a high abundance of Proteobacteria (2-13%), whereas the conventional tillage-based scenarios were dominated by the bacterial phyla Acidobacteria and Chloroflexi and found statistically differed among the scenarios (p ≤ 0.05). Composition of the major phyla, i.e., Proteobacteria, Actinobacteria, and Firmicutes were associated differently with either CA or farmers-based tillage management practices. Overall, the present study indicates the importance of CA-based tillage-cumcrop establishment methods in shaping the bacterial diversity, earthworms population, soil organic carbon, and plant nutrient availability, which are crucial for sustainable agricultural production and resilience in agro-ecosystem. [ABSTRACT FROM AUTHOR]

Sub-optimal wheat productivity in the eastern Indo-Gangetic plain of India can largely be attributed to delayed sowing and the use of short duration varieties. The second week of November is the ideal time for sowing wheat in eastern India, though farmers generally plant later. Late-sowing farmers tend to prefer short-duration varieties, leading to additional yield penalty. To validate the effect of timely sowing and the comparative performance of long- and short-duration varieties, multi-location on-farm trials were conducted continuously over five years starting from 2016–2017. Ten districts were selected to ensure that all the agro-climatic zones of the region were covered. There were five treatments of sowing windows: (T1) 1 to 10 November, (T2) 11–20 November, (T3) 21 to 30 November, (T4) 1–15 December, and (T5) 16–31 December. Varietal performance was compared in T3, T4, and T5, as short-duration varieties are normally sown after 20 November. There is asymmetry in the distribution of samples within treatments and over the years due to the allocation of fields by farmers. Altogether, the trial was conducted at 3735 sites and captured 61 variables, including yield and yield attributing traits. Findings suggested that grain yields of long-duration wheat varieties are better even under late sown scenarios. Dataset:  https://hdl.handle.net/11529/10548817 Dataset License: Creative Commons CC0 Public Domain Dedication [ABSTRACT FROM AUTHOR]

Deteriorating soil health, diminishing soil organic carbon (SOC), development of subsurface hard compact layer and declining system productivity are barriers to achieving sustainable production in the traditional rice–wheat cropping system (TA) in the eastern Indo‐Gangetic Plain of India. Conservation agriculture (CA), which favours minimum soil disturbance, crop residue retention and crop diversification could be a viable alternative to the TA to address most of those major problems. With that in mind, a long‐term experiment is being implemented at ICAR‐RCER, Patna, Bihar, India, with four treatments: (a) TA, (b) full CA (fCA) and (c and d) partial CA (pCA1 and pCA2), differing in crop establishment methods, cropping system and crop residue management in a randomized complete block design. Measurement of soil health parameters was carried out in the 11th year of the experiment. The results revealed a beneficial effect of CA and 46 and 40% increase in SOC concentration and stock, respectively, under fCA over TA in the 0–7.5‐cm soil layer. The effect of partial CA (pCA1 and pCA2) was variable, but an increasing trend was always observed under pCA compared to TA. There was an enrichment in SOC content of aggregates under CA irrespective of size class; however, no relation was found between SOC content and aggregate diameter. The contribution of macroaggregates to SOC stock was larger (36–66%) under CA in the 0–7.5‐cm soil layer. Adoption of CA improved the macroaggregate content, MWD and GMD of aggregates, and aggregation ratio. Soil macropore content was greater under fCA, whereas other parameters were similar among treatments. The impact of CA was mostly limited to 0–7.5 cm soil layer and a maximum up to 15 cm soil depth while evaluation until 60 cm soil depth was realized. The yield of rice in CA was comparable to or higher than in TA, whereas the system rice equivalent yield was always higher (38–53%) under CA than under the conventional practices. Therefore, a CA‐based cropping system must be encouraged, to increase SOC status, improve aggregation stability and, consequently, sustain or increase system productivity, in order to achieve food and nutritional security in the eastern Indo‐Gangetic Plain of India. Highlights: Effects of long‐term conservation agriculture (CA) on soil C, aggregation and yield were evaluated.CA improved SOC concentration and stock by 46 and 40%, as well as macroaggregate SOC stock by 36–66%.Macro‐aggregation and mean weight diameter improved in CA but was mostly limited to a shallow soil depth.CA can be promoted for sustainability of a rice–wheat system due to higher productivity (38–53%). [ABSTRACT FROM AUTHOR]

Timely crop planting is a foundation for climate-resilient rice-wheat systems of the Eastern Gangetic Plains—a global food insecurity and poverty hotspot. We hypothesize that the capacity of individual farmers to plant on time varies considerably, shaped by multifaceted enabling factors and constraints that are poorly understood. To address this knowledge gap, two complementary datasets were used to characterize drivers and decision processes that govern the timing of rice planting in this region. The first dataset was a large agricultural management survey (rice-wheat: n = 15,245; of which rice: n = 7597) from a broad geographic region that was analyzed by machine learning methods. The second dataset was a discussion-based survey (n = 112) from a more limited geography that we analyzed with graph theory tools to elicit nuanced information on planting decisions. By combining insights from these methods, we show for the first time that differences in rice planting times are primarily shaped by ecosystem and climate factors while social factors play a prominent secondary role. Monsoon onset, surface and groundwater availability, and land type determine village-scale mean planting times whereas, for resource-constrained farmers who tend to plant later ceteris paribus, planting is further influenced by access to farm machinery, seed, fertilizer, and labor. Also, a critical threshold for economically efficient pumping appears at a groundwater depth of around 4.5 m; below this depth, farmers do not irrigate and delay planting. Without collective action to spread risk through synchronous timely planting, ecosystem factors such as threats posed by pests and wild animals may further deter early planting by individual farmers. Accordingly, we propose a three-pronged strategy that combines targeted strengthening of agricultural input chains, agroadvisory development, and coordinated rice planting and wildlife conservation to support climate-resilient agricultural development in the Eastern Gangetic Plains. [ABSTRACT FROM AUTHOR]

In Indo-Gangetic plains (IGP) of India, natural resources (soil, water, and environment) are degrading under the conventional-till (CT)-based management practices in rice-wheat cropping system. A long-term field experiment was conducted to understand the soil bacterial diversity and abundance under different sets of management scenarios (Sc). The study comprised of four scenarios, namely, -Sc.I CT-based rice-wheat system (farmers’ practice); Sc.II, partial conservation agriculture (CA) based in which rice is under CT—wheat and mungbean under zero-tillage (ZT); Sc.III, full CA-based in which rice-wheat-mungbean are under ZT and Sc.IV, where maize-wheat-mungbean are under ZT. These scenarios varied in cropping system, tillage, and crop residue management practices. Using Illumina MiSeq sequencing technology, the variable regions V3-V4 of 16S rRNA were sequenced and the obtained reads were analyzed to study the diversity patterns in the scenarios. Results showed the presence of 53 bacterial phyla across scenarios. The predominant phyla in all scenarios were Proteobacteria, Acidobacteria, Actinobacteria, and Bacteroidetes which accounted for more than 70% of the identified phyla. However, the rice-based systems (Sc.I, Sc.II, and Sc.III) were dominated by phylum Proteobacteria; however, maize-based system (Sc.IV) was dominated by Acidobacteria. The class DA052 and Acidobacteriia of Acidobacteria and Bacteroidetes of Bacteroidia were exceptionally higher in Sc.IV. Shannon diversity index was 8.8% higher in Sc.I, 7.5% in Sc.II, and 2.7% in Sc.III compared to Sc.IV. The findings revealed that soil bacterial diversity and abundance are influenced by agricultural management practices as bacterial diversity under full CA-based management systems (Sc.III and Sc.IV) was lower when compared to farmer’s practice (Sc.I) and partial CA (Sc.II) scenarios. [ABSTRACT FROM AUTHOR]

Crop residue burning is a common practice in many parts of the world that causes air pollution and greenhouse gas (GHG) emissions. Regenerative practices that return residues to the soil offer a 'no burn' pathway for addressing air pollution while building soil organic carbon (SOC). Nevertheless, GHG emissions in rice-based agricultural systems are complex and difficult to anticipate, particularly in production contexts with highly variable hydrologic conditions. Here we predict long-term net GHG fluxes for four rice residue management strategies in the context of rice-wheat cropping systems in Eastern India: burning, soil incorporation, livestock fodder, and biochar. Estimations were based on a combination of Tier 1, 2, and 3 modelling approaches, including 100-year DNDC simulations across three representative soil hydrologic categories (i.e., dry, median, and wet). Overall, residue burning resulted in total direct GHG fluxes of 2.5, 6.1, and 8.7 Mg CO 2 -e in the dry, median, and wet hydrologic categories, respectively. Relative to emissions from burning (positive values indicate an increase) for the same dry to wet hydrologic categories, soil incorporation resulted in a −0.2, 1.8, or 3.1 Mg CO 2 -e change in emissions whereas use of residues for livestock fodder increased emissions by 2.0, 2.1, or 2.3 Mg CO 2 -e. Biochar reduced emissions relative to burning by 2.9 Mg CO 2 -e in all hydrologic categories. This study showed that the production environment has a controlling effect on methane and, therefore, net GHG balance. For example, wetter sites had 2.8–4.0 times greater CH 4 emissions, on average, than dry sites when rice residues were returned to the soil. To effectively mitigate burning without undermining climate change mitigation goals, our results suggest that geographically-target approaches should be used in the rice-based systems of Eastern India to incentivize the adoption of regenerative 'no burn' residue management practices. • Efforts to build SOC for climate change mitigation, while simultaneously avoiding burning, may have unintended consequences. • Tier 1, 2, and 3 modelling approaches were used to compare no-burn rice residue pathways. • Field hydrology had a dominant effect on methane emissions. • Soil incorporation of residues increased emissions relative to open burning, except in comparatively dry fields. • Biochar is estimated to have the lowest GHG emissions of the evaluated 'no burn' alternatives. [ABSTRACT FROM AUTHOR]

In the most productive area of the Indo-Gangetic Plains in Northwest India where high yields of rice and wheat are commonplace, a medium-term cropping system trial was conducted in Haryana State. The goal of the study was to identify integrated management options for further improving productivity and profitability while rationalizing resource use and reducing environmental externalities (i.e., “sustainable intensification”, SI) by drawing on the principles of diversification, precision management, and conservation agriculture. Four scenarios were evaluated: Scenario 1 – “business-as-usual” [conventional puddled transplanted rice (PTR) followed by ( fb ) conventional-till wheat]; Scenario 2 – reduced tillage with opportunistic diversification and precision resource management [PTR fb zero-till (ZT) wheat fb ZT mungbean]; Scenario 3 – ZT for all crops with opportunistic diversification and precision resource management [ZT direct-seeded rice (ZT-DSR) fb ZT wheat fb ZT mungbean]; and Scenario 4 – ZT for all crops with strategic diversification and precision resource management [ZT maize fb ZT wheat fb ZT mungbean]. Results of this five-year study strongly suggest that, compared with business-as-usual practices, SI strategies that incorporate multi-objective yield, economic, and environmental criteria can be more productive when used in these production environments. For Scenarios 2, 3, and 4, system-level increases in productivity (10–17%) and profitability (24–50%) were observed while using less irrigation water (15–71% reduction) and energy (17–47% reduction), leading to 15–30% lower global warming potential (GWP), with the ranges reflecting the implications of specific innovations. Scenario 3, where early wheat sowing was combined with ZT along with no puddling during the rice phase, resulted in a 13% gain in wheat yield compared with Scenario 2. A similar gain in wheat yield was observed in Scenario 4 vis-à-vis Scenario 2. Compared to Scenario 1, wheat yields in Scenarios 3 and 4 were 15–17% higher, whereas, in Scenario 2, yield was either similar in normal years or higher in warmer years. During the rainy ( kharif ) season, ZT-DSR provided yields similar to or higher than those of PTR in the first three years and lower (11–30%) in Years 4 and 5, a result that provides a note of caution for interpreting technology performance through short-term trials or simply averaging results over several years. The resource use and economic and environmental advantages of DSR were more stable through time, including reductions in irrigation water (22–40%), production cost (11–17%), energy inputs (13–34%), and total GWP (14–32%). The integration of “best practices” in PTR in Scenario 2 resulted in reductions of 24% in irrigation water and 21% in GWP, with a positive impact on yield (0.9 t/ha) and profitability compared to conventional PTR, demonstrating the power of simple management changes to generate improved SI outcomes. When ZT maize was used as a diversification option instead of rice in Scenario 4, reductions in resource use jumped to 82–89% for irrigation water and 49–66% for energy inputs, with 13–40% lower GWP, similar or higher rice equivalent yield, and higher profitability (27–73%) in comparison to the rice-based scenarios. Despite these advantages, maize value chains are not robust in this part of India and public procurement is absent. Results do demonstrate that transformative opportunities exist to break the cycle of stagnating yields and inefficient resource use in the most productive cereal-based cropping systems of South Asia. However, these SI entry points need to be placed in the context of the major drivers of change in the region, including market conditions, risks, and declining labor availability, and matching with the needs and interests of different types of farmers. [ABSTRACT FROM AUTHOR]

Millions of people living in the Eastern Gangetic Plains (EGP) of India engage in agriculture to support their livelihoods yet are income poor, and food and climate insecure. To address these challenges, policymakers and development programs invest in irrigation-led agricultural intensification. However, the evidence for agricultural intensification to lift farmers' incomes above the poverty line remains largely anecdotal. The main objective of this study is to use a large household survey (n = 15,572; rice: 8244, wheat: 7328; 2017/18) to assess the link between agricultural intensification and personal daily incomes from farming (FPDI) in the rice-wheat systems of the EGP – the dominant cropping system of the region. We use the Intensification Benefit Index (IBI), a measure that relates farm size and household size to FPDI, to assess how daily incomes from rice-wheat production change with irrigation-led intensification across the EGP. Relative to the international poverty line of 1.90 Purchasing Power Parity (PPP)$ day−1 and accounting for variations in HH size in the analysis, we found that small farm sizes limit the potential for agricultural intensification from irrigation to transform the poverty status of households in the bottom three quartiles of the IBI. The estimated median FPDI of households with intensified systems in the bottom three quartiles is only 0.51 PPP$ day−1 (a 0.15 PPP$ gain). The median FPDI increases to 2.10 PPP$ day−1 for households in the upper quartile of the IBI distribution (a 0.30 PPP$ gain). Irrigation-led agricultural intensification of rice-wheat systems in the EGP may provide substantial benefits for resilience to climatic change and food security but achieving meaningful poverty reduction will require complementary investments. Transforming the poverty status of most smallholder farmers in the EGP requires diversified portfolios of rural on- and off-farm income-generating opportunities. While bolstering food- and climate security, agronomic intervention programs should consider smallholders' limited monetary incentives to invest in intensification. Irrigation-led agricultural intensification programs and policies should explicitly account for the heterogeneity in household resources, irrigation levels, and degree of dependence on agricultural income. [Display omitted] • Irrigation is crucial for food security and climate resilience • We assess the link between agricultural intensification of smallholder farms and personal daily incomes from farming • Rice-wheat production can only lift large farms above the poverty line • Reducing farmer poverty needs multi-sectoral investments and off-farm jobs • Targeted investments are required to strengthen capacity for staple production [ABSTRACT FROM AUTHOR]

Weeds are one of the key threats in sustaining the productivity of the rice-wheat cropping system in the Indo-Gangetic Plains. The development of sound integrated weed management technologies requires knowledge of mechanisms that influence weed flora composition and weed seedbank dynamics. A long-term study was initiated in 2015 at Patna, Bihar, India to evaluate the effect of seven tillage and crop establishment methods on weed density, weed seedbank composition, and crop productivity in rice-wheat-mungbean rotation. All the treatments included zero-till mungbean after wheat. Tillage and crop establishment methods had differential effects on weed and weed seedbank composition. In rice, zero-till direct-seeded rice recorded 62% lower emergence of Cyperus iria , 82–90% of Echinochloa colona, and 81–83% of total weeds compared to tilled systems, but the system of rice and wheat intensification favoured E. colona. In wheat, the system of wheat intensification favoured the Phalaris minor and Solanum nigrum. Zero-till rice and wheat reduced the seedbank of Trianthema portulacastrum by 95%, and total weed seedbank by 62% compared to the system of rice and wheat intensification. Nearly, 72% of C. iria seeds, 62% of grasses, and 64% of broad-leaved weeds were in 0–15 cm soil layer. Zero-till direct-seeded rice produced a 13% lower rice grain yield than conventional puddled transplanted rice. Compared to the system of wheat intensification, zero-till wheat under triple zero-till systems produced an 11.5% higher grain yield. Managing weed seedbank is a long-term endeavour. The present study revealed that tillage and crop establishment methods influence weed density and diversity. Under zero-till rice-wheat system, rice yield decreases marginally, but the system productivity maintains due to improvement in succeeding wheat yield. This system is also helpful in reducing the weed flora density and soil weed seedbank. Regular monitoring and management of emerging pests such as armyworm (Mythimna separata) are, however, required. The study suggests that the adoption of triple zero-tillage can be a viable option for reducing the weed density and weed seedbank concurrently increasing the system productivity of the rice-wheat-mungbean cropping system in eastern Indo-Gangetic Plains. • Effect of tillage and crop establishment on soil weed seedbank in rice-wheat-mung bean system is poorly explored. • Direct-seeded rice (DSR)-based conservation agriculture (CA) system reduced weed density and seedbank than conventional. • More than 60% weed seeds were placed in 0–15 cm soil depth. • Zero-till wheat after DSR produced higher yield than conventional till wheat after puddled transplant rice. • After five years, CA system favoured infestation of armyworm (Mythimna separata) in wheat. [ABSTRACT FROM AUTHOR]

• DSR or MTR followed by ZT wheat gave higher system yield and gross margin. • Production cost reduced by US$ 149 and 77 ha−1 in DSR and MTR, respectively and increased by US$ 84 ha−1 in SRI than in PTR. • In wheat, ZT had higher yield and lower production cost (US$ 69 ha−1) but SRI increased cost by US$ 139 ha−1 than CT. Conventionally managed rice-wheat systems of the eastern Indo-Gangetic Plains (E-IGP) that rely on soil puddling for rice and intensive tillage for wheat are low-yielding and resource-inefficient, leading to low profitability. While a host of alternative tillage and crop establishment (TCE) methods have been advocated as solutions for sustainably enhancing productivity and profitability, few systematic comparisons of these methods are reported. To address this gap, a three-year field study was conducted in Bihar, India with the goal of identifying TCE methods for rice-wheat systems that are high yielding, less resource-intensive, and more profitable. The following systems were evaluated: 1) puddled transplanted rice (PTR) followed by (fb) conventional tillage wheat (CTW) or zero-tillage wheat (ZTW); 2) machine transplanted rice in non-puddled soil (MTR) fb ZTW; 3) the system of rice intensification (SRI) fb system of wheat intensification (SWI); and 4) dry-seeded rice (DSR) fb ZTW. Rice cultivar duration (short versus medium-duration) was incorporated as a subplot treatment in all systems. Rice yields were similar with all methods, except DSR yield was 11 % lower and MTR yield was 7% higher than PTR in the third year. Cost of production was US$ 149 and 77 ha−1 lower in DSR and MTR, respectively, and US$ 84 ha-1 higher in SRI than PTR. The gross margin and benefit-cost (B:C) ratio was highest in MTR followed by DSR and lowest in SRI. In wheat, ZT resulted in a higher yield than CTW, especially when ZTW was cultivated after non-puddled rice (e.g., DSR or MTR). ZTW reduced production costs by US$ 69 ha-1, whereas SWI increased it by US$ 139 ha-1 relative to CTW. The higher yield and lower cost of production resulted in a higher gross margin (US$ 82−355 ha−1 and US$ 129−409 ha−1 higher than CTW and SWI, respectively) and a higher B:C ratio in ZTW treatments than CTW and SWI. At the system level, MTR or DSR followed by ZTW had both superior crop yields and consistently higher gross margins (US $133 to 382 ha-1) than other practices. On the other hand, the SRI fb SWI system had no yield advantage and poorer economic performance than conventional practices. In all systems, the inclusion of a medium-duration rice hybrid resulted in higher rice and system yields. These results suggest that significant gains in profitability are possible with emerging TCE practices in rice-wheat systems, but alternatives such as the SRI and SWI will likely erode farmer incomes. [ABSTRACT FROM AUTHOR]