Search

The continuous rice–wheat cropping system in South Asia has caused irreversible environmental damage, raising concerns about the long-term sustainability of the region's agricultural systems. To address this issue, farm experiments were conducted for two successive years (2019–20 and 2020–21) to assess the impact of different cropping systems under conservation agriculture (CA) practices on the yield, productivity, and profitability of wheat. Results showed that the highest grain yield of wheat was observed in scenarios Sc6, Sc4, and Sc2, which involved full CA permanent-bed soybean (PB)–permanent-bed wheat (PB)–permanent-bed summer moong (PB), full CA permanent-bed maize (PB)–permanent-bed wheat (PB)–permanent-bed summer moong (PB), and partial CA puddled transplanted rice–Happy Seeder wheat–zero-till summer moong (ZT). Additionally, the highest irrigation water productivity (IWP), wheat grain macronutrient uptake, net return, and benefit–cost ratio (B:C ratio) were recorded under Sc6, full CA permanent-bed soybean (PB)–permanent-bed wheat (PB)–permanent-bed summer moong (PB) compared to farmers' practice puddled transplanted rice (PTR)–conventional-till wheat–summer moong (Sc1) during both years. The system productivity also increased in scenarios Sc2, Sc4, and Sc6 (by 9.72%, 9.65%, and 14.14% in the first year and 10.68%, 14.14%, and 15.55% in the second year) compared to Sc1—farmers' practice puddled transplanted rice (PTR)–conventional-till wheat–summer moong, Sc3—farmers' practice fresh-bed maize (FB)–conventional-till wheat–summer moong, and Sc5–farmers' practice fresh-bed soybean (FB)–conventional-till wheat (CT)–summer moong. The findings suggest that the conservation agriculture soybean–wheat–summer moong (Sc6) on permanent-bed cropping systems with inclusion legumes can be a potential option to enhance yield attributes, productivity, and profitability, as well as the sustainability of natural resources in the region while decreasing environmental footprints. [ABSTRACT FROM AUTHOR]

Conservation Agriculture (CA) aims to concurrently promote agricultural productivity, local livelihoods, climate resilience and other environmental objectives. We review the emerging evidence base in Eastern and Southern Africa to address whether CA is climate smart and why adoption rates by smallholders remain generally very low. We first develop an adoption framework that can be used to assess when and where the different components of CA are expected to be adopted under different conditioning factors and consider options to make CA climate smart. Our results suggest that CA can contribute positively to productivity and adaptation/resilience objectives, although the degree of success varies considerably by farm, household and regional characteristics. Overall, we find that capital-intensive (mechanized) CA is more likely to be adopted in areas of economic dynamism where capital is cheap relative to labor. Labor-intensive CA practices are more likely to be adopted in regions of economic stagnation where capital is expensive, and labor is abundant and cheap. A subnational focus is needed to identify economic conditions of different regions and agro-ecological zones and to test hypotheses derived from the framework in this paper and to propose the most appropriate CA packages for promotion. Our findings suggest that labor using variants of CA such as planting basins are more likely to be adopted than are capital using mechanized options in densely populated parts of Malawi, Ethiopia, Kenya, Tanzania, Zambia and Zimbabwe where labor is abundant, and presumably cheap, but capital is expensive. However, rising land scarcity (prices) and wages in the region present an opportunity for capital intensive, mechanized CA operations to be adopted if the cost of capital can be kept low and if there is a supportive environment for mechanization. We conclude that CA is climate smart and if adopted widely, it has the potential to help build resilience in smallholder farming systems. CA can be more climate smart, and its uptake can be enhanced by reframing, better targeting, adapting CA to location-specific economic and biophysical, and through greater and more effective public spending on agricultural research and development.

Across sub-Saharan Africa, climate change is leading to increasingly erratic weather patterns that challenge farming practices, particularly for smallholder farmers. Preparing farmers for these changes and increasing their resilience to extreme weather events is critical for food security in areas where populations are increasing. The El Niño event of 2015/16 led to drought conditions in Malawi which are expected to become more normal in the future. This resulted in widespread crop failure and the need for external food aid. The experiences of Malawian farmers during this time creates an opportunity to identify areas where adaptations in land management practices as part of resilience building initiatives can prepare farmers for future climates. This paper presents results of household surveys and interviews of 201 farmers from a case study in southern Malawi. Half of the farmers surveyed practice Conservation Agriculture (CA), a Climate Smart Agriculture technology that increased resilience to this drought event. The majority of households relied on agriculture for all their livelihood streams, indicating that diversification away from sole dependence on agriculture would increase resilience. Our study shows that poorer, female farmers are less likely to practice CA than wealthier male farmers. Results also illustrate that while farmers had access to seasonal weather forecasts, a key tool to guide land preparation and planting, they remained reluctant to believe them or to amend cropping or land management practices. Agricultural extension services within Malawi can play a vital role in preparing farmers for future extreme weather events and ensuring forecast communication link to predicted agricultural impacts and land management actions for building resilience into agricultural systems. Extension services need to focus on supporting poorer female farmers to adopt CA practices and providing farmers with the tools and knowledge to respond effectively to seasonal and sub-seasonal climate information.

Rainfed agro-ecosystems, the purported grey patches untouched by the Green Revolution or most technological advances, occupy a prominent position in Indian agriculture. Cropping intensities and crop yields are low and unstable in these areas due to unpredictable patterns of rainfall, a host of biotic and abiotic stresses and adherence to traditional farm practices. This precarious food security situation is especially dangerous in the central Indian tribal belt (also known as the poverty belt) which is a typical rainfed area dominated by tribal communities. More than 90% of the tribal people are totally dependent on agriculture and produce much of what they eat. Small land holdings and their low productivity, along with uncertainties in rainfall patterns, increases economic and social risks for these farmers. With degraded soils and unreliable weather patterns, return on investment is uncertain and likely to be much lower overall than under irrigated conditions with better soils. Under such conditions, one approach to achieve improved crop production is to minimize soil and other natural resource degradation by adopting a set of crop-nutrient-water-land system management practices, such as conservation agriculture (CA). To assess the effect of introduced technology under local ecological and socio-economic conditions, the study focused on two ecosystem services: a) provisional, and b) regulatory through five treatments consisting of farmers' traditional practice (FP) which was conventional tillage with broadcast of local variety maize ( Zea mays L.); and four CA treatments viz., conventional tillage with sole cropped maize using line sowing of the improved maize cultivar ‘Nilesh’ (CT-M); conventional tillage with maize intercropped with the improved cowpea ( Vigna unguiculata L. cultivar ‘Hariyalli Bush’) (CT-M + C); reduced tillage with sole cropped maize (MT-M); and reduced tillage with maize + cowpea (MT-M + C). After harvest of maize and cowpea, mustard was planted as a post rainy season crop and all the mustard plant residues were returned to their respective plots as residue cover except FP. Under provisional ecosystem services, performance of CA on crop yield, and profitability was assessed through maize equivalent yield and partial budget analysis, respectively. Results showed that reduced tillage combined with maize-cowpea intercropping (MT-M + C) followed by mustard residue retention had higher system productivity and net benefits, an increase of 200% and 230%, respectively over FP. Under regulatory ecosystem services, the soil quality was assessed through calculation of soil quality index (SQI) which was highest under MT-M + C followed by mustard residue retention and lowest under farmers' practices. In terms of CA treatment preference, 35% of the farmers indicated a strong preference for MT-M + C compared to 14% for FP. Combined, these results clearly demonstrate the potential of CA to simultaneously increase yield, diversify crop production and improve soil quality which should support a move towards sustainable intensification of crop production to improve future household income and food security. Additionally, using a transdisciplinary approach fully engaged all stakeholders in co-designing the CA treatments appropriate for the farmers and local environmental conditions leading to significant impacts on economic livelihoods, environmental sustainability and food security. [ABSTRACT FROM AUTHOR]

Resource scarcity (labor, water, and energy) and high production costs are challenging the sustainability of conventional methods for rice and wheat establishment in Central Asia. Water saving irrigation and conservation agriculture (CA) practices (e.g., dry seeded rice, zero tillage wheat, residue retention) are potential alternative, resource-saving establishment methods. The Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model (CSM) can both be a valuable ex-ante and ex-post tool to evaluate the effects of water saving irrigation and resource saving CA-practices. The CSM-CERES-Rice and CSM-CERES-Wheat models of DSSAT were evaluated using experimental data from the 2008 to 2010 rice and wheat seasons as monitored in Urgench, the Khorezm region of Uzbekistan for growth, development of these crops, as well as soil mineral nitrogen (N) and volumetric soil moisture content in these cropping systems. Thereafter, the models were used to explore the long-term impact of water saving irrigation and CA-practices on grain yield, soil organic carbon (SOC) dynamics, N dynamics, and water balance in a rice–wheat rotation for 39 years starting from 1971. The simulation results showed that the simulated yield of water-seeded rice without residue retention and flood irrigation (WSRF-R0-FI) is likely to remain the highest and constant over 39 years. The simulated yield of dry seeded rice (DSR) with alternate wet and dry (AWD) irrigation and varying levels of residue retention was penalized for the initial years. However, the simulated rice yield increased after 13 years of CA-practices and continued to increase for the remaining years. Wheat did not experience a yield penalty for any of the treatments and simulated yield increased over time across all CA-practices based treatments. In the long-term, the effect of tillage methods and different residue levels for both rice and wheat were apparent in terms of grain yield and SOC build up. The results of the sensitivity analysis showed that WSR using AWD irrigation with puddling (WSRF-R0-AWD-Puddled) could give equivalent yield with that of WSRF-R0-FI and that irrigation water for rice could be reduced from 5435 mm to 2161 mm (or by 60%). Deep placement of urea in DSR (CT-DSR-AWD-DPUS) has the potential to increase yields of DSR by about 0.5 t ha −1 . Despite the huge water saving potential through the adoption of water saving AWD irrigation in DSR, a major challenge will be to prevent N losses. Substantial amounts of N losses through leaching, immobilization by residue mulch, combined with gaseous losses through volatilization and denitrification are the major causes for the lower simulated yield of rice for the AWD treatments. During the rice season, the implementation of water saving irrigation can improve water use efficiency by reducing percolation and seepage losses, which is an option in particular for WSRF-R0-FI. For both crops, the water use efficiency can be improved by lowering evaporation losses e.g. through residue retention on the soil surface. The creation of a sub-surface hard pan (puddling) and deep placement of urea super granules/pellet (DPUS) fertilizer could be the key for water saving and better yields of rice. Because CA-practices require almost three times less irrigation water than conventional method, and provide a long-term positive impact on grain yields of both crops, the CA-practices should be considered for double, no-till, rice–wheat cropping systems in the irrigated semi-arid drylands of Central Asia. [ABSTRACT FROM AUTHOR]

Highlights: [•] Influence of land configuration & residue management on soil moisture was evaluated. [•] Highest infiltration rate recorded in raised bed with residue+hedge leaves under no till. [•] SMBC was highest in RB with residue+hedge leaf incorporation. [•] Highest groundnut equivalent yield in RB with residue+hedge leaf incorporation. [•] Water use efficiency of rapeseed was maximum in RB with residue+hedge leaves. [Copyright &y& Elsevier]

The benefits of conservation agriculture (CA), have been widely recognized and CA has been widely adopted in many parts of the world. However, there are some factors that limit the widespread adoption of CA in Asia. The most prominent factor appears to be the lack of suitable CA seeders for small to medium sized land-holding (SLH) farmers. This paper summarizes the small to medium no-till and minimum-till seeders currently available in Asia, and classifies these seeders into four types: manually operated units, animal traction seeders, two-wheel tractor and four-wheel tractor driven seeders. Detailed characteristics have been provided for some typical CA seeders and comparisons were made as to their suitability under particular working conditions. Typically manual and animal traction seeders are confined to small farms and hilly areas, while the larger CA seeders suited to four-wheel tractors are used on larger acreages. To ensure seeding performance on most four-wheel tractor CA seeders, two types of anti-blocking mechanisms (passive and active anti-blocking) have been fitted. Finally, the paper proposes a future direction and development of CA seeders for small/medium size farms in Asia, and also suggests changes in policy support, improvement of anti-blocking mechanisms, suitability for various crops, geographical zones and the contribution of development by public private partnerships to advance the adoption of CA seeders. [ABSTRACT FROM AUTHOR]

The improvement of soil quality in agro-ecosystems is one of the major objectives of conservation agriculture (CA) strategies. The objective of this study was to evaluate, quantify and compare the effects of two tillage practices, four crop rotation sequences, two residue management systems and their interactions on the soil quality of a Haplic Plinthosol in South Africa using the Soil Management Assessment Framework (SMAF). The evaluation was done on a CA field trial established in 2012 in the Eastern Cape Province of South Africa. The trial was laid out in a split-split-plot design with tillage: conventional tillage (CT) and no-till (NT) as main plot treatments. Sub-treatments were crop rotations: maize-fallow-maize (MFM); maize-fallow-soybean (MFS); maize-wheat-maize (MWM); maize-wheat-soybean (MWS). Residue management treatments: removal (R -) and retention (R +) were in the sub-sub plots. Soils from the CA trial were sampled at 0 – 5 and 5 – 10 cm depths after five cropping seasons (2012–2015). Thirteen soil quality indicators were determined to assess soil quality. The SMAF soil quality index (SMAF-SQI) was used as an indicator of overall soil quality. The study results demonstrated the dominance of tillage practices in significantly affecting soil biological, chemical and physical properties in the short term than crop rotation sequences and residue management systems. The soil biological indicators viz. SOC, MBC and BG activity were more sensitive to CA strategies, which confirmed their effectiveness as tools for soil quality assessments in the short-term. The study also revealed the short-term significant effects of tillage on the overall SMAF-SQI while crop rotation and residue management had no significant effects. Overall soil quality assessment using the SMAF technique provided a sound basis for distinguishing the short-term impacts of CA strategies on the function of the Haplic Plinthosol in Eastern Cape, South Africa. • The SMAF algorithms were sensitive to changes induced by CA strategies. • The impact of tillage practices were more dominant in the short term. • CT registered significantly higher SQI than NT in the short-term. • The soil biological indicators were more sensitive to CA strategies. [ABSTRACT FROM AUTHOR]

Abstract: The conversion of native vegetation (NV) into agricultural land by clearing and tillage disrupts the soil structure, and depletes soil organic carbon (SOC) pool. The data on changes in SOC pools are needed to enhance scientific knowledge regarding the effects of land use and no-till (NT) systems on soil fertility, agronomic productivity, and soil C sink capacity. Thus, the objective of this study was to quantify changes in SOC fractions due to conversion of NV to agricultural land, and to assess the rate of recovery of SOC fractions and the resilience index of NT cropping systems under sub-tropical (Ponta Grossa/PR — PG) and tropical (Lucas do Rio Verde/MT — LRV) regions of Brazil. The conversion from CT to NT was 29 and 8years at the PG and LRV sites, respectively. Five different fractions of SOC pools were extracted by chemical methods (i.e., C in the polysaccharides — CTPS, hot-water extractable C — HWEOC, chemically-stabilized organic C — CSOC), and physical fractionation (i.e., particulate organic C — POC, and mineral-associated organic C — MAOC). Land use change primarily altered the labile (HWEOC, TPS, and POC) and also some of the stable (MAOC) pools at both sites. The CSOC pool was almost constant throughout the soil profile and represented, across land uses, 7.2gCkg−1 at the PG and 3.1gCkg−1 at the LRV sites. At the PG site, the HWEOC and CTPS concentrations in the 0–5cm depth decreased by 56% (1.21gkg−1) and 45% (7.21gkg−1) in CT soil, respectively. At the LRV site, concentrations of HWEOC and CTPS in the 0–5cm depth decreased by 50% (0.4gkg−1) and 42% (4.8gkg−1), respectively. In contrast, concentrations of HWEOC and CTPS fractions in soil under NT in the 0–20cm depth were closer than those under NV, and exhibited a distinct gradient from surface to sub-soil layers. The adoption of CT reduced POC by 46% (4.7Mgha−1), and MAOC by 21% (15.1MgCha−1) in the 0–20cm depth at the PG site. Using CT for 23years at the LRV site, decreased SOC fractions in the 0–20cm depth at the rate of 0.25 and 0.34MgCha−1 yr−1 for POC and MAOC, respectively. In contrast, adoption of intensive NT systems in tropical agro-ecoregions increased POC at the rate of 0.23 to 0.36MgCha−1 yr−1, and MAOC by 0.52 and 0.70MgCha−1 yr−1. An important effect to be emphasized is the possibility of recovering, at least partially, the SOC fractions by adopting high biomass-C inputs under NT management, and despite the fact that the experimental duration at the LRV site was only eight years. With a high and diversified input of biomass-C in intensive NT systems, higher resilience index was observed for CTPS, HWEOC, and MAOC. The variation in SOC among CT and NT systems was mainly attributed to the MAOC fraction, indicating that a significant proportion of that fraction is relatively labile, and that spatial inaccessibility of SOC plays a significant role in the restoration of SOC. [Copyright &y& Elsevier]

Climate change models predict an increase in climate variability in the future, with more rainfall extremes and greater risks, causing a negative impact on crops produced by smallholders in West Africa. Conservation Agriculture (CA) systems can be effective in mitigating yield loss in environments with increased weather risk. This study aimed to evaluate CA cropping systems that can minimize both economic and climatic risks under erratic climatic conditions in West Africa. We tested upland rice-based CA systems and conventional systems with tillage (CT), in rotation with maize in some of the cases, without and with fertilization, at different sowing windows in the Bouaké region, Côte d'Ivoire, from 2015 to 2020. Sowing in June showed in a higher rice yield (1183 kg ha-1 and 1370 kg ha-1 without and with fertilization, on average over the 2017–2020 period) than in March (521 kg ha-1 and 495 kg ha-1 without and with fertilization) or in July or August (335 kg ha-1 and 498 kg ha-1 without and with fertilization). During the first four years, rice yields tended to be lower under the CA systems than under the CT systems, especially when water availability was not a major constraint. However, after this transition period, and especially when water stress occurred, as in 2020, rice yields under CA systems (1835–2021 and 2147–2254 kg ha-1 without and with fertilization) were higher than under CT systems (1350 kg ha-1 and 1435 kg ha-1 without and with fertilization). CA systems having relatively longer duration for growing cover crops tended to produce higher upland rice yield grown in the subsequent season. In both CT and CA systems, the impact of fertilization on rice yield was small over the study period, and the mean rice yield increase due to fertilization was on average 451 kg ha-1 even when rice was sown in the summer season, resulting in negative economic return. These results indicate that whereas low-input CA upland rice-based systems together with optimizing sowing window for rice could be promising options for sustaining rice yield and mitigating yield loss in environments with increased weather risk, further research is needed for reducing transition period to CA systems in order to enhance their adoption by smallholder farmers. Desirable cover crops should be less labor-demanding, generate incomes from their products, and produce large biomass under erratic climatic conditions. • Conservation agriculture (CA) was compared to conventional tillage (CT) for 6 years. • In years 1–4, CT performed better than CA in favorable climatic years. • After 4 years, CA performed better than CT, especially in dry conditions. • Fertilization was not profitable in both CT and CA systems. • Associating cassava and stylo is a profitable option for soil regeneration. [ABSTRACT FROM AUTHOR]