Conservation Agriculture Research Updates - April 2026

This research from NW India analyzed data from a 17-year long term experiment that concentrated on crop establishment, tillage and residue management in a rice-wheat system. This cropping system and region of India is impacted by residue burning and GHG emissions. The experiment had 5 scenarios from the traditional system of puddled transplanted rice followed by tillage before planting wheat with all residues removed (Traditional) to NT direct seeded rice (NTDSR), NT wheat (NTW) and 1/3rd residue retention (RR) of both rice and wheat. Among the scenarios the NTDSR-NTW-RR one achieved the highest carbon management index across both the soil layers, indicating a reduced need for carbon management due to higher TOC  compared to the traditional system. They conclude that "reduced or no tillage combined with residue retention in RWS holds substantial potential for increasing carbon sequestration, reducing net GHG emissions, and lowering carbon footprints. Additionally, this practice offers an alternative to crop residue burning, a significant contributor to air pollution in the western IGP."

This paper starts out by saying that in Sub Saharan Africa (SSA) tillage and burning of residues is mostly used that causes soil erosion. Maize is also the major crop in smallholder diets. They used the APSIM model to simulate the productivity and protein yield of a variety of intercropping systems involving three crops (maize, cowpea and pigeonpea) under full CA practice relative to conventional tillage (CV) with the same intercropping system. The baseline scenario used daily climate data from 1997-2015 in Northern Mozambique. The results are given in the paper but the Authors conclude that "although under the CA system, there were ng declines in grain yields nevertheless, protein yields and overall productivity remained consistently higher under the CA system.

Conventional farming in Sub-Saharan Africa (SSA)  is resulting in soil degradation. This paper reviews current practices, challenges, and constraints to the adoption of CA in SSA to reverse this degradation. They show that CA is only adopted on 1.25% of cultivated land in SSA despite 2 decades of promotion. The paper lists 6 possible reasons for this lack of adoption of CA. They also suggest that adoption by smallholder farmers is also obstructed by socio-economic factors due to smallholder farmers’ focus on short term yield increases and their lack of access to markets, loans, and education. They conclude that wider adoption by smallholder farmers in SSA requires CA approaches that are downscaled to fit the existing tillage tools and the specific agroecological and socio-economic farm settings.

This paper evaluates the effectiveness of various furrow openers for tackling the problems associated with residue management and as an alternative for burning in India. The assessment was done in in a simulated soil bin and looked at various forward speeds and 3 straw densities at a consistent working depth of 5cm. Results showed that draft requirements increased with forward speed and straw density, while straw cutting efficiency decreased with these two factors. The double disk furrow opener showed the highest straw-cutting efficiency (81.36%) at a working speed of 1.5 km h−1 and a straw density of 1 t ha−1.

This article looks at alternatives for handling rice crop residues to reduce air pollution and GHG emissions. They chose 4 rice residue management systems -- burning, soil incorporation, livestock fodder, and biochar. Modeling approaches were used including 100-year simulations for 3 soil moisture categories - dry, median, and wet. The results are available in the paper including a more detailed description of the 4 management systems. I am surprised that the paper did not include a treatment where the residues were left on the soil surface and the next crop planted using no-tillage since this conservation agriculture management system is being promoted in the IndoGangetic Plains of South Asia.

This article suggests that conventional farming with intensive tillage and residue burning results in substantial degradation of soil health resulting in declining crop productivity of maize. A field experiment looked at NT with stubble residue mulch for 3 years compared to CT with residues or ridge tilled maize. The results showed that NT with residue consistently out yielded the CT and ridge tilled systems. In addition the traditional practice of stubble burning in all systems substantially reduced grain yields. Soil health improved in all NT + residue treatments compared to CT and ridge-till in terms of soil porosity, electrical conductivity, hydraulic conductivity (HC), available soil moisture, soil organic carbon, soil N, P and K content. They concluded the importance of switching to NT but with residue retention.

This book chapter is one of two parts that discusses "Mulches and cover crops". This part looks at different types of organic and inorganic (plastics for example) mulches and cover crops. The second part looks at their role in soil health and climate resilient agriculture. Mulching use in CA is seen as a replacement for burning. Cover crops can protect soils from erosion and help in increase soil fertility. The chapter also looks at the limitations in terms of disposal of non-biodegradable plastics, competing demand for residues, and lack of machinery and knowledge of farmers for field operations. The suggest that policy decisions can overcome these decisions. In the second part,  they conclude that policy decisions are needed to overcome limitations in adopting conservation agriculture, mulching and cover cropping so as to provide technical and financial support to farmers.

This is another paper from the Indian Himalayas that discusses degradation of environmental quality, water systems, and soil resources by present farming practices and the use of CA as an alternative option. The aim was to evaluate the effect of CA and weed management (WM) practices on carbon dynamics and biochemical properties of soil. The CA levels varied from conventional agriculture to partial CA (pCA1, pCA2, and pCA3) and full CA, while WM had three levels consisting of chemical control, integrated weed management, and weedy check. Results showed SOC and labile fractions of C were highest under full CA, but there were no differences for organic carbon. Full CA also had higher dehydrogenase and alkaline phosphatase activity than conventional agriculture. Full CA had the highest soil quality index and conventional the lowest. WM showed herbicide the best but little difference for weedy check or IWM.

This paper looks at the the practice of residue burning, a major issue  along with climate change in India. Some elements in the crop residue are lost on burning and also pollute the air. This review provides critical insights on the current status of residue production and in-situ management of crop residue via different routes using suitable machinery packages and discusses the relative advantages and challenges. The paper also discusses the use of the crop residues in CA combined with no-till that is also being practiced by rice-wheat farmers in India. Essentially an in-situ way of utilizing the previous crop residues that are found to improve soil health.

This interesting paper looks at the problem of loose straw after combine harvesting wheat and other crops. One farmer solution is to burn this straw, but that has negative impacts and pollutes air. This paper reports the effect of residue distribution on soil properties and crop establishment and yield under no-tillage and controlled traffic in cereal (wheat-wheat-barley) and diverse (wheat-legume-canola) rotations, over the final six years of a larger 12-year rotation experiment in Australia. For each crop and rotation, residue was either spread evenly or burnt. Increasing residue amount had a positive effect on establishment and yield when conditions were dry around seeding and early crop growth stages, possibly associated with increased water availability with increased residue load. In the longer term, higher residue amounts resulted in increased soil nutrients behind the harvester, which increased yields in some years. Therefore, research to improve uniformity of residue spread behind harvesters is crucial. 

This paper looks at residue management that is difficult to manage in modern agriculture without burning and can lead to late planting. This paper looks at zero-till residue management on soil health parameters in a maize-chickpea pattern in the black vertisols of India. After 4 years the soil bulk density was reduced by 3.0–10.2% and volumetric moisture content was improved by 10.2–19.3% at 0–10 cm soil depth in ZT with residue over conventional tillage (CT). Organic carbon and labile carbon,  P and K, total fungal and actinomycetes were also increased compared to CT at 0-10 cm soil depths.

Surface seeding (SS) is the purest form of no-till with seeds placed on the soil surface with no soil disturbance. This paper conducted a systematic literature review on SS of wheat reported in the IGP, with the aim to cover the concept of SS, its impact on wheat yield, soil properties, and the environment, with the potential benefits and constraints. Their review showed that SS-based rice-wheat systems improve productivity (~10%) and profitability (20-30%), while employing less irrigation water (15-30%) and energy input (20-25%) compared to a conventional system. In relation to soil properties the SS approach enhanced soil health by virtue of increased soil organic carbon and improved soil aggregation, as well as soil, water, and energy conservation.  SS consisting of no-tillage with substantial crop residue retention offered an alternative to crop residue burning. 

This study explores the short-term agronomic and economic differences between mechanized conventional tillage and mechanized CA in Zambia using a 4-wheel tractor. This on-farm study looked at 3 treatments: 1) disc harrowing (DH) plus residue burning, 2) ripping tillage (RT), and 3) no-till plus soil cover. Maize and soybean were the crops. It was for two years with a wet and dry year. In the dry year for both maize and soybean NT and RT had better yields than DH. But in a wet year, DH and RT yielded better than NT for maize but not soybean. NT and RT showed better stands of maize and soybeans at germination and maturity than DH. The study estimates the gross margins for both crops in the wet and dry seasons and conclude that the potential of mechanized CA among small and medium-scale farmers in SSA is good.

Burning of crop residue by farmers so they can easily prepare land for the next crop is common in India that creates a health issue by polluting the air. It also contributes to C02 and black carbon emissions that then affects climate change negatively. This paper points out that the introduction of the Happy Seeder from Australia allows farmers to sow the next crop without removing the previous crop residue and so is an effective alternative to burning. However, the supply of this seeder is limited and this delays planting of wheat after rice that results in lower wheat yields. This paper looks at how this predicament can be resolved in India through Government policies. 

This paper addresses the issue of managing the large amount of biomass straw after combining rice in India. The easiest and most common farmer way is to burn the straw so land preparation is easier, but this comes with negative environmental problems especially air pollution from the smoke. CA can be a good option since the surface straw can help improve soil health, but low temperatures and nitrogen levels slows decomposition rates, immobilizes nitrogen and hinders land preparation, although CA uses no-tillage. This paper applies fungal inoculants to enhance bacterial degraders. The paper also looks at the genomic insights for choosing appropriate decomposers. The paper talks about incorporation of straw, whereas in CA, the idea is to maintain the straw as a surface mulch and minimize soil disturbance through tillage. Just enough to sow the seed into the mulch with equipment designed to plant efficiently into the residue.

This paper looks at the issue of residue burning in the rice-wheat areas of the Indo Gangetic Plains of India. This is an easy way for farmers to handle rice residue problems before planting wheat, but it has negative impacts on air pollution and GHG emissions. The authors analyzed data from 60 focused group discussions and 24 interviews with farmers and key stakeholders involved with agriculture to get perspectives on crop residue burning (CRB). The people surveyed highlighted the diversity of machinery used in this cropping system and identified the time from rice harvest to wheat planting to implement CR management.Farmers mentioned a mistrust and uncertainty of incentives  for no-burn CRM and access to no-burn technology and equipment.

This paper evaluated the impacts of residue retention and nutrient management practices on SOC and its pools, storage, soil biology, and yield in a multi-ratooning sugarcane system. Residue burning (RB) was compared with residue retention (RR) combined with 3 fertilizer doses with different basal applications of NPK followed by topdress by fertigation. Soils were sampled initially and after 6 years with the first sugarcane crop and 4 ratoons. Results showed that RR had higher SOC compared to RB and also higher DHA, APA, and GBA enzyme activity and higher microbial counts. Residue retention also had higher C sequestration, carbon retention efficiency, and yield with a potential to reduce GHG emissions as compared to traditional practices. 

Burning of rice residues after harvest in India and the IndoGangetic Plains of South Asia are causing serious air pollution health problems and other environmental issues that this paper is addressing. Residue management is a major problem for Indian farmers in the intensive rice-wheat system and farmers need alternatives to just burning the residues but are constrained by lack of viable economic solutions. Technical solutions are available, classified mainly as on-site (in situ) and off-site (ex situ) solutions. The in situ solution includes a variety of machines that can be used to incorporate or surface mulch residue efficiently and allow wheat to be planted into this residue. While ex situ management collects the residue from field for various applications such as energy production, briquetting, composting, paper and cardboard making, and for mushroom cultivation. Awareness and enabling programs are needed to inform farmers of the benefits of these alternative systems described in this paper.

This paper looks at CA as a possible system to reduce residue burning in India by assessing the optimum residue levels for CA. It used the APSIM simulator model to analyze 37 years of diverse CA scenarios for yield, sustainability and carbon footprints in rice-wheat cropping systems (RWCS). The analysis indicated that the maximum system productivity was under the highest residue (HR) compared to conventional tillage with stable yields achieved under CA. SOC was predicted to increase by 30-95% with CA with higher sequestration rates and water productivity was highest with HR. They conclude the APSIM model is efficient in capturing CA effects in South Asian RWCS and that the adoption of CA results in greater and stable yields, higher water productivity, and more carbon capture over the long term, while reducing production costs.

This paper starts by saying "Burning of agricultural residues, cultivation of single crop varieties such as rice and wheat, and traditional soil tillage practices collectively contribute to the degradation of environmental quality, water systems, and soil resources. They describe CA as a viable alternative including weed management (WM). CA treatments varied from CT, three partial CA and a full CA. WM varied from Herbicide, Integrated WM and weedy check. They measured SOC, labile carbon fractions, total organic carbon, and several biochemical indicators of soil health. Results showed that CA had higher SOC and labile carbon fractions, and biochemical indicators resulting in a higher soil quality index value.

This review paper starts by saying agroecosystems sustainability is mainly challenged by unsustainable agricultural practices that lead to land degradation and amplified climate change. It also blames soil degradation and loss for 25% of World's land area deterioration. They suggest CA as a way to restore this land. They mention that global annual adoption of CA was 7 M ha yr−1. CA-based soil and crop management practices enhanced water productivity, soil organic carbon, crop productivity, and energy use efficiency over conventional practices under diverse agroecosystems in India. This study provides in-depth insights into the role of CA in restoring agroecosystem services, attaining SDGs, and ensuring global food security. 

Crop residue burning in the intensive rice-wheat systems of the Indo-Gangetic Plains is a traditional practice but one that deteriorates the soil and environment including air quality. This paper looks at the impact of residue burning and excessive tillage on soil biological properties such as SOC, microbial biomass carbon (MBC), Soil Respiration (SR), Bradford reactive soil protein (BRSP), nitrogen mineralization rate and microbial community structure at two soil depths 0-15 and 15-30 cm. Four different burning treatments included with and without burning residues and tillage and no-till (NT). Results indicated that crop residue burning and tillage pose significant impact on soil biological parameters and soil microbial community especially at surface soil. They conclude that no burn and NT is a more ecologically sustainable system for soil biology. 

This study looks at tillage intensity, crop residue management and green manure (GM Sesbania) on SOC within micro- and macro-aggregates after 6 years of growing rice-wheat in India. The plot treatments included ZT and CT with and without different % of residues and with and without GM. The ZT with 100% rice residue  (ZTWR100) significantly increased soil moisture retention compared to CT w/o residue (CTWR0) and also increased the dehydrogenase (DHA), cellulase, and β-glucosidase activities and the easily extractable glomalin (EEG)- and total glomalin (TG)-related soil protein compared with the CTWR0 treatment. Crop residue retention plus GM significantly improved the proportion of total water-stable aggregates (WSA), mean weight diameter (MWD), and aggregate ratio (AR), compared with the treatments involving residue removal and no GM. 

This paper reviews recent findings to understand and summarize the different aspects of crop residue management, including the impact of the residues on crop and soil health, natural resource recycling, and strategies related to residue retention in farming systems. This is important since modern agriculture results in higher yields of biomass that then need to be managed for beneficial effects rather than improper systems like burning. The authors suggest that suitable residue management techniques  will fit well under existing farming system practices without compromising the systems’ productivity and environmental sustainability.

This report looks at the potential and opportunities for sustainable development in the high rainfall, hilly areas of NE India where erosion and soil degradation is rampant. It looks at CA as a possible management system to address the issues in this area if India and result in better food and environmental security, reduced cost of cultivation, enhanced cropping intensity, crop diversification and improved soil properties. In this area residue burning/removal, repeated soil tilling, monocropping, low to very low use of organic manure and fertilizers result in soil loss, poor soil properties, low productivity and income. They conclude that large scale research, demonstration and capacity building programs along with adequate policy support is required to promote CA in the region with an ultimate objective of achieving sustainable the Development Goal (SDG) of zero hunger, conserve natural resources, biodiversity and climate resilient agriculture.