Conservation Agriculture Research Updates - April 2026

A field experiment and meta-analysis was used by the Chinese study to look at the effects on no-tillage on wet stability of aggregates (WSA), clay dispersibility (ClayDis), mean weight diameter (MWD), and aggregate SOC distribution and mineralization in rice paddies. Four tillage practices: no-tillage, rotary tillage and moldboard plow tillage with rice straw retention (NTS, RTS and CTS respectively), and moldboard plow tillage with rice straw removal (CT). Additionally, the meta-analysis showed that no-tillage increased the macroaggregate content, WSA and MWD. They conclude that In rice paddies, the increased macroaggregate content may contribute to increasing SOC, which improves soil structural stability (SSS) under no-tillage.

This field experiment evaluated energy budgeting, carbon footprints (CF) and greenhouse gas (GHG) emissions from rice-wheat cropping systems under long-term tillage and residue management practices in NW India. There were 3 tillage treatments; CT, RT and NT, with and without residue retention. Energy consumption ranged from 51.87 GJ ha−1 (ZT-R) to 64.91 GJ ha−1 (CT + R) and irrigation water was the major energy intensive input (41–44%) followed by chemical fertilizer (32–40%). Overall, switching from CT–R to ZT + R lowered energy consumption (19%), GHG emission (16%) and carbon footprint (78%), making it the best-bet option for climate change mitigation and global warming related environmental protection.

This study includes research soil-water studies on maize-wheat system where maize is used instead of rice. They use CA and sub-surface drip irrigation (SSDI) as key strategies to address water scarcity in South Asia. The field study used a process-based model (HYDRUS 2D) to understand water transport, root water uptake and components of soil water balance in maize grown in rotation with wheat after five years of continuous adoption of conservation agriculture. The study included CA, SSDI, permanent beds, with and without residues and different N-rates and compared with CA on beds with furrow irrigation and conventional tillage on beds without residue. In CA+ based plots (CA + SSDI) significantly had higher biomass production and radiation use efficiency with reduced water use than CA (furrow irrigation) and CT.

This article looks at the issue of weeds and the weed seed bank when converting from CT to CA in Bangladesh intensive rice-based systems. Two rotations were studied: wheat-mungbean-winter rice and monsoon rice-mustard-winter rice. Strip tillage plus residues was compared with CT and no residues. The weed seed bank was determined at several depths. After 2 years, ST+residue had a lower emerged weed count from the weed seed bank. Overall, ST plus 50% residue had a more diverse seed bank than CT without mulch. The majority of weed seeds were amassed in the 0-5 cm soil depth of the ST, while most of them were accumulated in the 10-15 cm layer of the CT.

This study on the rice-wheat system of the Indo-gangetic plains of South Asia addresses the negative issues of the tillage, water, energy and capital intensive practices of this traditional system. There is also a major issue of crop residue burning, especially during rice harvest. 6 management scenarios are used consisting of business as usual (BAU) as the check compared with various combinations of ZT and RT; residue use; recommended dose of fertilizer (RDF); use of the Greenseeker tool as a nutrient-expert tool. The latter listed as "Climate Smart Agricultural Practices (CSAP). They conclude that  CSAPs can cope better with climatic extremes than BAU and should be further promoted.

This 6-year study examined the residual effect of tillage and nutrient management applied to summer rice on root growth-attributes and impact on morpho-physiology of succeeding winter pea  grown uniformly under NT. Increased root exudation was observed under NT and MT (minimum till) along with organic residue addition. Also, enhanced chlorophyll pigmentation and favourable leaf characteristics were observed in the pea crop grown under NT with 50% NPK+weed biomass (WB)/green leaf manure (GLM) applications. They conclude that adoption of MT/NT along with 50% NPK+WB/GLM in summer rice is recommended for inducing favourable root environment and optimised pea production in succeeding winter season in study region of the Eastern Himalayas,

This study evaluated eight integrated crop management (ICM) systems in the rice-wheat systems of NW India where direct seeded rice followed by NT wheat are seen. The various ICM's evaluated were ICM1&2- conventional transplanted rice fb flatbed wheat (check), ICM3&4- conventional direct seeded rice (DSR) fb furrow irrigated raised bed wheat without residues, ICM5&6- conservation agriculture (CA)-based modules [zero tilled (ZT) DSR and ZT wheat] with the wheat and rice residues, and ICM7&8- CA-based modules (ZTDSR and ZT wheat) with wheat, mungbean and rice residues. They conclude that it is important to to have adequate input integration and adoption of CA based ICM's, especially ICM 7&8, improved the soil carbon dynamics, crop yields, farm profits, and provided water savings 

This 8-year study in India looked at the shift in weed species and diversity with different CA scenarios. The scenarios were Sc1, conventional tillage (CT)-based rice–wheat system with flood irrigation (farmers’ practice); Sc2, CT-rice, zero tillage (ZT)-wheat–mungbean with flood irrigation (partial CA-based); Sc3, ZT rice–wheat–mungbean with flood irrigation (partial CSA-based rice); Sc4, ZT maize–wheat–mungbean with flood irrigation (partial CSA-based maize); Sc5, ZT rice–wheat–mungbean with subsurface drip irrigation (full CSA-based rice); and Sc6, ZT maize–wheat–mungbean with subsurface drip irrigation (full CSA-based maize). Weed density, biomass and diversity remained almost the same across years. Observed shifts in weed species were therefore attributed to different CA scenarios that are discussed in this paper.

This paper concerns issues of weeds in direct seeded rice (DSR) rather than no-till rice, but had some interesting results. They suggest that DSR can save water, labor, energy, reduce GHG's and improve soil properties so would be an important management system for rice in the future. However, weed control is essential to achieve high yield and resource efficiencies. Herbicides are one solution, but efficacy is influenced by weed species present. This study evaluated pre- and post-emergent herbicides on weeds, crops, economics, water productivity and nutrient efficiencies. Results showed treatments reduced weeds by 68-84% compared to an unweeded control. Net returns were also positive and even better than a weed free control. They concluded that integrating herbicide use with brown manuring and hand weeding was the best practice. In the brown manuring treatment, Sesbania aculeata was broadcast in the rows between the line sown rice, with this legume killed using 2,4 D after 28 days after seeding.

This study looks at the data from a long-term trial in Eastern India with 4 treatments: Traditional rice-wheat (TA), Full CA (fCA), and two partial CA's, pCA1 and pCA2 that differ in crop establishment methods, cropping system and crop residue management. Soil health parameters were measured 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. 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. They conclude that CA can be promoted for sustainability of a rice–wheat system due to higher productivity (38–53%).

This paper studied the effects of tillage, crop residues, and green manure on soil carbon pools and hydrolytic enzyme activity in a sandy loam after five cycles of the rice-wheat system (RWS). Four main plot rice treatments included (1) puddled transplanted rice (PTR) with no wheat straw, (2) PTR with 25% wheat stubbles (12–15 cm long) retained, (3) PTR with no wheat straw plus GM, and (4) PTR with 25% wheat stubbles plus GM. Three subplots treatments in wheat were (1) conventional tillage with rice straw removed, (2) zero tillage (ZT) with rice straw removed, and (3) ZT with 100% rice straw retained as a surface mulch. The results showed that PTR with wheat stubbles retained plus GM and ZT wheat with rice straw retained (ZTWRS100) significantly increased all the carbon pools and hydrolytic enzymes except phenol oxidase and peroxidase activities.

This letter suggests that the development and adoption of a single agricultural practice may not help in the holistic mitigation of the impacts of climate change and may result in economic vulnerability to farmers. Instead there is a need to develop and recommend a group of agricultural practices having compatibility for one another. The research used a library search to look at CA, SRI, Organic and soil applied biochar as the major agronomic practices being used to improve ecosystem services such as improving nutrient cycling, soil fertility and crop productivity as well as climate change mitigation. The letter mentions the issue of adoption but suggests that scientific communities are exploring the role of combined agricultural practices.

This is an interesting paper from Cambodia looking at nematode issues in lowland rice managed using CA. They compared nematode populations, rice yield and soil organic matter in conservation agriculture management, conventional rice systems with greenmanure management (GMCT) and conventional plough-based tillage systems. Results demonstrated that GMCT for one year (GMCT1) and the long-term CA for seven years (CA7) reduced nematode densities in both soil and in rice roots, almost throughout the study period, compared to the CT system. For rice yield components and soil fertility, CA7 proved to be effective in increasing plant height, the number of tillers/plant and soil organic matter.

This study looks at the issue of weed control in CA systems that has labor and costs of production problems. This study looked at a CA based rice (direct seeded)-wheat-mungbean cropping pattern over two years of study. The goals were to study the types and distribution of weeds in non-puddled rice and following strip-tilled wheat fields, and to find the most economic way to manage the weeds in both crops. The latter goal included using herbicides. The most most effective treatments involved two herbicides with one applied pre- and one post emergent in wheat and two other herbicides in direct seeded rice also applied pre- and post-emergent.

This article looks at the effect of 10 years of CA on soil quality under cropping scenarios in NW India. Sc1-transplanted puddled rice (TPR) followed by conventional tilled broadcasted wheat (CT-wheat) with residue removal (farmer practice); Sc2-TPR rice followed ZT wheat and ZT-mung bean with partial residue retention; Sc3-direct seeded rice (DSR) followed by ZT-wheat and ZT-mung bean with full residue retention; Sc4-DSR is replaced by ZT-maize followed by ZT-wheat and ZT-mung bean Sc5 was Sc3 with sub surface drip irrigation (SSDI) and; and Sc6 was Sc4 + SSDI. The results show that CA based maize-wheat-mung bean cropping system should be recommended for better soil quality and yield sustainability.

In the IGP rice-wheat system farmers are adopting NT wheat but there is limited data on the effect of CA on soil aggregation and enzyme activity. This paper investigated the effects of direct seeded rice (DSR)-NTW, DSR-NTW with brown manuring (BM) or mungbean (Vigna radiata) residue retention (MBR) with rice residue retention (RR) on soil aggregation, glomalin content and soil enzymatic activities after four years under an irrigated rice–wheat system. DSR + MBR-ZTW + RR-ZTMB treatment resulted in an improved soil microbial environment after four years of rice–wheat cropping in the IGP. The enhanced soil properties were mainly due to residue retention of crop residues, zero tillage (NT) in two crops (in the first three years) and triple ZT (in the fourth year), and growing of a legume crop in the conventional rice-wheat system in the IGP.

This is an interesting article from India on the impact of CA on insect pests and their natural enemies in wheat in the rice-wheat system of the Western Indo-Gangetic Plains. Major insect pests (foliar aphids, root aphids, termites, and pink stem borer) and their natural enemies in wheat managed under three tillage practices, i.e., zero-till (ZT), reduced tillage (RT), and conventional tillage (CT) with (protected) and without (unprotected) insecticide protection scenarios, was investigated. Foliar aphids and termites were lowest in the ZT-protected treatments and highest in the CT-unprotected system. Root aphids were highest in the reduced tillage-unprotected system. More fine-tuning of insect-pest management tactics based on these relations would enhance the success of CA systems. 

This chapter 11 in the book listed above is devoted to CA in rice-wheat areas of South Asia. This geographic area is challenged to feed almost 2.5 billion people while the resource base is being degraded and climate change is causing significant problems. CA is being promoted as a management system to combat some of the challenges arising from previous intensive tillage systems. Much work has been done on the rice-wheat systems with CA management. Recently, these practices have also been applied to other crops and systems in South Asia with encouraging results. This chapter describes some of these successes.

This 7-year field experiment using the rice-wheat cropping system in Haryana, India looked at weed management issues in this system. Weed infestation was more intensified and diversified in direct seeded rice (DSR) than puddled transplanted rice (PTR), and even eliminating puddling in rice-induced more infestation of Phalaris minor in succeeding wheat crop. Residue retention in zero-till (ZT) DSR and rotating conventional till (CT) DSR with PTR reduced weed pressure compared to continuous DSR. Root knot and plant parasitic nematodes were less in DSR than PTR but reverse was true for saprozoic nematodes in DSR and ZT situations. There was also improvement in soil health under ZTDSR/MTR (higher OC, N, P and K, and lower bulk density) compared to PTR. 

This article is included since rice residue burning in parts of India has become a major issue affecting air quality, human health, soil nutrient and biodiversity loss. Once a wealth, the straw has become a waste subjected to burning due to technical, structural, institutional, and socioeconomic challenges. This paper describes multiple alternate uses of this biomass instead of burning including its use in CA management. The economic and environmental gains and losses of alternate straw management options were estimated and shown to be economic and provide an environmental gain and give a key insight to policy makers to tackle this complex issue of straw-burning.

This study looks at Pearl Millet (PM) and mustard (IM), two important dryland crops in India, with the objective to improve the soil quality, productivity of the system and make it more profitable by shifting from traditional to an innovative conservation agriculture (CA) farming system. The study was conducted on a rainy season PM based system with four dry winter season crops, IM and three legume crops- chickpea (CP), fieldpea (FP) and lentil (L) under two methods of land levelling viz. conventional (CLL) and precision laser-assisted land levelling (PLL), and three tillage and seed sowing (TSS) methods- conventional tillage (CT), zero tillage (ZT) and permanent raised broad bed- furrow (PBBF). They conclude that the TSS method with PBBF in conjunction PLL system was more productive and economically profitable, and would improve soil quality and save resources.

Based on the findings from peer-reviewed literature, this review aims to identify unsustainability issues and research gaps in the R–W system in South Asia and propose possible solutions to mitigate those issues and technological interventions to close the research gaps. Issues that the review has identified are declining crop, water and land productivity, deterioration of soil health, emissions of greenhouse gases due to intensive tillage and residue burning, deepening of groundwater levels and shift in weed flora and development of herbicidal resistance in crops. Potential solutions or technological interventions to mitigate the unsustainability issues include resource conservation technologies (RCTs) such as rice residue management, reduced tillage, laser land leveling, soil matric potential based irrigation scheduling, delayed rice transplanting, cultivation on permanent raised beds, direct-seeded rice (DSR), mechanical transplanting of rice and crop diversification with legumes. Sustainable R–W production technologies with reduced water, energy and C footprints are required for increased water and energy productivity and C sequestration for the NW IGPs of South Asia.

This study looked at the effects of earthworm inoculation and cropping systems on upland rice systems over a four-year period in the Highlands of Madagascar. Each year endogeic earthworms were inoculated or not inoculated on three cropping systems; CA, and traditional tillage with and without worms. Soil and plant properties were measured the first 3 years and soil biological properties the 4th year. Earthworm inoculation increased their density 3-fold. Earthworm density in the CA system was higher than either of the CT systems. Earthworm inoculation had positive effects on soil macroaggregation (+43%), aboveground biomass (+27%), rice grain yield (+45%), and N grain amount (+43%). 

This study looked at CA based tillage with zero, minimum and strip-till tillage in farmer fields for a rice-maize system in Bangladesh run for 5 years. They compared participating versus non-participating farmers conducted by household surveys for 606 farmers. During five years of the trial period, participatory and non-participatory farmers respectively adopted CA-Ts in 12% and 3% of annual cropped areas with overall adoption of 6.6%. Variations in adoption existed between locations, cropping systems, and seasons. Yields either remained unchanged or were higher in the CA-T practices compared to farmers’ practices. Access to critical inputs, knowledge dissemination, capacity building and cropping season influenced the diffusion of CA-T practices.

This paper looks at ways to improve the productivity of the rice-wheat system in the eastern Gangetic Plains of South Asia. They evaluated the performance of three RW system intensification options with different management interventions over two years, comparing a conventional RW rotation (CS1), with two stages of conservation agriculture (CA) interventions, (i) the simple inclusion of mungbean (CS2), and (ii) the inclusion of mungbean together with full CA implementation (CS3) at two sites in the EGP that differed with respect to soil type, water table dynamics, and agro-climatic conditions. The addition of mungbean into the conventional RW rotation produced significantly higher system productivity (rice equivalent yield, REY) compared with the existing double-crop rotation across sites. The baseline system was enhanced further when CA-based management practices were adopted, however, the magnitude of system benefit from CA was site and situation-specific.