Conservation Agriculture Research Updates - December 2025

This paper evaluates the role of increasing soil C levels with an expectation of mitigating and adapting to climate change needs. They contend that reduced soil disturbance, retention of crop residues, planting cover crops, or diversification of crop rotations with perennials are indeed effective, especially in the long term (>10 years), in improving soil properties that enhance climate change adaptation, but not so much climate change mitigation. They question whether current programs that pay for C stored in soil are sufficient to incentivize farmers to change their operations due to the high cost to test soil C to validate their efforts. Instead they propose that to promote wider adoption of sustainable conservation agricultural practices, and to make large-scale positive impacts through their use, farmers should be paid to “do the right thing”. The right thing is using the three principles of CA!

This review article looks at the relationship between agroecology and water management in order to identify strategies for sustainable agriculture in North African countries. The paper looks at agroecological approaches to water management, including agroforestry, conservation agriculture, water-efficient irrigation, and landscape design. It looks at integrating biodiversity for water regulation, leveraging ecosystem services for purification, and adopting advanced technologies, such as precision agriculture and remote sensing, and policies needed for efficient water management. They conclude that there is a need for interdisciplinary collaboration among agronomists, hydrologists, ecologists, policymakers, and local communities to develop holistic approaches that seamlessly integrate agroecology and modern water management, ensuring sustainable agricultural systems in the region. 

This is a paper from Uzbekistan on wheat where agriculture is 25% of the national GDP. The study looks at ways to close the yield gap in wheat. They used reviews, crop modeling and machine learning to identify ways to improve wheat yields. The simulations optimized seeding dates, nitrogen fertilizer rates, cultivar selection, and water management practices as ways to be self sufficient in wheat by increasing yields from 4.55 to 6.62 t/ha. Conservation agriculture also showed a 26 % increase in yields compared to conventional tillage. Other results showed that high-yielding, stress-tolerant wheat varieties released after 2010 increased wheat productivity, seeding between September 15 and October 15 maximized yields, while delayed sowing reduced yield by up to 57 kg ha−1 day−1. Seed rates of 160–180 kg ha−1 also helped reduce the yield gap. They concluded that these findings hold relevance for wheat production in other arid and semi-arid regions facing similar food security.

This paper from India evaluated contrasting tillage and residue management in the rice wheat systems of the Indo-Gangetic Plains to identify sustainable and energy efficient systems. Treatments include various triple cropping patters that include a legume, but also no-till wheat and rice that were compared with conventional  puddled rice and tillage wheat. NT systems had significantly lower operational energy for irrigation (∼40%), sowing (∼26%), and land preparation (100%) compared to a conventional-tillage (CT) system and also resulted in higher system yields, net energy returns, energy ratios, energy productivity and energy intensity. The authors conclude that the conventional system should be replaced with these more efficient and higher yielding NT + legume systems. 

This study from NW India using on-farm research explored how different duration's of CA (2, 4, 8, and 12 years) compared to conventional tillage (CT) on SOC, soil aggregation, and system productivity. Results showed that adopting 8-12 years of CA led significant increases in SOC in the topsoil (5cm) and 5-15cmand improved percentages of macroaggregates. But 8-12 years of CA resulted in20-25% reduction in soil inorganic carbon compared to CT. They conclude that enhancing SOC with long-term CA can improve climate-resilient wheat yields in NW India

This paper looks at wheat production in subtropical systems where terminal heat, lodging and erratic rain are common climate induced stresses. The data is collected from 8 locations in India. There were two tillage treatments; CT and NT and permanent raised beds (PRB). They had early and timely planting dates and 3 wheat varieties. Results show that NT and PRB significantly reduced lodging and increased grain yields compared to CT. Early sowing (early November) and the use of lodging-resilient varieties reduced crop lodging, improved crop performance, and increased wheat grain yield compared to late sowing (late November) and the lodging susceptible variety.

This paper utilized bibliometric analyses to map the conceptual and intellectual structure of soil health research from 1996-2021. They reviewed 984 peer reviewed papers that they divided into 3 major research clusters. The analysis revealed critical gaps, including limited integration of pedological modeling to quantify ecosystem services and insufficient long-term studies on conservation agriculture. They recommend that interdisciplinary collaboration among agronomists, microbiologists, policymakers, and climate scientists to align soil health metrics with global targets providing a roadmap to integrate soil health into climate-smart land-use policies.

This research from Brazil studied the SOC stocks to 1-meter deepth for 3 land uses; native vegetation (NV), no-till system (NTS) and plough based tillage (PBT) from 63 sites collecting 3402 soil samples from the Atlantic Forest biomes and Cerrado of Brazil. There was a significant loss of SOC stocks from the PBT compared to the NV treatment.  The SOC stocks of 16 NTS sites exhibited levels that exceeded those under NV, and SOC stock was restored from 80 to 100 % of its NV levels in 27 other NTS sites across the Brazilian biomes. The duration of NTS to restore SOC stock to that under NV ranged from 36.4 to 55.0 years for the Cerrado and Atlantic Forest biomes, respectively. 

This paper starts by saying challenges from climate change require new eco-friendly systems to make farming economic with social dimensions compatible with the environment plus ecosystem resilience. The suggest that CA can help by increasing C-sequestration in soils and plants. This research looks into the benefits of improved SOC when using CA in Portugal from the INFOSOLO legacy database was analyzed through statistical methodologies and machine-learning approaches. 

This paper from China looks at the role of residue mulching in CA with respect to soil gaseous (NH4 and N2O) and hydrological leaching and runoff N losses. Their results show that N2O emissions increased but N leaching was reduced when using residue mulching compared to unmulched soils. Soil nitrate, dissolved organic N, and microbial biomass N increased significantly after SM adoption, as did the denitrification genes (nirS, nirK, and nosZ). The metaforest model suggested that field management contributed substantially to NH3 volatilisation and N runoff during the RM and that climatic conditions determined N2O emissions. 

This 4-year study in the Lower Mississippi Delta on farm size plots compared soybean yield and soil health benefits comparing CT with NT. Both plots were under maize for 11 years prior to growing soybeans using CT and NT soil management for each plot. Results showed that NT compared to CT, in the 0-20 cm layer, increased soil bulk density (rho), total nitrogen (TN), and soil organic carbon (C) but field-saturated hydraulic conductivity (Kfs) decreased in the 10 cm below the soil surface under NT. Yields of soybeans over the 4 years were similar for CT and NT plots. But NT resulted in less expenses without affecting soybean yields.

This study was done in the US upper Midwest over 3 years. There were 15 field pairs with one using conventional (CM) and the other soil health management (SH) (reduced tillage, cover crops and crop diversity). They assessed these plots by looking at soil organic matter pools, microbial indicators and a physical indicator. Wet aggregate stability improved in the SH plots compared to the CM ones. Results showed that most soil properties were significantly responsive to two management combinations, 1) tillage x cover crops, and 2) tillage x cover crops x crop diversity. Microbial indicators along with potentially mineralizable nitrogen (PMN) exhibited the strongest increases in the SH plots.

This review article explores the role of farmer agency in enhancing the effect of extension models related to soil health. They want to empower farmers to innovate and adapt knowledge to identify more efficient systems. It reviews several factors that can improve farmer agency including education, economic opportunities, social networks and supportive policies. The paper proposes the need for policies and programs to improve farmer decision-making opportunities and farmer centered learning platforms, digital tools and to strengthen social networks with the hope that adoption and adaptation soil health solutions improves.

This study looked at the components of CA individually and in combinations with a control on soil carbon and nitrogen dynamics for a direct rice seeded-green gram system. Reduced tillage alone and in combination with rotation resulted in 10% and 6% lower CO2-C release than the plots with residue retained. The paper has results on the role of rotation and crop residue on various enzymes. They conclude that rotation and residue retention are effective for better C and N cycling in this system. Tillage on the other hand needs a longer time to show beneficial results than the 4 years of this study. The increase in soil enzyme activities improved microbial activity, which can further enhance nutrient availability for plants. and help improve soil health.

Excessive tillage of soils in semi-arid Mexico has resulted in severe soil degradation, physical and chemical. The aim of this research was to evaluate how CA can reverse this issue over the long term (25 years) in a maize-triticale rotation under irrigation comparing conventional tillage against CA. They measured various soil physical properties and grain and forage yields. In 18 of the 19 soil quality indicators were higher for CA compared to CT. The highest estimated sustainability was 85% for CA, compared to 59% for CT. CA had greater structural stability with higher porosity values and lower bulk density, important factors for soil structure and crop yields.

This interesting paper from Science promotes the future use of Drones and the paper says that uses of drones in agriculture has taken off globally in the past 5 years. This rapid change has been largely unnoticed by researchers outside of the specialized technical worlds of aeronautical engineering and precision agriculture. This paper explores the diffusion and implications of drones for agriculture amd implications for sustainability. It also proposes an agenda for future agricultural science and policy.

This paper from Bihar, Eastern India, looks at raised bed planting (RBP) for smallholder maize farmers. They evaluated this management system for 4 rabi (winter) seasons and compared with conventional flat planting (FP). They looked at yield, profitability, water use efficiency (WUE), and nutrient use efficiency (NUE). Maize yields were much higher under RBP than FP but also more profitable with higher net returns, better WUE and NUE. Farmers need to be motivated to adopt this system for Rabi maize. 

This paper reports on the long-term effects of different tillage practices and crop residue management on soil biological and physical health using winter wheat and a fodder radish cover crop. The experiment started in 2003 and samples taken in 2021. There were three tillage treatments: direct sowing (NT), harrowing to 10 cm H), and moldboard plowing to 20 cm (MP). Residue was either removed or left in the plots. The biological soil measures were two fatty-acid biomarkers arbuscular mycorrhizal fungi (AMF)and glomalin-related soil protein (EE). Soil physical indices were water stable aggregates (WSA) and five soil pore characters and SOC. CA practices increased AMF biomass and harrowing and NT resulted in stratified SOC. Residue increased SOC levels. They conclude that their study identified the significant role of AMF in maintaining soil health.

This paper from Poland was based on a long-term experiment started in 1999 and evaluated in 2016-2019. The crop studied was faba bean and looked 4 tillage systems; conventional (CT), reduced (RT), strip (ST) and no-till (NT). Over the 4 years there were two favorable years and two with prolonged drought with the weather conditions affecting faba bean yields more than tillage.The highest faba bean seed yield was obtained in 2017 when they ranged from 6.73 t ha−1 in NT to 7.64 t ha−1 after ST and they conclude that NT and ST are the most sustainable. NT provides the best soil protection and
conservation, but in favorable weather conditions, it limits the yield level of faba beans.

This study from Brazil looked at the effect on conservation tillage in a subtropical area of China in order to evaluate its suitability for maize in such areas. There were 3 tillage treatments; no-tillage (NT), earthworm bio-tillage (EBT), and traditional rotary tillage (RT). Also 3 residue treatments; none (O), straw (S), and composted cow manure (M). Maize yield and soil samples (0–10 cm) were collected after four growing seasons to determine the maize production, soil properties and microbial communities. Both no-tillage and earthworm bio-tillage increased soil pH, organic carbon, nitrogen and phosphorus contents, especially with cow manure additions, and increased the general bacteria and gram-positive bacteria under none input. No-tillage significantly increased microbial biomass carbon, especially with none and straw inputs.

This paper from Southern India assesses the impact of different tillage and weed management practices on soil nutrient stratification ratio (SR), carbon sequestration rate (CSR), carbon management indices (CMI), carbon retention efficiency (CRE) and monitor the grain yield of maize after three-years in CA with a cotton-maize-Sesbania cropping system. There are 3 tillage practices; CT cotton and maize, no sesbania = farmer practice; CT cotton- NT maize-ZT Sesbania; and NT for cotton, maize, and sesbania. 4 Weed treatments were herbicide, herbicide rotation, integrated weed management, and hand-weeded control. They conclude that NT plus residue retention and herbicide use would be a viable way to imporve soil health and imptove productivity of the cotton-maize-sesbania system.

This paper from NW Cambodia compares use of conventional tillage (CT) with CA in maize cultivation looking at soil health, agronomic, and economic differences. The experiment was set up in 2020 comparing CT and CA with one cover crop (CAS) and CA with a mix of three cover crops (CAM). Soil health was assessed using a Biofunctool. Soil health (SH) was positively increased under CA. However, in the 1st year CA. had lower plant density and suggested that there was a need to improve NT sowing methods. This problem resulted in no significant differences in maize yield between the 3 treatments. Gross value added under CA was 12.7% less than CT in 2021, it surpassed CT by 43% in the second year.

This paper looks at the rice-wheat system in Eastern India where smallholder farmers are using excessive water and nitrogen with soil degradation. They used field studies and a crop simulation model to assess resilience, viability, and sustainability of this cropping system under CA with different irrigation methods and nitrogen rates. They had 4 treatments from the puddled transplanted rice (PTR) and zero-tilled wheat (ZTW) with flood irrigation to direct seeded rice (DSR) fb ZTW with sub-surface drip irrigation and 75% and 100% recommended N and a N control plot. The DNDC model accurately predicted soil mineral N. DSR-ZTW with drip irrigation  enhanced sustainability and productivity compared to PTR-ZTW and reduced methane emissions by 70-80%. This system also provided the highest system yield, lowered water losses and improved N use efficiency, and reduced GHG emissions. 

This paper from Nepal looked at CA practices plus different N rates on soil chemical and physical properties, nutrient uptake, and yields of a rice-mustard-maize cropping system in an on-farm 2-year experiment. NT+Residue was compared with CT without residue using two crop varieties (hybrid vs local) and 4 nitrogen rates. They conclude that CA plus optimal N significantly improved soil health and yields. Hybrids had higher yields than local varieties.

This paper looks at land in the Lower Mississippi Delta where 70% of the land is furrow irrigated and where NT and bed planting issues hinder NT adoption. Ridge making and furrow maintenance are crucial in this area. This paper looked at the impact of adopting long-term NT compared to conventional tillage (the traditional system). NT increased soil total nitrogen, organic matter, organic sulfur, magnesium, calcium, cation exchange capacity, and stored soil water compared to CT during 4 years of soybean production following 11 years under corn. CT resulted in loss of nutrients as a result of disturbing the soil surface. CT also developed a thick plow pan at 10cm depth. I wonder if they should think of having permanent NT beds with residue retention that is practiced successfully in other parts of the World.