Conservation Agriculture Research Updates - April 2026

This paper presents results from a long-term experiment from the University of California Division of Agriculture and Natural Resources since 1999. The study site is located in the San Joaquin Valley. 19 years of reduced tillage with cover crops (CTCC) was compared with conventional tillage without cover crops (STNC). Results showed CTCC increased surface soil carbon by 50%, nitrogen by 83%, and air filled porosity 2.5 fold at high water potentials compared to STNC. CCTC respiration rates also increased over 100% under wet conditions, that the authors suggest is due to formation of macropores that become microbial hot spots upon re-wetting that results in accelerated carbon cycling. The authors conclude that "their findings highlight that soil structure–moisture–microbe interactions represent a critical frontier for optimizing conservation agriculture for carbon sequestration, requiring a balanced approach to tillage, organic inputs, and irrigation management to minimize rapid carbon losses. 

This paper from Pakistan reviews using existing literature the impact of CA on SOC, GHG fluxes, soil health and crop yield. The found that CA management significantly increased soil properties including physical (bulk density, water retention, and aggregate stability), chemical (pH, nutrient availability, and C:N ratio) and biological (microbial and enzymatic) activity. They conclude that "These improvements are critical for maintaining soil health and boosting agroecosystem resilience to climate change. The findings underscore CA as an effective strategy for preserving SOC, improving soil quality, reducing agriculture's environmental footprint and enhancing climate change adaptation in agricultural systems."

This is another article from the Central Valley of California that assesses 20 years of conservation agriculture management that looks at soil physical, chemical and structural properties comparing reduced tillage with cover crops with conventional tillage without cover crops. In brief, the CA management achieved dynamic equilibrium characterized by fundamental shifts in carbon stabilization pathways. Water stable aggregates also exhibited 136% greater stability with CA than with CT. This paper discusses the implications of these differences. They conclude "This mechanism shift represents a new soil system equilibrium that maintains enhanced functionality and continued carbon sequestration potential in Mediterranean agricultural systems."

This review assesses the effect of CA management on soil biological, chemical and physical properties. Results show that CA improves soil structure, enhances soil organic carbon sequestration, promotes microbial activity, increases water-use efficiency, and reduces erosion and nutrient losses. The paper also reports on environmental, economic, and social benefits of CA that include biodiversity conservation, reduced greenhouse gas emissions, improved yields, and increased food system resilience. They also look at the the socioeconomic conditions, institutional frameworks, and policy interventions that shape CA adoption and impact and the CA research gaps and future of CA directions.

This paper looks at the impact of no-tillage (NT) and conventional tillage (CT) on soil water and physical properties in Romania using undisturbed soil columns from a field experiment that was a continuous cropping system for 8 years with a 4-year rotation (wheat, maize, sunflower and peas). Various soil physical and water measures were taken. The various measurements can be found in the paper abstract. They conclude that the "findings demonstrate that long-term NT improves key soil hydro-physical properties, supporting its integration into sustainable farming systems to balance productivity and environmental stewardship."

This article explores the interaction of genotype (16 cold tolerant) and tillage (3) for chickpeas in dryland areas of Iran over three cropping seasons. Tillage treatments were moldboard with residue removed (CT); minimal tillage (MT) with a chisel plow with residue; and no-till (NT) with residue retained. Results were positive for no-till + residue with increases in SOC, potassium, phosphorus, nitrogen and soil moisture compared to the start of the experiment. There were differences in performance between the different genotypes with some better with no-till and others with MT and others with CT. Chickpea genotypes cultivated under the NT system demonstrated superior performance (41%) in comparison to those grown using conventional tillage (CT) practices during the third year.

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 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 5 year study from Lithuania,  looked at soil physical and earthworms as indicators of soil health following conventional (CT) and no-tillage (NT) across 3 rotations; three crops per rotation (with three variants), two-crop rotation (with two variants), and monoculture winter wheat. Earthworm abundance had a strong negative association with bulk density and a positive correlation with total porosity in the upper soil layer. Earthworm numbers were similar between CT and NT. Rotations affected earthworms more than tillage with with 3 and 2 crop rotations having more earthworms than monoculture.

This paper looked at longterm soil ecosystem status of farmers adopting CA under two different management and environmental conditions in Southern Africa using conventional systems and grazed grasslands as checks. Various soil chemical, physical and biological properties were measured. At one of the sites pasture and conservation agriculture systems presented elevated organic matter content and microbial activity due to continuous organic cover and minimal physical disturbance and essentially healthier soils. In the second site differences between conservation agriculture systems were strongly associated with soil texture differences, influencing organic matter and respiration rates. This means that tailored systems to complement on-farm options and local conditions are needed.

This review looks at several ways to improve soil physical health. They define this as physical, chemical and biological characteristics. It includes structure, porosity,  and water retention. They include  soil management like CA, cover crops, and organic amendments. They also suggested precision farming and remote sensing as ways to monitor and manage soil health. They found they had constraints to undertake this and so recommend that future efforts focus on multidisciplinary research to better understand complex relationships.

This article is concerned with the impact of climate change (CC) will have on the productivity of the rice-wheat system in the Indo-Gangetic Plains of South Asia and India that is the breadbasket of these countries. This long term research looks at the potential of long term conservation agriculture (CA) management to address this CC issue. The paper describes 6 different production scenarios with one the traditional system and 5 others that have various improvements on the traditional system including just NT wheat, both NT rice and wheat, addition of a mung bean legume, NT maize and wheat, and one with sub-surface drip for irrigation (SSDI). They conclude that overall, soil organic carbon was higher in all CA scenarios compared to the traditional scenario. "By substantially enhancing soil health and crop productivity, as well as boosting resilience, CA emerges as a promising solution for meeting the increasing food demand in Northwest India and beyond and cropping seasons between and across regions."

This 15 year long-term experiment from Haryana State in India using a rice-wheat system was designed to measure the impact of 15 years of tillage and residue management on the soil quality index (SQI) and yields. There were treatments: 1. CT without residue (-R); CT with +R incorporated; Reduced tillage (RT) with -R; RT +R incorporated; NT -R; and NT +R left on surface. Soil measurements included various physical, chemical, and biological properties. Results showed that NT+R had the lowest bulk density and soil penetration resistance at the surface soil leading to better water infiltration. Also improved SOC, and microbial activities. Wheat yields were higher for NT + R, but lower for rice yields. This was related to using direct seeded rice and probably having more weeds than in the transplanted conventional rice. 

This Brazilian paper looks at Crop–livestock–forest integration (CLFI) systems that can enhance soil organic carbon (SOC) content within various aggregate size classes, thereby improving soil productivity and its capacity for atmospheric carbon (C) sequestration.  Treatments included long term CFLI with pasture rotation, CFLI with crop rotation, continuous conventional cropping (CCC), permanent pasture without and with fertilizer. The native Cerrado was used as the check. Results showed that after 23 years of CCC, SOC was reduced by 53%. compared to the Cerrado check. The CFLI treatments had much less SOC loss. They conclude that "the findings highlight the potential of CLFI systems to store carbon in the soil and promote macroaggregate formation, comparable to pastures established for 25 years and the native Cerrado. 

This article from China starts by saying short term no-till increases bulk density, reduces total porosity and microporosity that affects aeration. Their goal was to see if over time NT can overcome these negative effects. They used a 4-year field experiment that used rotary tillage (RT), subsoiling (SS) and NT and evaluated soil gas diffusivity and water retention across a range of soil matric potential. They used Undisturbed soil samples (0-40 cm depth) using X-ray Computed Tomography (X-ray CT) to characterize pore structure. Results showed that NT reduced total soil porosity and macroporosity in the upper 30 cm compared to RT and SS but increased plant-available water content. NT also maintained higher gas diffusivity under wet conditions by forming irregular-shaped pore networks that increased specific diffusivity compared to RT and SS. They conclude that "NT effectively balances soil air-water conditions at higher moisture levels despite initial compaction, underscoring its potential waterlogging resistance."

This article describes the history of California's Conservation Agriculture Systems Innovation (CASI) that increased the sustainability of agriculture in the San Joaquin Valley of California, by reducing soil erosion, conserving soil moisture, using systems thinking, creating farmer networks, advisors, and researchers since 1998. It used CA management that included reducing soil disturbance for better soil structure and biological activity, retaining biomass on the soil to support soil life, and diversifying crops to enhance biodiversity. They calculate that CASI involves more than 2200 farmers and private sector, university, public agency and environmental groups as partners. The paper describes the benefits of CA in maize, small grains, vegetables, cotton, beans, and melons. They conclude that "reducing soil disturbance for better soil structure and biological activity, retaining biomass on the soil to support soil life, and diversifying crops to enhance biodiversity."

This study examined CA practices in a maize-wheat system in India using a 2-year field study with 15 treatment combinations. Their results showed that No-tillage (NT) with residue retention (+R) and phosphorus dose (34.4 kg P ha⁻¹) produced the highest (8.17 t ha⁻¹) maize equivalent yield, system productivity, and net economic return. NT + R also significantly enhanced soil organic carbon, water-stable aggregates, microbial biomass, and enzymatic activities. In contrast, phosphorus application with microbial inoculants under NT without residue (-R) yielded the highest energy use efficiency. They conclude that "integrating CA-practices and optimal phosphorus management enhances system productivity, profitability, and soil sustainability."

This review from Romania highlights the importance of soil health for sustainable agriculture and identifies practices that result in improved soil health that includes, physical, chemical and biological properties. The explored rotation, cover crops, no-till, CA, and use of organic amendments to achieve SH properties that includes better soil structure, increased organic matter and biological diversity. Increasing soil organic carbon (SOC) is vital. Their results show that CA is a better option to restore soil health than conventional systems although they mention that this topic is still controversial among scientists and farmers. 

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 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 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 study assessed the 10 year effect (experiment started in 2012) on CA practices on soil physical properties in a sub-humid area of South Africa. It had 16 treatments and 3 replications. They looked at CA vs CT, 4 rotations, and plus and minus residue cover. They collected soil samples from 3 soil depths in 2023/2024 for various soil physical measurements. Their results showed that tillage practices had a greater impact on bulk density (BD), porosity (phi) and aggregate stability (AGS)/ stability index (SI) compared to crop rotations and residue management. Rotations with soybeans had lower BD values that ones without soybeans and the authors suggest this maybe the result of faster soybean residue decomposition than maize and wheat residues. R+ plots had higher gravimetric water content and higher volumetric water content than R- plots, due to the substantial amount of SOM returned by residue decomposition. 

This review explores a number of soil and water conservation practices, organic amendments, and agroforestry for specific soil types (7)  for the many diverse agroecological zones in Africa. In particular it looks at the role of soil through physical management to ensure resilience to climate change using long-term studies that are essential for improving soil structure, moisture retention, reducing erosion and enhancing SOM. However, adoption of these practices that improve resilience to climate change faces challenges due to diverse soils and ecologies, barriers to adoption and resource constraints. The authors advocate an integrated approach combining local expertise with scientific advancements and appropriate policy interventions.  to achieve the needed resilience.

This paper looks at cassava using CA in Peru. The objective of this study was to compare soil properties, cassava physiology, and yield under conservation agriculture (CA) and traditional agriculture (TA) practices, with and without mulch, in a water-scarce environment. CA out performed TA for several measured properties and they conclude CA is superior to TA in this drought prone area and improves soil properties, cassava physiology and yield.

CA is being used in this coastal area of the USA to improve soil health, reduce environmental impacts, and improve farmer profits. They commonly use cover crops, strip, minimal, and no tillage. The paper evaluates the changes in soil properties from various CA  practices. They evaluated 4 tillage systems: conventional, strip, minimal, and no-tillage; 3 winter cover crop systems; fallow, winter cash crop, and high biomass CC. They then measured 6 soil properties over 7 years. Altogether, soil carbon showed a more consistent response to conservation management than the other soil properties, which tended to show greater variability based on the time since tillage. They conclude that conservation practices need to be applied for multiple years in order to improve soil properties.