Conservation Agriculture Research Updates - March 2026

This another report for a long-term experiment (60 years) from the Triplett Van-Doren No-Tillage and Crop Rotation Experiment established in 1962 in Wooster, Ohio, USA that was designed to evaluate the impact of no-tillage and crop rotation on corn and soybean yields. This experiment is conducted on two contrasting soils, one well-drained and one poorly drained. There were 3 tillage practices; moldboard, chisel and no-till with the residue from the previous crop left in the field and 3 rotations; continuous maize, a 2-year maize-Soybean, and a 3 year maize-forage-forage. Crop rotation was the main driver of long-term crop performance, with the most favorable responses observed when forage crops were included in the cropping system at both sites. Note the forage crops contained mixtures with legumes. The paper contains a lot of interesting data. They conclude that " By evaluating long-term trends, we found that no-tillage can be viable even in clay soils under temperate climates when perennial crops are included in the rotation system. Our results demonstrate that longterm crop yields can significantly benefit from the implementation of both practices adopted together in cropping systems."

This paper presents some of the data from  a family farm in Ohio, one of the oldest continuous NT and cover crops adapted farms in Ohio since 1971. The objective of the study was to assess the effects of no-till (NT) management over 0, 6, 20, and 35 years in a rainfed corn-soybean system, incorporating cereal rye as a cover crop, on soil organic C (SOC) sequestration and total N accumulation across different pools. The results show a significant increase under NT compared to conventional for SOC, total N, microbial biomass C, active C, passive C, particulate organic C and N. They conclude that "long-term NT consistently facilitates SOC sequestration and total N accumulation in different pools, with these benefits distributed non-linearly across distinct SOC and total N pools at the 0-15 cm depth and linearly at the 15-30 cm depth in rainfed corn-soybean systems."

This paper from Brazil looks at the role of cover crops to improve soil fertility, plant nutrition and soybean yield in the Cerrado area in a dryland area. There were 8 cover crops, and fallow preceding soybeans grown in the off-season. This area had cultivated soybeans under no-till for 10 years. They measured the biomass of the cover crops, but also soil chemical and biological properties, soybean foliar nutrients, yield and quality. Data can be found in the paper and abstract. They concluded that "Cover crops improved soil fertility while increasing soybean productivity, thus being an effective strategy for the achievement of sustainable soybean production."

This paper from Brazil assessed the carbon dioxide equivalent (CO₂e) emissions based on soil organic carbon (SOC) stock changes in 1-m depth by plow-based tillage (PBT) and the mitigation potential through a no-till system (NTS) across 26 sites in the Cerrado biome and 37 sites in the Atlantic Forest biome. The tropical climate zone had significanly less emissions than the sub-humid climate zone. Thier results showed that "adoption of NTS demonstrated a high capacity for offsetting CO2 emissions, achieving 5.40 Tg CO2e in the tropical equatorial zone (recovering 98 % of the total emissions), 2.57 Tg CO2e in the tropical central zone (68.7 %), 2.67 Tg CO2e in the subtropical humid zone (83.2 %), and 2.88 Tg CO2e in the subtropical temperate zone (68.6 %). 

This research looked at long-term adoption of residue retention on soil-water and temperature for wheat grown under CA in both a field experiment and crop model simulation using the APSIM (Agriculture Production System Simulator) model. Two tillage practices were NT + Residue retention (NT+R) and CT with residue incorporation (CT+R). The results indicated that the model accurately simulated crop phenology, leaf area index, above ground biomass, and grain yield under both tillage treatments. Soil water content, transpiration and drainage were higher in NT+R compared to CT+R. Evaporation and soil temperature were higher in CT+R. The authors were happy with the APSIM model for identifying the effect of tillage and residue on wheat yield components. 

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 study from China investigated the erosion processes and carbon dynamics across eroded slopes after adopting various conservation practices based on the data obtained from field experiments across the globe. Their results interestingly showed that adoption of CA compared to CT significantly did not reduce runoff but did lead to a significant reduction in sediment loss. CA also significantly increased soil organic carbon (SOC) in the top 10cm layer and reduced SOC loss. The results further highlighted the critical contribution of straw mulching in erosion control, soil organic carbon loss reduction, and soil organic carbon accumulation, while reduced tillage represented the least effective measure. 

This long-term field experiment with Winter wheat looked at 3 tillage systems: conventional (CT), reduced (RT), and No-till (NT) since 1995. They collected data on SOC, microbial biomass, and enzymatic activity in four-year crop rotation periods from 2005-2024. There were 3 rotations: winter oil seed rape, winter wheat, pea, and winter wheat.Data was collected from 3 crop depths: 0-10, 10-20, and 20-30 cm. Residues were incorporated in CT, partially in RT and left as surface mulch in NT. Results showed that NT had the highest C-sequestration followed by RT and CT. The weather conditions during the year (abundance of precipitation) influenced crop yields significantly more than the tillage practices with wheat yields and N in grain the highest in CT followed by RT and lowest in NT. NT treatments increased the organic carbon and microbial activity in soils.

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 interesting article from Japan looks at a solar powered mower integrated into a NT system that reduces GHG emissions. This study evaluates NT and intercropping with solar-powered machinery in organic cherry tomato production. They compared two tillage methods (NT} and rotary tillage (RT)] and two cropping patterns [cherry tomato/peanut intercropping (TP) and monocropping (M)]. Solar-powered robotic mowers replaced conventional mowers in NT to enhance environmental benefits. They assessed the results by crop yield, energy efficiency, carbon footprint, and profitability. They conclude that "NT-TP's potential to enhance yield, energy efficiency, and profitability while reducing the carbon footprint, makes it a sustainable management system for organic farming. 

This study from Poland looked at various tillage methods and their impact on soybean yield and quality. The four tillage methods were: a) Plowed tillage plus conventional row seeding (PCR); b) Plowed tillage plus strip till planting (PSD); c) No plough tillage + strip drill planting (NSD); and d) No-tillage + strip drill (ZSD). The paper presents the data on these 4 treatments. ZSD enhanced protein levels and stabilized protein and fat yields. They conclude that future studies should explore how tillage practices affect soil health, economic sustainability, and yield stability over time, especially under changing climatic conditions.

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.

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. 

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 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 is another article in this February newsletter from South America that provides very long term data on CA from a research experiment that considered 5 treatments representing agricultural systems relevant to Paraguay and assessed after 32 years. Treatments in a wheat-soybean system included conventional tillage (CT), reduced tillage (RT), and no-tillage (NT1). In addition, two diversified no-tillage rotations with increasing adoption in the region were included: NT2, composed of black oat–soybean, wheat–soybean, and black oat–soybean; and NT3, consisting of wheat–soybean, vetch–maize, and black oat–soybean. These crop sequences were implemented continuously in three-year cycles over the 32-year study period. The study focused on nutrient stocks, however, consistent relationships between pH and nutrients were observed while pH remained below the minimum threshold recommended for the regional commercial crops . They conclude that "diversified no till farming conserves fertility in low input contexts, but the benefits are limited due to soil acidity. Finally, integrating periodic soil diagnosis with amendments, particularly liming, offers a practical pathway to sustaining production in Paraguay."

This paper from North America synthesized data from 30 meta-analyses to comprehensively assess the impacts of the no-till (NT), reduced till (RT,) and mixed NT+RT on crop yields and GHG emissions. Results showed that the yields of wheat, maize, rice, fibers, cotton, and cereals were not significantly affected by NT, while the yields of soybean, oilseeds, and legumes were enhanced by NT. NT did not influence soil CO2 emissions, and none of the tillage treatments influenced soil CH4 emissions. However, NT increased soil N2O emissions whereas RT and NT+RT had no significant effect on soil N2O emissions. They suggested that the varied impacts of tillage can be attributed to soil properties and practices like crop residue management, irrigation type, and nitrogen rates. 

This research from Uganda looks at nitrogen fixation with pigeon peas in a maize dominant cropping pattern to investigate the effect of biochar under CA on nitrogen fixation at three sites located in different agro-ecological zones. CA involved minimum tillage with planting basins established by hand hoeing. There were 4 treatments: (1) conventional tillage with crop rotation (CT), (2) minimum tillage with crop rotation (CA), (3) CA and plus biochar, applied in both first and second year (CA+BC+BC), and (4) CA and biochar, applied once in the first year (CA+BC). Grain yield was significantly increased by biochar application in CA systems compared to conventional practices, in all seasons and sites. They conclude that "Biological N2-fixation was positively influenced by biochar application under CA systems". 

This paper suggests that CA adoption is crucial for enhancing SOC and mitigating climate change for future food security. The research assesses the effectiveness of various factors controlling SOC sequestration derived from literature reviews and 469 data points spanning 42 years.Results showed that CA significantly increased  SOC by almost 30% compared to CT. The highest SOC result was no-till, plus chemical fertilizer (CF), and straw return (S). Interestingly, CF + S or CF + manure led to greater SOC sequestration compared to the application of CF alone. Also, the annual SOC change rate (ASCR) of CA is closely linked to the experimental duration of its application, demonstrating an overall exponential decline followed by stabilization after several years. Overall. this paper contributes to the understanding of how CA sequesters carbon in soil.

This paper from Ohio State University's Triplett-Van Doren long-term tillage and crop rotation experiment (one of the oldest NT experiments in the World) looked at the temporal dynamics of soil N and C pools in a maize growing season, in a 55 year old tillage and crop rotation experiment. Tillage treatments were no-till (NT) + residue, Chisel-till (CT) + 30% residue and moldboard till (MT) - residue incorporated. There were 3 rotations: continuous maize, maize-soybean (2-year rotation), and maize-forage-forage (3 year rotation). Their results suggest that crop diversification with perennials enhances soil C and N; NT has stronger effects in clay loam than silt-loam soils; and although C and N pools vary seasonally, long-term management effects persist throughout the growing season.

This paper identifies some knowledge gaps and opportunities to narrow the soil carbon gap existing in croplands today. They suggest that adoption of regenerative, CA and cover crops without understanding the mechanisms for carbon capture will not result in C capture in the soil profile. Even though NT results in improved soil carbon, most of this is found in the soil surface.. They suggest that increased plant biomass is needed to improve C capture by increasing higher above and below ground biomass. They conclude that many factors affect C gains, but the most critical  factor is boosting biomass C into the soil profile  when trying to narrow the C gap. 

This paper looks at how nature manages resources and describe living soil and its productivity using nature's laws to improve soil management. They promote the three principles of CA to achieve improved living soils since conventional soil tillage and poor crop diversity are resulting in soil degradation and loss of productivity. Mechanical tillage is not found in natural ecosystems whereas CA emulates natural systems leading to reversal of soil degradation, improved soil health that leads to improved yields and economic and environmental benefits to all farmer land sizes. The CA nature based systems are recommended to offset the issues of climate change and tillage induced soil degradation to help with future food security. 

Crop residue is crucial in CA management to improve soil health and increase yields. This paper from India looks at a residue cleaning system (T1) to help overcome the challenges of residues left after combine harvesting and included design, development and field testing. They first tested the equipment in a soil bin before testing in a field trial consisting of a wheat-greengram-maize cropping pattern and comparing with the Happy Seeder (T2) (an earlier equipment used for sowing into crop residue). T1 and T2 had similar yields but T1 required less energy although it slightly higher carbon emissions. They concluded that T1 had lower B/C ratio compared to T2 but increasing the number of rows in the T1 treatment could enhance field capacity, potentially reducing carbon emissions and improving economic returns.

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 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.