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 2-year on-station experiment from IARI, India looked at the impact of conventional (CT), CA and Organic (OA) on pigeonpea grown in a PP-wheat system. CA 1, 2 and 3 were on permanent narrow beds (PNB), broad beds (PBB) and flat (PFB), respectively. All 3 CA treatments performed better better than CT and OA for several parameters. CA2 had greater plant height and dry matter accumulation in both years. All CA treatments had better nodulation, nitrogen fixation and soil health. Yields were better in the 3 CA treatments with CA2 to highest compared to CT and OA. Cost of cultivation was a little higher in CA treatments than CT but gross returns were higher. They conclude that "CA enhances pigeonpea productivity and farmers' income in the upper and middle Gangetic plains of India.

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 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.

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 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 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 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 article from Mexico evaluates rainfed, monocrop maize CA cropping systems in semi-arid areas from 2 field experiments on 17 farmer fields planted from 2013-2020. The measured yield and profitability. Maize under conventional tillage was compared to maize on permanent beds with soil mulch, either monocropped or in rotation with triticale, oats, or common beans. Results varied between the two experimental sites. In one site bed planted maize was higher than conventional (CT), while in the other field yields did not significantly differ. In the 17 farmer fields bed planting yielded 70% higher maize than under CT. They conclude that "The most profitable system was permanent beds with a maize-bean rotation in field experiments and with maize monocropping in farmers’ fields."

This long term field experiment at 3 sites in India and one in Bangladesh to assess 4 scenarios: S1 - double cereal rotation with conventional practices; S2 - double cereal plus legume rotation with partial CA; S3 - double cereal plus legume rotation with full CA; and S4 - futuristic diversified cereal-legume rotations with full CA. The main objective was to study the dynamics and stabilization of SOC within these scenarios. Average results showed with passive C pools, , TOC, and Walkley-Black C followed S4>S3>S2>S1 in the 3 Indian sites but reversed S4 and S3 in Bangladesh. Stabilization of C as SOC was higher in the 3 CA scenarios compared to S1 and in rice-rice, compared to Rice-wheat. They concluded that "full CA systems with best management practices (S3) and best management practices with crop diversification (S4) are recommended for sustainable crop production in the major double cereal growing regions of South Asia.

This paper from Iran looks at the effect of 5 years of CA managment on the quality and diversity of soil macrofauna in rainfed in semi-arid areas of Iran. Treatments included conventional moldboard tillage (CT), reduced tillage with a Delta  model and roller (RT1), Chisel plow and roller (RT2) and no-tillage. There were 3 subplots with no residue, 1/3 residue and 2/3 residue. Wheat rotated with chickpea was the cropping pattern. The results showed that no-tillage led to a significant increase in macrofauna biodiversity in both wheat and chickpea soils. Also keeping 1/3 residue led to an increase in macrofauna diversity.

This paper from India looks at the causes of a plateau in rice-wheat yields in South Asia. They used a 2-year on-farm study to look at wheat productivity in a RW system. They introduced various system optimization practices (SOP) that include legume inclusion, NT wheat, Direct seeded rice, and bed planting. Benefits of SOP's were reduced global warming potential, reduces water use, reduced weed density, higher partial factor productivity, wheat yield and net return increases, lower energy use compared to traditional practices. They conclude that wheat production with SOP's of legume inclusion and zero tillage achieve higher productivity and profitability with less environmental footprint in the Indo-Gangetic Plains and similar agroecological regions.

This study from Italy initiated in 1994 looks at the long term effects of CT and NT initially on Durum wheat but added Vicia faba cover crop in 2009 in half of each tillage treatment. They monitored  microbial biomass, soluble N, and enzyme activities (EA). Between 2009 and 2018, CT yields were on average 15% higher than NT, especially during high rainfall years, but NT increased SOC in the 0-30 cm soil depth and higher levels of soluble N, dsDNA, and EAs at 0-10 cm depth. Introducing cover crops over 4 years did not yield significant impacts.They conclude that adopting NT practices resulted in higher SOC concentration, enhanced soil biological activity, and improved biogeochemical cycles, emphasizing the positive impact of NT on soil health and sustainability.

Manual methods of farming are common in Africa and also in Zimbabwe where this paper was written. It measures the fuel consumption needed to use a two-wheel tractor to relieve the drudgery of manual farming in this country. This is important for calculating the cost of mechanizing agriculture and GHG emissions. This study measured fuel consumption for 2-wheel tractors in direct seeding for sorghum and pearl millet crops in sandy soils at varying speeds of operation. The information in this paper can be used by farmers and other operators of 2WTs for planning the fuel quantity and budgetary requirements.

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.

This paper from New Zealand starts by saying soil health decline is a major constraint to achieving higher yields and looks at the interaction of tillage, legumes and nitrogen on reversing declines in SH for a cotton-wheat on a bed planting system. There were two tillage systems; NT and Conventional tillage (CT). Three legumes: soybean, mungbean, and mash bean. 2 nitrogen levels. Results showed that the best treatment for soil organic matter and microbial population (improved soil health) was cotton + mungbean-wheat with NT and the recommended N and a significant increase in wheat yield compared to CT treatments. 

This paper starts by saying conventional agriculture is labor, energy and water inefficient and so reports of experiments to identify more sustainable, productive and efficient crop production in a maize-wheat-mungbean system started in 2009-10 and assessed in 2018-19 to 2019-20. Treatments included CA-based bed planting methods such as permanent narrow, broad and flat beds with and without retention of crops residues and 75% and 100% of the recommended dose of nitrogen (N) were compared with conventional tillage (CT) treatment. Results show that adopting the CA practice involving a permanent broad bed with residue using 100% N in this maize-wheat-greengram system was more productive and efficient for nutrients, water, and energy.

The authors mention that there are 3.5mha of CA in India but little data on the effects of CA on soil nutrient dynamics like N, P, and S. They have a nine year study on these nutrients in a maize-wheat cropping pattern that compares CA with conventional methods. Results show that CA and N addition significantly enhanced various soil chemical properties and microbial biomass compared to CM for N, P and S and concluded that "These findings contribute crucial knowledge for sustainable development by offering valuable perspectives on N, P and S management strategies."

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. 

In this study, a 20-year experiment was used to investigate the long-term effects of no-tillage in CA on soil organic carbon (SOC) and nitrogen (N) mineralization, plant N uptake, grain yields, and the grain quality of durum wheat. NT was compared with CT in a wheat/legume crop rotation. After 20 years the CA plot  had 43% more absolute potentially mineralizable N (N0) in the topsoil than the CT plots, with no significant differences observed in deeper soil layers (15–30 cm and 30–45 cm). Other comparisons are made in this paper for different wheat parts. Their results highlight the benefits of long-term CA adoption to increase soil N mineralization, providing a substantial base for N uptake during the critical growth stages of durum wheat, thus leading to increased crop yield. 

This paper from Malawi looks at ways to overcome the problem of climate change impacts that have affected food production. They looked at improved varieties on total productivity and nutrition under maize-legume CA systems over 13 years of on-farm experiments in Malawi. the 3 main treatments were 1. CT of sole maize planted on raised beds; 2. NT of sole maize on retained ridges + residue; and 3. CA maize intercropped with either cowpea, pigeon pea or groundnut on retained beds using NT. The results showed that total system nutrition was highest on the 3rd main treatment. The yields of maize were significantly higher in the 2nd and 3rd treatments irrespective of the variety grown. They conclude that "Conservation agriculture and NT systems have more influence on productivity of smallholder farms, despite the genotypes used (hybrids or OPVs)."

This paper from South Africa looks at the production performance, soil greenhouse gas emissions, and soil carbon sequestration of different crop rotations. They measured nitrous oxide and methane fluxes over one year and analyzed 20 years of historical data on soil carbon sequestration, yields, fertilizer use, and wheat protein content. Results showed that rotations that contained legumes and livestock produced more wheat and canola yields and higher wheat protein. All systems showed an increase in SOC over the 20 year period. They concluded that "Legumes and livestock incorporation in crop rotations interact with nitrogen management. Most N2O emissions occurred after precipitation in the otherwise dry summer, making reduction difficult as minimal management activities occur over this fallow period.

This paper from India evaluated a 12-year old CA based pigeon pea-wheat cropping pattern on permanent broad beds with residue (CA-PBB), permanent flat bed with residue (CA-PNB) and conventional (CT). The results showed that the 2 CA treatments enhanced total SOC compared to CT. The CA flat bed showing the highest SOC at 0-5cm and 5-15cm depths. They conclude that residue input increases cumulative mineralization and SOC decay rate vis-à-vis helps to sequester carbon in the recalcitrant fraction, leading to higher stable carbon in soil.

This experiment from dryland cotton areas of India looked at the impacts of tillage and weed management on soil quality index and system yield in a cotton-maize system. Treatments included various combinations of conventional tillage (CT) and no-till (NT) in cotton and maize with and without the legume Sesbania rostrata.Weed treatments (sub-plots) included use herbicide (H), herbicide rotation (HR), integrated weed management (IWM), and one hand weeding (HW). The experiment was run for 3 years. They measured 40 soil variables for soil chemical and physical properties. The soil quality index and yield increased by 23% and 52%, respectively for the NT with cotton + Sesbania rostrata residues–NT with maize + cotton residues–NT with Sesbania rostrata + maize stubbles compared to the farmer practice that used CT and no Sesbania. They conclude that NT for Cotton, Maize and Sesbania with residue retention and IWM had better soil quality and yield.

This paper from India looked at the effect of CA and N management on soil N, P, and S release and the enzymes involved. The results showed that CA significantly enhanced the mineral N, Olsen P and CaCl2-S release and the soil enzymes involved compared to CT + R plots. They conclude that CA alongside optimum nitrogen management enhances the soil enzymatic activities and nutrient mineralization that results in higher crop output while maintaining soil health.