Conservation Agriculture Research Updates - March 2026

This paper did an extensive literature review to look at the biodiversity of pulse systems and ecosystem services using different management systems in terms of food/feed provision and soil health.  Most studies examined soil quality, especially chemical quality, followed by grain yield. Very few studies surveyed biodiversity, most of which used arable flora as an indicator. Their results and conclusions showed significant positive impacts with organic farming on biodiversity, no tillage on soil health and yield, and rotations on yield.

Since plant residues are important for CA no-till management, I chose this paper that looks at the Global impact of cover crops in farming systems. CA plus cover crops is gaining popularity among farmers in the USA. This study assessed the global impact of cover crops on yield. They reviewed 104 articles to collect field based yield data (1027 records) to quantify the impact of CC's on main crop yields. Their data showed that CC's led to an overall increase in major crop yield of 2.6%. The utilization of leguminous cover crops, cultivation in coarse soil texture and dryland areas, and the implementation of longer cover cropping duration were found to be conducive scenarios to enhance crop yields. Conversely, the use of non-legume cover crops, introducing them to fields under a short-term no-till system, especially in fine-textured soils, lowered main crop yields. More data is available in the paper but they conclude that understanding and comprehensive information advances the appropriate and targeted adoption of cover crops for policymakers, extension services, and farmers.

The traditional rice-wheat-mung cropping system in North Bihar, India has experienced declining yields and water constraints. This paper looks at alternative tillage and crop establishment (TCE) practices to remedy this problem. Five different TCE practices were evaluated in on-farm experiments. The best yields were found with Zero-tilled direct seeded rice (ZTDSR) followed by Happy Seeder ZT wheat (HSZTW) and HS gram (HSG). This treatment also provided the highest net returns with this CA based system out-performing traditional systems.

This paper from Lithuania looks at the relationship between root network development and CO2 emission as affected by different cropping and tillage strategies. They tested 5 different cropping systems with or without cover crops (CC) using different tillage practices. Results showed that with no-till (NT) C02 emission was higher than in conventional tillage (CT). Increase in CO2 emission also varied between 30 and 35% depending on the share of legume and CC inclusion. Root growth and development were significantly affected  by soil depth and cropping strategies in terms of root length and root volume changes. The inclusion of CC resulted in a decrease in root volume. Root length and root volume had a significant impact on soil CO2 emissions. They concluded that crop diversification and addition of CC helped reduce C02 emissions and improved root networks better than monocropping.

This paper explores the performance of cropping systems with different legume diversity on maize productivity in Zambia and determine the minimum land required to reach maize self sufficiency at the household level using the different systems. Six maize-based cropping systems, comprising maize monocropping, maize-legume rotations and intercrops under ‘conventional’ tillage and conservation agriculture, were evaluated across 40 farms in Zambia. The results are provided in this paper. They conclude that introducing legumes into their maize systems can increase yields of maize and intercropping legumes can be used in land restricted farms.

Since cover crops (CC) are gaining acceptance in USA farming together with CA, I decided to add two articles that review the benefits of CC on soil properties. This review article looks at grasses, and broad leaf legume and non-legume as cover crops. It covers single and mixed cover crops and later their impact on soil health. may reduce soil bulk density, improve soil structure and hydraulic properties to facilitate increased water infiltration and storage. They review some of the benefits of crop residue additions such as enhancing soil organic C and N accretion, increase availability of P, K, Ca, Fe and Mg in some soil types under certain climatic conditions, provide a better condition for microbial activity, abundance, and diversity and through proper management provide an essential component of soil conservation practices for enhanced soil health.

This article starts out by saying farmers growing rice-wheat in the Indogangetic plains have problems adopting 100% but do adopt partial CA, especially NT in the wheat or other upland crop. So the paper looks at the impact of partial CA after 9 years. The treatments were tillage (main plot), crop residue management (sub-plot), and crop rotations (sub-sub-plot), respectively with permanent tillage or tillage only on rice, without or with all crop residues rice-legume combinations. Results show that post rice NT + residues in rice-chickpea-mung and rice-wheat-mungbean systems significantly increased SOC and carbon index from 0-15cm depth compared to the conventional practice after 9 years. Crop residue addition also increased SOC and C index compared to residue removal. Mean rice grain yield and sustainable yield index of the different systems after nine years were positively correlated with SOC storage.

This research looks at soil extracellular enzyme activities (EEA) on soil nutrient cycling using a meta-analysis with 3238 observations on the effects of NT and legume incorporation into a rotation system. Results show that NT significantly increased the activities of C, N and P acquiring, and oxidative enzymes. Combining NT with legumes did not affect on EEA's, but crop diversity did. They also identified climate, soil properties and agronomic practices as important factors affecting NT-induced changes in EEA's.

This field experiment from India looked at the effects of nitrogen (N) and residual sulphur (S) on maize in the 11th year of a long term CA maize-mustard system. CA (3) was NT maize with mustard residue + brown manuring (not described in the paper) and NT mustard with maize residue had the highest maize height and dry weight than other CA and CT treatments except CA (4) that had mungbean residue for the NT maize that had similar height and dry weight. The 100% and 75% recommended dose of N gave comparable grain yield under all CA-based treatments, indicating a saving of 25% N compared to CT. The sulphur applied to mustard did not show any residual effect on maize grain. They conclude that the CA framework enhances yield and incomein a maize-mustard system.

This article looks at humic acid (HA) quality and the clay-humus complex to provide information regarding soil carbon (C) and recalcitrant C under CA in a field experiment. No-till with and without residue was compared with conventional tillage without residue (CT) in a maize-wheat-pigeonpea system. Results showed that the NT+R treatment had more positive results than NT-R or CT in terms of humic acid quality and the clay-humus complex. NT+R also had higher yields than CT in both the cropping systems except in wheat crops in the M-W system. They conclude that ZT+R has the potential to enrich the organic carbon (C) quality in soil and increase the aromaticity of HA, leading to carbon stabilization in soils.

This article conducted a systematic review to compare crop yield from cropland with conventional management versus different CA practices, specifically reduced- or no-tillage, agroforestry, organic farming and cover crops. The data was first analyzed for different climate regions, soil textures, and cash crop types followed by how yield responses correlated with soil properties change under different CA practices. Their results showed that CA practices provided a mean increase of yield of 12% primarily with maize that had a 41% yield increase. Agroforestry increased crop yield by 66% and cover cropping by 11%, likely due to increases in soil water content and nutrient availability and decreases in erosion and surface runoff. However, other agricultural systems showed no significant increase after CA compared with conventional row cropping practices.

This paper looks at biological soil health for a long-term rice-wheat system using CA practices in India. The 6 treatments were 1) zero till direct seeded rice (ZTDSR)–zero till wheat (ZTW); 2) ZTDSR + wheat residue (WR) - ZTW + rice residue (RR),  3) ZTDSR + WR + sesbania brown manuring (SBM)–ZTW + RR, 4) ZTDSR–ZTW–zero till mungbean (ZTMB), 5) ZTDSR + mungbean residue (MR)–ZTW + RR-ZTMB + WR, 6)transplanted rice (TPR)-conventional till wheat (CTW)–conventional till mungbean (CTMB). Soil from 0-5 cm depth were analyzed for labile organic carbon pools, soil enzyme activities, and populations of bacteria, fungi and actinomycetes, and two microbial functions using qPCR methods. The results showed that the triple/double ZT plus crop residues caused an increase in the pools of carbon, enzymes, and microbial populations compared to the traditional system. Addition of mungbean and Sesbania improved nifH gene abundance compared to other treatments.

The link above will take you to a copy of this interesting book on CA farming in  a part of Australia.It covers the history of conservation farming from the early 1960's to the early 2020's. It covers the adoption of CA and mentions some of the leading innovators - NSW State agricultural scientists, University and CSIRO scientists, consultants in the private sector, agribusiness, pesticide companies, farm machinery and engineering sector plus progressive farmers. Bare fields of tilled soil are now rarely seen.Instead the fields are covered with crop and pasture residues that protect the soil and water. There have been adoption of many varied rotations. This book salutes all those who have been part of this soil revolution.

This paper from India looks at microbial potential in low input-based CA to improve productivity. They looked at an array of microbial groups; bacteria and fungi, in 3 cropping systems; a rice-maize-cowpea, rice-wheat-mungbean, and rice-cauliflower-winter rice with 3 tillage practices CT, reduced tillage (RT), and NT with different levels of residue and fertilizer. The early stage of CA adoption showed a sharp decline in microbial population compared to the initial population except for the fungal components.The abstract has other results. They conclude that although the transition stage of CA shows a decline in microbial population, long term adoption of CA gradually restored the higher microbial numbers and biomass in soil.

This paper from Malawi, looks at the effects of using the legumes pigeonpea (PP) and cowpea (CP) as intercrops with maize (M) in a deep bed farming (DBF) system compared to conventional tillage (CT) over two years on a farmers field. There were 7 main plots that included just M, CP and PP; M intercropped with CP and PP; CP intercropped with PP; and M plus N topdress. The subplots were DBF and CT. DBF is a form of CA that starts by doing deep tillage with a pick axe or hoe to break the plow pan so roots are deeper, better aeration, infiltration of water. Then CA management is done. The beds can be made along a contour. Results showed DBF and CT with legumes had higher yields than without. DBF was better than CT. Intercropping had higher land productivity than sole cropping indicating the introduction of a legume improves yields.

This meta-analysis compares the yield and nitrogen use efficiency (NUE) between conservation tillage (CA?) and conventional (CT) for different cropping systems , mulching methods, N levels and addition of manure in US and China. The results show that CA at high-N enhanced the yield and NUE, and reduced the yield and NUE at low-N, compared to CT. NT with leguminous cover crops (LCC) significantly increased wheat yield NUE under low-N compared to CT. They conclude that based on the results, moderate N with LCC and manure application is recommended for growing winter wheat in dryland regions of the USA and China.

This 4 year field experiment in China looked at 1. tillage practices, mulch, and Sesbania alley-based food-fodder cropping system affect on weeds and 2. the yield of this system. They had 3 crop systems; sorghum-chickpea, sorghum-barley, and sorgum-mustard; and 3 tillage systems; conventional (CT), minimum (MT) during rainy season, and no-till (NT) during the winter. CA management saw a shift in weed flora in all systems. The lowest total weed biomass was recorded for  MT + NT+mulch in all tillage combinations. They conclude that the Sesbania alley-based food-fodder system with reduced tillage and mulching  improved  yield and altered weed dynamics. Double cropping without compromising fodder needs by employing suitable tillage and mulching is possible.

Soil sodicity is expanding in arid and semi-arid areas of the world. This paper examines the reclamation potential of CA based management on this soil issue. They look at NT, use of legumes in rotation, residue mulch (R+), and sub-surface drip irrigation (SDI)  for 3 years in a rice-wheat system in India. The paper provides detailed results on productivity, economics, water and N use efficiency, soil pH, exchangeable sodium percentage, extractable anions, soil organic carbon, soil solution cations. They conclude that CA practices can reduce sodicity and improve soil chemical properties for a profitable crop production.

This paper states that the future of the rice-wheat system, a major food security system for South Asia is at stake because of "Traditional practices like conventional tillage (CT) residue burning, and indiscriminate use of groundwater with flood irrigation". As such this paper studies the role of CA, mungbean integration, water, N, and energy use efficiency in the RW system. The results showed that bundling CA with subsurface drip irrigation (SDI) saved substantial water in both rice and wheat compared to traditional farmer practice. Based on the 3-year mean, CA with SDI (mean of Sc5–Sc8) recorded −2.5% rice yield, whereas wheat yield was +25% compared to farmers practice and rice and wheat yield under CA with flood irrigation were increased by +7 and + 11%, compared to their respective CT practices. Mungbean integration added 26% to productivity. They concluded that CA with SDI for precise water and N management proved to be a profitable solution to address the problems of groundwater, residue burning, sustainable intensification, and input (water and energy) use with the potential for replication in large areas.

This paper looks at diversification of maize-based systems with legumes  to counteract climate change and soil fertility decline in Zambia. Maize-legume diversification strategies included single row intercropping, strip cropping and crop rotation under CT and CA in 4 Districts in Zambia. Data was collected from on-farm trials over 3 growing seasons. Results showed no significant effect of cropping systems on individual maize and legume grain yield across growing seasons, but substantial nutritional and economic benefits of intercropping systems due to simultaneously growing two crops especially in maize-legume intercropping strategies compared to sole maize and maize-legume rotation. Although there was increased labour requirements to manage the intercrops, these cropping systems had much higher net benefits and returns to labour and inputs than the other cropping systems tested.

This paper from Uzbekistan looked at soil productivity and yield of a legume based rotation comparing CT with NT in a saline soil in an arid area. CA consistently out yielded CT for wheat, millet, chickpea and maize over two years. The increased residue retention under NT facilitated soil porosity, structural stability, and water retention, thereby improving soil quality and organic matter content. Soil salinity decreased under NT compared  to CT, reducing salinity buildup. They concluded that the NT method with legume-based intensive cropping helps maintain soil health and crop yield leading to more sustainable land management of drylands.

This paper is based on two long-term experiments started in 2013 in Zimbabwe. There were 6 treatments: Conventional tillage (CT); CT plus rotation (CTR); No-tillage (NT); NT+ mulch (NTM); NT+ rotation (NTR); NT + mulch+rotation (NTMR). Maize was the main crop with treatments using rotation growing cowpea. SOC and soil bulk density (SBD) were taken from 9 depths from 0-100cm. Results show that SOC stocks were higher in NTM, NTR and NTMR treatments compared to NT and CT in the upper soil samples (0-5 and 0-10cm). NT alone had a small negative impact on upper SOC stocks. Cumulative SOC stocks were not significantly different between treatments in the whole 100cm soil profile. NTM enhances SOC stocks but only in the topsoil and showed the highest cumulative organic carbon inputs. Last, results showed thatat least 2 CA principles were needed to increase SOC stocks in these low-nitrogen-input cropping systems.

This article reviews the question "Can farmers in sub-Saharan Africa (SSA) increase yields and make food more available without using mineral fertilizer?" Supporters that say yes suggest that the principles of agroecology that rely on recycling, better efficiency and practices such as use of legumes and manure will mean more chemical fertilizer is not needed to raise yields. But this paper after extensive literature review suggests that more mineral fertilizer is needed in SSA. They put forward 5 reasons for this conclusion and can be found in this paper. They conclude there is a critical need for more mineral fertilizer in combination with the use of agroecological practices backed up by adequate policy support.

This paper looks at Climate Smart systems like CA and intensification in millet cropping systems. They looked at residue management and tillage practices in pearl millet (PM) yield stability and biofortification. NT systems with intercropping of other legumes with PM, increased yield of PM, micronutrient content, protein and oil content, and the fatty acid profile of PM compared CT-based tillage systems. The best combination for achieving stable yields and micronutrient fortification was residue retention in both (wet and dry) seasons coupled with a NT pearl millet + cowpea-mustard (both with and without barley intercropping) system. 

This paper's objective was to identify suitable agricultural strategies with high yields, energy use efficiency (EUE) , and carbon use efficiency (CUE) for an array of different crops grown in India - cereals, legumes, oilseeds, and sugarcane in both rainfed and irrigated cropping systems. Irrigated systems had higher environmental impact (EI) and carbon footprint (CF) than rainfed systems. But rainfed crops had higher CUE than irrigated ones.  Adoption efficient irrigation strategies (micro irrigation), enhanced fertilizer use efficiency (site specific nutrient management or slow release fertilizer), conservation agriculture (conservation or reduced tillage) rice cultivation methods (SRI or Direct seeded rice) were some mitigation strategies identified..