Conservation Agriculture Research Updates - April 2026

This article looks at soil microbial communities that play a role in nutrient cycling, organic matter decomposition, SOC, and GHG emissions in particular under CA under a 10 year rainfed, semi-arid pigeonpea - castor bean cropping system. It looked at tillage and residue management in CA management on soil bacteria diversity, , enzyme activity, GHG emissions and nutrient availability. Overall, the results of the study indicate that CA improves the relative abundance of soil bacterial communities, nutrient availability, and enzyme activities, and may help to contribute to the mitigation of climate change, and sustainability in rainfed areas.

This paper looked at the impacts of cover crops with NT on soil and crop productivity in a rainfed, semi-arid, continuous cotton system in Texas, using a Denitrification (DNDC) model. Treatments included CT and NT and NT with pea, clover, vetch, mixture, and winter wheat. Simulation results showed that vetch and peas had more biomass and highest SOC and total N (TN) followed by the mixture, wheat and clover. Cotton yields with cover crops were not different from those without when the cover crop was terminated 6 weeks before planting cotton. Later termination of the cover crop can lead to lower cotton yields due to water depletion by the cover crop. They conclude that cover crops and NT improves soil health without loss in cotton yields in the discussion section of the paper. 

This literature review looked at SOC change in arid and semi-arid areas where cover crops, diversified rotations and reduced or no-tillage were used to find out the role of CA in SOC sequestration. The paper reviews published articles from 1990 to 2021for this review. Results showed that SOC sequestration of 271 kg C ha−1 yr−1 and 235 kg C ha−1 yr−1 with cover cropping and diverse crop rotation, respectively, in the upper 30 cm soil depth but the potential varied depending on soil type and tillage with medium textured soils having more SOC sequestration by 10% with conservation tillage than conventional till. They also found that SOC sequestration rate was high in the first 5 years and then decreased until reaching a new equilibrium. They conclude that conservation systems can benefit arid and semi-arid agrosystems by enhancing SOC sequestration and that stacked conservation practices could effectively harness greater benefits.

This paper looks at two winter wheat varieties with rotation and tillage as treatments in Iran on an experiment station. They had three rotations with either vetch (V-W), chickpea (C-W) or safflower (S-W) and three tillage conventional (CT), minimum (MT) and no-tillage (NT). Soil moisture was highest in NT. The highest relative water content (RWC), normalized difference vegetative index (NDVI), stomatal conductance (gs), and transpiration rate (E) were obtained from the Baran genotype in the V-W rotation under NT. In the last year of the experiment, rainfall productivity in NT treatment improved by 32%, compared to CT. The V-W rotation yielded higher than C-W or S-W and is recommended along with NT for this cold dryland area.

This is another paper that says climate change, land degradation, demographic change and persistent poverty pose major challenges to smallholder farmers in the arid and semi-arid lands of sub-Saharan Africa and look at how household resilience varies over time. A longitudinal analysis was used to assess how the resilience of smallholder households in south-eastern Kenya has varied from 2012 to 2015. They used the Livelihood Resilience Indicator Framework to examine the linkages between livelihood outcomes and livelihood resilience (buffer capacity, self-organization and capacity for learning) from 134 households. They conclude that under drought conditions in 2012, conservation agriculture practices significantly contributed to maize yields. In both years 2012 and 2015, there was a positive correlation between resilience dimensions and food security.

This paper examines farmer adoption decisions for CA in two semi-arid areas of SW Ethiopia. They surveyed 392 households in two District farming systems. Two groups of farmers that practice that practice CA and CT were selected. A binary logistic regression model was used to answer the question of factors that determine smallholders' initial decision to adopt CA. Nine explanatory variables were included in the analysis. The results show that CT groups have higher schooling, farmland holding, and livestock relative to CA-practicing households. Farmers decision to adopt CA was high when extension services were available and they lacked of access to small-scale irrigation. The impact of extension service has indispensable benefits in extending the knowledge to younger smallholders.

This paper looked at productivity, profitability, and sustainability of barley genotypes that adapt to restricted resource settings and low energy-carbon management. 5 barley genotypes were evaluated under two contrasting  tillage/residue systems; NT + residue retention (NT+RR) and conventional tillage + residue incorporation (CT+ RI) in the semi-arid plains of NW India. The (ZT+RR) system, and the barley genotype RD-2552 followed by BH-946, provided significantly higher crop productivity and profitability compared to CT+ RI and other genotypes. The NT-RR system enhanced energy and carbon use efficiencies and provided lower energy-carbon footprints.

This Global Meta-analysis used 5230 paired observations from 446 studies to evaluate NT on upland crop yield and SOC. Overall NT decreased upland crop yields by 5% and increased SOC sequestration by 9.9%. Specifically, wheat and maize yields decreased by 7.7% and 2.3%, respectively. However, NT combined with crop residue return and crop rotation reduced the negative effect of NT on crop yield from 5% to 2.4% and increased SOC up to 12.8%. No-till increased yields in relatively arid areas, but reduced yields in more humid areas, whereas SOC was more likely to increase in humid regions. The paper suggests that more research is needed for NT with residue retained since their results show that CT was better than NT. But many papers show that NT is better then CT when residues are retained.

This is an article that looks at CA for dryland chickpea cultivation. It looked at the effects of different soil management (reduced tillage (RT), no-tillage (NT), and conventional tillage (CT)) on morpho-physiological characteristics of chickpea during the 2017–2019 cropping seasons in Iran. This experiment also looked at the mycorrhizal colonization and sporulation, rhizobium nodules, and various plant physiological parameters. Theresults showed that the NT system improved relative leaf water content, reduced antioxidant enzymes, had positive effects on measured morpho-physiological traits, and increased the yield and stability of chickpea compared to RT and CT systems under rainfed conditions.

This paper looks at tillage practices (CT, NT and rotational tillage (RT)) and nitrogen rates on abundance and order of soil microfauna in monocropped maize in dryland South Africa. NT and RT showed an increase in abundance of macrofauna compared to CT. Macrofauna was negatively affected by increased N. The paper describes the impact of tillage and N on various orders of macrofauna. They conclude that NT and RT with mulch favored the establishment of various macrofauna communities in the studied cropping system.

This paper from research in Morocco looks at the issues of intensive land use and irregular rainfall, serious threats to food security. It looks at the using a long-term NT system started in 2004 to compare NT vs CT under irregular rainfall. Yields (grain and biomass) of crops (wheat and lentil) under NT and CT were analyzed and compared over the years of study. Results showed that crop yields varied over the years but under NT were greater or equal to CT yields. CT yields were correlated with with rainfall, whereas NT yields were not and are more adaptable in these dryland areas..

This Kenyan study looks at the ability of cowpeas intercropped with maize can fix nitrogen using the three CA principles -- NT, residue and rotation. The experiment had been running for 6 years before sampling and compared the CA with the CT treatment. They found that the number of nodules formed was greater in the CA treatment although not significant to the CT one. There was a difference between the monocrop and intercrop cowpea with about 3 times more yield in the monocrop, as expected. The highest %N was found in the monocropped cowpea but highest in the CA treatment in the intercropped cowpea. They conclude that more research is needed to look at the spatial dynamics of CA cowpea grown with maize.

This paper looks at various impacts on water of various sustainable agricultural measures. Straw retention and reduced tillage were mentioned as the most successful measures in arid and semi-arid regions. As such this review looks at these two factors in respect of SOM, soil moisture, soil temperature, soil microorganisms, soil enzyme activity, soil fertility, soil carbon emissions, pests, weeds, soil erosion, water use efficiency and yield under different tillage systems. Straw mulching increased SOM, soil moisture and reduced drought, but can increase pest and diseases and change the microbial community. But straw mulch does enhance WUE and yield. Reducing tillage maintained soil integrity, which is conducive to soil and water conservation.

The goal of this paper was to look at the long-term interactive effects of cover crops and residue retention on yield of cash crops and environmental outcomes in dryland cropping systems under climate change. They used the APSIM model to assess the combined influences of cowpea cover crops and three residue retention levels on soil water balance, soil organic carbon (SOC), nitrogen (N) dynamics, crop yield and gross margin across six crop rotation systems during the near future and far future in southeast Australia. Results showed cover crops decreased soil moisture on the day of sowing the succeeding cash crop but led to greater SOC stock,  reduced N loss through leaching, and enhanced N uptake and yield of cereals, but decreased N uptake and yield of field pea. The effects of cover crops on yield and gross margin became more positive in the far future. Cover crops were profitable in the wetter parts of the study region (east), but reduced gross margin in the drier west due to depletion of soil water reserves for the next cash crop.

This paper looked at the potential of CA in a Pakistan dryland area to reduce C02 emissions and alter SOC fractions in plots that had been under NT for 4 years. 4 tillage treatments included CT (moldboard), minimum, Chisel 35cm (MT), reduced, Chisel 45cm (RT) and NT. There were 3 cropping patters; sorghum-wheat, mungbean-wheat and fallow-wheat. All the wheat, mung , and sorghum residues were returned to the NT plots. In the other treatments the residues were incorporated into the soil by harrowing after plowing. Results showed that CT plots had lower SOC than NT or RT plots. The F-W and M-W had higher microbial carbon and organic carbon than S-W. Cumulative C02 flow was lowest in NT plots in all cropping patterns and suggest NT and RT are potential systems for carbon sequestration  in dryland soils.

This paper from the World Agroforestry Center in Kenya, looks at the combination of CA with trees as a way to increase profits, yields and lower production costs. This study was started in 2012. There were two systems; conventional agriculture (CT) and CA. There were 10 subplots with 3 shrub species; Calliandra, Pigeon pea and Gliricidia, each planted at 3 spacings to allow maize-legume intercrops. Data included costs of production, local market costs for the maize and legume crops, and calculation of benefit-cost ratios (BCR).  Results showed significantly higher BCR under conservation agriculture in all seasons. They conclude that conservation agriculture both with and without trees is beneficial for the farmer, with higher net benefits compared to conventional tillage

This is another paper on declining water availability but from the Ogalla Aquifer in the USA and changes in cropping systems in the arid and semi-arid regions including transition from irrigated to dryland cropping. This review discusses published literature on the challenges associated with crop production and highlights management strategies to sustain soil health, enhance agricultural production, and farm profitability including soil health and water conservation practices, conservation tillage, crop residue management, crop diversification, cover cropping, and livestock integration in cropping systems. They report that adopting conservation systems can increase soil organic carbon (SOC) storage, water infiltration, soil microbial activities, water use efficiency, and decrease N fertilizer inputs compared to conventional systems. 

This paper from NE Himalayas, where low yielding maize-fallow is the main cropping system on the sloping hilly areas is a daunting task for increasing farm productivity, nutritional security and economic viability. The paper explains the results of a field experiment over 3 years under organic management that looks at CA vs CT and 6 diversification  options. Results show CA had higher productivity than CT. Crop diversification also had higher system productivity, net returns, net energy returns than the local cropping system. They conclude that conservation agriculture improved soil health and performed better than conventional agriculture in maize-based intensive cropping systems. Crop diversification with maize-sweet corn- pea or broad bean can potentially increase calorie and protein consumption and farm profitability.

This paper looks at the problems of conventional tillage (CT) in semi-arid regions of Morocco that include exposing soil that is already fragile to degradation. The objective of this study is to assess the role of CA to address the soil physical properties compared to CT and reverse soil degradation. Results show that most of the physical properties were improved with CA in both locations. SOM also increased under CA. They recommend that CA be encouraged in this semi-arid area.

This paper summarized the results of 47 global studies with humid subtropical climates investigating the sources of variation in SOC responses to CA. Overall the effect of CA on SOC accumulation in the plough layer was 12% greater in comparison to conventional agriculture. However, the effect was variable depending on the SOC content under conventional agriculture. For soils with less than 40 Mg C ha(-1), increasing the proportion of crops with bigger residue biomasses in a CA rotation was a solution to increase SOC. The effect of CA on SOC also depended on clay content and became null with a SOC/clay index of 3.2. They conclude that SOC increments due to CA application can be achieved especially in agricultural soils with less than 40 Mg C ha(-1) and located in the middle latitudes or in the dry conditions of Mediterranean and humid subtropical climates.

This study looks at the potential impact of drought predictions on a faba bean crop, and evaluates the adoption of conservation tillage practices to reduce this effect in dryland areas of Spain. It sampled a long-term trial that was started in 2008 and looked at soil water storage (SWS), crop productivity and mineral nutrition, plant ecophysiology and biomass quality, as well as the colonization of roots by arbuscular mycorrhizal fungi (AMF) and symbiotic Rhizobium bacteria. It sampled the non-tillage (NT), reduced tillage (RT) and traditional tillage (TT)- and rainfall reduction treatments. The percentage of biomass yield reduction by rainfall exclusion was 30% for NT, 50% for RT and 20% for TT. They conclude that, despite no effect on soil water storage, in the conservation tillage systems the increase in the mycorrhizal colonization in roots, particularly under NT, could be beneficial for plants to face drought stress. However, in a scenario of reduced rainfall it will be necessary to invest more resources in weed control under RT.

This study looks at the combined effects of straw mulching (+ and -) and tillage methods (no-tillage, rotary tillage, and plow tillage) on soil water, N, root distribution, plant N nutrition, tiller capability, and grain yield of dryland maize-wheat. Straw mulching with no-tillage showed higher soil moisture, mineral N, and Olsen-P content, and increased root length and surface area (in the 0-20cm but not the 20-40cm soil layer) compared to no-mulch with rotary tillage or plow tillage. Straw mulching with no-tillage showed greater above ground plant dry mass and shoot N%, leading to increased plant N nutrition, tillering capability, and grain yield. The recommend maize straw mulching with no-tillage for dryland farming communities to replace the rotary tillage conventional system.

This paper looks at the issue of sulfur deficiency in Pearl Millet in dryland areas of India using a field experiment with CA and foliar applications of S (ammonium thiosulphate). Their results showed that pearl millet grain and protein yield were significantly higher under no-tillage +3 t/ha crop residue mulching (NTCRM) as compared to no-tillage without mulch (NoTill) and conventional tillage (ConvTill), whereas the stover yield under NTCRM and ConvTill remained the same. S application also resulted in higher grain protein, yield and net returns than no S in the control.

This review looks at soil and water conservation (SWC) in terms of farmer practices to explore how SWC represent a pathway to improve soil health and sustainable agriculture in Africa and what the best-fit SWC practices in rainfed situations. They show that options, such as Conservation Agriculture (CA), Agroforestry (AF), as well as integrated soil fertility management (ISFM) and field-scale rainwater harvesting (RWH), remain promising for the preservation and improvement of soil health in Africa’s farmlands and improving the resilience of agrosystems to climate change and variability as well as droughts.

This paper addresses the issue of declining water tables and increases in soil salinity in irrigated drylands. The paper assesses the potential of CA practices - water saving irrigation, water quality, and nitrogen rates to sustain rice-wheat (RWS) and cotton-wheat cropping (CWS) systems. The study included mixed-method approaches of two years of field experiments, and soil profile and groundwater salinity simulation using Hydrus-1D model, and multi-criteria trade-off analysis for the holistic assessment of alternative innovations in RWS and CWS. Fourteen sustainability indicators computed from experiments and simulation were compared to evaluate the sustainability of those cropping systems and to reveal the potential of those practices for improving sustainability. This study showed the importance of agronomic, soil, and water management practices for minimizing soil salinity and demonstrated the role of CA in sustainable agricultural production particularly under CWS in salt-affected irrigated drylands.