Conservation Agriculture Research Updates - March 2026

The authors used a mobile, closed chamber system to determine soilborne, greenhouse gas (GHG) emissions from rainfed, farmer-managed CA- and conventional agriculture (CONV), in northern Zimbabwe in on-farm sites that varied in soil fertility and environmental conditions. Field emissions were highest under
warm-moist conditions, which are prevailing for large
parts of the growing season. See the abstract for detailed results. They conclude that "the mitigation effects of CA are highly
site-specific and that CA management practices can have unexpected negative effects on GHG fluxes. The
unimodal rainfall distribution with a long dry winter
period of 7 months and recurrent dry spells in north-
ern Zimbabwe may prevent a net carbon sequestration
under CA management that would have occurred in
the humid tropics.

This paper from NW Cambodia compares use of conventional tillage (CT) with CA in maize cultivation looking at soil health, agronomic, and economic differences. The experiment was set up in 2020 comparing CT and CA with one cover crop (CAS) and CA with a mix of three cover crops (CAM). Soil health was assessed using a Biofunctool. Soil health (SH) was positively increased under CA. However, in the 1st year CA. had lower plant density and suggested that there was a need to improve NT sowing methods. This problem resulted in no significant differences in maize yield between the 3 treatments. Gross value added under CA was 12.7% less than CT in 2021, it surpassed CT by 43% in the second year.

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 paper reviews the history of agricultural extension in Zimbabwe and presents recent research findings on Ag Extension Officers (AEO) training and gaps in the curriculum. The data suggests that a gap in skills exists because of insufficient AEO training in essential areas including farm management, market access, emerging technologies and being able to support the changing needs of farmers. The authors suggest that the greatest need is for agricultural extension services for new farmers and emerging agricultural technologies compared to well-established farmers and farming methods.

This paper looks at a rainfed, winter wheat system from 2019-2023 in Uzbekistan. They were looking at identifying a suitable rotation system for winter wheat under no-till using chickpea (CH), safflower (SA), flax (FL), barley (BA), and canola (CA) compared with continuous Winter wheat. Results showed that the integrated effect of NT x crop diversification x residue retention positively affected crop productivity. The best rotation was a rotation with CH-WW-SA-WW. This rotation alongwith SA-WW-CA-WW had the highest WW yields. The lowest were with the conventional tillage system. Residue mulch also consistently improved yield compared to no mulch. They conclude that using NT and incorporating a second crop in the rotation with WW and retaining residue on the soil surface  can help rehabilitate rainfed croplands. 

This article from China looks at the long-term affect of tillage and nitrogen addition on yield and soil quality in rainfed maize. Their results show NT plus increased N resulted in higher yield especially in wet years. Over the 18 year period yield enhancement attributed to nitrogen varied from 8.2 to 24.5% with the highest yield under NT. They also found improvements in organic carbon, N availability and P was higher in NT treatments.

This is Chapter 8 in a new 2024 CRC Press book on soil and drought edited by Rattan Lal. The author suggests CA is increasingly endorsed as a type of Climate Smart Agriculture, contributing to both climate change adaptation and mitigation. The objective of this chapter is to describe and review the benefits of CA increasing water use efficiency in dryland agriculture where water is the most limiting factor and the impacts of SOM on soil hydrological properties and crop yields. Management of soil carbon is also central to maintaining soil health and ensuring global food security. The organic carbon content of soil is a key indicator of soil health that indicates the efficient functioning of many ecosystem processes.

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 looks at how CA affects subtropical dryland farming systems in Pakistan. In a field experiment, fallow-wheat (farmers' practice) and the conservation tillage methods minimum tillage (MT), reduced tillage (RT), and zero tillage (ZT) were compared to conventional tillage (CT) in the main plots and the cropping systems sorghum-wheat (S-W) and mungbean-wheat (M-W) to fallow-wheat (F-W) in the sub-plots. They look at SOC, total organic carbon (TOC), microbial biomass carbon (MBC), particulate organic C (POC), and mineral associated organic C (MOC). They show that regardless of cropping system, cumulative CO2 flow was lowest in ZT plots. The CENTURY model confirmed that continuous use of tillage  is a major threat  to soil fertility and production.

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 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 looks at growing maize intercropped with ruzigrass (Urochloa sp.) on soil physical properties over three years including maize and soybean yield under no-tillage and rainfed conditions. There were three intercropping systems; ruzigras sown  before maize; sown at the same time; and sown 15 days after maize. Soybeans were grown every summer. Soil physical properties included bulk density at 10-20cm, and macroporosity and were better when ruzigrass is sown before maize. Soybean yields were not affected two of the three years nor by soil physical properties. Maize yielded 17% more when ruzigrass was planted 15 days after maize than before maize.

This study from Spain, evaluates no-till, cover crops, and organic amendments as an alternative for conventional practices (CM) for rainfed cereal cropping on a calcareous soil based on the analysis of soil water retention curves (SWRC) and soil structure. The alternate treatment (AM) includes no-tillage (18 years continuous) after conventional tillage, crop rotation, use of cover crops and occasional application of organic amendments. CM involves continuous conventional tillage (chisel plow), mineral fertilization, no cover crops and a lower diversity of crops in the rotation. Their results showed more macropores under CM while mesopores and micropores were the same in both CM and AM. There were more stable macroaggregates in AM than in CM, as well as more organic C storage, greater microbial activity, and biomass. They also say that adoption of AM would not lead to a loss in yields.

This paper indicates that CA adoption in India is mostly in the irrigated IndoGangetic Plains and typically uses agrochemicals. This study explores the adoption of CA in a rainfed area of Central India  where farms are organic and look at the factors that led to adoption. Results showed that the variables that were important were farmers’ age, household size (a proxy for labour), extension frequency, farmer’s initiative-taking ability, farming experience, and market accessibility. The majority (90%) of the adopters indicated improvements in soil health, reduction in water use, and increases in yields and quality. They also indicated (80%) that CA led to lower costs, and higher incomes. However, biomass was an issue since farmers use the residues for cattle feed. The conclude that "To scale CA and produce food sustainably in rainfed areas, it is necessary to initiate supporting policy and institutional interventions that would improve extension, biomass production, and availability within the farming system.

This paper looks at the impact of CA on durum wheat in Tunisia as a possible way to mitigate climate change. They looked at yield and water use efficiency. They assessed this over 12 years looking at conventional (CT), minimal (MT) and no-till (NT). Note that their weather data shows a significant decrease in precipitation and increase rain-free days over these 12 years. Results showed that NT had the smallest decrease in yield and the smallest coefficient of variation and thus greater stability. They concluded that the benefits of CA are particularly pronounced in years with extreme drought events, highlighting the importance of adopting such agricultural innovations to mitigate the impacts of climate change.

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.

Low yields are often related to variable rainfall in semi-arid regions under conventional farming. This paper from the highlands of Mexico evaluates CA in 2 sites on-farm experiments and 17 farmer fields from 2013-2020 to assess yields and profits. Maize grown conventionally on the flat (CT) was compared with maize on permanent beds with residue mulch. The latter plots had monocrop maize and three rotations with either triticale, oats, or common beans. Results showed that average maize yields on beds exceeded CT maize by 70% in one location. Whereas in a second location there was no difference in maize yields between CT and CA systems. On the farmer fields, bed planting was 70% better then the CT. The most profitable rotation was maize-beans in farmer fields and the 2 on-farm trails.

This is another adoption paper from the Mediterranean region -- Morocco, Spain and Tunisia. The study objectives were to investigate the sociocultural aspects of CA adoption, where they examined farmers’ understandings of ‘good soil management’ and a ‘good farmer’ identity. Crop rotation was a prominent concept cognitively tied to fertilizer application, bridging conventional and reduced tillage practices. CA farmers’ mental models of soil management were also more complex than conventional farmers. The ability to have good productivity and experience and knowledge were the most prominent aspects of farmers’ understanding of a ‘good farmer’. For CA farmers, environmental responsibility and innovation were important, whereas for conventional farmers, tillage and the use of mineral fertilizers, was valued more highly.

This paper looks at the impact of CA on the soil microbial community under rainfed conditions in Spain. They compare soil bacterial changes in relation to tillage practices. The experiment was sampled from 0-15 cm depth after 19 years of minimum tillage (MT) and no-till (NT) practices, along with rotation. They show that sampling time and tillage affected the bacteria community, the crop had little effect. May had more bacterial diversity than December. NT was found to significantly decrease bacterial diversity compared to MT. They conclude that after 19 years, NT did not promote bacterial diversity in the upper soil layers.

This article reports the results of evaluation of new wheat cultivars in on-farm conditions using different tillage systems. There were 7 wheat cultivars (3 bread wheat and 4 durum) and 3 tillage systems; conventional (CT), reduced (RT), and No-Till (NT) in two locations for 3 cropping seasons. Overall the CT treatment had the highest yield and NT the lowest. But maybe that was because there was no residue mulch or there were problems with the NT equipment or soil moisture at planting. NT needs a higher soil moisture at seeding that a CT soil. However, there were differences in yield between the different cultivars by tillage. Some cultivars had better yield under CT and others under NT. The experiment needs to look at cultivars by tillage with and without residue and plant the NT when the moisture is higher and not wait for the CT plots to be planted.

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.. 

This paper looks at ammonia (NH3) emissions under field conditions since they have impacts on health, climate change, and natural environments. They used fields with barley in Spain to compare NH3 losses in NT and CT plots. NT plots produced the highest NH3 emissions after applying basal and topdress N fertilizers with basal having more NH3 emissions than topdressed ones. They conclude that NT requires the optimized management of N (timing, rate and particularly source) to abate the potential side effects of NH3 volatilization, while the use of robust measurement methods are needed with enough replicates to increase the precision in estimating differences.

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. 

The paper stats by explaining the negative impacts of conventional management on degradation of soils and loss of soil health. The research looks at ways of reversing soil degradation using CA in a long term experiment (after 8 years) with 4 cropping systems, and three tillage systems; CT, RT and NT. Soil samples were collected from 3 soil depths; 0-10, 10-20 and 20-30 cm depths and data collected on soil chemical, physical, and biological properties in a Vertisol in Central India. @0 soil properties were used to calculate soil quality indices (SQI). The paper lists the results of this research. They conclude that the soil quality index was significantly highest in NT, followed by RT and CT at all soil depths. CA based practices favoured carbon storage, lowered carbon emission, foot print and soil quality compared to conventional farming. 

Soil erosion is a major problem on tropical hillsides. This descriptive study in Mexico looked at water runoff and its runoff coefficients in four modalities of the “milpa intercropped with fruit trees” (MIAF) system, traditional and zero tillage, under rainfed conditions.  The MIAF.system reduced surface runoff by 46.13 % with respect to that obtained in LM-QR (minimum tillage with residue burning). The LO system (Zero tillage with crop residue distribution over the surface) had the lowest volume and runoff coefficient.