Conservation Agriculture Research Updates - April 2026

This study assessed the biophysical and biogeochemical impacts and the potential contribution of cover crop practices to sustainable land use using a global dynamic vegetation model LPJmL (Lund-Potsdam-Jena managed Land) V. 5.0-tillage-cc to simulate responses of agroecosystem components to cover crop cultivation in comparison to bare-soil fallowing practices on global cropland for a period of 50 years. They found that cover crops with tillage reduced annual nitrogen leaching rates from cropland soils but also the productivity of the following main crop for the 2 analyzed decades. The largest reductions in productivity were found for rice and modestly lowered ones for maize and wheat, whereas the soybean yield revealed an almost homogenously positive response to cover crop practices replacing bare-soil fallow periods. Their results suggest that having no tillage is a suitable complementary practice to cover crops, enhancing soil carbon sequestration and the reduction in nitrogen leaching, while reducing potential trade-offs with the main-crop productivity due to their impacts on soil nitrogen and water dynamics. 

Climate change is causing declining rainfall (more variability) and increasing temperature extremes and when added to declining soil fertility, food security in rainfed Morocco is threatened. The objective of this study was to systematically evaluate agronomic, economic, and soil fertility indicators under CA and conventional tillage (CT) using field experimentation (medium-term) and simulation modeling (long-term) for a clay soil in Morocco. They looked at the effect of CA on wheat, barley, lentil and chickpea to determine yield, stability, profits, WUE, and soil fertility. They also used Dynamic simulation modeling to assess the long-term effect of adopting CA and CT in these cereal rotations. Both their 5-year field experiment and the modeling showed that adoption of CA improves a range of agronomic, economic and soil fertility indicators compared to CT.

This study surveys 442 farmers in China and use a logistic-ISM model to determine the influencing factors of farmer's adoption of CA. The three main factors of 8 found are age, knowledge of Government subsidies and number of labor force. Two other factors are education and knowledge that the Government is promoting CA. Two others are received technical knowledge of CA  and whether their planting area is scattered. The authors suggest some policy suggestions to improve extension, implementation of land transfer and subsidies, strengthen rural social services, and publicize the importance of protecting black soils.

This paper from India looked at the long term effect of various CA practices on infiltration of water using modeling. Treatments included a check (CT), Permanent narrow beds (PNB) and wide beds (PBB) with and without residue (+R) and NT. The initial and cumulative infiltration rates were highest in the PBB+R treatment and lowest in CT. Bed planting with residue was better than BP without residue that was better than NT without residue. After checking the model performance, it was found that simple empirical Kostiakov (1932) infiltration model represented the infiltration rate and time relationship in a better way and characterized the best fit with the experimentally observed field infiltration data.

This long term no-till article in Kentucky used a agroecosystem model along with environmental datasets to quantify effects of NT on yield and GHG emissions in corn-soybean cropping systems. Tillage scenarios were CT and NT. Overall, NT reduced soil CO2 (−1.6% for corn and −4.53% for soybean) and N2O emissions (−10.5% for corn and −19.6% for soybean) compared to CT. However, corn and soybean yields with NT were not significantly different from those with CT. The summary does no indicate residue management that is important in helping with SOM accumulation and improved soil health. The authors conclude that the findings provide insights into how NT can enhance agroecosystem production stability and support climate change mitigation. 

.

This study includes research soil-water studies on maize-wheat system where maize is used instead of rice. They use CA and sub-surface drip irrigation (SSDI) as key strategies to address water scarcity in South Asia. The field study used a process-based model (HYDRUS 2D) to understand water transport, root water uptake and components of soil water balance in maize grown in rotation with wheat after five years of continuous adoption of conservation agriculture. The study included CA, SSDI, permanent beds, with and without residues and different N-rates and compared with CA on beds with furrow irrigation and conventional tillage on beds without residue. In CA+ based plots (CA + SSDI) significantly had higher biomass production and radiation use efficiency with reduced water use than CA (furrow irrigation) and CT.

This a second article on N20 emissions looking at soil-weather effects using a conditional inference tree (CIT)  learning method able to untangle complex interactions while providing an interpretation model. The goals of this study were (a) to assess the effect of N fertilizer on N2O emissions, and to use CIT to identify (b) the main soil-weather drivers of daily N2O hot moments and (c) fertilizer management options to mitigate them in a 2-year no-till maize experiment.2013 was drier and had less N20 emissions than 2014. Only subsurface-banded fertilizer with a nitrification inhibitor (NI) consistently abated N2O losses. The main hot moment conditions were within ∼80 d of fertilizer application when soil temperature >15 °C and WFPS >57%. 

This Ethiopian study assessed the long-term impact of different conservation management systems (CMS) on soil organic carbon (SOC) using the DAYCENT model over a 30 year period. The management systems considered were minimum tillage, crop residue (CR) retention, fertilization and their combinations.Data came from studies in the literature. The alternate systems were compared with the business as usual treatment (BAU). Results showed CMS increased SOC in the 0-20 cm layer compared to BAU. The individual effect of fertilization, CR retention or minimum tillage management practices on SOC stock were lower than the response of the combined conservation management practices. They conclude that the combined 50–75% CR retention, NT, and increased N fertilization have a potential to increase SOC sequestration in resource-limited smallholding croplands. 

This article applies an endogenous switching regression model to a case study of 2296 wheat fields in Morocco, to provide evidence on the socio-economic impacts of residue retention. 30% and 60% plus of crop residues were retained respectively on 35% and 14% of wheat fields. These levels of residue retention led to 22% and 29% more yields, 25% and 32% higher gross margins and 22% and 25% more consumption of wheat, respectively. Residue retention is economically and biophysically beneficial even for owners of livestock as the monetary value of the additional grain yield more than offsets the cost of purchasing an equivalent amount of feed from the market—all providing good economic justification for residue retention. Development and/or import of alternative feed sources, introducing crop insurance, and raising the awareness of the economic, biophysical and environmental benefits of residue retention among farmers are needed.

This study used the DayCent biogeochemical model to identify the best management practices for SOC sequestration. They used data from two long-term field sites in Western Kenya that used two promoted management practices: integrated nutrient management and conservation agriculture. Correlations at both sites between measured and simulated SOC were low to moderate, and in most cases produced fairly accurate predictions of SOC trends. The conclude that model results suggest that response of the passive SOC pool to the different management practices is a key driver of the long-term SOC trends at the two study sites.

This paper looks at various methods for scaling new agricultural uses .practices and technologies and assess their effectiveness. They collected data from 875 smallholder farmers. in central Mozambique. They used a continuous treatment model within the framework of a generalized propensity score matching to empirically assess the effectiveness of community-based extension activities in fostering the adoption of a set of conservation tillage practices . The results show that controlling for socio-demographic factors such as gender of decision maker, land size and access to government services, the area under conservation tillage doubled when respondents had been exposed to targeted extension activities for at least six seasons, from a baseline exposure of two seasons. The study offers an important first step in making an empirical case for multi-year investments in extension activities.

In this paper, a process-based model, Denitrification-Decomposition (DNDC), was validated on midterm (9 years) and employed depending on the local climate, soil and management conditions, to assess the impacts of alternative management practices on SOC stock under two tillage systems, in a semi-arid region of Morocco. Modeled results pointed out that, under no-tillage practice (NT), the SOC content increased by 30% compared to conventional tillage (CT). During the simulated period (9 years), the SOC sequestration potential (CSP) has been greatly improved with increased crop residue rate and application of farmyard manure (FY-manure). They conclude that an increase in crop residue rate returned at surface after harvest and application of organic fertilizer, especially under NT practice, can substantially improve SOC stock in a semi-arid region.

This 4perMile initiative objective was to increase the annual amount of C in soils of the world by 0.4%. No Tillage (NT) potential applied in annual crops is presented in this paper as one way to achieve this. The comparison between the annual carbon sequestration (CS) through NT and the contents in SOC in annual crops, allowed the calculation of the potential importance of NT, within the regional framework, of the 4perMille Initiative. This methodology for calculating the NT potential over the 4perMille Initiative can be easily replicated in regions and countries around the world.

This paper uses a model to estimate crop yields and GHG emissions. It develops a biophysical modelling framework encompassing a farm typology, a crop model, and a farm-focused GHG calculator to assess productivity (crop yield) and GHG emissions of crop management practices concurrently to study cropping systems based on CA on different farm types. All farm types had net sources on GHG across all farm types. But using CA-based practices independently and in combination into farm-type maize-based cropping systems showed significant potential in improving crop yields and lowering GHG emissions across all farm types and were found to be more efficient with higher yields and ecosystem services that help with climate change mitigation.

This paper investigated how much tillage reduces weed infestation and yield loss, and which systems and weed species are the most affected by tillage suppression. Data was collected from 395 arable cropping systems mainly in France. They used the data and simulated them over 30 years with 10 weather repetitions using the FLORSYS model. Three series were simulated, (1) using the recorded systems, (2) eliminating tillage without any other changes, (3) eliminating herbicides without any other changes. Among the recorded systems, herbicide treatment frequency index (HTFI) averaged over rotation increased when tillage frequency decreased. No recorded no-till system was herbicide-free. The simulations indicated that two CA pillars (diverse crop rotations, cover cropping) were essential to manage weeds while reducing (or eliminating) both tillage and herbicide use. More no-till cropping systems must be investigated to determine whether sustainable no-till herbicide-free systems are possible.

This study estimated the the spatial-temporal variations of maize yields from 13-year on-farm trials from 4 countries in Southern Africa. Agronomic data from long-term CA trials is used with gridded biophysical and socioeconomic variables. Comparisons were made between CA and CT practices with above and below average precipitation. The variable importance analysis showed that the altitude, precipitation, temperature, and soil physical and nutrients conditions variables explained most of the variation in maize grain yield. Maps were generated to identify the locations where CA had a yield advantage over CP during seasons with below and above-average precipitation. The paper concludes that multi-source remotely sensed data, coupled with advanced and efficient machine learning algorithms provides accurate, cost-effective, and timely platforms for predicting the optimal locations for upscaling sustainable agricultural technologies. 

This long-term experiment (14 years) combined fertilization rate (no, low and high N fertilizer, N0, N1 and N2), straw additions (no, low and high addition, S0, S1 and S2) with conservation tillage (no-tillage, NT) in the North China Plain. A Denitrification Decomposition model (DNDC) was used with the data collected and then applied  to simulate the changes of crop yields, soil organic carbon (SOC), and N2O emissions under different management practices combined with climate change scenarios, under low and high emission scenarios of societal development pathways (SSP245 and SSP585, respectively) with climate projections from 2031 to 2100. They conclude that CA can potentially offset crop yield reductions, increase soil quality, and reduce greenhouse gas emissions in the NCP, and ensure crop production to meet the growing demand for food under future climate change.

This study evaluated 2 crop models CSM-CERES for maize and CSM-CROPGRO for soybean for NT and CT systems and compared the long-term impacts of NT and CT on crop yield and SOC using 5 years of data. The results from these long-term (30-year) simulations suggest that compared to CT, the NT system enhanced SOC over time and, hence, crop yield and biomass production. They conclude that application of NT can be beneficial for enhancing the soils and crop production in the long-term as compared to the CT system.

This paper presents an approach that integrates long-term field experimental data and modeling to quantify resilience of NT at a watershed scale in Michigan. Recharge, groundwater table, soil moisture, yield, and net return were used as resilience metrics. The DSSAT sequence crop model was developed for a corn-soybean-wheat rotation and calibrated using the yield and soil moisture data from a long-term (1993–2019) experiment for the conventional and the no-till treatment conducted within the study area. Their results show evidence of higher recharge and net return under the no-till treatment, which were statistically significant for all crops at the watershed scale. The NT treatment also retained more soil moisture that helped mitigate drought impacts. The groundwater table also rose in NT treatments.

This study assessed the relationships between soil health and cropping system performance for three maize-based cropping systems in New Caledonia. There were two CA systems compared a conventional tillage system: direct seeding into dead mulch (CA-DM) and into a stylo living mulch (CA-LM). Soil health was evaluated using Biofunctool®, a set of ten in-field tools that assess soil carbon transformation, structure maintenance and nutrient cycling functions. Weeds, maize growth and yield components were monitored using a Structual Equation model (SEM). Soil structure maintenance and nutrient cycling functions were higher under CA-DM and CA-LM than under CT, and carbon transformation function was higher under CA-DM than under CT and CA-LM. Overall, the soil health index (SHI) was 1.3-fold higher under CA systems than under CT.

This paper looks at the problem of soil erosion in the mountains of Guatemala. It looks at the effectiveness of CA to reduce soil erosion in maize cultivation. The study was conducted over a three-year period, from 2017 to 2019, on three experimental plots managed under conventional tillage (CT), reduced tillage (RT) and no-tillage (NT). The general-to-specific (GETS) method, based on reduction theory, was used to generate explanatory models of the erosion-affected surface. The results showed different rates of eroded soil surface between the three management systems: 73.2% under CT, 41.3% under RT and 20.4% under NT. Three conclusions are derived and discussed in this paper. Litter layer was the key explanatory factor for erosion that was highly influenced by the agricultural management system. The paper recommended for the area of this study that soil management under NT with a dense and well distributed litter cover is best to control erosion.

This is a study of the parasitic weed, Striga, a frequent problem for smallholder farmers in South Africa. They used system dynamic modeling to assess the efficacy of various striga treatments (SCPs) across different seasons and agroecosystems in maize based cropping systems. Model simulations indicate that while a combination of SCPs are necessary to manage the weed, future research should focus on developing smallholder-adapted SCPs that address the attachment stage of the weed's lifecycle (e.g., timely manure application) rather than its germination, emergence or flowering stages. They conclude that it is imperative to develop decision support tools like systems models to evaluate SCPs for smallholders that help extension agents to provide correct information to farmers.

This study uses an endogenous switching regression model to a nationally representative sample of 1901 wheat fields in Morocco to analyze the impacts of partial or full adoption of all three components of the CA system. Model results show that adoption of the complete CA system leads to 307 kg/ha (35 %) higher yields, US$99/ha (44 %) higher gross margins, and 23 kg/capita/year (38 %) more consumption of wheat relative to the conventional system. Adopting only two of the 3 pillars also leads to improved livelihood indicators compared to adoption of only one or none of the pillars. But adoption of one pillar is better than none. They conclude transition from the conventional system to CA requires the following: (1) flexibility to let farmers incrementally adopt one or more of the CA components, learn at their own pace, use some of the benefits, and improve it over time to exploit the full potential of the CA system with close follow-up and technical support from experts and extension specialists; and (2) sustained policy and institutional supports that provide incentives for farmers to adopt and for the private sector to be actively involved, especially in service provision.

This 16 year long term study in Hungary looked at the effect of conservation tillage (CT) on run-off, soil loss and soil in large plots and compared with ploughing tillage (PT). By the end of the study period, significantly higher water-stable aggregates (PT: 20.0 %, CT: 30.4 %), higher soil organic matter (PT: 1.4 %, CT: 1.9 %), greater earthworm abundance (4.9 times that in PT plots) was recorded on the CT plots. The difference between PT and CT was significant for mean annual soil erosion, with values of 2.8 t ha−1 and 0.2 t ha-1, respectively. They conclude that the use of CT enabled the maintenance of a major fraction of precipitation on arable land, and consequently, soil loss remained an order of magnitude lower than its tolerable value.

The objective of this study was to evaluate CA cropping systems for rainfed maize as an alternative to the traditional tillage-based cropping systems (CT) in the context of family farms, using a multi-criteria model that represents the point of view of farmers in Brazil. Farmers evaluated based on 5 criteria a) costs; b) yield; c) labor; d) human health and environment; and e) risks. CA did not differ from CT for the `costs' criterion but was superior for the `yield' and `labour' criteria. In contrast, CT obtained better ratings for the criteria `human health and environment' and `production risks'. Considering all criteria, CA was better appraised than CT. However, a new local policy measure that subsidizes the hiring of mechanized tillage services overturns this outcome, indicating the importance of exogenous factors.