Conservation Agriculture Research Updates - April 2026

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.

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 looks at smallholder farmers issues with tractor mechanization using a survey of 208 farmers, 18 focus groups and 28 key informants in 3 Districts of Zambia. Issues looked included adoption, preferences for ownership, and financing. Tractor ownership revolves around improvement in productivity but also income generation from service provision to other farmers tied to better timing and narrowing planting windows. Differences in gender affect ownership with males preferring individual ownership and females prefer group ownership. Incentives for ownership were best for risk-contingent credit especially if bundled with repair insurance. Barriers to adoption included high maintenance costs' poor access to spare parts and financial issues. They conclude that "successful interventions must be flexible, gender-responsive and tailored to the local context." 

Food security is a challenge in Malawi where agriculture is crucial for livelihoods and rural development. This paper looks at the diversity of different CA systems adopted by rural farmers a District in Malawi. 390 farmers were surveyed who had adopted CA in some form. 97% of these farmers were aware of CA, but adoption rates were much lower because of high labor costs and limited resources. Intercropping was used by 37% of farmers and 30% used manure. Mulching and mixed cropping had low adoption rates. They concluded that "to enhance the adoption of these technologies, it is recommended that strategies be developed to address labour and resource limitations, including context-appropriate training programs, resource enhancement initiatives, and targeted promotional efforts focused on local farming systems.

This paper looks at the impact of CA in an Ethiopian district on crop productivity using cross-sectional household data from 322 subjects in two agro-ecological zones. There were 168 CA and 154 non-CA farmers. The project's findings highlighted the need for policies that support and enable a more frequent and successfully established communication link between farmers with agricultural experts at the regional, zonal, and district levels, as well as agricultural extension personnel at the local level. There is a need to adopt crop and soil management systems on farmland,that results in improved soil quality consistently for improved crop productivity.

This paper suggests that CA is often though to under perform in high rainfall areas like Northern Zambia. This paper evaluates a long term (9 year) study in this area of maize cropping systems and rainfall variability on yield, , soil pH, and SOC. Three CA systems were compared to 2 conventional systems. Results showed despite rainfall variability across years, CA systems did better than conventional systems especially in low rainfall years. However, bed planted traditional systems out performed CA systems in high rainfall years. However over time yield declined faster in the conventional system than the CA systems as nutrients declined. They conclude that CA systems can improve maize yields in high rainfall areas but strategies are needed to mitigate waterlogging  after heavy rain and sustain soil fertility.

This paper used a meta-analysis of CA and/or biochar use on soil-nitrate-N, N20 emissions, biological N-fixation, N derived from the atmosphere, grain Y, and Nitrogen use efficiency (NUE). They used 87 papers from 15 countries in SSA with 1643 paired observations. Their results showed that on average over all studies CA and/or biochar significantly increased grain yield and NUE compared to conventional systems. In addition, Residue retention resulted in a significant increase in soil NO3-N and N2O emission, compared to conventional practices. Biochar also increased biological N-fixation, grain yield and NUE. N2O emission increased significantly in soils with < 0.05 % total N, while biological N2-fixation increased significantly in soils with > 0.2 % Total N.

Despite CA being promoted and a possible solution for food insecurity resulting from climate shocks and soil degradation, adoption in Malawi is still low. This paper looked at social capital as a way of approving adoption. The interviewed 1512 smallholder farmers to find out how different social capital elements influenced farmer decisions to adopt CA. Factors that positively affected adoption were group membership, relations with leadership, land size, extension services, livestock ownership, and available credit. Full adoption of CA was limited compared to partial adoption. They conclude that better policy is needed to promote farmer organizations, community engagement, and training programs to enhance adoption.

This study from Tanzania looks at farmer strategies for adaptation to climate change. They surveyed 330 smallholder farmers. It was found that farmers have a number of strategies but the following 4 were key ones: drought resistant varieties, early maturing ones, resistant livestock breeds and conservation agriculture, with farmers choosing more then just one. The paper also categorizes the samples into 4 groups taht you can find in the paper. The conclude that these factors need to be considered in any policy decisions to ensure better adoption and adaptation strategies.

This paper from Malawi where maize is the main staple food evaluated over 7 seasons four maize genotypes under different CA and conventional practices across on-farm communities. Results showed significant G×E and E×M interactions with hybrids such as DKC 80–53 and PAN 53 higher yielding than the other hybrid and the OPV in most of the environments. However, the OPV ZM523 variety had greater yields in environments with above-average rainfall and shorter in-season dry spells. CA practices out yielded conventional ones. Interestingly intercropping maize with pigeonpea or cowpea didn't perform as well as growing these two legumes after the maize. The recommend that smallholder farmers should adopt hybrid maize and CA-based management, although OPV's could be considered for variable climate areas.

This paper looks at farmer strategies for future climate variability and climate change in Tanzania. They used a cross-sectional research design in a survey of a random sample of 330 small-scale farmers. The results show that farmers use a number of strategies, but 4 key adaptation strategies - drought resistant varieties, earlier maturing varieties, resistant livestock breeds and conservation agriculture (CA) - emerged. Farmers also used more then one strategy with choice determined by multiple factors. The paper categorizes the factor into 4 groups that in summary include individual farmer/household; farm characteristics; institutional factors and; local knowledge. They suggest these factors should be available for policy development.

Sentinel sites that had promoted CA for a long time were used in this paper. The paper attempted to understand what led to the success of CA adoption. They surveyed 620 farmers in Malawi divided into two groups ; those who had contact with host farmers and a control group. Almost a third of the farmers in both groups adopted full CA over a 2-year period, but 57% of the farmers in the treatment area adopted full CA but on 7% in the control group. However, fewer farmers adopted CA for a longer period even in the treatment areas with some dis-adoption. The key adoption factors in the sentinel sites include the availability of training, dedicated longer-term extension support coupled with farmer experiential learning through demonstration plots managed by host farmers. This peer to peer learning over time is critical for sustained adoption.

There has been a rise in the number of market-oriented farmers, known as `emergent farmers,' who acquire and utilize tractors and associated implements for agricultural production to Zambian agriculture. This study examined the behavioral intentions of Zambian emergent farmers concerning Mechanized Conservation Agriculture (MCA) using the Decomposed Theory of Planned Behavior constructs: attitudes, perceived behavior control, subjective norms, and farmers' background factors by surveying 119 emergent farmers. Factors such as media influence, social influence, technical training, and extension services had positive but insignificant effects on farmers' intention to adopt MCA. Background factors, including overall farm size, farmer's age, area under CA, and years of CA use, showed a positive and significant correlation with farmers' intention to adopt MCA.

This review from Zimbabwe reviews the Pfumvudza/Intwasa initiative that has been promoting conservation agriculture (CA) practices among smallholder farmers in this country. In terms of policy this project provides guidelines for implementation, resource allocation, and support systems. The review examines the role of government policies and institutional frameworks in sustaining CA practices in Zimbabwe using a literature review analyzing peer-reviewed articles, policy documents, and government reports published between 2000 and 2024. Results both strengths and limitations. The authors mention that policies promote conservation agriculture, inclusive participation, and resource distribution, but challenges such as inadequate institutional coordination, limited extension services, and funding constraints limit the success of this program. The report recommends "policy harmonization, targeted investments in extension services, and the promotion of equitable resource distribution. Additionally, leveraging technology for monitoring, enhancing market access for smallholders, and fostering public-private partnerships will support the scalability and sustainability of this project"

This paper presents the results of a study to look at CA performance of a cassava-legume cropping system in terms of yield, nutrition, and economics in Northern Zambia. They used a mother and baby trial setup  with 6 cropping systems that combined tillage (flat and bed planting) and legume intercrops (common beans and groundnut) compared to sole cassava. They measured root yield, legume yield, protein yield, energy and economic returns. See the paper for more details, but 3 treatments were planted on the flat under no-till and 3 treatments planted on hand hoed ridges (traditional system for cassava). Results showed cassava planted on the flat especially with legume intercrops under CA did not compromise cassava yield and significantly enhanced legume grain, protein, and energy yields. Economic analyses revealed higher net benefits and return to inputs in flat-planted intercrops, though labour costs were also higher.

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 paper from Rwanda looks at the low yields of maize, a critical staple crop in this country. The study evaluates the agronomic and economic results of CA compared to conventional systems (CT) by interviewing 222 farms in dry areas of Eastern Rwanda. They found that CA farmers incurred higher total production costs, particularly for fertilizers, seeds, weeding, and irrigation, while CT farmers had significantly higher land preparation costs. But CA achieved 40% higher net profit, 20% higher maize yields, and higher P use efficiency compared to CT. They identified irrigation frequency, seed rate, and nitrogen and phosphorus fertilizer application as key determinants of maize yield using CA compared to CT. 

This paper looks at the success of CA in high rainfall areas of Northern Zambia from a long term (9 year) experiment to determine if CA is a viable system under these conditions. The experiment looked at three different CA systems, basins, animal ripped line planting, and dibble stick planting and compared with conventional inversion tillage and ridge and furrow tillage. Yearly rainfall over these 9 years was variable. The 3 CA systems mostly did better than the 2 conventional systems, especially in medium to low rainfall years. But ridge and furrow systems did better in high rainfall years because of better drainage, but overtime, yields declined because of nutrient decline. They conclude that CA systems can be recommended in these high rainfall areas in management systems to overome waterlogging and sustain soil fertility are included.

This article looks at the issue of declining soil health, soil organic carbon (SOC) and soil degradation and ways to sustain ecosystem services and human well being and food security in Africa. Aklso the need to do this when there are negative consequences of climate change. The paper says "soils of most agro-ecosystems in Africa have been subjected to land misuse and soil mismanagement, and thus are, severely depleted of their SOM content because of extractive farming practices. Thus, agronomic productivity, use-efficiency of inputs (e.g., fertilizers, irrigation, energy-based farm operations, seeds of improved varieties or choice of other species of animals or plants) and the nutritional quality of food produced is low." The paper then discusses options for reversing this declining soil health including CA, cover crops, crop-livestock systems, integrated soil fertility management, integration of crops and trees and more. The paper also suggests ways of encouraging farmers to adopt improved farming practices.

The authors of this paper are looking at traditional grains like sorghum, pearl and finger millet to combat climate change and drought in sub-Saharan Africa (SSA) as alternatives to maize the staple food in this area. The main objective of this review paper is to identify suitable equipment for smallholders to mechanize growing these traditional grains. They reviewed six databases to find suitable equipment used globally. They found that the mechanisation of traditional grain production operations is lagging behind that of other cereals and so there is a need to work on development of suitable equipment  for smallholder farmers. They suggest use of two-wheel tractors and service providers as a way to move forward. Policy decisions and recommendations for improvement were made.

This study collected soil samples from paired farms that had used CA or conventional tillage (CT) and looked at tillage effects on physio-chemical properties including SOC by soil depth. SOC was higher in CA soils. But higher SOC was measured at depths of 0-10 cm compared to 10-30 cm under CA. In fact, soil depth had significant effects on most soil properties compared to tillage. The paper concludes that CA improved total SOC and its associated fractions, a finding relevant towards understanding effects of land management on carbon storage. However, challenges of competing residue use as feed, mulch, and fuel continued to impede mulching under CA systems.

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.

Conventional farming in Sub-Saharan Africa (SSA)  is resulting in soil degradation. This paper reviews current practices, challenges, and constraints to the adoption of CA in SSA to reverse this degradation. They show that CA is only adopted on 1.25% of cultivated land in SSA despite 2 decades of promotion. The paper lists 6 possible reasons for this lack of adoption of CA. They also suggest that adoption by smallholder farmers is also obstructed by socio-economic factors due to smallholder farmers’ focus on short term yield increases and their lack of access to markets, loans, and education. They conclude that wider adoption by smallholder farmers in SSA requires CA approaches that are downscaled to fit the existing tillage tools and the specific agroecological and socio-economic farm settings.

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.

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.