Conservation Agriculture Research Updates - April 2026

This article from NW Vietnam looks at how CA practices (CAPs) can be adopted to overcome the problems associated with conventional agriculture in this region that has resulted in soil degradation because of intensive tillage and intensive use of chemical fertilizers without adding organic matter. They surveyed 400 maize-farming households. Their analysis shows "that the joint adoption of CAPs is facilitated by education of the household heads, total farmland area, farmers’ access to credit, interactions with extension agents, training on CAPs, proximity to cooperatives, participation in farmers' groups, and plot-specific characteristics." Adoption of CAPs leads to better maize yields and net incomes, especially when all aspects of CA are adopted.  

This study is undertaken at the Ifugao Rice Terraces in the Philippines, an Agricultural Heritage system. They surveyed farmers in this region on the socio-demographic, environmental, and economic factors influencing the adoption and persistence of Environmental Conservation Agriculture (ECA). They found the shift to high-yielding rice in ECA led to a decline in the use of Tinawon rice, an important component of this Heritage site. They suggest it is important to balance modern practices with continued use of the traditional system to preserve biodiversity, soil health, and cultural identity. Climate change presents both challenges and opportunities for adaptation, making it essential to integrate traditional knowledge with modern techniques to build resilience. 

This study evaluated the effect of NT compared to moldboard (MB) with rye CC versus fallow on SOC and active C, aggregates and other soil physical properties. Rye significantly increased aggregate-associated C. NT combined with RY significantly increased SOC and AC in the surface layer and volumetric water content at all soil depths. The results showed that the NT system increased plant residue, reduced soil evaporation, increased SOC content and soil water retention, and bonded soil microaggregates into macroaggregates better than the MP system. NT plus rye CCs reduces drought effects that result from climate change.

This paper looks at the use of CA to help overcome the problems associated with Meloidogyne and Hirschmanniella the most damaging plant-parasitic nematodes (PPNs) in rice production in Asia. Thery investigated the effects of two components in Cambodia (i) CA practices, no-tillage with a cover crop Stylosanthes guianensis, versus conventional plow-based tillage with no cover crop. Under CA, the abundance of PPNs extracted from the roots was reduced by 88%. Soil quality was also improved that provided more basal resources for beneficial microbes. They conclude thier study confirms that CA is an alternative to nematicides to limit infection by PPNs in rice cropping systems.

This is a study from Indonesia analyzes the economic and environmental impacts of conservation agriculture in maize. There are two comparisons; a) application of manure, mulch of previous crop residue and legumes as cover crop, and b) non-CA, chemical fertilizer, herbicide, no mulch and plants only maize. Observations by researchers, farmers, and extension workers were taken. Results show that CA with application of manure and mulch of previous crop residues, economically was able to reduce the purchase of herbicides and chemical fertilizer, save labor costs and time in plant maintenance. CA also reduced air pollution, use less groundwater, and increase SOM. Farmer income also increased.

This is an interesting paper from Cambodia looking at nematode issues in lowland rice managed using CA. They compared nematode populations, rice yield and soil organic matter in conservation agriculture management, conventional rice systems with greenmanure management (GMCT) and conventional plough-based tillage systems. Results demonstrated that GMCT for one year (GMCT1) and the long-term CA for seven years (CA7) reduced nematode densities in both soil and in rice roots, almost throughout the study period, compared to the CT system. For rice yield components and soil fertility, CA7 proved to be effective in increasing plant height, the number of tillers/plant and soil organic matter.

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.

The paper suggests that the increase in carbon sequestration under long-term NT and cover crop management is a sustainable agricultural system with an increase in SOC and soil respiration. This study looks at the addition of biochar on soil respiration in Japan. Long-term tillage practices, such as NT and moldboard plowing (MP), cover crops such as rye (RY) and fallow (FA), and biochar application such as with biochar (WB) and no biochar (NB) were applied to a split–split plot in a randomized complete block design with four replications. NT had higher respiration compared to MB. Rye had a higher respiration than fallow. Biochar significantly reduced respiration in the soybean and cover crop growing seasons but enhanced carbon sequestration. It reduced respiration by regulating the soil temperature, soil moisture and protect the SOC from decomposition. Biochar also increased SOC, decreased bulk density that improved soil porosity.

This paper reviewed 92 empirical studies that investigated the effects of 17 regenerative farming practices across 11 broad categories of crops on SOC stock or content in Southeast Asia. They found that use of organic amendments like biochar, compost, and manure, as well as cover cropping, crop rotation, and conservation tillage to increase SOC. However, addition of compost and manure reported increases in greenhouse gas emissions like methane (CH4) and nitrous oxide (N2O), demonstrating that increases in SOC may be offset by increases in greenhouse gas emissions. Only a few studies measured both the changes in SOC stocks and greenhouse gas emissions and none of the studies completed full greenhouse gas inventories. 

This is a second paper from the ASABE conference in Nebraska. It reports progress with CA in Cambodia. Adoption is slow at the moment because of low engagement of local services for machinery. This also compared different no-till seeders for maize. Sunn hemp was grown as a cover crop before planting maize. Three main treatments were implemented with (i) sunn hemp used as green manure crop and buried through tillage, (ii) sunn hemp crimped by Cambodia made crimper, and (iii) sunn hemp crimped by USDA crimper. Two different no-till seeders, the one-row Morrison seeder mounted on a 19-hp Oggun tractor and a four-row Brazilian seeder mounted on 75-hp John Deere tractor. The Brazilian seeder saved 50% seed and 80% of the time. Corn yield was also higher. Crimped plots had higher yields than disked plots. The conclude no-till seeders lead to higher corn yields.

This paper was given at the 1st International conference on Sustainable Land Management in Indonesia. This paper looks at the impact of CA in a semi-arid area of Indonesia. All the farmers in this project say that CA increased maize productivity and some farmers were even able to plant two maize crops with good yield in a drought year. Integrating forage into CA based farming also enabled farmers to provide enough feed 1-2 cattle per household. In this area basins were dug and then CA used. Labor was an issue but I suggest they make these basins permanent to lessen labor in the second crop/year. The residue mulch is also needed for animal feed. Similar to other dryland areas.