Conservation Agriculture Research Updates - March 2026

Interesting paper on the effect of CA practices and especially tillage (with and without), residue management (burned, incorporated or surface mulch) and fertilizer (with or without) on tilled or permanent beds (PB) on the soil microbial community in a long term maize-wheat experiment in NW Mexico. The soil organic carbon was highest in the PB, residue retained treatment and loweest in the burned and tilled plots. Bacterial communities were affected by tillage-residue, fertilizer and soil organic carbon. The paper has data on how the different bacterial communities were affected.

They measured CH4 and N2O fluxes under 3 tillage and residue management systems and 4 N-levels in NW India. Significant CH4 only in the conventional RW system. irrespective of N-level. But N-level did affect N2O emissions. Highest under crop establishment phase using 80% recommended dose.Overall ZT-based RW system reduced CH4 emission but this benefit is counterbalanced by higher N2O production compared to CT-based RW system.

CA was introduced to Malawi to address soil degradation, declining yields and mitigate climate change. CA oubtyielded conventional methods in two Districts by 22 and 31% and increased incomes by 50 and 83% using 28-39 less labor days. Although successful there are still issues of residue retention, weed control, rotations, pest and disease control and socioeconomic constraints. But these are researchable issues at the local level.

CA is claimed to mitigate climate change through soil carbon sequestration. This paper is a meta-analysis of SOC with CA practices in SSA and IGP (Asia). In IGP CA compared to conventional increased SOC by 0.16 to o.49 Mg C/ha/yr. In SSA increases were more, 0.28 to 0.96 but with much greater variation and a significant number of cases with no change. The authors warn that CA C increases can be overestimated if sampling is not done properly. They also suggest that in IGP where nitrogen fertilizer use is already high, improved management of nitrogen would be a better way to mitigate climate change.They conclude that CA should be promoted for its many benefits but that any climate change mitigation is just an additional possible benefit and not a major policy driver for its adoption.

This paper looks at direct (no-till), rip-line and basin seeding with maize on yield, soil health and profitability across agro-ecological regions of Zimbabwe over 6 years using a review of literature and a meta-analysis. Overall CA yielded better than conventional although there was a yield decline the first two years. direct seeding gave higher yields than rip-line or basins. CA reduced erosion, bulk density and increased water content in most studies. With more residue CA had more macro-fauna abundance and diversity than conventional, especially termites. More labor was needed for hand hoeing in CA but herbicides reduced this labor cost. CA benefits included earlier planting, weeding, fertilizer and herbicide use, and proper training on equipment use. The weeding, extra fertilizer and herbicide cost makes CA less economic. rip-line seeding was best in drier areas than direct seeding.

Many medium and large scale farmers  with tractor-based farming have moved to CA and no-tillage technologies in Paraguay, Brazil and Argentina. Few wish to return to a conventional system. The same is not true with smaller farms with animal traction or manual farming. This is discussed in this paper. Suggest two reasons for this. One is the inability of small-scale farmers to cope with factors related to CA and the other with extension approaches and strategies to promote this knowledge and learning intensive management system. They suggest adoption of adaptable and long term approaches to CA with smallholders.

What does Sustainable Intensification mean? It originally meant producing a higher level of output from the same area of land while minimizing environmental impacts. The authors indicate that some NGO's are worried that SI is repackaging of intensive, high input models and using biotech as a means to achieve it. While the NGO propose agroecokogy and genetics as a way to increase productivity. Sustainability has also met with reservations since it needs to include social and economic elements such as livelihoods, equity, social justice and economic viability. Also the need to look at the farming system as a whole including livestock is needed. This paper sifts through these debates and inquires what is needed for the future of agriculture and food security

This paper looks at the emerging rice-maize system in NW India as an adaption strategy foe future water scarcity. The results show that zero-till direct seeded rice followed by zero-till maize with partial residue retention from both the crops improved SOC content, soil physical properties along with gradual increase in RMS yields and profitability over conventionally tilled rice and maize.

The Australian government wants to reduce agricultural emissions by changing practices. CA is reduces farm emissions and sequesters carbon. This paper presents a series of systems models that describe the process of how Australian dryland grain farmers decide to change and adopt conservation agriculture practices. Results indicate that a number of economic and social factors drive the rate of practice change, and change seems to be motivated mostly by the pursuit of productivity benefits rather than environmental benefits. They conclude that emission reduction outcomes and carbon payments would not be the primary driver for change.

A paucity of empirical evidence on MT yields from Zambia encouraged this paper that applied survey data from 48,000 households over 4 years to answer the above question. The conclude that ripping and planting basins can raise maize yields if done early before the onset of the rains that results in early land preparation.

An interesting paper concerning blade geometry and rotary speed on two wheel tractors for use in strip tillage. 

Conventional blades resulted in a poor furrow backfill (36% at 500 rpm). Straight blades improved the furrow backfill (74% at 500 rpm). Soil tilth was affected by rotary speed, but not by blade geometry. The straight blade is a recommended alternative to the conventional blade for strip tillage.

This paper highlights the challenges facing agriculture in the future.The challenges of farming are exacerbated by a changing and uncertain climate, increase in risks of soil degradation by erosion and other processes driven by decline in soil organic carbon (SOC) concentration and pool, increase in dependence on energy-based inputs such as fertilizers and pesticides, high risks of shifts in spectrum of pests and pathogens, and decrease in availability of soil and water resources because of diversion to nonagricultural uses. Increasing adoption of CA requires prudent strategies to address limitations and uncertainties of NT. The objective of this article was therefore to deliberate on a system approach to CA for minimizing uncertainties and limitations while maximizing merits and ecological benefits. 

Interesting data from Cambodia on use of CA to increase soil organic carbon in rice, soybean and cassava cropping systems. Included conventional and no-till treatments and C was compared with an adjacent reference vegetation. On average, NT SOC stocks at 0–5 cm depth was greater than those of CT by 10%, 20% and 18% and STN stocks by 8%, 25% and 16% for RcCS, SbCS and CsCS, respectively. But sub-soil layers had less SOC in NT compared to CT. Cover crops were used for providing resides. Amount and diversity of crop residues added impacts on particulate organic C and can be an indicator of C accumulation. The results confirm the hypothesis that short-term CA associated with high biomass-C inputs (particularly bi-annual rotations) promotes SOC recovery in the topsoil layer and creates a potential to increase SOC in the subsoil layers when deep-rooting cover crops are included in crop rotations.

Used 4 cropping system scenarios in Haryana, India with different CA components and N-rates. Measured methane and nitrous oxide fluxes in farmer fields. CH4 emissions controlled by floodwater with fertilizer N having no effect. But fertilizer N did affect N2O emissions. These could be avoided by applying N to wet soil or irrigating not later than one day after application. Crop residues applied to soil surface had no effect on CH4 or N2O. CA can reduce GWP by 16-26% compared to conventional RW but mainly due to decrease in diesel and electricity consumption than direct emissions of CH4 or N2O which were higher in maize-wheat than rice-wheat systems. 

One of the benefits of CA is improving soil quality including biological diversity of the soil. This paper describes how CA affects arthropod predators and pests in a maize-wheat system in Mexico under no-till with residue versus tillage with no residue. Conclude that the type and amount of residue that remains on the soil surface influences arthropod dynamics that helps control insect pests. Spiders more in no-till treatments with residue retained.

Residue retention in SSA is constrained by livestock grazing but also termite incidence. This paper looks at termites prevalence and crop damage of different amounts of surface applied maize residues on maize yields under CA and conventional tillage. Lodging increased in the CA systems but no significant difference was observed in lodging under CA with increasing residue rates. Interestingly higher maize yields were obtained under CA compared to conventional (average 30%) but extra residue did not increase maze yields. 

There is a dearth of CA studies that consider gender and gender relations to adoption. This is the subject of this paper for East and Southern Africa. CA interventions would have implications on labor needs and allocation, investment decisions on mechanization and use of inputs, crops grown, pest and animal interactions and household nutrition. It suggests this issue needs more attention.

This 3 year study looked at pigeon pea-wheat system under CA for yield and water use efficiency in Western IGP. Conventional tillage was compared to no-till on permanent beds (PNB) with and without residue. The best PP yields were on permanent beds with residue. Wheat grain yields were similar to CT in all three years. Suggests bed planting PP-W is a useful technology in the region. 

Integrating crops and livestock is more profitable than crops alone for small farms and so a 12 year study of the trade-offs on maize residue use was initiated for these systems. Retaining crop residues in the field reduces livestock feed and farm income although grain yields increased. They conclude that it is logical that farmers prioritise the sustenance of cattle with crop residues over soil fertility management. 

CA is being promoted in Malawi as a way to sustainably improve water-use efficiency, reduce soil erosion, and boost crop production. In this study, three cropping systems – continuous no-till maize, CA rotation, and conventional tillage rotation – were established on smallholder farms in the Nkhotakota and Dowa districts, two distinct agroecological zones in Malawi. No-till and residue cover improved soil–water relations in hot, sandy conditions. Residue retention was critical in reducing soil erosion and increasing earthworms. No-till and residue cover did not increase yields of alternative food crops. Crop rotations had a greater impact on maize yields than tillage practices.

Adoption of CA changes weed dynamics and communities and therefore necessitates adjusting weed control methods. This paper reviews the literature on this topic. No-till systems accumulate seeds near the soil surface where they are more likely to germinate but are also exposed to greater mortality risks through weather variability and predation. Assuming no seed input into the system, germinable seedbanks under no-till decrease more rapidly than under conventional tillage. Reducing tillage may shift weed communities from annual dicots to grassy annuals and perennials. Combining no-till, crop rotation and surface residue offers superior weed control. An integrated weed management approach is recommended. 

This research hypothesized that adopting CA system would improve system productivity and efficiency, hence resulting in higher profits. Four tillage treatments, including farmers’ practice (residues removed), conventional tillage (residues removed) and two CA practices with residue retention (zero tillage and furrow–ridge), were laid out in 22 farmers’ fields. Data was collected from 4 seasons from 2010-2012. Joint use of zero tillage and furrow–ridge provided higher WUE and yield advantage (25–34%) in the third and fourth seasons compared to the conventional practices. Weddings costs were reduced in CA but only because they used herbicides and reduced labor costs. They concluded that CA will certainly increase crop yields,WUE, generate more revenue and diversify risks during poor seasons. However, these benefits may not necessarily be earned in the first season, but will accrue in subsequent seasons.

No-till, especially in tropical and sub-tropical areas has been shown to reduce yields in many cases. This paper suggests nitrogen fertilizer use is a major component and helps explain these yield declines. Strong NT yield declines occur when residues are removed, and when crops are not rotated. This was based on a meta-analysis of 325 studies from 1980-2013. Applications of N fertilizer at rates of up to 85 ± 12 kg N ha−1 yr−1 significantly reduced NT yield declines in these scenarios. It is important to distinguish between no-till, a component of CA and the vital role of permanent ground cover and rotations in CA. 

A simulation study that looks at the economic and risk effects of different crop residue retention practices for a crop-livestock agricultural household in western China. Retaining minimal crop residues produced highest profits in the short term whereas full crop residue retention produced highest profits in the long term. Calls for comprehensive crop residue retention are unlikely to be attractive when farmers discount future profits, and when crop residues have significant value as a fuel and feed source. The economic benefits of crop residue retention can take numerous years to eventuate and retaining crop residues also increased simulated ground cover and this positive environmental impact extends beyond individual farm boundaries. Because of these time lags and external environmental benefits, providing financial incentives to retain crop residues during the initial transition years could be a policy option.