Conservation Agriculture Research Updates - March 2026

This is another article in this February newsletter from South America that provides very long term data on CA from a research experiment that considered 5 treatments representing agricultural systems relevant to Paraguay and assessed after 32 years. Treatments in a wheat-soybean system included conventional tillage (CT), reduced tillage (RT), and no-tillage (NT1). In addition, two diversified no-tillage rotations with increasing adoption in the region were included: NT2, composed of black oat–soybean, wheat–soybean, and black oat–soybean; and NT3, consisting of wheat–soybean, vetch–maize, and black oat–soybean. These crop sequences were implemented continuously in three-year cycles over the 32-year study period. The study focused on nutrient stocks, however, consistent relationships between pH and nutrients were observed while pH remained below the minimum threshold recommended for the regional commercial crops . They conclude that "diversified no till farming conserves fertility in low input contexts, but the benefits are limited due to soil acidity. Finally, integrating periodic soil diagnosis with amendments, particularly liming, offers a practical pathway to sustaining production in Paraguay."

This study used 6 plots using CA installed in 1984 in Uruguay to quantify changes in soil quality contribute to current runoff and soil erosion in a cropping system under soil conservation practices - NT, residue retention and cover crops. Plots were grouped in three treatments with contrasting historic index of agricultural intensification (IAI). The IAI was developed combining the duration of land use under agricultural production and the number and intensity of tillage activity resulting in the treatments: tillage with crop-pasture rotation (TIL_CP), no-tillage under several rotations (NT_Mix) and tillage with continuous cropping (TIL_CROP) with an increasing IAI of 3.5, 7.1 and 11.8, respectively. Rainfall events, runoff water and total, fixed and volatile solids were studied from 2017 to 2019. Soil physical and chemical parameters were measured. The lowest soil losses were observed in TIL_CP. They conclude that CA minimized soil erosion losses in all plots and years, and erosion was much lower than the maximum tolerable threshold of 7,000 kg/ha for this particular soil.

This meta-analysis reviewed experimental results (32 field studies) obtained throughout the Pampas Region in Argentina focused on the immediate effects and duration of soil mechanical alleviation measured by relevant soil physical properties and by the impact on maize and soybean yield. Treatments were a) Control (no tilled soils), and b) Subsoiled (no tilled soil subjected to mechanical compaction alleviation by deep non-inversion tillage). Soil compaction alleviation works had a durability of not more than 17 months (±2.8 months) after being performed. They conclude that deep non-inversion tillage could be a promising practice to close rainfed crop yield gaps in the region. But due to its low durability in time, further compaction prevention and structural regeneration practices such as cover crops, diversified crop rotations and controlled traffic will be needed

This paper looks at tillage, crop residue and N-management in the high-slope mountains of Ecuador where high rainfall causes significant soil erosion. In the initial phase 3 out of the 4 crops NT had the highest yields. Later, with addition of N fertilizer, yields were higher in 4 out of 5 crops not fertilized. Leaving the crop residue on the surface increased the yield of one crop. Higher net returns were found with NT compared to tillage.

This paper looks at cassava using CA in Peru. The objective of this study was to compare soil properties, cassava physiology, and yield under conservation agriculture (CA) and traditional agriculture (TA) practices, with and without mulch, in a water-scarce environment. CA out performed TA for several measured properties and they conclude CA is superior to TA in this drought prone area and improves soil properties, cassava physiology and yield.

This is a paper from the Andean region of Ecuador where small scale farming is on steep slopes and vulnerable to erosion, soil degradation, and productivity loss making the current agricultural practices unsustainable and food security a major issue. Climate change is also going to be a negative factor in this region. Past research on CA in this region suggest that cost savings and better yields make it a better system than CT. Immediate benefits did not arise but at least CA productivity did not decline. On the medium term CA resulted in better soil health (lower erosion) and higher profits than CT. The paper points out that adoption of CA is slow due to lack of any extension, so there is a need improve communication with local farmers and effectively explain to them the benefits of new technology and CA.

This chapter outlines the challenges for meeting food security needs now and in the future. It mentions many issues that make this challenge even more difficult. Management systems that make more efficient use of natural resources. These sustainable land management (SLM) practices must also provide the farmers with the means and incentives to experiment with them and encourage farmers to share their experiences with other farmers. This chapter uses three agricultural case studies from three different geographical areas to highlight the challenges encountered in increasing crop productivity, some of which are common to all three regions, while others are specific to the climatic, edaphic, economic and social situations found in a particular region. In all three regions CA has been promoted to farmers in the past few decades as one way to responsibly intensify food production. The case studies explore the drivers of CA adoption in the region and the adaptations that have been made to adapt CA to the particular local conditions. The first two case studies end with a list of agronomic research requirements for the particular region, while the third explores what a Brazilian type of experience with green manure cover crops means for CA systems worldwide.