Conservation Agriculture Research Updates - April 2026

This study aimed to quantify the effect of tillage, crop rotation and crop residue management on aggregate stability, binding agents and the resulting aggregate microstructure in a sweet sorghum-based cropping system in a low organic carbon soil. Two tillage levels; no-till (NT) and conventional tillage (CT), two crop rotations, i.e., sweet sorghum-grazing vetch-sweet sorghum (S-V-S) and sweet sorghum-fallow-sweet sorghum (S-F-S) and three crop residue retention levels, i.e., 0%, 15 % and 30 % were tested. The study showed that tillage is the main factor that influences soil aggregation followed by residue management. The study also demonstrated that aggregate stability is linked to aggregate microstructure and regular pores are dominated in degraded soils with low SOC.

This Brazilian study looked at water retention in relation to soil physical and chemical properties on Cambisols with different land uses in a semi-arid region of Brazil.  The environments studied were Preserved Forest - reference area, Cajarana Orchard Area, Corn/Bean Consortium, Watermelon/Pumpkin Consortium, and Agroecological Cultivation. The Preserved Forest presented the highest field capacity, permanent wilting point, and available water. The study concluded that the soil tillage systems alter the chemical, physical and structural attributes of Cambisols of the semiarid area studied and that minimum tillage is the most suitable tillage system for the region.

This review assessed the impact of anthropogenic interventions, including crop diversification in rotations, soil physical disturbance, synthetic chemical inputs, and biofertilizer use on soil microbial community structure and function, and the consequential effects on agroecosystem productivity and environmental sustainability from 160 medium- to long-term experiments across the globe and in various soil-climatic zones. Excellent conclusions are made and the study concludes that the key is to establish a rational balance between anthropogenic activities for agroecosystem productivity and potential negative influences on the soil microbial community and long-term soil health.

The UK launched a program to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of agricultural water pollution on river ecology whilst maintaining food production capacity. This study looked at the impacts on soil health of two types of conservation tillage (direct drill and shallow non-inversion) against conventional mouldboard ploughing after five years. Results revealed that conservation tillage alone is ineffective at improving the short-term environmental sustainability of farming practices in this lowland intensive arable setting and indicates that a broader, integrated approach to conservation agriculture is required incorporating aspects of cover cropping, crop rotations and precision farming techniques. The improvements in farm business performance do, however, demonstrate land managers can make important financial gains by converting to a conservation tillage system.

This study investigated the effects of CA and CT on soil organic carbon (SOC)and selected hydraulic properties in two contrasting areas in Malawi using on-farm trials. Sole maize with CA and CT plus maize-legume intercropping with CA were used. Soil samples were taken after using CA for 10 years at 6 different depths. At all sites CA improved total SOC, carbon stocks and stable fraction of of particulate organic carbon. They conclude that changing management practices from CT-SM to CA has the potential to improve the soil organic matter and soil hydraulic properties across agro-ecological zones in Malawi.

The paper reports the results of the duration of CA adoption on soil carbon dynamics and system sustainability on farm in 30 villages in Karnal District of India. Soil samples were taken from existing CA  and CT farms. Looked at soil physical, chemical and biological properties. The paper concludes that farmers in Karnal district should be encouraged to adopt CA practices as they can increase SOC and move the systems from “sustainable with high input” to “sustainable”.

This study uses Collembola numbers as a good indicator of improved soil properties following a change in land management. They looked at these springtail populations in systems with a history of CA and crop-livestock use in South Brazil. The samples were also evaluated for soil chemical, physical and microbiological properties. CA and CLI management varied in the association of different Collembola's -- epigeic in CA and hemiedaphic and edaphic ones in CLI but these differences were related to different soil conditions. They conclude that Collembola community structure and species diversity were modified by the soil management systems and suggest that the Collembola community may indicate changes across land management systems in conservation agriculture.

The objective of this study was to assess the changes in soil physicochemical and microbiological parameters between four different agricultural practices from a 7-year experiment using two seasons with contrasting soil water content. They compared conventional tillage with maize (CTM); no-till with maize (NTM); no-till with maize and soybean rotated (NTM/S); no-till with annual rotation of maize intercropped with Brachiaria rhuziziensis and soybean monoculture (NTMB/S) compared to a long-term fallow (>40 years secondary forest) in both winter (rainy) and summer (dry) seasons. In sum, they show that the benefits of conservation agriculture for soil quality in this region were most obvious in the summer and depended on the agricultural practices, with NTMB/S showing the greatest conservation of soil physicochemical quality.

Challenges that have arisen with the adoption of NT include soil compaction, weed management, and stratification of organic matter and nutrients. As an attempt to overcome these challenges, occasional tillage (OT) has been used as a soil management practice in NT systems. The objectives of this meta-analysis were: 1) to summarize the effects of OT on crop productivity, soil physical, chemical and biological properties, soil erosion and weed control; 2) to discuss the main aspects of NT management to optimize the use of OT; 3) to point out shortcomings in the diagnosis of soil compaction in NT systems, which may lead to erroneous decision-making processes regarding the use of OT. They conclude that proper NT implementation and management, with the correct application of NT principles, will overcome problems associated with NT. As soil compaction is the main justification for the use of OT, methods of diagnosis and monitoring of soil compaction should be improved to assist in decision-making.

This paper looks at ways to minimize the negative affects of continuous puddled rice transplanting by looking at alternative ways to establish rice and their effects on soil health, crop productivity, resource saving and global warming mitigation potential. Innovations in machinery especially for smallholder farms have supported the adoption of the new establishment techniques. They conclude that no single rice establishment technology is superior to others in all circumstances, rather a range of effective technologies that can be applied to different agro-climates, demography and farm typologies.

This paper contends that to meet future food needs, soil organic carbon needs to be preserved. This review examines the literature published worldwide over the last 30 years to assess the impact of one widely applied agricultural management system, conservation agriculture (CA), on its ability to maintain SOC and the subsequent impacts on soil physical, chemical and biological properties, and yield. The paper concludes that farmers require access to a range of tools and resources to allow them to identify if the principles of CA are likely to be appropriate for their situation and well-designed, locally adapted systems to successfully overcome the agronomic, social and economic challenges that can be associated with its use.

This paper used a NT System Participatory Quality Index (PQI) that requires the participation of farmers to assess key soil quality attributes associated with the implementation of the PQI methodology during a large scale dissemination of a NTS campaign in Brazil. Farmers often fail to adopt all the principles of NTS; therefore, the system requires a quality measurement. A classification system to help farmers and agricultural professionals make good soil management decisions was proposed. The tool was trialed on 40 areas of farmland under different farm systems in a Paraná River Watershed. The NTS Participatory Quality Index (PQI) was used to successfully evaluate soil management quality.

This study suggests CA can be widely promoted to overcome SSA climate change and food security issues but suggest little is known about the impact of CA on soil physical properties such as soil structure and hydraulic properties. The aim of this report was to assess the impact of 10-12 years of maize-based CA on soil physical properties with CA and conventional tillage treatments in Malawi. The results show that CA systems have significant changes to soil hydraulic properties that correlate with improved soil structure. There was no significant build-up of organic matter in CA systems but residues were not included. They conclude that CA should include residues to enhance soil OM levels.

This paper reports on the effect of cover crops on modifying soil surface response to penetration and the relation to soil water content. The research used two crops, barley and vetch, as cover crops and compared them with a bare fallow in a 10 year long term trial in Spain. The soil resistance to penetration was closely related to the surface soil water content (R2 = 0.65) and cover crops affected it through soil moisture modification. The greater biomass of barley compared to vetch increased the soil water content prior to main crop seeding and reduced the resistance to penetration. The good performance of barley resulted in a reduction of more than 60% of the soil resistance to penetration between the 3rd and 8th year of the experiment. Even under bare fallow, soil strength was decreased after ten years with reduced tillage. The maintenance of cover crop residues over surface soil together with reduced tillage enhanced the soil surface conditions and steadily reduced the risk of crust formation.

This study was conducted at three different locations in South Dakota, USA, to compare the natural (undisturbed) ecosystem (NE) with the tilled (CT) and no-tilled (NT) practices, and to evaluate the tillage effects on soil organic carbon (SOC) and total nitrogen (TN) contents, bulk density (ρb), enzymatic activities and aggregate stability under a corn (Zea mays L.)-soybean (Glycine max L.) cropping system. Results support that NT practices improved soil aggregation as compared to the CT and stored higher SOC and TN concentrations in the aggregates, however, NE treatment outperformed both the tillage systems. Their comparative evaluation with a NE treatment concludes that tilled practices negatively affect soil properties but recommend adoption of NT farming to enhance the soil properties in agroecosystems.

This study assessed the impact of long-term conservation tillage and N fertilization in wheat-soybean rotation on soil aggregate distribution, nutrients stocks and functions of soil microorganisms. They compared conventional tillage and minimal tillage and 2 N levels; 0 and 200kgN/ha. Residues were incorporated to 25 cm in CT and 50% to 15cm in MT. Tillage was the most discriminant factor explaining 72% and 60% of total variance of soil parameters at 0-15 cm and 15-30 cm soil depth. All enzyme activities were higher under MT, whereas the majority of soil chemical parameters were higher under N200. They conclude that maintaining or even increasing SOC conservation in their silt loam soils may require both reduced tillage systems and N fertilization, shifting microbial community toward taxa more effective in contrasting soil degradation

The specific objective of this study was to develop soil quality indices with key soil physical, chemical and biological indicators under the conservation and conventional tillage practices in a rice–mustard systems in NW India. Eight treatment combinations including tillage and crop establishment, crop residue and cropping system intensification with inclusion of short duration summer mungbean were used. The highest SQI was obtained in the zero till direct seeded rice (ZTDSR) – zero till mustard (ZTM) –ZT summer mungbean (ZTSMB (+R). They conclude that the medium-term CA with triple or double zero tillage with crop residue retention maintains agricultural sustainability under the rice-mustard system and can be recommended to farmers for adoption.

This study examined the impact of different tillage systems on soil organic matter dynamics in wheat based systems on an Inceptisol soil in India over nine years. It compared NT with CT with 4 residue practices none, wheat, soybean and wheat + soybean residue. The results indicated that SOC content increased by ∼48, 42 and 36%, respectively, in WR + SR, SR and WR plots compared with the NR plots in the 0-5 cm soil layer. The SOC content within macroaggregates were ∼30 and 25% higher in the ZT plots than CT in the 0-5 and 5-15 cm soil depths, respectively. The results suggest that ZT management could be adopted for C stabilization within aggregates.

This study identified a site under a long-term NT production system where a known compaction force of 0 Mg axle load (control, C-0), two (C-2) and four (C-4) passages of 2.5 Mg water wagon axle load was applied to cover the entire plot for 20 consecutive years to assess changes in soil hydraulic properties at a site in the Central Ohio, USA. The field was under NT-based corn–soybean rotation since 1997. A wooded lot was chosen as a baseline for comparison. They concluded that further monitoring of the impacts of compaction on soil hydraulic properties particularly on some other properties (e.g., water infiltration and air permeability) across the years is needed.

Chapter 17 in a 2021 book, "Improving Cereal Productivity Through Climate Smart Practices". An article looking at laser land leveling combined with CA to produce more crop per drop of water. But the chapter also looks at other factors besides NT that are required and obtained by adopting CA. It concludes that to achieve the higher productivity and profitability, adoption of a multipronged strategy of using improved varieties, balanced fertilization, appropriate irrigation, and weed management practices are a must.

This study looked at best management practices involving tillage and residue management to obtain improved soil health for the important rice-wheat cropping system of South Asia. Their soil quality index was based on soil physical, chemical and biological properties. They looked at  conventional practices with transplanted rice followed by broadcast, tilled wheat versus zero-tilled, direct seeded rice followed by ZT wheat. The highest rice equivalent yield of 12.41 t ha-1 was observed at SQI values of 0.90 at 0-10 cm and 0.86 at 10-20 cm in the ZTDSR fb ZT wheat. They conclude that crop residue retention on the surface with zero tillage is beneficial for the sustainability and productivity of the RWCS in EIGP of India.

This study, reported the results obtained during a 2-year field experiment of a 7-year experiment started in 2010–2011, combining two tillage practices (Conventional Tillage (CT) and Zero Tillage (ZT)) with two crop sequences (Wheat monocropping (WW) and Wheat-Faba bean (WF)) in Italy. Soil Quality (SQ) was monitored through the selection of some chemical, physical, and biological indicators measured by both visual–Visual Soil Assessment (VSA)–and standard field or laboratory measurements. They conclude that under dry Mediterranean areas, ZT practices, especially when combined with the other conservation principles (i.e., crop rotation), ameliorate several SQ indicators already even after a 7-year period of adoption, allowing a positive trend for soil preservation.

This paper explores the effectiveness of high-resolution topography in characterizing no-tillage (NT) versus conventional tillage (T) surface morphology in order to better understand the hydro-geomorphic processes associated with these crop systems in a clay loam soil in Italy. Surfaces in the NT plots were rougher, had more pronounced slopes and curvatures, sediments with a widespread connection to the plot boundaries, had more irregular flow paths, and had a higher water storage potential due to surface concavities. The NT surface morphology significantly reduces surface runoff, sediment transport, and the off-site movement of agricultural chemicals.

This 4-year study objectives were (a) monitoring the changes in soil physical, biological and chemical properties and crop productivity, (b) development of a soil quality index-(SQI), and to monitor SQI changes against system productivity as a management goal, and (c) studying the changes in soil organic carbon-SOC in relation to annual C input. The 3 tillage practices were ZT, Permanent Beds (PB) and CT with 4 nutrient management treatments under a continuous maize-wheat-mungbean system in NW India. They conclude that adoption of CA with SSNM and Ad-hoc nutrient management in intensive cereal based systems of NW-IGP is essential for improving nutrient cycling, soil quality, crop productivity and C-sequestration potential.

Data presented is from the 6th season of an on-station trial with CT and NT and 4 crop rotations that included maize, wheat and soybeans. The residues were left on the surface in NT and incorporated in the CT after every cropping season. Soil physical properties were measured. The study concluded that the crop rotations, MWM and the MWS under the no-till coupled with the residue retention improved the soil porosity and the soil water content levels the most.