Conservation Agriculture Research Updates - March 2026

This paper looks at barley and maize in Mexico's major growing area for barley where barley is irrigated followed by rainfed maize. Groundlevel water levels are declining in this area and water saving technologies are needed in this area. This study looked at water use and grain yields with CT and CA with furrow and drip irrigation in 3 year experiment and in adjacent farmer fields. Results show water use reductions differed strongly between years, depending on weather. The water saving through conservation agriculture in farmers' fields was similar to the water saving in the controlled experiment with about 17%. Farmer's fields conservation agriculture also reduced greenhouse gas emissions by 192 kg CO2/ha and improved soil health.

This paper focuses on soil and water agricultural conservation systems for South Africa. The objective of this paper is to summarize Conservation Agriculture (CA) systems practiced in South Africa. These include measures to control wind and water erosion as well as soil compaction through implementation of rip on the row, vertical mulching, controlled traffic, crusting control, mulching, water harvesting and crop rotation. No-tillage is not in the scope of this paper, although aspects of reduced and minimum tillage are covered. The paper concludes that CA specialists should be trained to assist farmers in the selection, adoption and implementation of appropriate CA systems.

85% of N20 emissions are related to N fertilizer in agriculture. This paper looks at ways to reduce N20 emissions in agriculture by limiting optimal soil N and water for production of this GHG. The objective was to assess N2O emissions from different N management strategies under long-term tillage systems. Treatments included (a) source (compost and urea) and (b) placement (broadcast and surface-banded application of urea under conventional till and no-till systems). Overall, soil N2O emissions were affected by the availability of inorganic N and precipitation rather than tillage. Banded application of N increased overall N2O emissions by 30% compared with broadcast N application without affecting yield and N uptake. Synthetic N sources increased N20 more than organic ones but carbon content of organics could increase emissions.  .

This article looks at the understanding and decoding of site-specific complexities of CA systems using a multidisciplinary approach. It is more of a discussion rather than a research paper. They make the following comments. CA typically improves soil quality and water conservation; however, its effect on crop productivity is highly variable and dependent on local conditions/management. Crop residue retention plays a crucial role in CA and can help to improve overall soil health and ultimately crop productivity and sustainability. However, weed control, herbicide resistance, and weed shift under residue retained fields is a challenge. CA can also increase water infiltration and reduce soil loss and runoff. This reduces the surface transport of nitrate and phosphorus from agricultural fields and the eutrophication of water bodies, although leaching of nitrate to groundwater can potentially increase. In addition, CA has been proposed as one of the components in climate-smart agriculture, owing to its reduced period to seed/plant next crop, reduced soil disturbance and low consumption of fossil fuels.

Based on the findings from peer-reviewed literature, this review aims to identify unsustainability issues and research gaps in the R–W system in South Asia and propose possible solutions to mitigate those issues and technological interventions to close the research gaps. Issues that the review has identified are declining crop, water and land productivity, deterioration of soil health, emissions of greenhouse gases due to intensive tillage and residue burning, deepening of groundwater levels and shift in weed flora and development of herbicidal resistance in crops. Potential solutions or technological interventions to mitigate the unsustainability issues include resource conservation technologies (RCTs) such as rice residue management, reduced tillage, laser land leveling, soil matric potential based irrigation scheduling, delayed rice transplanting, cultivation on permanent raised beds, direct-seeded rice (DSR), mechanical transplanting of rice and crop diversification with legumes. Sustainable R–W production technologies with reduced water, energy and C footprints are required for increased water and energy productivity and C sequestration for the NW IGPs of South Asia.

Increasing climate variability is affecting  smallholder farmers in southern Africa. This study looks at Conservation Agriculture (CA) as a way to improve the resilience of farming systems against the adversities of climate, specifically moisture stress.CA and CT practices are assessed over a 14 year trial period on soil moisture and infiltration rates in Zambia. Soil chemical properties were also evaluated for these two tillage systems. Results showed significant differences in average soil moisture in the first 60 cm among the cropping systems in different years with the basins plus mulching system having highest moisture content in most of the years. Water infiltration rates were highest and averaged 48.5 mm h−1 in the CA-based systems and the lowest in CT which averaged 12.6 mm h−1. Soil chemical properties did not differ across tillage systems. The increased infiltration and available moisture in CA systems can buffer the effects of climate variability and provide greater resilience.

This study introduced CA to manage agro-ecosystems for improved and sustained productivity, and increased farmers’ profits while maintaining natural resources in rice-wheat systems of the IndoGangetic Plains of India. The project managed natural resources at the farm, village, and landscape scales to increase synergies between food production and ecosystem conservation. The results show that the CA-based rice-wheat (RW) system integrated with mungbean improved the system productivity by ∼10%, profitability by 20–30% using 15–30% less irrigation water, and 20–25% less energy input compared to conventional RW system in the IGP. Replacing rice with maize improved the productivity by 10-15% and profitability by 40–50% using ∼70% less irrigation water. CA layered with subsurface drip irrigation (SDI) in CA-based rice/maize systems recorded ∼5% higher system productivity and saved ∼50% of irrigation water compared to flood irrigation in CT-based systems. CA-based systems are found more adapted to extreme climatic conditions and can mitigate the negative effects of climatic stresses like terminal heat and water stress.

This paper looks at the use of CA to overcome soil erosion and land degradation leading to loss of Eco-system services required to maintain food security. It includes an estimate of the global adoption of CA of 180 Mha (12.5% of annual cropland) and increasing annually at 10 Mha. The paper looks at water-related services and food security, shows that CA to meet, or exceed, most of the current shortfall in projected global agricultural water demand by 2050.

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 paper contends that efficient water use is vital for arid zones that rely on irrigation from available water. This paper's objective was to look at the effect irrigation before or after sowing with conventional or conservation agriculture practices on beds on bacterial community structure in soils. The bacterial communities were identified with Illumina MiSeq sequencing where the 16S rRNA gene was targeted. They conclude that soil water content was the principal factor shaping the bacterial community structure. While the three most dominant phyla were affected by the difference in water content in the tillage practices under dry and wet sowing, it was at the genera level that these fluctuations were more obvious.

This study evaluated the effect of CA on crop and water productivity, profitability, and soil carbon status in a rice-mustard (Brassica juncea L.) rotation in North-western IGP of India for five consecutive years. Eight treatments comprising of tillage, crop residue, brown manuring (BM) using Sesbania bispinosa, and summer mungbean were used. They conclude that the CA system being productive, profitable, and resource-efficient can be recommended for North-western IGP of India and in similar agro-ecologies of the tropics and sub-tropics. It can be adopted with suitable site-specific refinement in South-Asian countries, where decline in crop productivity and soil health is a consistent pervasive problem due to continuous cereal-cereal rotation.

This study looked at different tillage systems on-farm in three farmer fields in Malawi. Diverse crop rotations included sweet potato, cassava, common bean, soybean, cowpea and pigeopea.Th effects on labor use and financial returns were measured. Over the three years of the study, continuous NT maize produced the greatest gross and  net revenues, despite having higher production costs. But the diversified cropping systems were also profitable for farmers because of lower production costs. Farmgate prices for the various crops was the major factor affecting profitability.They conclude that policies that reduce input price volatility and increase farmgate prices of alternative food crops would have the greatest impact on adoption of other diverse crops.

This study looks at ways to overcome the scarcity of water and dropping water table in the rice-wheat areas of NW India. It also looked at ways to overcome the air pollution problem associated with rice residue burning after harvest and excessive tillage. This study looked at residue mulch, , different spacing and depths for sub-surface drip lines and fertigation (SSDF) on permanent bed planting on yield, water productivity nitrogen efficiency and net returns. There were water savings with the buried drip lines in both rice and wheat. Residue mulch resulted in higher water savings, wheat yield, water productivity compared to no residues. Net returns were higher for buried 15cm deep drip lines compared to flood irrigation.

This paper explores the irrigation potential from surface and groundwater sources under different water application and farming systems in Ethiopia. Two tillage systems were evaluated -- CA and CT. Two irrigation systems - drip and overhead. They looked at various irrigated vegetable crops. Their results showed that CA plus drip was best in terms of irrigable land from groundwater recharge. In comparison, the CT system with overhead irrigation was the worst treatment. They conclude that decision makers must consider the introduction of feasible and affordable technologies to make use of groundwater and direct runoff, to maximize the potential of dry season production through efficient and appropriate CA and water management practices. 

This is the second chapter highlighted from Rattan Lal's 2021 book on Soil Organic Matter. This chapter collates and synthetizes the information on research in relation to improvements in achieving sustainability and mitigating anthropogenic climate change—through adoption of no-till (NT) systems over existing conventional agriculture systems (e.g. crop productivity, soil quality, erosion control, and carbon emissions and sequestration). It concludes that conversion to NT systems for management and control of soil erosion can also reduce losses of SOC in water- or wind-transported sediments and contribute to reducing emissions and sequestration of carbon.

This study evaluated eight integrated crop management (ICM) systems in the rice-wheat systems of NW India where direct seeded rice followed by NT wheat are seen. The various ICM's evaluated were ICM1&2- conventional transplanted rice fb flatbed wheat (check), ICM3&4- conventional direct seeded rice (DSR) fb furrow irrigated raised bed wheat without residues, ICM5&6- conservation agriculture (CA)-based modules [zero tilled (ZT) DSR and ZT wheat] with the wheat and rice residues, and ICM7&8- CA-based modules (ZTDSR and ZT wheat) with wheat, mungbean and rice residues. They conclude that it is important to to have adequate input integration and adoption of CA based ICM's, especially ICM 7&8, improved the soil carbon dynamics, crop yields, farm profits, and provided water savings 

This paper evaluated the chemical and physical processes in two different agricultural soils under no-tillage and conventional management practices to determine their impact on water related soil functions at field scale in the United Kingdom.Two farms were monitored; one had used NT in 2013 and the other conventional tillage with MB plow. Two soils were evaluated under each farming practice over two years. The conversion to no-tillage changed the soil structure, leading to a higher bulk density and soil organic matter content and thereby increasing the soil moisture levels. These changes impacted the denitrification rates, reducing the soil nitrate (NO3) levels. The increased plant material cover under no-tillage increased the levels of soil phosphate (PO43-) and PO43- leaching. 

This review paper looked at the smart solutions that enabled the spread of CA in the Mediterranean Basin by looking at the evolution of strategies and the machines used to perform CA in the last 30 years. They also looked at the effects of their adoption on the productivity of herbaceous and horticultural crops, weed control, and economic feasibility compared to conventional systems using soil inversion. They conclude that farmers play a crucial role in the adoption of smart solutions for increasing the sustainability and productivity of crops. However, farmers have barriers like inadequate policies, subsidies, direct farm payments, available machinery and suitable weed control practices. Appropriate incentives and governance practices are needed to guide farmers.

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.

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.

The RW system of the Western Indo-Gangetic Plains of India has issues of deterioration  in soil, water and environment quality coupled with low profitability. This paper looked at crop diversification and CA to address these issues. Compared to prevailing farmers’ practice (FP), results suggest that CA-based rice management increased profitability by 13% and energy use efficiency (EUE) by 21% while reducing irrigation by 19% and global warming potential (GWP) by 28%. Substituting CA-based maize for rice resulted in similar mean profitability gains (16%) and adding mungbean increased productivity, profitability and EUE by 11, 25 and 103% while reducing irrigation water by 64% and GWP by 106% compared to FP. However, adoption of maize-wheat systems are low because of poor market demand.

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 paper presents results from a study done in the sub-humid and semi-arid location of Kenya, focusing on the effects of CA- and/or ISFM-based practices on maize yield on farmer fields.  Maize grain yield increase compared to the control was highest under ISFM in the low fertility fields in both locations and all seasons. The higher SWC observed under NTR and NTRM was related to no tillage with residue retention while under CTM it was related to improved soil organic matter through manure addition. The high NUE under CA was attributed to the placement of urea in the planting holes while maintaining residue on the soil surface. The low NUE under NTRM was linked to fertilizer N immobilization. Lastly, from the biomass yield, our study showed that monocrop maize under NTR requires a kick-starting by an ISFM-based practice in the low fertility fields of the semi-arid region.

This study evaluated the level of tillage and quantity of soil cover for CA to work under irrigated conditions in the highlands of Mexico. Treatments included conventional tillage (CT), two types of reduced tillage, and permanent beds (PB) without tillage and 4 levels of soil cover in a maize, fodder oats rotation. Both crops yielded most under PBs without tillage and had the highest net returns. . 

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.