Conservation Agriculture Research Updates - May 2025

This paper from South Africa explored soil fauna, physico-chemical properties, soil health, and multi-functionality management in 4 different land uses: Conventional (CT), livestock integrated (LA), conservation agriculture (CA) and natural grassland. Results showed that CT favored some nutrients, but soil of both LA and CA had physical and chemical properties indicative of good soil quality like low compaction, low C:N ratio and stable aggregates. Soil fauna abundance was more responsive to management than diversity. Ct where tillage is used had the lowest soil fauna and soil quality due to its disruption compared to no-tillage. They conclude that implementation of sustainable soil management practices that improve soil physical and chemical status will be beneficial for productivity but also for the promotion of important soil fauna, better soil quality and ecosystem multi functionality.

This paper from Japan reviewed 68 papers to look at 13 field management categories in terms of importance for mitigation of climate change.The management categories were evaluated in terms of yield, area-scaled greenhouse gas emissions (GHG), and yield-scaled GHG emissions against base management practices. Yield increases varied from -6 to +12%. Only non-puddling increased yield and reduce both types of GHG emissions. Water management, (alternate wetting and drying or single and multiple drainage and notillage), reduced both GHG emissions, but reduced yield slightly. The paper concludes and recommends nonpuddling, water management and no-till as climate mitigation options, but suggests other categories like soil fertility be included.

This paper looks at Ridge Tillage (RT) in Germany that results in better root growth and reduced erosion. The study develops an auto-steered living mulch seeder using a navigation satellite system to guide making ridges. It also compares weed control for ridge-hoeing with conventional flat tillage (FT). They also looked at RT compared to FT for maize root development, yield, soil temperature, and soil moisture. Root penetration was 40 % higher in RT than in FT with RT producing more maize root biomass compared to FT.

This two year study from India, looked at tillage and nitrogen in relation to growth, development and yield of a CA based wheat-maize system. There were 3 tillage treatments: conventional + residue (CT+R), No-till + residue (NT+R), and permanent beds + residue (PB+R). Also 5 N levels as sub-plots. Results showed both tillage and N levels affected wheat. For tillage treatments LAI and Yield had the trend of PB>NT>CT. They conclude that using PB plus urea super granules can improve wheat growth and yield.

This paper from Brazil looks at SOC storage, crop yield, and soil resilience from a long-term (26 year) experiment in Paraná State that was established in 1989. This LT experiment looks at a gradient of soil disturbance combined with contrasting fertilizer regimes. The main plots comprised the treatments related to soil management systems: 1) conventional plow-based tillage – CT; 2) minimum tillage (Chiselling replacing plowing) – MT; 3) no-till with one chisel plowing every three years – NTch; and 4) continuous no-till system – NTS. The sub-plots comprised full crop fertilization (FCF) for all crops and low crop fertilization (LCF) by suppressing K and P fertilization and maintaining N in broadcast application. SOC stocks significantly improved as the soil disturbance diminished, resulting in higher soil resilience indexes for NTS and NTch. The paper concludes that combining CA principles ultimately defined the potential for SOC sequestration.

This paper collected undisturbed soil cores from the FArming System and Tillage long-term field experiment (FAST) near Zurich (Switzerland) to compare conventional. organic, and conservation agriculture systems for soil structure and physical conditions. This site has been under these 3 systems since 2009. The assessed 28 soil chemical and physical properties and related them to root growth, microbial biomass and bacteria and fungi diversity. They conclude that each management system creates contrasting soil physical environments. It also highlights the trade-off between creating a facilitative environment for root growth by tillage and maintaining complex and diverse soil microhabitats for microbes under conservation agriculture.

This paper s based on an on-farm field trial under a long=term no-till (NT) system to evaluate the residual effect of one-time occasional tillage (OT) on crop performance, soil water, and water-use efficiency (WUE) one and two years after OT implementation from a dryland area of Morocco. Shallow and Deep OT options were evaluated with and without residue retention. 3 crops all grown under NT were evaluated - Durum wheat, faba bean, and chickpea. Results showed that the grain yield of wheat and chickpea were negatively affected by OT for all years considered. Average soil water storage measured at 0–60 cm at sowing was also lower in deep OT (133 mm) compared to NT with crop residue retention (151 mm) for all years and rotations considered. The comparison of WUE between treatments showed that, under NT with crop residue retention, the crops produced more grain and aboveground biomass per mm of water. 

This paper has created a database using 218 response variables from the following 5 common categories of CA from the Mid-Western USA from 1980-2020: cover crops, tillage management, pest management, nutrient management, and crop diversification. The data was collected from the Web of Science. They also have summarized all this data on a web site, https://www.agevidence.org/

They conclude that this web site and database will be useful for the many stakeholders involved in making decisions on how to make more food with less environmental impact.

SOC sequestration is an important tool for mitigation of climate change within the EU soil strategy for 2030. This review synthesizes existing knowledge, identifies knowledge gaps and provides research recommendations on trade-offs and synergies between SOC sequestration or SOC accrual, non-CO2 GHG emissions and N leaching related to selected soil management strategies using 87 peer-reviewed articles categorized under tillage management, cropping systems, water management and fertilization and organic matter (OM) inputs. This review provides guidance for policymakers and a framework for field experiments and model simulations.

The traditional rice-wheat-mung cropping system in North Bihar, India has experienced declining yields and water constraints. This paper looks at alternative tillage and crop establishment (TCE) practices to remedy this problem. Five different TCE practices were evaluated in on-farm experiments. The best yields were found with Zero-tilled direct seeded rice (ZTDSR) followed by Happy Seeder ZT wheat (HSZTW) and HS gram (HSG). This treatment also provided the highest net returns with this CA based system out-performing traditional systems.

This is a Springer Science book chapter that is part of a book series " Advances in Global Change Research ((AGLO,volume 78))". The chapter says that "agricultural research should focus on developing eco-friendly and sustainable crop production systems with higher crop productivity to achieve sustainable development goals. Also that conventional agriculture that has excessive tillage and crop residue removal is degrading soil health by losing SOC, losing good soil physical properties including compaction and negatively impacting soil biology. It concludes that "global policy initiatives should promote CA practices to conserve natural resources and better maintain soil health, as our sustainable future strategy for crop production."

This book on Regenerative Agriculture edited by Indian Agricultural Scientists has 16 chapters that look at the current knowledge of this term  that is recently been used as a solution for negative effects of climate change influenced by GHG emissions from burning fossil fuels and degradation of the natural resource base agriculture depends on. The book says Regenerative Agriculture involves the use of CA management practices such as no-till, mulch ground cover using previous crop residues (or the use of cover crops) and rotations. But it goes further and includes "integrating crops and livestock, improving animal welfare, improving social and economic well-being of communities, sequestering carbon, improving soil health, increasing yields and profit with a positive impact on food access or food safety regardless of farm size". The next article in this newsletter in a chapter from this book.

This paper from Romania assesses changes in soil properties from a long-term field experiment established in 2009 with various tillage practices and then adapted in 2019-2022 for addition of residues. Results showed that compared to CT, conservation tillage (CA) with partial straw retention (MT) and NT with straw mulching increased SOC, total N, and available K in the 0-30cm soil depth. MT and NT only increased total P and K in the 0-10cm soil depth. The paper also looked at micro nutrients (Zn, Cu, Fe, Mn) but found little differences between tillage and residue systems. But they concluded that CA might be best for maintaining soil quality and high yields.

This paper from China assesses the balance between productivity and environmental impacts to find ways to reduce the threat of GHG emissions and climate change. They had 8 treatments that include 2 key components: the evaluation of economic and environmental parameters encompassing carbon footprint, energy consumption, and the carbon sustainability index. The results showed the benefits of no-till treatments (NT) coupled with introduction of soybeans in a rotation compared to conventional tillage (CT). However, the CT-MW treatment had the highest yield: combining conventional tillage with minimum tillage practices. Despite the higher cost to grow soybeans, their use increased net income. They conclude that the adoption of conservation agriculture optimizes the delicate equilibrium between environmental preservation and economic prosperity. 

This study from Tanzania looks at farmer strategies for adaptation to climate change. They surveyed 330 smallholder farmers. It was found that farmers have a number of strategies but the following 4 were key ones: drought resistant varieties, early maturing ones, resistant livestock breeds and conservation agriculture, with farmers choosing more then just one. The paper also categorizes the samples into 4 groups taht you can find in the paper. The conclude that these factors need to be considered in any policy decisions to ensure better adoption and adaptation strategies.

This paper from Malawi, looks at the effects of using the legumes pigeonpea (PP) and cowpea (CP) as intercrops with maize (M) in a deep bed farming (DBF) system compared to conventional tillage (CT) over two years on a farmers field. There were 7 main plots that included just M, CP and PP; M intercropped with CP and PP; CP intercropped with PP; and M plus N topdress. The subplots were DBF and CT. DBF is a form of CA that starts by doing deep tillage with a pick axe or hoe to break the plow pan so roots are deeper, better aeration, infiltration of water. Then CA management is done. The beds can be made along a contour. Results showed DBF and CT with legumes had higher yields than without. DBF was better than CT. Intercropping had higher land productivity than sole cropping indicating the introduction of a legume improves yields.

This is an interesting paper from France uses drones (UAV's) with remote sensing to produce images that can be used to assess the impact of different and temperature distribution and compare NDVI and MTVI2 dynamics as a function of their illuminance. They can do a good job of separating vegetation, no-vegetation, shade, and sun. The paper presents data from two adjacent maize plots that have used conventional (CT) and conservation (CA) agriculture practices. The non-vegetated areas had increased NVDI values as a result of the crop residues in CA plots.

Conservation Agriculture scientists suggest that by not tilling the soil greenhouse gases can be reduced and help store carbon in the soil. However, other scientists question the benefits of CA for climate change. This paper based on a case study in Germany suggests that the full application of CA results in the carbon footprint from agricultural food production is significantly reduced and so helps mitigate climate change and make CA agriculture carbon neutral. Read the paper for full details.

Low yields are often related to variable rainfall in semi-arid regions under conventional farming. This paper from the highlands of Mexico evaluates CA in 2 sites on-farm experiments and 17 farmer fields from 2013-2020 to assess yields and profits. Maize grown conventionally on the flat (CT) was compared with maize on permanent beds with residue mulch. The latter plots had monocrop maize and three rotations with either triticale, oats, or common beans. Results showed that average maize yields on beds exceeded CT maize by 70% in one location. Whereas in a second location there was no difference in maize yields between CT and CA systems. On the farmer fields, bed planting was 70% better then the CT. The most profitable rotation was maize-beans in farmer fields and the 2 on-farm trails.

This paper from Italy is designed to better understand the relationship between soil organic matter (SOM) and the main farming systems found in the Po Valley of Italy. They developed a dataset of topsoil (0-20cm) SOM together with environmental and farming information collected from 597 locations (145 fields and 62 farms). Higher SOM contents were detected in Cambisols (3.11 %) and in field managed according conservation agriculture practices (3.22 %) as compared to other farming systems. Results also showed that the inclusion of fodder crops in the rotation and the use of no-tillage were two of the most effective practices for increasing and preserving SOM. 

This article is a three field study that looks at CA as a cost-effective alternative  to conventional tillage (CT) in rice-wheat systems in Karnal, Haryana, India using a flooded (FL) and sub-surface drip (SDI) irrigation. Results show that in rice, in ZT direct seeded rice with residue (+R) and SDI recorded 73% less weeds than the CT-puddled transplanted rice after 3 years. However, the ZTDSR without residue (R-) with flooding had the highest weed density and weed dry matter 37% less rice yield after 3 years. The paper lists the various weeds present. The same was found in wheat with the lowest WD and WDM in the ZT + SDI in year 3. The CA system improved yields over CTRW systems in weed free (WF) conditions, regardless of residue and irrigation management and should be recommended for RW systems.

In Brazil soil and water conservation has made no-tillage the leading method for preparing land. This paper looks at the adoption rates of NT and CA within Parana State farmers using data from the Brazilian Institute of Geography and Statistics' censuses from 2006-2017. Data shows a rise in the adoption of NT from 68.5% to 78.9% and CA from 14.6% to 27.7% over this time period. The highest rates were in areas where soybeans, maize and wheat are grown. The lowest in areas where pasture, sugarcane, cassava and rice are grown.

This is a book chapter from the 2024 Soil Science Society of America, Soil Health Series, volume 3. The chapter presents a case study of CA use in a family farm in Brazil where a long-term participatory study looked at the economic analysis  that included maize and cassave crops. The soils in this area of Brazil are prone to degradation through deforestation and burning that required alternative management to reverse this issue. They conclude that "the results of this study can be separated into lessons learned and those to be learned. During these first 16 years, although the best management practices had a limited impact on the health of the sandy soils in the Juruá region, crop productivity was clearly significantly increased and income was ensured, which determines the profitability of family farming.

This chapter describes some of the negative issues of rice-based systems in South Asia in terms of feeding an expanding population when groundwater and soil resources are degrading, and climate change is negatively impacting productivity. The mention that some recent management systems like conservation and organic agriculture have shown promise to mitigate the above mentioned negative impacts. But they suggest that adoption of regenerative agriculture that has a more holistic (natural resources, climate change, animal crop interactions, social and economic etc.)  approach may be needed in the future.  It sounds very much like the move from cropping systems to farming systems to Ecosystems suggested in the latter part of the 20th century. Just getting CA management components adopted by farmers has been a major challenge and taken a lot of time. Farmers also adopt parts of the package first rather than the more complex whole package.