The authors used a mobile, closed chamber system to determine soilborne, greenhouse gas (GHG) emissions from rainfed, farmer-managed CA- and conventional agriculture (CONV), in northern Zimbabwe in on-farm sites that varied in soil fertility and environmental conditions. Field emissions were highest under
warm-moist conditions, which are prevailing for large
parts of the growing season. See the abstract for detailed results. They conclude that "the mitigation effects of CA are highly
site-specific and that CA management practices can have unexpected negative effects on GHG fluxes. The
unimodal rainfall distribution with a long dry winter
period of 7 months and recurrent dry spells in north-
ern Zimbabwe may prevent a net carbon sequestration
under CA management that would have occurred in
the humid tropics.

This paper looks at smallholder farmers issues with tractor mechanization using a survey of 208 farmers, 18 focus groups and 28 key informants in 3 Districts of Zambia. Issues looked included adoption, preferences for ownership, and financing. Tractor ownership revolves around improvement in productivity but also income generation from service provision to other farmers tied to better timing and narrowing planting windows. Differences in gender affect ownership with males preferring individual ownership and females prefer group ownership. Incentives for ownership were best for risk-contingent credit especially if bundled with repair insurance. Barriers to adoption included high maintenance costs' poor access to spare parts and financial issues. They conclude that "successful interventions must be flexible, gender-responsive and tailored to the local context." 

This paper looks at the impact of no-tillage (NT) and conventional tillage (CT) on soil water and physical properties in Romania using undisturbed soil columns from a field experiment that was a continuous cropping system for 8 years with a 4-year rotation (wheat, maize, sunflower and peas). Various soil physical and water measures were taken. The various measurements can be found in the paper abstract. They conclude that the "findings demonstrate that long-term NT improves key soil hydro-physical properties, supporting its integration into sustainable farming systems to balance productivity and environmental stewardship."

Food security is a challenge in Malawi where agriculture is crucial for livelihoods and rural development. This paper looks at the diversity of different CA systems adopted by rural farmers a District in Malawi. 390 farmers were surveyed who had adopted CA in some form. 97% of these farmers were aware of CA, but adoption rates were much lower because of high labor costs and limited resources. Intercropping was used by 37% of farmers and 30% used manure. Mulching and mixed cropping had low adoption rates. They concluded that "to enhance the adoption of these technologies, it is recommended that strategies be developed to address labour and resource limitations, including context-appropriate training programs, resource enhancement initiatives, and targeted promotional efforts focused on local farming systems.

This paper uses the term Resource Conserving Technologies (RCT's) as practices that help reverse the negative affects of climate change on food and water productivity. RCT's they include are CA, cover crops, mulching, drip irrigation, soil moisture sensors-based smart irrigation, rainwater harvesting, site-specific nutrient management, leaf color chart, fertigation, and precision agriculture that can result in long-term sustainability by enhancing food production and sequestering soil carbon in conventional field farming. They can also reduce greenhouse gas emissions (GHGs), result in higher yield and water savings. Some RCT's require high-cost machinery and it is suggested they should be tested in diverse production systems for sustainability and large-scale adoption. 

This paper from Rwanda looks at the low yields of maize, a critical staple crop in this country. The study evaluates the agronomic and economic results of CA compared to conventional systems (CT) by interviewing 222 farms in dry areas of Eastern Rwanda. They found that CA farmers incurred higher total production costs, particularly for fertilizers, seeds, weeding, and irrigation, while CT farmers had significantly higher land preparation costs. But CA achieved 40% higher net profit, 20% higher maize yields, and higher P use efficiency compared to CT. They identified irrigation frequency, seed rate, and nitrogen and phosphorus fertilizer application as key determinants of maize yield using CA compared to CT. 

This article from NW Vietnam looks at how CA practices (CAPs) can be adopted to overcome the problems associated with conventional agriculture in this region that has resulted in soil degradation because of intensive tillage and intensive use of chemical fertilizers without adding organic matter. They surveyed 400 maize-farming households. Their analysis shows "that the joint adoption of CAPs is facilitated by education of the household heads, total farmland area, farmers’ access to credit, interactions with extension agents, training on CAPs, proximity to cooperatives, participation in farmers' groups, and plot-specific characteristics." Adoption of CAPs leads to better maize yields and net incomes, especially when all aspects of CA are adopted.  

This book chapter 16 from a 2024 published book on Greenhouse Gases in Climate Smart Agriculture covers the perspective on CA and GHG. It talks about how to feed a growing population when climate change is a major issue. Issues include burning of previous crop residues and loss of soil health and nutrients. This chapter discusses how CA can help with future food security. It concludes that "several studies have shown that CA practices reduce farm-related GHG emissions, improve soil health and structure, increase carbon sequestration, reduce soil erosion, and modify the microclimate" 

This is one of several papers on the importance of soil health in modern agriculture especially for securing future food security written by a renowned soil scientist. He talks about a disturbance based classification of agricultural systems that includes tillage and chemical use: does the system allow , minimize or avoid physical or chemical disturbance in soil ecosystems and do these systems help with reversing the degradation of soil and its health? This paper discusses conventional, organic, no-till, regenerative, and regenerative organic farming in terms of physical and chemical disturbance. 

This is a chapter from the Cover Crops and Sustainable Agriculture book listed next that is devoted to cover crop use in conservation agriculture. This chapter looks at the issue of an expanding global population (10 billion by 2050) with a traditional farming system that uses intensive tillage and monoculture that is slowly degrading the soil, the environment and the ability to feed the future population, especially as climate change adds a further challenge for food production. This chapter provides information on cover crop mixes that are relevant for conservation agriculture to not only improve the benefits of a surface residue mulch needed for no-till systems but also a way to improve soil health vital for sustainable agriculture and future food security.

This paper from India starts by saying India with 121 million small and marginal holdings, faces challenges from a growing population, limited land, and restricted resources.Their review identifies potential innovative technologies suitable for resource poor farmers and what effective ways are needed like public-private partnerships, cooperative farming, and custom hiring centers to overcome adoption barriers and identified enabling factors such as funding, education, and institutional support. They also suggest that a multi-faceted approach with policy, financial, and educational support is essential for adoption. They conclude that findings are relevant to policymakers and development practitioners focused on enhancing food security and resilience in smallholder farming.

This paper from Ohio State University's Triplett-Van Doren long-term tillage and crop rotation experiment (one of the oldest NT experiments in the World) looked at the temporal dynamics of soil N and C pools in a maize growing season, in a 55 year old tillage and crop rotation experiment. Tillage treatments were no-till (NT) + residue, Chisel-till (CT) + 30% residue and moldboard till (MT) - residue incorporated. There were 3 rotations: continuous maize, maize-soybean (2-year rotation), and maize-forage-forage (3 year rotation). Their results suggest that crop diversification with perennials enhances soil C and N; NT has stronger effects in clay loam than silt-loam soils; and although C and N pools vary seasonally, long-term management effects persist throughout the growing season.

This paper from New Zealand starts by saying soil health decline is a major constraint to achieving higher yields and looks at the interaction of tillage, legumes and nitrogen on reversing declines in SH for a cotton-wheat on a bed planting system. There were two tillage systems; NT and Conventional tillage (CT). Three legumes: soybean, mungbean, and mash bean. 2 nitrogen levels. Results showed that the best treatment for soil organic matter and microbial population (improved soil health) was cotton + mungbean-wheat with NT and the recommended N and a significant increase in wheat yield compared to CT treatments. 

This paper presents the results of a study to look at CA performance of a cassava-legume cropping system in terms of yield, nutrition, and economics in Northern Zambia. They used a mother and baby trial setup  with 6 cropping systems that combined tillage (flat and bed planting) and legume intercrops (common beans and groundnut) compared to sole cassava. They measured root yield, legume yield, protein yield, energy and economic returns. See the paper for more details, but 3 treatments were planted on the flat under no-till and 3 treatments planted on hand hoed ridges (traditional system for cassava). Results showed cassava planted on the flat especially with legume intercrops under CA did not compromise cassava yield and significantly enhanced legume grain, protein, and energy yields. Economic analyses revealed higher net benefits and return to inputs in flat-planted intercrops, though labour costs were also higher.

This research from Uganda looks at nitrogen fixation with pigeon peas in a maize dominant cropping pattern to investigate the effect of biochar under CA on nitrogen fixation at three sites located in different agro-ecological zones. CA involved minimum tillage with planting basins established by hand hoeing. There were 4 treatments: (1) conventional tillage with crop rotation (CT), (2) minimum tillage with crop rotation (CA), (3) CA and plus biochar, applied in both first and second year (CA+BC+BC), and (4) CA and biochar, applied once in the first year (CA+BC). Grain yield was significantly increased by biochar application in CA systems compared to conventional practices, in all seasons and sites. They conclude that "Biological N2-fixation was positively influenced by biochar application under CA systems". 

This paper describes conservation agriculture (CA) as a way of achieving the Sustainable Development Goals (SDGs). The authors suggest that "CA can prove to be a viable option for meeting the targets of the sustainable agenda. This practice supports environmental, social and economic justice, which creates a holistic developmental route that supports the burgeoning population." CA also reduces production costs that favors farmer adoption. However the paper concludes that "while CA demonstrates significant benefits across scales, its adoption remains constrained by socioeconomic factors and limited mechanization in the smallholder context. Advancing CA requires a multidisciplinary, participatory research paradigm coupled with policy support, institutional support and capacity building for farmers. 

This paper suggests that CA adoption is crucial for enhancing SOC and mitigating climate change for future food security. The research assesses the effectiveness of various factors controlling SOC sequestration derived from literature reviews and 469 data points spanning 42 years.Results showed that CA significantly increased  SOC by almost 30% compared to CT. The highest SOC result was no-till, plus chemical fertilizer (CF), and straw return (S). Interestingly, CF + S or CF + manure led to greater SOC sequestration compared to the application of CF alone. Also, the annual SOC change rate (ASCR) of CA is closely linked to the experimental duration of its application, demonstrating an overall exponential decline followed by stabilization after several years. Overall. this paper contributes to the understanding of how CA sequesters carbon in soil.

This paper from Iran explores the factors that are responsible for adoption of CA in Iran since they suggest this system is important for environmental sustainability and resilience. They show it helps reverse soil degradation by improving moisture retention and increasing soil organic matter. Data were collected through questionnaires and analyzed using structural equation modeling. They conclude that "attitude and self-efficacy emerged as the most significant determinants influencing farmers' decisions to adopt CA. The information will provide valuable recommendations  for policy makers hoping to promote CA. 

This review from Romania highlights the importance of soil health for sustainable agriculture and identifies practices that result in improved soil health that includes, physical, chemical and biological properties. The explored rotation, cover crops, no-till, CA, and use of organic amendments to achieve SH properties that includes better soil structure, increased organic matter and biological diversity. Increasing soil organic carbon (SOC) is vital. Their results show that CA is a better option to restore soil health than conventional systems although they mention that this topic is still controversial among scientists and farmers. 

This is another chapter in another 2024 book that has chapters on Principles of Agronomy for Sustainable Agriculture. Chapter 18 looks at soil conservation and negative issues of tillage and goes on to describe the role CA can play in reversing the issue of soil degradation when using tillage. They understand that adoption of CA will take time as farmers transition from conventional tillage. Literature has many examples of what is needed to accelerate adoption of this new management system. CA needs to address weed issues in the early years of adoption and suitable machinery availability for seeding. Use of cover crops in less intensive cropping systems in temperate climates are growing in acreage and supply the needed residue cover for CA.  

This is another article on soil health in this special edition on soil health of this journal. One question raised is "What is soil health"? Also how does one describe it to non-soil scientists and why it is so important to everyone? The authors of this paper who organized this series of papers on soil health share their thoughts and own opinions on soil health in this paper. The conclude by saying "Our goal is that each of you will be enriched by the articles in this issue and the impact of soil health on conservation and the future of our ecosystem."

This paper talks about the role of soil as a basis for all terrestrial life as well ecosystem services for nature and mankind. It is essential to protect, restore and manage soils in a sustainable way so that soil health is maintained and improved. This will require humans working together including the various stakeholders in the public, private, scientific and extension groups but also policies to make sure the soil is a protected resource. 

I included this book that was published in 2021 because it deals with the role of cover crops that are becoming more popular in modern agriculture and used in sustainable agriculture like conservation agriculture to provide the essential surface mulch needed to make no-till systems productive. This book is an encyclopedia of cover crop management by 2021. Papers in the 18 chapters indicate the long-term benefits for soil health, structure, water quality, nutrient contributions, soil biodiversity, air quality and climate change. The book looks at the "whys" as well as the "hows" for different locations and how to terminate them when needed. As part of a continuous no-till system, cover crops provide long-term biological, chemical and structural benefits. The resulting increase in soil organic matter means the agronomic crop yields benefit from better water infiltration and water holding capacity, greater availability of nitrogen and other nutrients, deeper rooting, and increased soil microbial activity in the root zone.

This study from China investigated the erosion processes and carbon dynamics across eroded slopes after adopting various conservation practices based on the data obtained from field experiments across the globe. Their results interestingly showed that adoption of CA compared to CT significantly did not reduce runoff but did lead to a significant reduction in sediment loss. CA also significantly increased soil organic carbon (SOC) in the top 10cm layer and reduced SOC loss. The results further highlighted the critical contribution of straw mulching in erosion control, soil organic carbon loss reduction, and soil organic carbon accumulation, while reduced tillage represented the least effective measure. 

This paper from Europe used a Meta-analysis to to evaluate the impact of management practices related to carbon and nutrient, vegetation, pest and disease and soil management, as well as grazing management on soil biota and soil biology. They screened 698 articles and came up with 90 that were eligible with a total of 790 pairwise combinations and 74,526 observations. Their study showed what agricultural practices improve or reduce soil biology that is useful for selection of sustainable farming systems. They found that reduced tillage, organic fertilization, cover cropping and intercropping resulted in positive improvements in soil health factors. They also developed a “Utility-Robustness” scoring system for soil actors, using a systematic framework to inform biological indicator selection tailored to specific management contexts.