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Vulnerabilities of the global fuel-fertilizer-food nexus have been revealed by a regional geopolitical conflict causing sudden and massive supply disruptions. Across over- and under-fertilized agricultural systems, nitrogen (N) fertilizer price spikes will have very different effects and require differentiated responses. For staple cereal production in India, Ethiopia, and Malawi, our estimates of N-fertilizer savings show the value of integrated organic and inorganic N management. N-deficient systems benefit from shifting to more cost-effective, high-N fertilizer (such as urea), combined with compost and legumes. N-surplus systems achieve N savings through better targeted and more efficient N-fertilizer use. Globally, there is a need to re-balance access to N-fertilizers, while steering the right fertilizer to the right place, and managing N in combination with carbon through near-term interventions, while striving for longer-term sustainable management. Nationally, governments can invest in extension and re-align subsidies to enable and incentivize improved N management at the farm level.

Knowledge is a critical enabling factor for healthy agri-food innovation systems (AIS). AIS and related knowledge management (KM) frameworks face significant implementation challenges. We review ap...

Maize (Zea mays L.) is Mexico's primary staple food, but the Country's degrading soils and climate variability limit its productivity. Conservation agriculture (CA), a management technique that combines minimal tillage, permanent soil cover, and crop diversification, could reduce soil degradation and help improve soil health. There is however a lack of information about the effects of CA on soil health in the diverse agroecological conditions in Mexico. This study reports results of a field trial network established to adapt CA to Mexico's diverse cropping systems and local conditions. Physicochemical soil health, also referred to as soil quality, was studied in 20 trials in agro‐ecologies ranging from handplanted traditional systems to intensive irrigated systems, initiated between 1991 and 2016. Soil in CA was compared to the local conventional practice (CP), which commonly involves tillage, residue removal, and continuous maize production. Across the sites, organic matter and nitrates were higher in the top (0–5 cm) layer of soil and soil aggregate stability was greater under CA than under CPs. For other soil health parameters, such as nutrient content, pH or penetration resistance, the effects of management varied widely across sites and soil types and most were determined more by local soil type than by management. CA increased maize yields at most sites and on average by 0.85 ± 1.80 t ha⁻¹. Given the significant variation across agro‐ecologies, local adaptive trials are important to assess the effects of CA on soil health and fit the practice to local conditions.

Conservation agriculture (CA) systems represent a set of three soil management principles: minimarbance, permanent soil cover and crop rotations - whereas the CA-based systems in this study add the bed and furrow tillage techniques as integral elements of CA. Studies on the effects of long-term CA-based systems on soil health and crop productivity are rare globally, particularly in Ethiopia. This study aimed at investigating the long-term (2005-2013) influence of CA-based systems on soil health and crop productivity in northern Ethiopia. The treatments we used include two types of CA-based systems (permanent raised bed PRB and contour furrowing CF) and conventional tillage (CT) arranged in a randomized complete block design. Soil samples were collected at 0-10 cm soil depth to assess soil health. Piecewise structural equation modeling (PSEM) was used to analyze linkages between management practices, soil health and crop productivity. Arbuscular mycorrhizal fungi spore abundance and root colonization was higher in PRB followed by CF compared to CT (p < 0.05). Significantly different soil N of 1.4 and 0.9 g kg(-1) and available P of 6.7 and 4.1 ppm were recorded for PRB and CT, respectively. Higher straw and grain yield of 12 and 4.3, 10 and 3.5, 8 and 2.8 t ha(-1) were recorded for PRB, CF and CT, respectively. Outputs of the PSEM highlighted two pathways in which CA-based systems contributed to improved productivity: (a) via higher density of bacteria and improved hydraulic conductivity, and (b) via higher density of fungi and increase soil organic carbon content in the topsoil. The study concludes that CA-based systems have the potential to improve crop productivity through improved soil health.

Implementing practices that maximize water use efficiency in arid zones is important as agriculture relies mostly on irrigation in these agroecosystems. The aim of this study was to identify the effect of combining different sowing irrigation methods (dry and wet) with contrasting tillage practices (conventional practices and conservation agriculture) on bacterial community structure in soils from the Norman E. Borlaug experimental field (CENEB), Yaqui Valley, Sonora. Soil samples were collected consecutively four times in the month after sowing from permanent and conventionally tilled beds under wet and dry sowing at CENEB. Soils were characterized and the bacterial communities were identified with Illumina MiSeq sequencing where the 16S rRNA gene was targeted. The bacterial community structure was affected by soil water content. Streptomyces and Balneimonas were enriched in dry sowed soil, the first in conventionally tilled beds and the latter in permanent beds, while Acinetobacter was enriched in wet sowed soil under conservation agriculture. Shannon index indicated that there was a high species diversity in both conventional practices and conservation agriculture. 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.

Appropriate agronomic management of breeding trials plays an important role in creating selection conditions that lead to clear expression of trait differences between genotypes. Good trial management reduces experimental error to a minimum and in this way facilitates the detection of the best genotypes. The field site should be representative for the target environment of the breeding program, including soil and climatic conditions, photoperiod, and pest and disease prevalence. Uniformity of a field site is important to provide similar growing conditions to all plants. Field variability is affected by natural and management factors and leads to variability in crop performance. Additionally, pest and disease incidence tend to concentrate in patches, introducing variability not necessarily related to the susceptibility of affected genotypes. Precise agronomic management of breeding trials can reduce natural field variability and can contribute to reduce variability of crop performance. Through specialized agronomic management, contrasting selection conditions can be created in the same experimental station. The use of adequate machinery like plot seeders and harvesters contributes to precise trial management and facilitates operation. Machine seeding assures even seeding depth and density. Plot combines can be equipped with grain cleaners, on-board weighing systems and sensors to measure grain humidity and weight, which can greatly facilitate data collection.

Crop residue management and tillage are known to affect the soil bacterial community, but when and which bacterial groups are enriched by application of ammonium in soil under different agricultural practices from a semi-arid ecosystem is still poorly understood. Soil was sampled from a long-term agronomic experiment with conventional tilled beds and crop residue retention (CT treatment), permanent beds with crop residue burned (PBB treatment) or retained (PBC) left unfertilized or fertilized with 300 kg urea-N ha−1 and cultivated with wheat (Triticum durum L.)/maize (Zea mays L.) rotation. Soil samples, fertilized or unfertilized, were amended or not (control) with a solution of (NH4)2SO4 (300 kg N ha−1) and were incubated aerobically at 25 ± 2 °C for 56 days, while CO2 emission, mineral N and the bacterial community were monitored. Application of NH4+ significantly increased the C mineralization independent of tillage-residue management or N fertilizer. Oxidation of NH4+ and NO2− was faster in the fertilized soil than in the unfertilized soil. The relative abundance of Nitrosovibrio, the sole ammonium oxidizer detected, was higher in the fertilized than in the unfertilized soil; and similarly, that of Nitrospira, the sole nitrite oxidizer. Application of NH4+ enriched Pseudomonas, Flavisolibacter, Enterobacter and Pseudoxanthomonas in the first week and Rheinheimera, Acinetobacter and Achromobacter between day 7 and 28. The application of ammonium to a soil cultivated with wheat and maize enriched a sequence of bacterial genera characterized as rhizospheric and/or endophytic independent of the application of urea, retention or burning of the crop residue, or tillage.

Tillage and residue retention affect nitrogen (N) dynamics and nutrient losses and therefore nitrogen use efficiency (NUE) and crop fertilizer use, however, there is little information about residual fertilizer effects on the subsequent crop. Micro‐plots with ¹⁵N‐labelled urea were established in 2014/2015 on a long‐term experiment on a Vertisol in north‐west Mexico. N fertilizer recovery (NFR) and the effects of residual fertilizer N for summer maize (Zea mays L.) and the subsequent wheat (Triticum durum L.) crop were studied in three tillage–straw management practices (CTB: conventionally tilled beds; PB‐straw: permanent raised beds with residue retention; PB‐burn: permanent raised beds with residue burning). Fertilizer ¹⁵N recovery rates for maize grain across all treatments were low with an average of 11%, but after wheat harvest total recovered ¹⁵N (¹⁵N in maize and wheat straw and grain, residual soil ¹⁵N) was over 50% for the PB‐burn treatment. NFR was lowest in CTB after two cropping cycles (32%). Unaccounted N from applied fertilizer for the maize crop averaged 120 kg ¹⁵N ha⁻¹ after wheat harvest. However, more than 20% of labelled ¹⁵N was found in the 0–90 cm soil profile in both PB treatments after wheat harvest, which highlights the need for long‐term studies and continuous monitoring of the soil nutrient status to avoid over‐application of mineral N fertilizer.

In Central America, population and food demands are rising rapidly, while yields of staple crops, maize and beans, remain low. To identify the main factors limiting production, field trials were established in six maize- and bean-producing regions in Guatemala, Honduras and El Salvador, representing about three-quarters of the maize-producing area. Potential yield-limiting factors were evaluated in 2017 and included: water stress, nutrient deficiency, pest and disease pressure, and/or inter-plant competition. When considering all sites, improved fertilization and pest and disease control significantly improved yields in maize by 11 and 16%, respectively but did not have a significant effect in beans. Irrigation had no effect due to good rainfall distribution over the growing season. Optimized planting arrangement resulted in an average 18% increase in maize yield, making it the most promising factor evaluated. The treatment and site combinations that increased both crop productivity and net profit included management changes that improved resource use efficiency. However, the contribution of each limiting factor to yield gaps varied across sites and no treatment was effective at increasing yield consistently across sites. Production constraints are highly dependent on local management practices and agroecological location. Therefore, public and private development efforts that seek to increase production should conduct multi-year, participatory experiments to identify limitations pertinent to the area in question. The next step is then to evaluate sustainable and profitable practices, to address those limitations and provide sound recommendations to farmers while decreasing the environmental and economic costs.

En México el extensionismo como actividad profesional ha sido revalorizada, por parte del propio Gobierno de la República mexicana, de acuerdo con datos de la SAGARPA existen al menos 23 mil técnicos en el padrón registrado. Se han definido los segmentos de atención de los productores en México y se construyen nuevos programas donde la inclusión es un común denominador. Durante dos años un grupo de 20 especialistas de otras tantas instituciones se reunieron con el auspicio del CIMMYT-Mas Agro, para convencionar acerca del concepto de extensionismo, se llegó elaborar un documento de trabajo donde se describen los principios filosóficos, metodológicos y operativos del extensionismo en México.

While several studies have focused on the actual adoption of agricultural apps and the relevance of the apps’ content, very few studies have focused on drivers of the farmer’s intention and initial decision to adopt. Based on a survey of 394 smallholder farmers in 2019, this study investigated willingness to adopt an agricultural advice app in Guanajuato, Mexico. A structural equation modeling approach, based on the unified theory of acceptance and use of technology (UTAUT), was applied. To understand the farmers’ adoption decisions, extended constructs were studied (e.g., mastery-approach goals) along with the farmers’ age and participation in an innovation hub. Results showed that the intention to adopt the app is predicted by how farmers appraise the technical infrastructure and acquire new knowledge by using an app. The multi-group analysis revealed that performance expectancy is a relevant predictor of the intention to adopt, whereas the mastery-approach goal is relevant only for younger farmers and farmers not connected to the innovation hub. This study provides valuable insights about the innovation hubs’ role in the intention to adopt apps, offering precision agriculture advice in developing countries. The findings are useful for practitioners and app developers designing digital-decision support tools.

While current studies have focused on adoption and the relevant content of the app to become a decision support system, very few studies have focused on the farmer's intention and initial decision to adopt. Based on a survey of 394 smallholder farmers this study investigated Mexican farmers’ willingness to adopt an agricultural advice app. A Structural Equation Modelling approach, based on the Unified Theory of Acceptance and Use of Technology (UTAUT) was applied. To understand farmers’ adoption decision, extended constructs were studied (e.g. mastery-approach goals) along with farmers’ age and participation in an innovation hub. Results showed that the intention to adopt the app is predicted by how farmers believe that technical infrastructure exists and by the expectation of the farmers using the app to acquire new knowledge. The multi-group analysis revealed that performance expectancy is a relevant predictor of the intention to adopt, whereas the mastery-approach goal is relevant only for younger and farmers not connected to the innovation hub. The results may well be a baseline to research further suitable non-financial incentives for different farmers’ groups, then encourage initial adoption and enhance uptake. The findings are useful for practitioners and app developers designing digital decision support tools.

Precision planting represents an opportunity for farmers to increase income. Seeders and associated seed meters are prerequisite to achieve optimal plant density. However, to assure seed meter performance in smallholder conditions, a comprehensive procedure is lacking. This study develops a methodology for mechanical maize meter evaluation that compares diverse meters in terms of seed singulation, seed damage, and spatial distribution. An experiment assessed 10 m, representing roller types, and inclined, vertical, and horizontal plates collected from various continents and representative of commonly used devices by smallholders. A conveyer-belt setup allowed for seed distribution analysis and the influence of vibration and topography on the seed singulation was determined. Results revealed that a rotational velocity of 20 revolutions per minute (RPM) was optimum for most meters, while all complied with the norm NMX-O-168-SCFI-2009 in terms of seed damage. Independent of the singulation mechanism, devices with the ability to adjust to seed size performed better. The Fitarelli horizontal plate, followed by the BARI-9 inclined plate meter, are considered ‘best-bet’ performers. Although, considering absolute efficiency, two inclined plate devices worked at near-perfect performance with large seeds. Our study develops a low-cost methodology, easily replicated and implemented, and provides a baseline for continued research on seed meter evaluation.

There is great untapped potential for farm mechanization to support rural development initiatives in low- and middle-income countries. As technology transfer of large machinery from high-income countries was ineffective during the 1980s and 90s, mechanization options were developed appropriate to resource poor farmers cultivating small and scattered plots. More recently, projects that aim to increase the adoption of farm machinery have tended to target service providers rather than individual farmers. This paper uses the Scaling Scan tool to assess three project case studies designed to scale different Mechanization Service Provider Models (MSPMs) in Mexico, Zimbabwe, and Bangladesh. It provides a useful framework to assess the gap between international lessons learned on scaling captured in forty tactical questions over ten “scaling ingredients” as perceived by stakeholders involved in the projects, as well as private sector actors and government employees. Although at first sight the case studies seem to successfully reach high numbers of end users, the assessment exposes issues around the sustainable and transformative nature of the interventions. These are highly influenced by the design of the projects and by the environment and context of the intervention areas. Across the three case studies, large-scale adoption of the models was found to be hampered by lack of finance to set up MSPMs and insufficient collaboration among the value chain actors to strengthen and foster Mechanization Service Provider (MSP) entrepreneurs. Applying a scaling perspective on each case study project exposed important lessons on minimizing project dependencies. Positive examples include integration of capacity development materials in vocational training centers in Zimbabwe, promotion of MSPMs by other donors in East Africa and levering of nearly USD six million of private sector investment in appropriate machinery in Bangladesh. On the other hand, there is still a high dependency on the projects in terms of coaching of service providers, facilitating collaboration along the value chain, and provision of leadership and advocacy to address issues at governance level. These results have important implications for similar development interventions aimed at increasing smallholder access to mechanization services at scale and is to our knowledge the first cross-continental assessment of these issues to date., Highlights • Service providers can successfully improve access to appropriate mechanization. • Applied a novel analytical tool to analyze constraints to scaling in three countries. • Stakeholders are dependent on projects to address bottlenecks for scaling. • Service providers need support to transition from project to market finance. • Scaling Scan helps stakeholders identify opportunities to accelerate scaling.

SUMMARYA major problem faced by small-scale farmers in northern Ethiopia is reduced crop yield due to increasing soil degradation resulting from repeated tillage and inadequate agronomic management practices. These practices have left soils and rainfed crops susceptible to hazardous climatic events such as droughts. Sustainable farm practices such as minimum tillage and surface residue retention have been shown to improve soil health and crop productivity. The objectives of this field study were thus to evaluate the impacts of conservation agriculture (CA) practices on crop yield and economic productivity over 6 years in the eastern Tigray region of northern Ethiopia. Using a barley–wheat rotation from 2010 to 2016, the applied treatments were (i) permanent raised beds (PRB); (2) semi-permanent raised beds (SPB) and (3) conventional tillage (CT). Average barley and wheat biomass and grain yields in PRB and SPB treatments were consistently greater than yields under CT each year. In addition, the highest marginal rate of return was obtained in PRB and SPB compared to CT in all years (2010–2016). These results suggest that the CA practices of PRB and SPB can improve crop yield and profit compared to CT practices in the Tigray region.

Research and development agencies, as well as policy makers and agri-food enterprises, need reliable data to support informed decisions that can improve the sustainability of agricultural landscapes. We present a review of agricultural sustainability assessment frameworks (ASAF) that identifies the features most relevant to monitoring progress towards sustainability goals for agricultural landscapes. This qualitative review considers a variety of approaches for defining goals and for selecting stakeholders, spatial and temporal boundaries, indicators, and analytical approaches. We focused on assessment frameworks that (i) include environmental, social, and economic implications of agriculture; (ii) are applicable to multiple, non-specified farm system types; (iii) are described in an English language, peer-reviewed publication; (iv) have been developed for use at a farm system to regional spatial scale; (v) engage stakeholders; (vi) provide case studies; and (vii) could be used in a variety of contexts across the globe. Based on the review, we provide recommendations for further development and use of assessment frameworks to better address the needs of agricultural research, extension, and development organizations. We recommend an agro-ecosystem approach to help stakeholders identify appropriate indicators for their situation. Assessment methods need to be flexible enough for adaptation to a spectrum of agricultural landscapes and changing environmental conditions, and remain relevant as farmers and other stakeholders acquire new information, resources, and different management techniques. We find that to address information gaps across different scales from farm to region will require creativity and some reliance on local knowledge systems to support adaptive management. Assessment results should communicate relationships among ecosystem services and socio-economic activities affected by agricultural landscapes. Visualization tools can facilitate understanding of trade-offs and synergies among sustainability goals as reflected by individual indicators.

Agronomic systems based on zero tillage and residue retention are becoming more important due to their potential for climate change adaptation through the reduction of soil erosion and improved water availability. Denser soil surface conditions and large amounts of crop residues, however, may be a constraint for early plant establishment, especially in irrigated production areas with high yield potential. Genotype by tillage interactions for yield are not well understood and it is unknown whether tillage should be an evaluation factor in breeding programs. Twenty-six CIMMYT bread ( Triticum aestivum ) and durum ( Triticum turgidum ) wheat genotypes, created between 1964 and 2009, were tested for yield and agronomic performance at CIMMYT’s experimental station near Ciudad Obregon, Mexico, over six years. Treatments included conventional and permanent raised beds with full and reduced irrigation. The objectives were to study breeding progress in distinct agronomic systems and to elucidate the importance of tillage and genotype by tillage interaction for yield and agronomic traits. Breeding progress was achieved irrespective of agronomic treatment. Tillage influenced plant growth and number of grains per m 2 in both wheat types. In bread wheat, genotype by tillage interaction was significant for yield, test weight, and growth parameters. However, no cross-over effects were detected and rank changes were small. In durum wheat, genotype by tillage interaction was only significant for plant growth. The results do not indicate the need for separate breeding programs. However, the question of a need for selection under zero tillage to increase breeding progress is yet to be answered.

Nitrate (NO 3 -N) leaching from agricultural soils can lead to substantial losses of fertilizer nitrogen (N) and cause considerable contamination of aquatic ecosystems and groundwater. This study aimed at estimating NO 3 -N leaching losses for three tillage-straw management systems in the intensely cropped Yaqui Valley, Northern Mexico using ion exchange resin samplers. To this end data were collected in 2013/2014 from a tillage experiment established in 2005 as a randomized complete block design with two replications and three subplots on a Hyposodic Vertisol. Tillage-straw treatments were conventionally tilled beds with incorporated crop residue (CTB-straw incorporated), permanent beds with crop residue retained at the surface (PB-straw retained) and permanent beds with residue burning (PB-straw burned). Ion exchange resin samplers were installed at 90 cm depth in a consecutive crop rotation of wheat ( Triticum durum L.) and maize ( Zea mays L.) for 6 and 5 months, respectively (from first pre-plant fertilization to harvest). Leaching losses were higher with maize than with wheat cultivation (68.2 and 53.5 kg ha −1 season −1 NO 3 -N; P = 0.25). Tillage-straw treatment did not significantly affect NO 3 -N leaching in wheat, but it did in maize. NO 3 -N leaching for wheat was 51.1 kg ha −1 season −1 NO 3 -N in CTB-straw incorporated, 60.8 kg ha −1 season −1 NO 3 -N in PB-straw retained and only 46 kg ha −1 season −1 NO 3 -N in PB-straw burned. For maize, overall leaching losses were highest for PB-straw retained (81.9 kg ha −1 season −1 NO 3 -N), followed by 75.6 kg ha −1 season −1 NO 3 -N for CTB-straw incorporated and 47.7 kg ha −1 season −1 NO 3 -N for PB-straw burned. Soil NO 3 -N concentrations were significantly affected by sampling date and depth. PB-straw burned had highest residual soil NO 3 -N after crop harvest. Ion exchange resins-based NO 3 -fluxes displayed high spatial variability, therefore a large number of repetitions was necessary. As 19% of N applied to wheat and 34% of N applied to maize was lost through leaching, farming practices that could lower the risk of nitrate contamination during cropping should be promoted. Additional multi-annual studies are necessary to assess the effects of reduced irrigation, climatic variation and different fertilizer application on nutrient leaching in different tillage-straw systems of northwestern Mexico.

Permanent raised beds (PB) are a conservation agriculture option for irrigated conditions that can improve soil quality, increase soil moisture conservation and stabilize yields compared to conventional furrow irrigation. In irrigated wheat (Triticum sp.) production, wet sowing (i.e. applying irrigation before sowing) is most widely used. It allows pre-sowing weed control but reduces sowing time flexibility. Dry sowing, i.e. applying irrigation after sowing, reduces options for weed control but improves water use efficiency and sowing time flexibility. This study evaluated the performance of durum wheat (Triticum durum L.) under conventionally tilled (CTB) and PB with wet and dry sowing in northwestern Mexico. In those four tillage-sowing irrigation environments (ENV), five nitrogen (N) fertilization treatments were tested. Plant stand, grain yield, and grain quality were measured for ten years and fertilizer-based N use efficiency indices were assessed in three years. Plant stand, wheat yield and quality were significantly affected by ENV. The lowest plant stand and yield were found in PB-Dry sowing. On average, only 54 plants m-2 emerged in PB-Dry whereas 159 plants m-2 emerged in CTB-Wet. Plant stand showed high yearly fluctuations, with plant stand in dry sowing favored by lower reference evapotranspiration, with CTB-Dry favored more by high minimum temperature and PB-Dry by high maximum temperature. Yield ranged between 4.20 and 7.94 t ha-1. Yield in PB-Dry was on average 0.35 to 0.50 t ha-1 lower than in the remaining ENV, but positive interactions between year and dry sowing systems were associated with high minimum temperatures at germination and tillering. N fertilization management affected wheat quality, but not wheat yield, possibly due to high levels of soil mineral N available at sowing that were not measured in this study. Split application of N increased grain N content compared to basal N application. Research should address reduced plant stands with dry sowing in conservation agriculture to find management options that improve wheat emergence. Further efforts to optimize N fertilizer management in PB are required to improve grain quality components.

Increased agricultural production through both intensification and extensification is a major driver of the current biodiversity crisis. As a response, two contrasting approaches have been advocated: ‘land sparing’, which minimizes demand for farmland by increasing yield, and ‘land sharing’, which boosts densities of wild populations on farmland but decreases agricultural yields. While these approaches have been useful in drawing attention to the impact of meeting the growing global demand for agricultural products on biodiversity, they have been driven mainly by conservation ecologists, and have often overlooked important issues related to farming. As agricultural scientists with practical experience in developing, testing and scaling alternative forms of agriculture in some of the most biodiversity-rich areas of Latin America, Eastern and Southern Africa and South Asia, we are pointing in this paper at what we see as being two major limitations of the land sparing/sharing framework: (1) the reliance on yield-density relationships that focus on trade-offs and overlook synergies between agriculture and biodiversity, and (2) the overemphasis on crop yield, neglecting other metrics of agricultural performance which may be more important to local farmers, and more strongly associated with positive biodiversity outcomes. It is our hope that this paper will stimulate other agricultural scientists to contribute to the land sparing/sharing framework, in order to develop together with conservation ecologists viable solutions for both improved agricultural production and biodiversity conservation.

Conservation Agriculture (CA) is promoted by research and development (R&amp, D) agencies to sustainably intensify agricultural systems with the goals of improving food security and livelihoods and adapting food systems to global climate change. Despite the many benefits of CA, there are few farmers around the world that have simultaneously implemented all facets of the strategy. In part, this reflects the challenges in applying, adapting, and understanding this complex and multi-dimensional agricultural innovation in the context of diverse farming systems. In this paper, we applied an integrated framework that combines bioeconomic simulation, risk analysis, adoption theory, and impact assessment to investigate how various combinations of CA components (no-tillage, soil cover, crop diversification, plus growing a new crop or variety) performed over a 10-year period in representative farms in a central Mexican case study. We found significant differences in profit, net value, downside risk, and risk-aversion cost between double-component scenarios (and improved CA to a lesser extent) and all other scenarios, which suggested that disaggregating CA into smaller component packages could increase farmer adoption in risky contexts. Our findings provided valuable insights on CA feasibility and could help establish policy and reporting metrics. The study highlighted the need for employing a range of research tools to understand the relative value of agricultural innovations and to identify and reduce trade-offs and uncertainty in farming systems.

Agri-food systems are besieged by malnutrition, yield gaps, and climate vulnerability, but integrated, research-based responses in public policy, agricultural, value chains, and finance are constrained by short-termism and zero sum thinking. As they respond to current and emerging agri-food system challenges, decision makers need new tools that steer toward multi-sector, evidence-based collaboration. To support national agri-food system policy processes, the Integrated Agri-food System Initiative (IASI) methodology was developed and validated through case studies in Mexico and Colombia. This holistic, multi-sector methodology builds on diverse existing data resources and leverages situation analysis, modeled predictions, and scenarios to synchronize public and private action at the national level toward sustainable, equitable, and inclusive agri-food systems. Culminating in collectively agreed strategies and multi-partner tactical plans, the IASI methodology enabled a multi-level systems approach by mobilizing design thinking to foster mindset shifts and stakeholder consensus on sustainable and scalable innovations that respond to real-time dynamics in complex agri-food systems. To build capacity for these types of integrated, context-specific approaches, greater investment is needed in supportive international institutions that function as trusted in-region ‘innovation brokers.’ This paper calls for a structured global network to advance adaptation and evolution of essential tools like the IASI methodology in support of the One CGIAR mandate and in service of positive agri-food systems transformation.

Agricultural practices, such as crop residue management and tillage, change biological, physical and chemical soil characteristics. The aim of this study was to investigate the effect of the application of bean plant residue (Phaseolus vulgaris L.), one of the major crops in Mexico, on the bacterial community structure in soil cultivated conventionally (conventional beds, CB) or under a conservation agriculture system (permanent beds, PB) and compared it to the effect of maize plant residue application. Soil samples were incubated aerobically at ambient temperature (22 ± 2 °C) for 56 days. The bacterial community in the unamended PB soil was significantly different from that in the unamended CB soil, e.g. Acidobacteria, PB > CB, while Actinobacteria PB

The importance of building/maintaining soil carbon, for soil health and CO2 mitigation, is of increasing interest to a wide audience, including policymakers, NGOs and land managers. Integral to any approaches to promote carbon sequestering practices in managed soils are reliable, accurate and cost-effective means to quantify soil C stock changes and forecast soil C responses to different management, climate and edaphic conditions. While technology to accurately measure soil C concentrations and stocks has been in use for decades, many challenges to routine, cost-effective soil C quantification remain, including large spatial variability, low signal-to-noise and often high cost and standardization issues for direct measurement with destructive sampling. Models, empirical and process-based, may provide a cost-effective and practical means for soil C quantification to support C sequestration policies. Examples are described of how soil science and soil C quantification methods are being used to support domestic climate change policies to promote soil C sequestration on agricultural lands (cropland and grazing land) at national and provincial levels in Australia and Canada. Finally, a quantification system is outlined – consisting of well-integrated data-model frameworks, supported by expanded measurement and monitoring networks, remote sensing and crowd-sourcing of management activity data – that could comprise the core of a new global soil information system.

Searching for sustainable cropping systems has often focused on the optimization of system sustainability, yield or ideally both. It is important to also include wheat quality characteristics like grain protein concentration (GPC) and bread-making quality (loaf volume). The effect of placement and timing of nitrogen (N) fertilizer on performance and quality of the bread wheat cultivar Navojoa, was tested in two tillage systems under furrow irrigation: conventionally tilled beds (CTB; new beds formed after disc ploughing and residue incorporation) and permanent beds (PB; only furrows reshaped and residues retained on the surface). N fertilizer (120 kg N ha−1 as urea) was broadcast, applied in furrows or disk-banded on top of beds. The timing treatments were all fertilizer applied before planting or split between pre-planting and first node. Permanent beds had the highest yield and grain quality was highest with split bed and furrow application. Averaged over four years, N use efficiency and GPC were significantly higher in CTB (24.5 kg kg−1 and 10.1 %, respectively) than in PB (22.2 kg kg−1 and 9.9 %, respectively) indicating the necessity in PB for optimal N management to obtain stable yields and acceptable grain quality. A reduced number of cold hours and solar radiation negatively affected grain yield. Broadcast fertilizer application reduced grain quality and N use efficiency. N fertilizer management in furrow-irrigated wheat cropping systems should combine splitting the N dose and disking it on the bed pre-planting and in the furrow later in the season, depending on the crop needs at the application time.

Water infiltration, soil carbon content, aggregate stability and yields increased in conservation agriculture practices compared to conventionally ploughed control treatments at the Henderson research station near Mazowe (Zimbabwe). How these changes in soil characteristics affect the bacterial community structure and the bacteria involved in the degradation of applied organic material remains unanswered. Soil was sampled from three agricultural systems at Henderson, i.e. (1) conventional mouldboard ploughing with continuous maize (conventional tillage), (2) direct seeding with a Fitarelli jab planter and continuous maize (direct seeding with continuous maize) and (3) direct seeding with a Fitarelli jab planter with rotation of maize sunn hemp (direct seeding with crop rotation). Soil was amended with young maize plants or their neutral detergent fibre (NDF) and incubated aerobically for 56 days, while C and N mineralization and the bacterial community structure were monitored. Bacillus (Bacillales), Micrococcaceae (Actinomycetales) and phylotypes belonging to the Pseudomonadales were first degraders of the applied maize plants. At day 3, Streptomyces (Actinomycetales), Chitinophagaceae ([Saprospirales]) and Dyella (Xanthomonadales) participated in the degradation of the applied maize and at day 7 Oxalobacteraceae (Burkholderiales). Phylotypes belonging to Halomonas (Oceanospirillales) were the first degraders of NDF and were replaced by Phenylobacterium (Caulobacterales) and phylotypes belonging to Pseudomonadales at day 3. Afterwards, similar bacterial groups were favoured by application of NDF as they were by the application of maize plants, but there were also clear differences. Phylotypes belonging to the Micrococcaceae and Bacillus did not participate in the degradation of NDF or its metabolic products, while phylotypes belonging to the Acidobacteriaceae participated in the degradation of NDF but not in that of maize plants. It was found that agricultural practices had a limited effect on the bacterial community structure, but application of organic material altered it substantially.

Conservation agriculture (CA) encompasses three principles: reduced tillage, residue retention, and crop rotation, and is thought to hold great potential for improving soil function and maintaining long-term productivity in agricultural systems. However, the benefits of CA likely depend on the biophysical and socioeconomic context in which CA technologies are implemented and whether or not all components of CA are in place. To better understand the effect of key CA components on soil quality and nutrient use efficiency, an on-farm field trial was conducted during the second year of an irrigated field experiment in Chiapas, Mexico. The experiment included two levels each of tillage and residue management in a full factorial design (three replicates each) with the following treatments: 1) conventional tillage with crop residue; 2) conventional tillage without crop residue; 3) zero tillage with crop residue; and 4) zero tillage without crop residue. In each replicate plot (8 × 20 m) a 15N labeled microplot (0.95 × 0.93 m) was established and fertilized according to standard rates. Mid-season soil samples were analyzed for total and available (Bray) P, as well as microbial community composition using phospholipid fatty acid (PLFA) analysis. Crop yield, nutrient uptake, and aggregate-associated soil organic matter were evaluated at harvest. Crop residue retention led to small increases in aggregate stability and greater fungal PLFA. The retention of crop residues also resulted in a 110% increase in the recovery of fertilizer-derived N in vegetative biomass, leading to a marginally significant increase of 41% for total recovery of fertilizer N in the soil-crop system. Effects of tillage were less prominent, but conventional tillage was found to improve mid-season available P by roughly 60%. These results indicate that CA technologies, residue retention in particular, offer a promising set of options for farmers to improve soil functioning and reduce fertilizer-N losses, particularly for sandy soils within sub-humid tropical regions.

As a system of practices involving crop rotations, reduced soil disturbance, and the retention of organic matter at the soil surface, conservation agriculture (CA) increases soil quality, reduces erosion, and provides a favorable habitat for beneficial soil-dwelling organisms which may provide improved pest control. To determine the effect of CA on generalist arthropod predators and pests, we assessed the ground-dwelling arthropod assemblage prior to crop planting and shortly after crop emergence in a long-term CA trial at the International Maize and Wheat Improvement Center (CIMMYT) in central Mexico. We used pitfall traps and in-field sentinel insect assay arenas to evaluate arthropod activity-density and predation, respectively, in a maize–wheat rotation, planted under CA (zero tillage, retention of residues) and conventional agriculture (tillage and no surface residue). In maize, activity-density of generalist predators (excluding ants) was higher in conventional agriculture treatments than in CA treatments prior to crop planting ( P = 0.03), but no significant differences were apparent in arthropod activity-densities at the treatment level at any other time. In multivariate analyses, the arthropod community was affected by tillage in maize at both sampling dates ( P ≤ 0.05), and by residue after crop emergence in wheat ( P = 0.03). Spiders trended toward a greater association with no-till treatments in maize and treatments with residue retained in wheat. In wheat, predation (biological control potential) was significantly lower in conventional compared with CA treatments ( P ≤ 0.05). According to multiple linear regressions, higher levels of soil cover significantly explained predation before and after planting in maize, and before planting in wheat ( P ≤ 0.05). Our results indicate that the type and amount of residue that remains at the soil surface may influence arthropod community dynamics. This first report of the effects of CA on arthropods in this long-term trial indicates that CA in central Mexico may contribute to conservation of certain arthropod predators and biological control of insect pests.

AIMS In this study, the species indicator test was used to identify key bacterial taxa affected by changes in the soil environment as a result of conservation agriculture or conventional practices. METHODS AND RESULTS Soils cultivated with wheat (Triticum spp. L.) and maize (Zea mays L.) under different raised bed planting systems for 20 years, that is, varying crop residue and fertilizer management, were used. Taxonomic- and divergence-based 16S-metagenomics, and IndVal analysis were used to study the bacterial communities and identify indicator taxa (genus and OTU97 ) affected by agricultural practices. Although, some phyla were affected significantly by different treatments, the taxonomic assemblages at phylum level were similar. Bacterial taxa related to different processes of the N-cycle were indicators of different fertilization rates, for example, Azorhizobium, Nostoc and Nitrosomonas. A large number of OTU97 were indicators for conventionally tilled beds and their distribution was defined by soil organic carbon. IndVal analysis identified different taxa in each of the residue management systems. This suggests that although the same organic material remains in the field, crop residue management affects specific taxa. The taxa indicator of the burned residues belonged mainly to the order SBR1031 (Anaerolineae, Chloroflexi), and the genera Bacillus and Alicyclobacillus. CONCLUSIONS N-fertilizer application rates affected N-cycling taxa. Tillage affected Actinobacteria members and organic matter decomposers. Although the same crop residue was retained in the field, organic material management was important for specific taxa. SIGNIFICANCE AND IMPACT OF THE STUDY In this study, we report that agricultural practice affected soil bacterial communities. We also identified distinctive taxa and related their distribution to changes in the soil environment resulting from different agricultural practices.

Weed management is one of the main challenges of conservation agriculture. Although all three components of conservation agriculture (minimal tillage, permanent soil cover and crop diversification) can reduce weed populations, these effects may only become apparent in the medium to long term. This study evaluated weed biomass, density and diversity with and without herbicide control in a long-term trial initiated in 1991 in the Mexican Highlands to evaluate all three components of conservation agriculture. Data were collected in 2004, 2005, 2013, 2014 and 2015. Weed density and biomass were generally lower in conservation agriculture than with conventional tillage. The three components of conservation agriculture significantly reduced weed biomass, which was lower when all three components were applied together. When herbicides were applied, weed biomass in conservation agriculture was 91% lower in maize and 81% lower in wheat than in conventional tillage. Different treatments favored different weed species, but no trend toward increased perennial weeds was observed in conservation agriculture. These data supported claims stating that if adequate weed control is achieved in the initial years, weed populations in conservation agriculture systems are lower than in conventional tillage systems.

The combination of zero tillage (ZT) and crop residue retention can substantially improve soil structure and reduce the risk of erosion. Growing conditions for crops are substantially altered in such systems and the question whether specific varieties adapted to ZT conditions need to be developed is not answered. Most published research assessed Genotype by Tillage interactions, which are rarely significant, using genotypes generally developed under CT conditions. CIMMYT’s durum wheat breeding program went beyond this approach and performed parallel early generation selection within 16 crosses both in conventional tilled (CT) and ZT soils with the aim of comparing the effect of selection environment (either CT or ZT) on the performance of selected progenies. From 16 initial crosses, 234 lines were selected under CT and 250 under ZT. All 484 lines were subsequently tested for yield and growth traits during three seasons near Ciudad Obregon, Sonora, Mexico in three different testing environments. Those included ZT and CT with full irrigation and CT with reduced irrigation. Early vegetative growth was slightly improved with selection under ZT in all testing environments. Grain yield was highest in ZT testing environment, with a very small average difference in 2013 (0.11 t ha-1) and larger differences in 2014 (0.65 t ha-1) and 2015 (0.42 t ha-1). The differences between selection streams observed for yield were marginal and in most cases not significant. We conclude that, within the germplasm pool handled in CIMMYT’s durum wheat breeding program, selection can be conducted under either tillage conditions without affecting negatively the performance of resulting progenies. The neutrality of selection under ZT in relation to performance of progenies is a likely hypothesis that should be tested in other ZT conditions and germplasm pool combinations.

Traditional agricultural extension services rely on extension workers, especially in countries with large agricultural areas. In order to increase adoption of sustainable agriculture, the recommendations given by such services must be adapted to local conditions and be provided in a timely manner. The AgroTutor mobile application was built to provide highly specific and timely agricultural recommendations to farmers across Mexico and complement the work of extension agents. At the same time, AgroTutor provides direct contributions to the United Nations Sustainable Development Goals, either by advancing their implementation or providing local data systems to measure and monitor specific indicators such as the proportion of agricultural area under productive and sustainable agriculture. The application is freely available and allows farmers to geo-locate and register plots and the crops grown there, using the phone’s built-in GPS, or alternatively, on top of very high-resolution imagery. Once a crop and some basic data such as planting date and cultivar type have been registered, the application provides targeted information such as weather, potential and historical yield, financial benchmarking information, data-driven recommendations, and commodity price forecasts. Farmers are also encouraged to contribute in-situ information, e.g., soils, management, and yield data. The information can then be used by crop models, which, in turn, send tailored results back to the farmers. Initial feedback from farmers and extension agents has already improved some of the application’s characteristics. More enhancements are planned for inclusion in the future to increase the application’s function as a decision support tool.

Conservation agriculture (CA) is based on minimum soil disturbance, permanent soil cover, and crop rotation; it is promoted as a sustainable alternative to systems involving conventional tillage. Adoption of CA changes weed dynamics and communities and therefore necessitates adjusting weed control methods. The objectives of this review are to summarize literature concerning CA principles and their interactive effects on weed life cycles and community composition, briefly review CA-appropriate cultural practices for additional weed control, and identify areas where further research is needed. No-till systems accumulate seeds near the soil surface where they are more likely to germinate but are also exposed to greater mortality risks through weather variability and predation. Assuming no seed input into the system, germinable seedbanks under no-till decrease more rapidly than under conventional tillage. Reducing tillage may shift weed communities from annual dicots to grassy annuals and perennials. Surface residues lower average soil temperatures and may delay emergence of both crops and weeds. Germination and growth of small-seeded annuals will suffer from restricted light availability, physical growth barriers and potential allelopathic effects from surface residue. Crop rotation affects weeds via allelopathy and altered timing of both crop management and resource demands. Rotations should incorporate crops sown in varied seasons (e.g., autumn and spring), annuals and perennials, different herbicides, and/or various crop families. Literature indicates implementing no-till without crop rotation can result in severe weed problems; greater rotational crop diversity results in easier weed management. Additional cultural practices for CA include: (i) selecting highly competitive varieties; (ii) altering planting dates; (iii) preventing weed seed recruitment; (iv) adjusting planting arrangement, densities, and fertilizer placement; and (v) microbial bio-controls. Further research is needed concerning: (i) the interactive effects of tillage and surface residue on weeds; (ii) the use of models and/or meta-analyses to predict weed responses, and to identify intervention points in CA; and (iii) the weed-suppressive potential of longer (4+ years) rotations.

Agricultural practices affect the bacterial community structure in soil. It was hypothesized that agricultural practices would also affect the bacteria involved in the degradation of crop residue. Soil was sampled from four different agricultural practices, i.e. conventional agriculture on the flat or on beds, or conservation agriculture on the flat or on beds. Cultivating crops on the flat is done traditionally, but cultivating crops on beds was introduced so as to avoid water logging during the rainy season and its potential negative effect on yields. Soil from these four treatments was amended in the laboratory with maize residue (Zea mays L.) or its neutral detergent fibre (NDF) fraction, mostly consisting of (hemi) cellulose, and incubated aerobically for 14 days. Maize residue was applied to soil as it is left in the field in conservation agriculture and NDF was added to study which bacteria were favoured by application of (hemi) cellulose. Soil was incubated aerobically while the carbon mineralization and the bacterial population were monitored. On the one hand, the relative abundance of phylotypes belonging to bacterial groups that preferred low nutrient environments was higher in soil with conservation agriculture (e.g. Acidobacteria 17.6%, Planctomycetes 1.7% and Verrucomicrobia 1.5%) compared to conventional practices (Acidobacteria 11.8%, Planctomycetes 0.9% and Verrucomicrobia 0.4%). On the other hand, the relative abundance of phylotypes belonging to bacterial groups that preferred nutrient rich environments, such as Actinobacteria, showed an opposite trend. It was 11.9% in conservation agriculture and 16.2% in conventional practices. The relative abundance of Arthrobacter (Actinobacteria) and Bacillales more than doubled when maize residue was applied to soil compared to the unamended soil and that of Actinomycetales when maize or NDF was applied. Application of organic material reduced the relative abundance of a wide range of bacterial groups, e.g. Acidobacteria, Bacteroidetes, Planctomycetes and Verrucomicrobia. It was found that application of organic material favoured the same bacterial groups that were more abundant in the soil cultivated conventionally while it reduced those that were favoured in conservation agriculture.