ALBERT

Description: Agrivoltaic (AV) systems integrate the production of agricultural crops and electric power on the same land area through the installation of solar panels several meters above the soil surface. It has been demonstrated that AV can increase land productivity and contribute to the expansion of renewable energy production. Its utilization is expected to affect crop production by altering microclimatic conditions but has so far hardly been investigated. The present study aimed to determine for the first time how changes in microclimatic conditions through AV affect selected agricultural crops within an organic crop rotation. For this purpose, an AV research plant was installed near Lake Constance in south-west Germany in 2016. A field experiment was established with four crops (celeriac, winter wheat, potato and grass-clover) cultivated both underneath the AV system and on an adjacent reference site without solar panels. Microclimatic parameters, crop development and harvestable yields were monitored in 2017 and 2018. Overall, an alteration in microclimatic conditions and crop production under AV was confirmed. Photosynthetic active radiation was on average reduced by about 30% under AV. During summertime, soil temperature was decreased under AV in both years. Furthermore, reduced soil moisture and air temperatures as well as an altered rain distribution have been found under AV. In both years, plant height of all crops was increased under AV. In 2017 and 2018, yield ranges of the crops cultivated under AV compared to the reference site were −19 to +3% for winter wheat, −20 to +11% for potato and −8 to −5% for grass-clover. In the hot, dry summer 2018, crop yields of winter wheat and potato were increased by AV by 2.7% and 11%, respectively. These findings show that yield reductions under AV are likely, but under hot and dry weather conditions, growing conditions can become favorable.

Description: In the face of a changing climate, yield stability is becoming increasingly important for farmers and breeders. Long-term field experiments (LTEs) generate data sets that allow the quantification of stability for different agronomic treatments. However, there are no commonly accepted guidelines for assessing yield stability in LTEs. The large diversity of options impedes comparability of results and reduces confidence in conclusions. Here, we review and provide guidance for the most commonly encountered methodological issues when analysing yield stability in LTEs. The major points we recommend and discuss in individual sections are the following: researchers should (1) make data quality and methodological approaches in the analysis of yield stability from LTEs as transparent as possible; (2) test for and deal with outliers; (3) investigate and include, if present, potentially confounding factors in the statistical model; (4) explore the need for detrending of yield data; (5) account for temporal autocorrelation if necessary; (6) make explicit choice for the stability measures and consider the correlation between some of the measures; (7) consider and account for dependence of stability measures on the mean yield; (8) explore temporal trends of stability; and (9) report standard errors and statistical inference of stability measures where possible. For these issues, we discuss the pros and cons of the various methodological approaches and provide solutions and examples for illustration. We conclude to make ample use of linking up data sets, and to publish data, so that different approaches can be compared by other authors and, finally, consider the impacts of the choice of methods on the results when interpreting results of yield stability analyses. Consistent use of the suggested guidelines and recommendations may provide a basis for robust analyses of yield stability in LTEs and to subsequently design stable cropping systems that are better adapted to a changing climate.

Description: Legume crops hold promise to diversify the currently simplified rotations that dominate Europe and to increase the sustainability of European farming systems. Nevertheless, most legumes have been ignored by farmers, advisors, and value chain agents in the EU, where legumes are estimated to occupy only ~2% of arable land. Recent surveys find that farmers see a lack of knowledge on the agroecological impacts of (re)introducing legumes as a key barrier to legume adoption. A review of current research on the agroecological potential of legume-inclusive cropping systems would help in assessing whether research targeting sufficiently supports farmers in overcoming this barrier. We have systematically reviewed and synthesized published literature reporting on agricultural ecosystem service delivery in European cropping systems with legumes included compared to those without legumes. Our analysis of 163 published articles revealed: (1) the bulk of published research addresses production-related services delivered by few legume species (pea, clover, faba bean, and vetch, 70% of reviewed studies) comparatively assessed in cereal-based rotations; (2) substantial knowledge gaps also exist, encompassing ecosystem services with less direct relevance to economic outcomes (e.g., biodiversity) and with potential for high variability (e.g., pest and disease suppression); (3) studies at plot-level and within-season scales dominate (92% and 75% of reviewed studies, respectively). Assessed in the context of recent complementary studies, we find that a limited research focus is both counter to knowledge demands from farmers and likely the result of self-reinforcing socio-technical regimes which prioritize production over non- or indirectly-marketable ecosystem services. We conclude that scientists in Europe should diversify research to include legume species, ecosystem services, contexts, and scales not yet well studied, in order to provide the agroecological knowledge base farmers need to amplify the potential benefits of crop diversity.

Description: Timely crop planting is a foundation for climate-resilient rice-wheat systems of the Eastern Gangetic Plains—a global food insecurity and poverty hotspot. We hypothesize that the capacity of individual farmers to plant on time varies considerably, shaped by multifaceted enabling factors and constraints that are poorly understood. To address this knowledge gap, two complementary datasets were used to characterize drivers and decision processes that govern the timing of rice planting in this region. The first dataset was a large agricultural management survey (rice-wheat: n = 15,245; of which rice: n = 7597) from a broad geographic region that was analyzed by machine learning methods. The second dataset was a discussion-based survey (n = 112) from a more limited geography that we analyzed with graph theory tools to elicit nuanced information on planting decisions. By combining insights from these methods, we show for the first time that differences in rice planting times are primarily shaped by ecosystem and climate factors while social factors play a prominent secondary role. Monsoon onset, surface and groundwater availability, and land type determine village-scale mean planting times whereas, for resource-constrained farmers who tend to plant later ceteris paribus, planting is further influenced by access to farm machinery, seed, fertilizer, and labor. Also, a critical threshold for economically efficient pumping appears at a groundwater depth of around 4.5 m; below this depth, farmers do not irrigate and delay planting. Without collective action to spread risk through synchronous timely planting, ecosystem factors such as threats posed by pests and wild animals may further deter early planting by individual farmers. Accordingly, we propose a three-pronged strategy that combines targeted strengthening of agricultural input chains, agroadvisory development, and coordinated rice planting and wildlife conservation to support climate-resilient agricultural development in the Eastern Gangetic Plains.

Description: Wheat yields in Ethiopia need to increase considerably to reduce import dependency and keep up with the expected increase in population and dietary changes. Despite the yield progress observed in recent years, wheat yield gaps remain large. Here, we decompose wheat yield gaps in Ethiopia into efficiency, resource, and technology yield gaps and relate those yield gaps to broader farm(ing) systems aspects. To do so, stochastic frontier analysis was applied to a nationally representative panel dataset covering the Meher seasons of 2009 and 2013 and crop modelling was used to simulate the water-limited yield (Yw) in the same years. Farming systems analysis was conducted to describe crop area shares and the availability of land, labour, and capital in contrasting administrative zones. Wheat yield in farmers’ fields averaged 1.9 t ha− 1 corresponding to ca. 20% of Yw. Most of the yield gap was attributed to the technology yield gap (〉 50% of Yw) but narrowing efficiency (ca. 10% of Yw) and resource yield gaps (ca. 15% of Yw) with current technologies can nearly double actual yields and contribute to achieve wheat self-sufficiency in Ethiopia. There were small differences in the relative contribution of the intermediate yield gaps to the overall yield gap across agro-ecological zones, administrative zones, and farming systems. At farm level, oxen ownership was positively associated with the wheat cultivated area in zones with relatively large cultivated areas per household (West Arsi and North Showa) while no relationship was found between oxen ownership and the amount of inputs used per hectare of wheat in the zones studied. This is the first thorough yield gap decomposition for wheat in Ethiopia and our results suggest government policies aiming to increase wheat production should prioritise accessibility and affordability of inputs and dissemination of technologies that allow for precise use of these inputs.

Description: Livestock farming occupies 57% of agricultural area in France and has contrasting impacts on the environment. Studies have analyzed relations between livestock farming and soil organic carbon (SOC) content, but the influence of livestock farming on soils is difficult to perceive at a large scale. The objective of this study was to increase understanding of impacts of livestock farming on soils that receive livestock manure depending on different initial levels of SOC content, at cantonal level. To this end, we used French soil and agricultural databases to analyze relations between livestock farming practices and SOC content. We used statistical data calculated from the French soil test database for the periods 2000–2004 and 2010–2014. For livestock farming practices, we used data from the French agricultural census of 2000 and 2010, and for spreading of livestock manure, data from the French program to control pollution of agricultural origin (2002–2007) and data from the French Livestock Institute. The novelty of our large-scale analysis is to differentiate the origin of livestock manure (herbivore or granivore) and the type of crop on which it was spread (crops or grasslands). Statistical analysis was performed at the cantonal scale for France using the method of generalized least squares. We show for the first time that, at the national scale, spreading of livestock manure influences SOC content and dynamics significantly. Our results also show the importance of the nature of the manure; solid manure increases SOC content, unlike liquid manure. Spreading herbivore manure on crops increases SOC content, but spreading granivore manure may decrease it. Livestock manure spread on grasslands has no significant effect on SOC content, possibly due to under-representation of grassland soils in the soil database. These results demonstrate the importance of the complementary between crop and livestock to maintain soil ecosystem services, including soil fertility.

Description: Conservation agriculture has been promoted to sustainably intensify food production in smallholder farming systems in southern Africa. However, farmers have rarely fully implemented all its components, resulting in different combinations of no-tillage, crop rotation, and permanent soil cover being practiced, thus resulting in variable yield responses depending on climatic and soil conditions. Therefore, it is crucial to assess the effect of conservation agriculture components on yield stability. We hypothesized that the use of all three conservation agriculture components would perform the best, resulting in more stable production in all environments. We evaluated at, eight trial locations across southern Africa, how partial and full implementation of these components affected crop yield and yield stability compared with conventional tillage alone or combined with mulching and/or crop rotation. Grain yield and shoot biomass of maize and cowpea were recorded along with precipitation for 2 to 5 years. Across different environments, the addition of crop rotation and mulch to no-tillage increased maize grain by 6%, and the same practices added to conventional tillage led to 13% yield increase. Conversely, adding only mulch or crop rotation to no-tillage or conventional tillage led to lower or equal maize yield. Stability analyses based on Shukla’s index showed for the first time that the most stable systems are those in which mulch is added without crop rotation. Moreover, the highest yielding systems were the least stable. Finally, additive main effects and multiplicative interaction analysis allowed clarifying that mulch added to no-tillage gives stable yields on sandy soil with high rainfall. Similarly, mulch added to conventional tillage gives stable yield on sandy soil, but under low rainfall. This is the first study that highlighted the crucial role of mulch to enhance the stability and resilience of cropping systems in southern Africa, supporting their adaptability to climate change.

Description: Thanks to their low fertilization requirements and high consumer demand, ancient wheats and old durum wheat cultivars represent an attractive option for the marginal areas of Mediterranean environments no longer cultivated due to the low grain yields attainable using modern wheat cultivars. Dual-purpose utilization may increase their value in these cropping systems, but no information is available on the suitability of ancient wheat species to this type of utilization. To fill this gap, Khorasan, einkorn, and emmer wheats, clipped at the terminal spikelet stage or left unclipped, were compared in a two-year field trial. The grains were sown in the month of October, in Sardinia (41°N, 80 m asl), Italy, on low-fertility soils and with low-medium fertilization rates. Einkorn cultivars produced the highest biomass yield (2–3 t ha−1), reflecting the longer time to the onset of the terminal spikelet stage (119–138 days). After clipping, all species recovered their ability to intercept radiation to the levels of the unclipped crops, but clipping lowered their radiation use-efficiency. Grain yield was not penalized by clipping: the increase in the harvest index compensated for the decrease in biomass. Here we show for the first time that ancient wheat species are suitable for dual-purpose utilization (herbage plus grain in the same season) rendering them valuable for marginal areas; this was because the early sowing adopted for dual-purpose utilization allowed them to take full advantage of their lateness in terms of herbage yield, and to bring flowering forward (i.e. make it earlier) so that a satisfactory grain yield was obtained, even under severe water stress. Dual-purpose utilization of ancient wheats increases the sustainability of mixed cropping systems, by making herbage available to animals in a critical period, without decreasing the grain yield attainable after grazing in the same season.

Description: Africa’s need to double food production and feed the burgeoning human population, without compromising its natural resource base, has raised the momentum for sustainable agricultural intensification on the continent. Many studies describe agronomic practices that can increase productivity on existing agricultural land without damaging the environment and without increasing the agricultural carbon footprint. However, there is limited information on specific practices with the greatest potential to contribute to sustainable intensification on smallholder farms in sub-Saharan Africa, while simultaneously keeping the carbon footprint low. The objectives of this review were to (1) identify good agronomic practices with potential for contributing to sustainable intensification across sub-Saharan Africa, (2) synthesize available information on benefits and synergies from these technologies, and (3) discuss bottlenecks in their adoption in order to obtain insights that inform the formulation of supportive policies. Agroforestry, cereal-legume intercropping, conservation agriculture, doubled-up legume cropping, fertilizer micro-dosing, planting basins, and push-pull technology were identified as key agronomic innovations widely promoted in sub-Saharan Africa. We show that these innovations can build synergies and increase resource use efficiency while reducing agricultural carbon footprint. We outline the benefits, trade-offs, and limitations of these practices and discuss their potential role in strengthening food sovereignty and climate change adaptation and mitigation.

Description: The sustainability of agriculture is questioned due to major negative environmental and socioeconomic impacts. To improve the state of agriculture, various management changes have been proposed. Different tools, with varying characteristics, sustainability framing and indicators, have been used to evaluate the impact of these changes on sustainability. Here, we review 119 tools for farm sustainability assessment and compare their use, sustainability dimensions, themes and types of indicators used for biodiversity conservation, farm viability and gender equity. Our main findings are that (1) tools could be classified into five groups that differ in stakeholder participation and model used for calculating sustainability, (2) seven different sustainability framings are used and (3) only two out of 29 indicators screened address impacts of farming system while the others address drivers, pressures or states of the system. The tools were grouped in “Long-term monitoring of farm activities” (11%), “Ex-ante assessment of sustainability with bioeconomic models” (9%), “Survey- and indicator-based assessment of tools” (41%), “Consultation-based assessment” (25%) and “Active engagement of stakeholder-based assessment” (14%). The “classical view of sustainability”, with the economic, social and environmental pillars, was used in 61% of the papers. Based on these findings, we suggest (1) development of temporal dynamic assessment of farm sustainability with active involvement of stakeholders in the framing of sustainability and design of indicators to achieve reliable and relevant assessment outcomes. We recommend (2) adoption of more complex sustainability framings dealing with emerging system properties, namely resilience, viability and stability. In these, (3) governance/institutional dimensions should be emphasised, and social themes targeting farmers’ characteristics should be included. Finally, (4) use of impact indicators in farm sustainability assessments is critical, and they should be designed to contribute to scientifically rigorous and relevant assessments of farming system sustainability.

Description: Yield gaps between organic and conventional agriculture raise concerns about future agricultural systems which should reduce external inputs and face an unpredictable climate. In the UK, the performance gap is especially severe for wheat that, as a result, has a small and shrinking organic acreage. In organic wheat production, most determinants of crop performance are managed at a rotation level, which leaves cultivar choice as the major decision on a seasonal basis. Yet, conventionally generated cultivar recommendations might be inappropriate to organic farms. Furthermore, uncertainty about field-scale crop performance hinders positive developments of the supply chain of organic grains and seeds. Here, we present a field-scale evaluation of winter wheat cultivars, integrated with an agronomic crop performance survey, across a network of organic farms. The relation between crop performance and climatic patterns is explored, to capitalise past growing seasons in cultivar and management decisions on-farm. Grain yield and grain protein content were linked by a dual relation, positive across environments and negative across cultivars. Feed-grade cultivars showed a relatively high yield (4.5–5.5 t/ha) but low protein (8.5–9.3%), whereas breadmaking and historic cultivars showed higher protein (10.4–11.1%) and lower yields (3.5–4.0 t/ha). Historic phenotypes showed better weed suppressive ability than modern ones, without trade-offs with yield or quality. Multiple regressions showed that weed abundance at wheat anthesis was the main yield predictor. The effects of two different post-emergence weed management strategies were observed. Farms relying on interrow hoeing showed lower weed abundance, but a higher relative abundance of the dominant species than that of those relying on spring tine harrowing. Future wheat breeding and cultivar testing should account for crop-weed relations, weed management strategies and their effects on nutrient use efficiency. Further data collection can inform plant breeding on critical traits for low-input farming and shed light on cultivar-environment-management interactions.

Description: Plant breeders’ knowledge of precise traits preferred by variety users would accelerate varietal turnover and widen adoption of newly developed maize varieties in Ghana. The objective of this research was to provide empirical evidence of trait preferences of farmers and other actors in the maize value chain in northern Ghana, based on which research strategies for maize improvement could be formulated. Participatory rural appraisal was conducted in 2016 to determine key traits preferred by maize value chain actors across the three regions in northern Ghana. A total of 279 maize value chain actors were interviewed. Different scoring and ranking techniques were used to assess the maize traits preferred by the different actors. Participatory variety selection trials were also conducted in the Tolon, West Gonja, Binduri, and Sissala East districts in northern Ghana from 2014 to 2016. The mother-baby trial approach was used to evaluate eight hybrids with 3000 farmers. Data on yield and agronomic performance of the hybrids and farmer’s selection criteria were collected. Data analyses were performed using GenStat Edition 16 and SPSS Edition 20 statistical packages. The participatory rural appraisal method identified farmers, input dealers, traders, and processors as the primary maize value chain actors in the study areas. Trait preferences of the different actors overlapped and revolved around grain quality including nutritional value, and stress tolerance and grain yield. Results of the participatory variety selection study revealed that across districts, farmers preferred high-yielding varieties with multiple cobs per plant, white grain endosperm color, and bigger and fully filled cobs. For the first time, our holistic assessment of the trait preferences of key actors of the maize value chain in northern Ghana revealed a comprehensive list of traits, which could be used by breeders to develop varieties that may be preferred by all value chain actors in northern Ghana.

Description: Diversifying cropping systems by increasing the number of cash and cover crops in crop rotation plays an important role in improving resource use efficiency and in promoting synergy between ecosystem processes. The objective of this study was to understand how the combination of crop diversification practices influences the performance of arable crop sequences in terms of crop grain yield, crop and weed biomass, and nitrogen acquisition in a temperate climate. Two field experiments were carried out. The first was a 3-year crop sequence with cereal or grain legume as the first crops, with and without undersown forage legumes and forage legume-grass crops, followed by a cereal crop. The second experiment was a 2-year crop sequence with cereal or legume as the first crops, a legume cover crop, and a subsequent cereal crop. For the first time, crop diversification practices were combined to identify plant-plant interactions in spatial and temporal scales. The results partly confirm the positive effect of diversifying cereal-based cropping systems by including grain legumes and cover crops in the crop sequence. Legume cover crops had a positive effect on subsequent cereal grain yield in one of the experiments. Using faba beans as the first crop in the crop sequence had both a positive and no effect on crop biomass and N acquisition of the subsequent cereal. In cover crops composed of a forage legume-grass mixture, the grass biomass and N acquisition were consistently increased after the grain legume, compared to the cereal-preceding crop. However, differences in the proportion of legume to grass in mixture did not influence crop yield or N acquisition in the subsequent cereal. In conclusion, these results support that increased crop diversity across spatial and temporal scales can contribute to resource-efficient production and enhance the delivery of services, contributing to more sustainable cropping systems.

Description: Poor soil chemical fertility and climate change restrict pearl millet grain yield in Niger Republic. Apart from the seedball technology, which targets majorly early phosphorus supply to the plants, the recommended practices of mineral fertilization and seed treatments (coating and priming) are barely affordable to the local farmers in particular. In the case of female farmers, who usually have chemically infertile farmlands often located far away from their homestead, low pearl millet grain yield can be exacerbated. In quest for a cheap, affordable, and effective solution, we hypothesized that the application of sanitized human urine (Oga), in combination with organic manure (OM) or solely, increases pearl millet panicle yield in women’s fields and on different local soils. In on-farm large-N trials (N = 681) with women farmers in two regions of Niger (Maradi, Tillabery), pearl millet panicle yields were compared between the control (farmer practice), and a combination of Oga and OM in the first and second year, and Oga alone in the third year. Our results showed an average panicle yield increase of about +30%, representing +200 to +300 kg ha−1. Major factors determining the yield effect are season, village, and local soil type. This study shows for the first time that Oga innovation can be used to increase pearl millet panicle yield particularly in the low fertile soils of women’s farmlands in Niger. Oga innovation is affordable, locally available, and does not pose a risk to resource-poor female farmers of Niger.

Description: The honey bee is an important fruit and vegetable pollinator and a producer of honey and other hive products. Beekeeping is a sustainable and high-potential activity for local communities and especially for the rural poor to gain additional income through non-timber forest products, does not require much land or high starting costs, maintains biodiversity and increases crop yields. Ethiopia is one of the top ten honey and beeswax producers in the world, but plays only a minor role in the international honey trade. Unlike large-scale beekeepers using modern techniques found in most leading honey-producing countries, the majority of Ethiopian beekeepers are small-scale producers practicing traditional beekeeping. In this article, we summarize the knowledge on Ethiopian beekeeping, honey bees, honey bee pests, marketing strategies, cultural aspects and major challenges of beekeeping. Furthermore, we used FAOSTAT data to calculate a pollination gap in order to draw the attention of stakeholders and decision-makers to bees and their importance in pollination and sustainable rural development. In regard to forage, we compiled 590 bee forage plants and their flowering times as a supplement to the article. This review outlines the following major points: (1) Ethiopia is a top honey and beeswax producer mainly for the domestic market; (2) Equipment for traditional beekeeping is easily accessible but brings disadvantages (gender gap, limitations in hive management and lower honey yield), while transitional and modern systems require certain beekeeping skills and higher starting costs; (3) Colony numbers increased by 72% from 1993 to 2018 and crop areas needing pollination by 150%; (4) Honey yield per hive and number of beehives managed per area of bee-pollinated crops increased by 20% and 28%, respectively; (5) Pesticide use has been increasing and there is a lack in pesticide use education. Recommendations to realize Ethiopia’s tremendous apicultural potential are discussed.

Description: Productivity of coffee plantations is threatened by both climate change and decreasing revenues of coffee growers. Using shade trees might protect against temperature variability, erosion and excessive radiation but there may be trade-offs in productivity and quality. While impacts of shade trees on arabica (Coffea arabica) have been reviewed, a global synthesis on robusta (Coffea canephora) coffee is lacking. We assessed how shade affects robusta growth and productivity, and what are the interactions and trade-offs. We conducted a systematic literature search in Web of Science and CAB Abstracts on 16 December 2019. Thirty papers fulfilled our inclusion criteria of being experimental studies on the impact of overstory trees with approximately half being from Brazil or India. Shade improved robusta tree growth and yield with some contrasting effects on physicochemical and biochemical properties. Shade (〉 30%) was associated with reduced beverage quality. Significant interactions between shade and location, rainfall level and robusta clone were found. Among the clones tested, 06V, C153, LB1, GG229 and JM2 showed a higher productivity and growth (from + 17 to + 280%) under moderate shade (41–65%). This is the first meta-analysis of the effects of shade on robusta coffee. By synthesizing data from different studies, we highlight for the first time that the effect of shade on robusta coffee depends on tree age. Shade had positive impacts on older robusta trees (mean of 16 years), while the impact of shade on younger trees was either insignificant or negative. We highlight the importance of both clone type and tree ages. Research gaps included a lack of knowledge on the effects of shade with respect to coffee and shade tree age as well as interactive effects. More in-depth studies are needed to understand the mechanisms of how shade trees affect robusta coffee.

Description: Agricultural mechanization is on the rise in Africa. A widespread replacement of manual labor and animal traction will change the face of African agriculture. Despite this potentially transformative role, only a few studies have looked at the effects of mechanization empirically, mostly focusing on yields and labor alone. This is the first paper that explores perceived agronomic, environmental, and socioeconomic effects together, thereby revealing linkages and trade-offs, some of which have been hitherto unknown. Data were collected using a novel data collection method called “participatory impact diagrams” in four countries: Benin, Kenya, Nigeria, and Mali. In 129 gendered focus group discussions, 1330 respondents from 87 villages shared their perceptions on the positive and negative effects of agricultural mechanization, and developed causal impact chains. The results suggest that mechanization is likely to have more far-reaching agronomic, environmental, and socioeconomic consequences than commonly assumed. Most perceived effects were positive, suggesting that mechanization can help to reduce poverty and enhance food security but other effects were negative such as deforestation, soil erosion, land-use conflicts, and gender inequalities. Accompanying research and policy efforts, which reflect variations in local agro-ecological and socioeconomic conditions, are needed to ensure that mechanization contributes to an African agricultural transformation that is sustainable from a social, economic, and environmental perspective.

Description: Fertilizers are required to improve productivity of cassava and meet the increasing demand for cassava as food, feed, or raw material for processing industries. Our objective was to develop nutrition indices for N, P, and K to provide quantitative insight in the dynamics of nutrient demand and uptake of cassava. On-farm experiments were conducted at six locations in Nigeria from 2016 to 2018, across the major cassava growing agro-ecologies of West Africa. Nitrogen, P, and K were applied at different rates. Uptake of nutrients was measured in leaves, stems, and storage roots at 4, 8, and 12 or 14 months after planting (MAP) and used to construct NPK dilution curves and nutrition indices. About 67, 61, and 52% of total N, P, and K were taken up at 4 MAP, with a maximum uptake rate of 0.21, 0.03, and 0.12 g/m2/d for N, P, and K, respectively. Nutrient concentrations in stems and storage roots declined gradually, in contrast to concentrations in the leaves that fluctuated within narrow ranges. Dilution curves and nutrition indices for N, P, and K were established for the first time in cassava. Dilution curves of N, P, and K in the crop for the highest NPK application treatment were described as Nc = 82DM−0.61, Pc = 7.4DM−0.54, and Kc = 43DM−0.54, when total biomass was between 5 and 57 t/ha dry matter (DM). The nutrition indices were linearly related to relative crop biomass. Insight into the nutrient uptake and dilution patterns during the growth cycle can help to understand the temporal nutrient demands of cassava and identify sustainable management practices. Initial ample supply of N and P and moderate K, with extra K top-dress during the second growth phase, will benefit cassava growth and yield. Furthermore, such information provides a basis to develop a dynamic model to simulate nutrient-limited growth of cassava.

Description: Walnut trees are among the most important hardwood species in the northern hemisphere, ecologically and economically. They are mainly cultivated for timber and nut production but are also attractive ornamental trees in parks. Establishing walnut orchards is difficult because seedlings have a coarse root architecture and few of them survive to transplanting. Planting success is mainly determined by the root system morphology and the nutrient status of the seedlings, so that rhizosphere conditions are critical for plant performance. Walnut trees can associate with soil-borne arbuscular mycorrhizal fungi, which are obligate biotrophs. In this association, plant-produced carbon compounds are traded against fungus-acquired soil mineral nutrients. The beneficial effect of arbuscular mycorrhizal symbiosis on hardwood seedling quality and field performance has long been known, but an integrated view is lacking about the effects of arbuscular mycorrhizas on walnut cropping. Therefore, we surveyed the literature published over the last 40 years to provide up-to-date knowledge on the relationships between arbuscular mycorrhizas and walnut trees. Our review outlines the major following points: (1) the arbuscular-mycorrhiza-mediated nutrient uptake capacity of walnut trees is associated with first- to third-order roots, and fibrous tip-ended roots are dependent on arbuscular mycorrhizal fungi, whereas pioneer roots are not; (2) early inoculation with arbuscular mycorrhizal fungi improves the survival and seedling performance attributes of transplanted walnut trees: biotization enhances walnut transplant success by increasing the number of lateral roots and plant P uptake, but these benefits are fungus- and host-dependent; (3) in the context of walnut agroforestry, deeply rooted walnut trees play a role as reservoirs of arbuscular mycorrhizal fungal propagules for the surrounding vegetation, but tree shade and soluble phosphate availability decrease walnut mycorrhizal dependency; and (4) the arbuscular mycorrhizal mycelium mediates the transport of juglone and thus plays a role in walnut tree allelopathy.

Description: The diversification of cropping systems has the potential to contribute towards a sustainable land use while preserving biodiversity. Mixed cropping is one possibility to increase biodiversity within farming systems. However, adoption of mixed cropping systems is challenging for farmers, as the agricultural sector has evolved around pure stands over the past decades and path dependencies have emerged. Yet, little is known about farmers’ motivation to adopt mixed cropping. Utilizing the theory of planned behavior as the main framework, this paper studies the psychological factors underlying farmers’ intention to adopt mixed cropping based on an online survey with 172 German farmers. In addition, the most crucial adoption obstacles are assessed. Using partial least squares structural equation modeling, we show for the first time that attitude, perceived behavioral control, and injunctive as well as descriptive group norms explain over 52% of farmers’ intention to adopt mixed cropping. Our results also demonstrate that perceived ecological benefits positively influence a farmer’s attitude towards mixed cropping. Missing sales opportunities for mixed yields, the uneven maturing of crops, and deficient economic benefits are ranked as the most crucial obstacles for the implementation of mixed cropping. These results, which can be relevant for other European countries as well, indicate that the introduction of a voluntary agri-environmental scheme could encourage adoption and that considering positive effects of group norms within policy schemes could further increase adoption on a large scale.

Description: Participatory research can improve the efficiency, effectiveness, and scope of research processes, and foster social inclusion, empowerment, and sustainability. Yet despite four decades of agricultural research institutions exploring and developing methods for participatory research, it has never become mainstream in the agricultural technology development cycle. Citizen science promises an innovative approach to participation in research, using the unique facilities of new digital technologies, but its potential in agricultural research participation has not been systematically probed. To this end, we conducted a critical literature review. We found that citizen science opens up four opportunities for creatively reshaping research: (i) new possibilities for interdisciplinary collaboration, (ii) rethinking configurations of socio-computational systems, (iii) research on democratization of science more broadly, and (iv) new accountabilities. Citizen science also brings a fresh perspective on the barriers to institutionalizing participation in the agricultural sciences. Specifically, we show how citizen science can reconfigure cost-motivation-accountability combinations using digital tools, open up a larger conceptual space of experimentation, and stimulate new collaborations. With appropriate and persistent institutional support and investment, citizen science can therefore have a lasting impact on how agricultural science engages with farming communities and wider society, and more fully realize the promises of participation.

Description: There is consensus that the global food system is not delivering good nutrition for all and is causing environmental degradation and loss of biodiversity, such that a profound transformation is needed to meet the challenges of persistent malnutrition and rural poverty, aggravated by the growing consequences of climate change. Agroecological approaches have gained prominence in scientific, agricultural and political discourse in recent years, suggesting pathways to transform agricultural and food systems that address these issues. Here we present an extensive literature review of concepts, definitions and principles of agroecology, and their historical evolution, considering the three manifestations of agroecology as a science, a set of practices and a social movement; and relate them to the recent dialogue establishing a set of ten iconic elements of agroecology that have emerged from a global multi-stakeholder consultation and synthesis process. Based on this, a consolidated list of principles is developed and discussed in the context of presenting transition pathways to more sustainable food systems. The major outcomes of this paper are as follows. (1) Definition of 13 consolidated agroecological principles: recycling; input reduction; soil health; animal health; biodiversity; synergy; economic diversification; co-creation of knowledge; social values and diets; fairness; connectivity; land and natural resource governance; participation. (2) Confirmation that these principles are well aligned and complementary to the 10 elements of agroecology developed by FAO but articulate requirements of soil and animal health more explicitly and distinguish between biodiversity and economic diversification. (3) Clarification that application of these generic principles can generate diverse pathways for incremental and transformational change towards more sustainable farming and food systems. (4) Identification of four key entry points associated with the elements: diversity; circular and solidarity economy; co-creation and sharing of knowledge; and, responsible governance to enable plausible pathways of transformative change towards sustainable agriculture and food systems.

Description: 〈h3〉Abstract〈/h3〉 〈p〉Homemade botanical insecticides are widely used by subsistence and transitional farmers in low-income countries. Their use is often driven by the limited availability or cost of commercial pesticides. Homemade botanical insecticides are often recommended by agricultural extension services and some development organizations. However, this could be questioned because scientific evidence of their efficacy and safety may not be available or accessible. Although botanicals with insecticidal properties have been widely studied, a synthesis focusing specifically on homemade preparations used in realistic field or storage conditions is missing. In this paper, we review efficacy assessments of botanicals used to prepare homemade insecticides. This covers twelve botanicals recommended by national extension partners in 20 countries within the global agricultural Plantwise program. These are as follows: garlic (〈em〉Allium sativum〈/em〉), neem (〈em〉Azadirachta indica〈/em〉), chili pepper (〈em〉Capsicum〈/em〉 spp.), Siam weed (〈em〉Chromolaena odorata〈/em〉), mother of cocoa (〈em〉Gliricidia sepium〈/em〉), chinaberry (〈em〉Melia azedarach〈/em〉), moringa (〈em〉Moringa oleifera〈/em〉), tobacco (〈em〉Nicotiana tabacum〈/em〉), clove basil (〈em〉Ocimum gratissimum〈/em〉), tephrosia (〈em〉Tephrosia vogelii〈/em〉), tree marigold (〈em〉Tithonia diversifolia〈/em〉), and bitter leaf (〈em〉Vernonia amygdalina〈/em〉). This review shows that (1) all the selected botanicals contain active ingredients with insecticidal, antifeedant, or repellent properties, and (2) homemade insecticides based on all the selected botanicals have been used with some success to control pests or prevent damage, although efficacy was variable and often lower than the positive controls (synthetic pesticides). Factors affecting the efficacy of homemade botanical insecticide include variation in active ingredient content and concentration in plant material, as well as variation in the preparation process. In conclusion, there is some evidence that homemade botanical insecticides could contribute to reducing losses in food production. Since further research is needed to better understand their variable efficacy and potential health and environmental risks, those who promote the use of homemade botanical insecticides should also communicate those “unknowns” to the farmers who use such products.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Work is a central concern for sustainable farming systems and rural communities, especially regarding specific issues of the agricultural sector, as the strong decrease in rural employment and the less attractive working conditions. Many articles covering diverse related topics have been published. However, the few studies analyzing the state of worldwide scientific research on work in agriculture give only a fragmented view, since they focus on specialized topics and disciplines. To fill this knowledge gap, the aim of this study was to review the state of research on work in agriculture addressed by the scientific literature, through a bibliometric analysis by country, institution, journal, author, and keywords. Our main finds are that (1) work in agriculture issues is divided into six main research domains: occupational health and safety, labor market and rural employment, labor and farm sustainability, work organization, agricultural policy and agrarian changes, and labor and family farms; (2) these research domains are analyzed by five scientific communities: ergonomics, agricultural economics, livestock farming systems, rural sociology, and agricultural policy; (3) the reference authors, most-cited articles, and main journals were identified for each scientific community; (4) USA, France, and China arise as leaders in the scientific landscape. We show for the first time the characteristics of the main scientific communities worldwide that have performed the most relevant research related to work in agriculture over the past 10 years. This review provides a benchmark for future research on agricultural work-related topics and encourages collaborations between researchers from different scientific communities for interdisciplinary innovation, which support sustainable working conditions in agriculture.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Australia’s farmers are among the most efficient in the world, despite a relatively large gap between potential and achieved water-limited grain yield. With wheat yield gaps typically 〉 1.7 t/ha or 50% of the water-limited yield, it is important to investigate the degree to which this gap may be attributable to (rational) subprofit-maximising input levels in response to risk and risk aversion in many major grain-growing regions, particularly those with lower and more variable rainfall. Here, we use a set of 14 case study sites across the Australian wheatbelt to examine the risk-return profile of several agronomic management practices and show the extent to which the farmers’ risk attitude determines their decision-making. Using a novel profit-risk-utility framework that incorporates crop simulation, probability theory, finance techniques and risk-aversion analysis, we were able to better demonstrate how farmers might select practices that manage economic risk across sites ranging from low to high rainfall. Results varied with risk preference and yield potential. However, there are real opportunities to close the yield gap by adopting non-limiting or near non-limiting nitrogen fertiliser practices and controlling fallow weeds. We show for the first time that yields associated with current best practice can be surpassed for most levels of risk aversion by adopting an emergent practice of optimising the site-specific time of sowing and matching variety to time of sowing. For some sites and risk profiles, the emerging best practice package which includes additional N fertiliser is also profitable under risk. We also propose a modified integrated framework for yield gaps. Here, we distinguish allocative input constrains due to risk aversion from those due to access to resources, and we account for an innovation gap where the current agronomic frontier is shifted upwards by growers successfully, implementing new technologies that are not yet part of current best practice.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Facing the challenge of the ecological transition of agriculture, biodiversity opens new avenues to enhance ecological interactions and reduce chemical input dependency. Designing biodiversity-based agrosystems requires an agroecological approach that combines key principles: exploring a wide range of concepts and solutions, adopting systemic reasoning, implementing a site-specific approach, developing an action-oriented process, and maintaining a continuous improvement dynamic. This type of approach has never been developed to harness mycorrhizal fungi, which are key components of soil biodiversity, because their beneficial action on crops depends on complex and underexploited ecological interactions. At present, mycorrhizae are mainly used through industrial inoculants that fit within the productionist paradigm. To shift toward agroecological approaches, we implemented a methodological framework conceived to better address the design of mycorrhiza-friendly cropping systems by sharing knowledge with farmers in four different study areas (Provence, French Guiana, Guadeloupe, and Martinique). This framework includes participative workshops, a board game, and prospective exercises to collect farmers’ proposals and the factors that prevent from implementing mycorrhiza-friendly cropping systems. We showed that 90% of the farmers proposed alternatives to industrial inoculants, 50% of them adopted systemic reasoning by combining these alternative proposals. Most farmers understood that they were all potential “mycorrhizae producers”. We showed, for the first time through on-farm experiments that valorization of indigenous mycorrhizal fungi strains using a donor plant is an effective practice to increase root colonization before planting (up to a frequency of 95% and an intensity of 32%). Considering the increasing supply of mycorrhizal inoculants and despite the uncertainty of related knowledge, we codesigned innovative practices. Learning communities (technical advisors, high school teachers, etc.) assumed responsibility for continuous improvement in knowledge and practices. Finally, beyond the issue of mycorrhizae, we showed that an agroecological approach could bring stakeholders one step further into the design of biodiversity-based agrosystems.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Ruminant farming systems are questioned for their contribution to climate change and feed-food competition. Here, we analyse the economic and environmental performances of five sheep farming systems optimised in terms of ewe productivity and feeding costs. Systems are located in contrasting biogeographical areas along a gradient of decreasing agronomic potential from Ireland to the French Mediterranean rangelands. Applying a mechanistic model of flock and farm operation management to evaluate these five systems made it possible to highlight trade-offs between their economic performance under standardised economic conditions, environmental performances, and feed-food competition, but also discrepancies between sheep farm strategy and meat industry demands. Different management strategies resulted in ewe productivity ranging from 0.82 to 1.66 lambs ewe〈sup〉−1〈/sup〉 year〈sup〉−1〈/sup〉 between farming systems and concentrate use from 0 to 148 kg ewe〈sup〉−1〈/sup〉 year 〈sup〉−1〈/sup〉. The two systems relying the most on grassland and rangelands show the best economic and environmental performances while minimising feed-food competition. This results from a good match between animal feed requirements and forage availability; these systems, however, generate a high seasonality of production that does not meet the industry demand for a regular meat supply throughout the year. The Irish system also follows a forage autonomy strategy, but with poorer environmental and economic performance due to intensification, higher price of land, and lower meat price. Both the accelerated reproduction system with three lambing periods in two years and the organic system generate a more regular lamb supply, but require a higher level of concentrate feed, which negatively affects performances. These results highlight for the first time that optimising economic and environmental performances at farm level does not fully fit with the meat industry demand for a regular lamb meat supply throughout the year and lamb conformation. Low-productivity but fully self-sufficient fodder livestock systems can achieve excellent economic performance, but require both specific skills and marketing adequacy.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sustainable cropping systems that balance agricultural productivity and ecological integrity are urgently needed. Overreliance on soil tillage and herbicides to manage weeds has resulted in a number of major environmental problems including soil erosion and degradation, biodiversity loss, and water quality impairment. Combining organic farming and conservation agriculture is a viable alternative to address these challenges. In particular, mulch-based no tillage systems can be used to reduce tillage in organic production, improving soil quality while decreasing labor and fuel requirements. This technique involves planting cash crops directly into terminated cover crops that remain on soil surface and serve as mulch to prevent weeds establishment and protect soil from erosion. Despite potential benefits, adoption of organic mulch-based no tillage is limited due to challenges with cover crop termination, weed suppression, and yields. Here, we (i) review international research on organic mulch-based no tillage systems (soybean and maize), (ii) identify production issues that limit the success of this technique, and (iii) outline research priorities. As result, organic mulch-based no tillage is knowledge intensive and requires advanced planning and careful management of the cover crop. Primary challenges include timely cover crop establishment and termination, nutrient management, reduced soil temperature and moisture at planting, and achieving adequate seed-to-soil contact when planting into thick mulch on soil surface. Long-term research is needed to better understand the effects of this technique production on soil health and on the broader environmental and economic impacts. To increase adoption of organic mulch-based no tillage, future research should focus on (i) screening species and cultivars to identify cover crop and crop combinations that optimize cropping system performance and (ii) developing equipment for improving cover crop termination and seed placement. Research conducted in partnership with farmers will be valuable for developing guidelines and increasing adoption of this technique.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Many cattle breeding programs were initiated in Africa to increase the productivity of indigenous cattle breeds. Most of these programs have failed, partly due to the lack of involvement of breeders. The present case study contributes to the understanding of such failures. The N’Dama cattle breeding program in Senegal was taken as a case study for an in-depth analysis of participation using mixed methods. Semi-structured interviews were conducted with 52 breeders: 26 who participated, 15 of whom recently resigned, and 27 who had never participated. Content and statistical analyses were conducted to evaluate the motivations of breeders and the factors influencing their participation in the breeding program. Results more particularly highlight the complexity of social issues within a breeding project, in face of classical determinants of adoption that are distance or production systems features. It pinpoints crucial levers of improvement, i.e., the management of animal property rights between the nucleus management and the participating breeders, the legitimacy of participants’ representatives in cooperatives, and the strategic mobilization of member social networks. Also, adding on previous works of the authors, this study highlights the need to take better account of the dynamics of production systems, then paying sufficient attention to the objectives, preferences, and ongoing strategies of the breeders for the future. The present study is the first to highlight the added value of mixed methods to analyze innovation adoption and participation in a livestock breeding program, taking both into account the overall innovation drivers and dynamics tied to actors’ strategies.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Integrated weed management encourages long-term planning and targeted use of cultural strategies coherently combined at the cropping system scale. The transition towards such systems is challenged by a belief of lower productivity and higher weed pressure. Here, we hypothesize that diversifying the crop sequence and its associated weed management tools allow long-term agronomic sustainability (low herbicide use, efficient weed control, and high productivity). Four 6-year rotations with different constraints (S2: transition from reduced tillage to no-till, chemical weeding; S3: chemical weeding; S4: typical integrated weed management system; S5: mechanical weeding) were compared to a reference (S1: 3-year rotation, systematic ploughing, chemical weeding) in terms of herbicide use, weed management, and productivity over the 2000–2017 period. Weed density was measured before and after weeding. Crop and weed biomass were sampled at crop flowering. Compared to S1, herbicide use was reduced by 46, 65, and 99% in S3, S4, and S5 respectively. Herbicide use in S2 was maintained at the same level as S1 (− 9%), due to increased weed pressure and dependence to glyphosate for weed control during the fallow period of the no-till phase. Weed biomass was low across all cropping systems (0 to 5 g of dry matter m〈sup〉−2〈/sup〉) but weed dynamics were stable over the 17 years in S1 and S4 only. Compared to S1, productivity at the cropping system scale was reduced by 22% in S2 and by 33% in S3. These differences were mainly attributed to a higher proportion of crops with low intrinsic productivity in S2 and S3. Through S4’s multiperformance, we show for the first time that low herbicide use, long-term weed management, and high crop productivity can be reconciled in grain-based cropping systems provided that a diversified crop rotation integrating a diverse suite of tactics (herbicides included) is implemented.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Weeds are one of the most important pests in agroecosystems, causing considerable economic losses on the production. The widespread use of herbicides during the last decades has led to an increased search for more environmentally sustainable methods for weed management. The manipulation of allelopathic interactions between crops and weeds, such as the introduction of an allelopathic species within a crop rotation, represents a valid alternative. In a multidisciplinary approach, we evaluated the effects resulting from three consecutive years of cultivation, in two different areas, with the three botanical varieties of 〈em〉Cynara cardunculus〈/em〉 L. (globe artichoke, cultivated and wild cardoon), compared with a classic Mediterranean wheat/faba bean rotation and an olive grove, on the quali/quantitative weed soil seed bank and the changes in the eubacterial communities. Furthermore, the in vitro antibacterial activity of aqueous, methanolic, and ethanolic leaf extracts of cultivated cardoon against three bacteria involved in the soil N-cycle was investigated. In both areas, 〈em〉C. cardunculus〈/em〉 caused a significant reduction (from − 34 to − 50%) on the amount of weed seeds in all treatments compared to controls; in some cases, a reduction of the number of weed species was observed. On one hand, the presence of cultivated cardoon had a negative influence towards 〈em〉Bacillus subtilis〈/em〉, while on the other, a positive one towards the beneficial soil bacteria 〈em〉Pseudomonas putida〈/em〉 and 〈em〉Azospirillum brasilense〈/em〉. Moreover, methanolic and ethanolic leaf extracts from cultivated cardoon showed an inhibitory activity on 〈em〉B. lichenoformis〈/em〉, while there were no negative effects on 〈em〉Rhizobium leguminosarum〈/em〉 and 〈em〉Sinorhizobium meliloti〈/em〉, two important bacteria involved in biological N〈sub〉2〈/sub〉 fixation. These results confirmed, for the first time, the field allelopathic activity of 〈em〉C. cardunculus〈/em〉 in monoculture and the possibility of introducing it within a crop rotation as an indirect method for a chemical-free weed seed bank control while respecting soil eubacterial communities.〈/p〉