Richard Coe

Agricultural systems are under significant strain due to increasingly complex and interconnected challenges, including climate change, conflicts and pandemics associated not only with inefficient f...

Summary: Smallholder farmers in sub-Saharan Africa grow maize under highly variable agro-ecological and socio-economic conditions, calling for breeding programmes that better address farmers’ conditions and needs. This study characterized farmers’ crop management practices and investigated genotype × environment (G × E) interaction patterns for maize yield in Eastern Zambia to guide the breeding strategy in this region. A participatory large-scale variety testing approach, comprising 980 mother and baby trials (MBTs) conducted under farmers’ own management practices, was implemented over the 2022 and 2023 seasons. Characterization of the MBT contexts revealed that adaptation to low nitrogen and delayed fertilization should be considered in the breeding strategy. In addition, delayed weedings explained a large proportion of genotype × farmer (G × F) interactions in both MT seasons, indicating that adaptation to weed pressure should deserve greater attention in breeding. These adaptation traits are particularly important for women, who provide most weeding labour and often have limited access to soil fertility resources. Non-repeatable G × F interactions across years, together with genotypic variance exceeding G × E interaction variance estimates, indicated that multi-year testing across MTs can identify superior and stable genotypes. At the same time, indications of specific adaptation to certain management conditions suggest potential for context-specific variety recommendations. This could offer a competitive advantage in Zambia’s maize seed market, where variety choice and information remain limited. Overall, decentralized farmer-managed testing underlined the importance of yield stability and generated reliable information on variety adaptation, while strengthening farmers’ capacity to make informed variety choices.

Agroecology has evolved and is promoted as an integrated pathway for the development of food and agriculture systems in ways that address the interacting social, economic, and environmental challenges of current dominant systems. Agroecology is usually described and defined by a set of principles that can be adapted and implemented in ways that are relevant to diverse contexts. Transition to wider use of agroecology depends on farmers and others who are not yet convinced deciding that agroecology provides the right pathway for them. We used 2 human behavioral models to highlight the influence of personal motivational factors such as attitudes and values in transitioning to agroecology. Current sets of agroecology principles generally do not refer to the values, beliefs, motivations, or attitudes that go along with, or are precursors to, change in practices. Insights from research on environmental education and pro-environmental behavior show that such values and attitudes, or mindsets, are built and nurtured through connection with nature, sense of place, group and individual identity, and self- and social efficacy. While recognizing the need for more comprehensive mindset principles for agroecology, we propose, based on our focus on achieving pro-environmental action, that a principle of deliberate building of ecological mindsets be added to the sets of agroecological principles. Transformational learning provides some practical ways of implementing that are well aligned with approaches to learning for agroecology that are already being used.

Assessing the potential drivers of farmers using pesticidal plants for crop protection is essential for wider adoption. However, few studies have focused on collaborative assessments of the underlying trade-offs when using pesticidal plant extracts for pest control. Smallholder farmers in northern Tanzania involved in farmer driven research assessing pesticidal plants evaluated the costs, benefits, trade-offs and areas for future investment. A questionnaire was used to collect demographic information from 77 farmers and their views on pest problems and crop protection in common bean production. This was followed by small focus group discussions (n = 9) using a participatory framework to elucidate the costs and benefits of adopting pesticidal plant technology. A multiple correspondence analysis showed that pesticidal plant use was associated with men greater than 50 years old, and synthetic pesticide use was associated with younger aged farmers and women. Farmers who used synthetics generally did not report the presence of common pest species found in common bean production, whereas farmers who used pesticidal plants were associated with more frequent reports of pest species. This participatory cost–benefit analysis highlighted that tools and processing challenges were the main costs to using pesticidal plants. The main benefit reported when using pesticidal plants was a general improvement to family health. Farmers expressed overall a positive outcome when using pesticidal plants for crop protection and recommended that future investments focus on improving access to tools and education regarding plant processing and extraction to improve uptake of the technology by smallholder farmers.

Questions: Our study tests the relative importance of different attributes of isolated trees in explaining the properties of the regeneration assemblage beneath their crowns to evaluate their effect on the composition of early successional stages and understand the processes underlying this effect. We asked: (1) does the regeneration assemblage contain a high proportion of individuals conspecific with the isolated tree; (2) how does the landscape surrounding an isolated tree influence the properties of the regeneration assemblage; and (3) what is the respective importance of structural variables and functional traits of isolated trees for their influence on the properties of the regeneration assemblage?Location: Three pasture sites in Guanacaste Province, a tropical seasonally dry area, Costa Rica.Methods: Ninety isolated trees were characterized by their position in the landscape relative to patches of trees, individual structural variables related to tree and crown size, and species functional traits. The assemblage of woody plants regenerating under their crowns was characterized by number of individuals and species, and taxonomic and functional composition. To understand the mechanisms underlying the facilitative effect of isolated trees on regeneration, correlations between their attributes and properties of the regeneration assemblage were assessed.Results: We found that a low proportion of regenerating individuals were conspecific with the isolated trees beneath which they have established. Landscape factors influenced the regeneration but their effects were site‐dependent. The attributes of isolated trees correlated well with the functional composition of the regeneration assemblage: their structure and phenological habits with traits associated with drought tolerance, and their dispersal syndrome with the dispersal syndrome of the regeneration assemblage. However, isolated tree attributes correlated poorly with the regeneration assemblage's taxonomic composition.Conclusions: Our study shows that an approach based on functional composition can provide a better understanding of community assembly mechanisms than does a taxonomic approach. Two main mechanisms are suggested to explain the influence of isolated trees on the regeneration assemblage: modification of micro‐scale environmental conditions (shade and moisture) and influence on dispersal agents. The effect of attributes of isolated trees on the properties of the regeneration assemblage predicts a long‐term legacy of the early stages of succession.