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Scientific knowledge, societal debates, and industry commitments around sustainable cocoa are increasing. Cocoa agroforestry systems are supposed to improve the sustainability of cocoa production. However, their combined agronomic, ecological, and socio-economic performance compared to monocultures is still largely unknown. Here we present a meta-analysis of 52 articles that directly compared cocoa agroforestry systems and monocultures. Using an inductive, multi-dimensional approach, we analyzed the differences in cocoa and total system yield, economic performance, soil chemical and physical properties, incidence of pests and diseases, potential for climate change mitigation and adaptation, and biodiversity conservation. Cocoa agroforestry systems outcompeted monocultures in most indicators. Cocoa yields in agroforestry systems were 25% lower than in monocultures, but total system yields were about ten times higher, contributing to food security and diversified incomes. This finding was supported by a similar profitability of both production systems. Cocoa agroforestry contributed to climate change mitigation by storing 2.5 times more carbon and to adaptation by lowering mean temperatures and buffering temperature extremes. We found no significant differences in relation to the main soil parameters. The effect of the type of production system on disease incidence depended on the fungal species. The few available studies comparing biodiversity showed a higher biodiversity in cocoa agroforestry systems. Increased and specific knowledge on local tree selections and local socio-economic and environmental conditions, as well as building and enabling alternative markets for agroforestry products, could contribute to further adoption and sustainability of cocoa agroforestry systems.

This paper explores the effect of agroecological service crops (ASCs), i.e., crops included in the crop rotation for their ecosystem services, terminated with an in-line tillage roller crimper (ILRC) on weed community composition and their functional traits in comparison to a tilled control without ASC. A two-year study was performed in a long-term experiment with vegetables under organic management. Four different cereal crops were introduced as ASCs. Weed abundance and richness and the functional traits were assessed at three different stages, i.e., before and after ASC termination and before harvest of the following crop, melon. All the ASCs showed strong weed suppression, with few differences between the cereals tested. Weed communities with ASCs had later flowering onset and wider flowering span compared to the control, which positively affects weed dispersal and attraction of beneficial insects. However, weed communities with ASCs had higher values for traits related to competition (specific leaf area, seed weight and more perennials). A trade-off between weed suppression and selection of more competitive weed communities by the introduction of ASCs managed with the ILRC should be evaluated in the long-run. The use of the ILRC alternating with other soil management practices seems the more effective strategy to benefit from the minimal soil tillage while avoiding the selection of disservice-related traits in the weed community.

Ageing plantations, poor genetic material, soil degradation, pests and diseases are, among other factors, limiting cacao production. To meet the increasing demand for cacao in the absence of productivity gains, forests are cleared and the use of external inputs is generalised, with severe negative impacts on biodiversity and GHG emissions. The use of improved plant genetic material should support a sustainable increase of production. In this study, we evaluate and compare the yield performance of four locally-selected clones with those of four widely-used international clones in South America and four full-sib families (crosses of the same international clones). The research was conducted in a long-term trial in Bolivia with different production systems, including monocultures and agroforestry systems under organic and conventional farming and a successional agroforestry system without external inputs. Their cacao yields and the factors determining productivity (pod index, flowering intensity, pod load, pod losses, aboveground biomass, harvesting period) were assessed during 5 years. The cacao trees grown in the two monocultures had higher yields than those in the agroforestry systems. This was the result of higher aboveground biomass, flowering intensity and pod load, and similar pod losses due to cherelle wilt and fungal diseases in the former when compared with the latter. No differences between conventional and organic management were observed. We did not identify any genotypes performing better in a specific production system. On average, the local clones had twofold and five times higher yields than the international ones and the full-sib families, respectively. This was related to their higher total pod load, bigger pods and higher yield efficiency, i.e., higher yield per unit of tree biomass. However, the local clones had less flowering intensity, more cherelle wilt and similar losses due to fungal diseases to those of the international clones. This study clearly shows the need to invest in selection and breeding programmes using locally-selected genetic material to increase cacao production and support renovation/rehabilitation plans. Breeding genetic material that is adapted to low light intensities is crucial to close the yield gap between monocultures and agroforestry systems, and to further promote the adoption of the latter.

Reduced tillage reduces soil erosion and increases topsoil organic matter compared with conventional tillage. However, yields are often reported to be lower, presumably, due to increased weed pressure and a slower N mineralization under organic farming conditions. The effects of reduced tillage compared with ploughing on weed infestation and winter wheat performance at four different crop stages, i.e., tillering, stem elongation, flowering, and harvest, was monitored for a single season in an eleven-year-old organic long-term tillage trial. To disentangle the effects of weed presence on crop yield and potential crop performance, subplots were cleaned from weeds during the whole cropping season. Weed biomass was consistently higher under reduced tillage. Soil mineral nitrogen contents under reduced tillage management were higher, which could be explained by the earlier ley termination in autumn compared with the conventional tillage system. Nitrogen status of wheat assessed with SPAD measurements was consequently higher under reduced tillage throughout the season. At harvest, wheat biomass and grain yield were similar in both tillage systems in the presence of weeds, but 15–18% higher in the reduced tillage system when weeds were removed. The negative impact of weeds on yields were not found with conventional tillage with a low weed infestation. Results suggest that reduced tillage can provide equivalent and even higher yields to conventional tillage in organically managed winter wheat if weed management is improved and good nutrient supply is assured.

The definition of “arable weeds” remains contentious. Although much attention has been devoted to specialized, segetal weeds, many taxa found in arable fields also commonly occur in other habitats. The extent to which adjacent habitats are favorable to the weed flora and act as potential sources of colonizers in arable fields remains unclear. In addition, weeds form assemblages with large spatiotemporal variability, so that many taxa in weed flora are rarely observed in plot-based surveys. We thus addressed the following questions: How often do weeds occur in other habitats than arable fields? How does including field edges extend the taxonomic and ecological diversity of weeds? How does the weed flora vary across surveys at different spatial and temporal scales? We built a comprehensive dataset of weed taxa in France by compiling weed flora, lists of specialized segetal weeds, and plot-based surveys in agricultural fields, with different spatial and temporal coverages. We informed life forms, biogeographical origins and conservation status of these weeds. We also defined a broader dataset of plants occupying open habitats in France and assessed habitat specialization of weeds and of other plant species absent from arable fields. Our results show that many arable weeds are frequently recorded in both arable fields and non-cultivated open habitats and are, on average, more generalist than species absent from arable fields. Surveys encompassing field edges included species also occurring in mesic grasslands and nitrophilous fringes, suggesting spill-over from surrounding habitats. A total of 71.5% of the French weed flora was not captured in plot-based surveys at regional and national scales, and many rare and declining taxa were of Mediterranean origin. This result underlines the importance of implementing conservation measures for specialist plant species that are particularly reliant on arable fields as a habitat, while also pointing out biotic homogenization of agricultural landscapes as a factor in the declining plant diversity of farmed landscapes. Our dataset provides a reference species pool for France, with associated ecological and biogeographical information.

Cocoa-based agroforests are promoted to replace monocultures for the provision of ecosystem services. However, shade tree pruning, an important tool to sustain cocoa yields, is not commonly implemented. This study investigates the effect of pruning on both agronomic and economic performance. In Bolivia, four famers’ sites were divided in half, and shade trees pruned in one of the two plots. Pruning resulted in a significant increase in cocoa yield, from an average of 430 to 710 kg ha−1 by boosting flowering and pod production, but not reducing the proportion of damaged pods, and of those lost to cherelle wilt. Additionally, scenario calculations using international and organic premium cocoa prices were conducted to evaluate the economic feasibility of pruning. The minimum, mean and maximum yield of 22 local cocoa-based agroforestry farms were used as reference for 25, 50 and 75% yield increase scenarios. Offsetting the pruning costs highly depended on the initial yield levels. Using the minimum yield, all scenarios led to a lower net income compared with no pruning. For the mean yield level, the net income was equal to that obtained without pruning when the yield increase was above 51%. At the maximum yield level, all increase scenarios resulted in a higher net income. Our results prove the importance of pruning agroforestry trees to increase cocoa yields. However, with current farm-gate prices for cocoa, farmers alone cannot cover the extra management costs. The cocoa sector should discuss different strategies to support pruning for a broader adoption of agroforests.

The global demand for cacao has recently increased. To meet this demand, the cultivated area has been expanded in tropical forest areas and production has intensified by replacing traditional agroforestry systems with monocultures. This has led to a loss of biodiversity in cacao-growing areas. More sustainable production systems such as agroforestry and organic managed systems are expected to yield less cacao, but by-crops and premium prices, respectively, might economically compensate for the lower yields. Here, we compared the productivity and the return on labor, that is the return per working day, of four different cacao production systems: agroforestry and monocultures under organic and conventional management. Cacao and by-crop yields, costs, revenues, and labor were registered during the first 5 years after establishment. Results show that cacao yields were, on average, 41% higher in monocultures, but the revenues derived from agroforestry by-crops economically overcompensated for this difference. Indeed, the return on labor across the years was roughly twice as high in the agroforestry systems compared to the monocultures. We found similar cacao yields and return on labor in conventional and organically managed agroforestry systems. However, in the monocultures, cacao yields were 48% lower under organic compared with conventional farming, but the return on labor was similar, mainly due to the higher costs associated to the conventional management. Overall, our findings show that cacao agroforestry systems have higher return on labor.

Key messageShade trees in agroforestry systems protect the understory cocoa from climate extremes. Shade tree pruning manages microclimatic conditions in favor of cocoa production while tree diversity is maintained. Adaptation of pruning has to consider seasonal changes in temperature and precipitation to protect the understory cocoa.ContextStructural characteristics of tree stands such as species diversity, tree density, and stratification can affect throughfall and microclimate. Pruning changes the canopy and may therefore modulate internal conditions.AimsThe aim of this study is to assess the environmental growing conditions of cocoa trees.MethodsWe monitored canopy openness and the impact of stand structure on throughfall and microclimate in three cocoa production systems (monoculture, agroforestry, and successional agroforestry) and a natural regrowth in a long-term trial in Bolivia from 2013 to 2015. We further focused on the effect of annual shade tree and cocoa pruning on these variables to evaluate the potential impact of this activity.ResultsAgroforestry systems buffered extreme climate events like temperature fluctuations compared to monocultures but reduced light and throughfall drastically. Spatial variability of throughfall and transmitted light were low under a high and closed shade tree canopy. Shade tree pruning resulted in higher canopy openness, light transmittance, and throughfall, while the buffer function of the agroforestry systems concerning temperature and humidity fluctuations was reduced.ConclusionDifferences between cocoa production systems regarding throughfall and microclimate were overlain by pruning activities. Cocoa agroforestry systems are temporal dynamic systems. Pruning timing and intensity is pivotal for balancing light and water availability under seasonally varying environmental conditions to conserve micro-environments for cocoa production with less exposure to unfavorable climate.

Both agronomic practices and spatial position can determine the assemblage of herbaceous species. We assess the dynamics and the contribution of these two aspects over time to the herb assemblages of different cocoa production systems. Braun-Blanquet surveys were performed over seven years in a long-term trial in Bolivia to compare different cocoa production systems: successional agroforestry (SA) with no external inputs, organic agroforestry (OA) and organic monoculture (OM), both including a leguminous perennial cover crop, conventional agroforestry (CA) and conventional monoculture (CM), where agrochemicals were applied. Using general linear models and multivariate analysis we found that assemblages were mainly driven by spatial position only at the beginning. After this, a very dynamic selection process related to the different management practices took place, which became more stable over the years. We observed a decline in species in both the CA and OA systems, due to the loss of heliophilous species and the low number of new species established in them. The OM presented the most conservative pattern, with the lowest number of new species and species lost, due to the presence of the cover crop. Both the most intensively managed system (CM) and the most diverse and least intensive one (SA) had the highest number of new species recorded over time, which led to highly specialized assemblages, with worldwide distributed and herbicide resistant species in the first case and secondary forest species, in the second. We conclude that the promotion of organic management and agroforestry systems, especially highly divers and successional agroforestry sytems would favour herb assemblages with high conservation value and prevent the establishment of globally distributed species.