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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.

The biotic release of nitric oxide (NO), a greenhouse gas, into the atmosphere contributes to climate change. In plants, NO plays a significant role in metabolic and signaling processes. However, little attention has been paid to the plant-borne portion of global NO emissions. Owing to the growing significance of global flooding events caused by climate change, the extent of plant NO emissions has been assessed under low-oxygen conditions for the roots of intact plants. Each examined plant species (tomato, tobacco, and barley) exhibited NO emissions in a highly oxygen-dependent manner. The transfer of data obtained under laboratory conditions to the global area of farmland was used to estimate possible plant NO contribution to greenhouse gas budgets. Plant-derived and stress-induced NO emissions were estimated to account for the equivalent of 1 to 9% of global annual NO emissions from agricultural land. Because several stressors induce NO formation in plants, the actual impact may be even higher.

Understanding water stress signaling mechanisms and screening for tolerant cocoa cultivars are major challenges when facing prolonged dry and rainy seasons in cocoa-producing areas. While abscisic acid (ABA) and proline are supposed to enhance drought tolerance in cocoa, the role of polyamines remains unclear. The aim of this study was to investigate the biochemical response and phenological adaptation of cocoa (Theobroma cacao) on different soil moisture conditions, with a focus on short-term (20 days) and long-term (89 days) stress conditions, and to compare the performance of three cocoa cultivars. In a split plot design with four blocks, cocoa seedlings of an international high-yielding cultivar (TSH-565) and two locally selected cultivars (IIa-22 and III-06) from the drought-exposed Alto Beni region, Bolivia, were arranged in pots under a roof shelter (cultivar: three levels). The seedlings were exposed to strong (VERY DRY) and moderate (DRY) soil moisture deficits, water logging (WET) and regular irrigation (MOIST) that served as a control (moisture: four levels). We examined the growth performance and the levels of ABA, proline, and polyamines in the leaves. Growth was reduced already at a moderate drought, while severe drought enhanced seedling mortality. Severe drought increased the levels of ABA by 453% and of proline by 935%, inducing a short-term stress response; both compounds were degraded over the long-term period. The polyamine concentration was unrelated to soil moisture. The cocoa cultivars did not differ in their biochemical response to soil moisture stress (proline: p-value = 0.5, ABA: p-value = 0.3), but the local cultivar III-06 showed a stronger height growth increment than the international cultivar TSH-565 (237%, p-value = 0.002) under drought conditions.

Increasing soil organic carbon (SOC) aims to increase and maintain soil quality for sustainable crop production and to achieve carbon removal targets. Agronomic practices are therefore needed to reduce carbon losses and increase SOC stocks, especially in deep soil layers, which promote long-term storage. Regenerative agriculture is an approach aimed at increasing soil quality for sustainable production and therefore should be suitable for achieving the required goals under organic farming conditions. We analysed SOC content down to a depth of 1 m and calculated the SOC stock based on bulk density after ten years of regenerative farming practices, i.e., reduced tillage, dead organic mulch, and high-quality yard waste compost application, in two organic field trials set up one year apart in Central Germany and we calculated the carbon (C) and nitrogen (N) input to the soil from organic amendments and from main crops and cover crops by applying C allocation factors for crop residues, roots, and rhizodeposition. C derived from crops was the main carbon input source over ten years. Increasing C input promoted an increase in the cumulative SOC stock down to 1 m. We observed greater SOC stocks dominated by topsoil changes with reduced tillage and compost application and with the combination of all practices (+ 16%) than in the control with conventional ploughing and no external carbon input while none of the farming practices affected the subsoil SOC stock. Mulch application had no effect at all on SOC stocks. Crop biomass contributed most C input. Farming practices, especially the combination of reduced tillage and compost application, enhanced topsoil SOC stocks and N but not subsoil C storage. Other farming practices and crop rotation adjustments must be identified to increase crop production as well as subsoil SOC stocks and promoting long-term C storage, e.g., by fostering deep-rooting crops and cover crops.

Soil organic carbon (SOC) monitoring is central to carbon farming Monitoring, Reporting, and Verification (MRV), yet high laboratory costs and sparse sampling limit its scalability. We present the first independent field validation of the Stenon FarmLab multi-sensor probe across 100 temperate European arable-soil samples, benchmarking its default outputs and a simple pH-corrected model against three laboratory reference methods: acid-treated TOC, temperature-differentiated TOC (SoliTOC), and total carbon dry combustion. Uncorrected FarmLab algorithms systematically overestimated SOC by +0.20% to +0.27% (SD = 0.25–0.28%), while pH adjustment reduced bias to +0.11% and tightened precision to SD = 0.23%. Volumetric moisture had no significant effect on measurement error (r = −0.14, p = 0.16). Bland–Altman and Deming regression demonstrated improved agreement after pH correction, but formal equivalence testing (accuracy, precision, concordance) showed that no in-field model fully matched laboratory standards—the pH-corrected variant passed accuracy and concordance evaluation yet failed the precision criterion (p = 0.0087). At ~EUR 3–4 per measurement versus ~EUR 44 for lab analysis, FarmLab facilitates dense spatial sampling. We recommend a hybrid monitoring strategy combining routine, pH-corrected in-field mapping with laboratory-based recalibrations alongside expanded calibration libraries, integrated bulk density measurement, and adaptive machine learning to achieve both high-resolution and certification-grade rigor.

A greenhouse experiment with sorghum sudangrass (Sorghum bicolor × Sorghum sudanense) and maize (Zea mays) was conducted to assess information on differences in their nitrogen and fertilizer utilization when used as energy crops. The aim was to contribute to the scarce data on sorghum sudangrass as an energy crop with regards to nitrogen derived from fertilizer (NdfF) in the plant’s biomass and fertilizer nitrogen utilization (FNU). Sorghum sudangrass and maize were each grown in eight bags of 45 L volume and harvested at maturity after 154 days. Each crop treatment was further divided in a control treatment (four bags each) that did not receive N fertilization and a fertilization treatment (four bags each) that received 1.76 g N, applying a 15N-labelled liquid ammonium nitrate fertilizer. Fertilization took place at the start of the experiment. After harvest, the whole plant was divided in the fractions “aboveground biomass” (ABM) and “stubble + rootstock” (S + R). Weight, N content and 15N content were recorded for each fraction. In addition, N content and 15N content were assessed in the soil before sowing and after harvest. The experiment showed that FNU of sorghum sudangrass (65%) was significantly higher than that of maize (49%). Both crops accumulated more soil N than fertilizer N. The share of fertilizer N on total N uptake was also higher with sorghum sudangrass (NdfF = 38%) compared to maize (NdfF = 34%). The observations made with our control plant (maize), showed that the results are plausible and comparable to other 15N studies on maize regarding yields, NdfF, and FNU, leading to the assumption that results on sorghum sudangrass are plausible as well. We therefore conclude that the results of our study can be used for the preliminary parametrization of sorghum sudangrass in soil organic matter (SOM) balance at field level.

The intensification of food production systems has resulted in landscape simplification, with trees and hedges disappearing from agricultural land, principally in industrialized countries. However, more recently, the potential of agroforestry systems and small woody landscape features (SWFs), e.g., hedgerows, woodlots, and scattered groups of trees, to sequester carbon was highlighted as one of the strategies to combat global climate change. Our study was aimed to assess the extent of SWFs embedded within agricultural landscapes in Germany, estimate their carbon stocks, and investigate the potential for increasing agroforestry cover to offset agricultural greenhouse gas (GHG) emissions. We analyzed open-source geospatial datasets and identified over 900,000 hectares of SWFs on agricultural land, equivalent to 4.6% of the total farmland. The carbon storage of SWFs was estimated at 111 ± 52 SD teragrams of carbon (Tg C), which was previously unaccounted for in GHG inventories and could play a role in mitigating the emissions. Furthermore, we found cropland to have the lowest SWF density and thus the highest potential to benefit from the implementation of agroforestry, which could sequester between 0.2 and 2 Tg of carbon per year. Our study highlights that country-specific data are urgently needed to refine C stock estimates, improve GHG inventories and inform the large-scale implementation of agroforestry in Germany.

Climate change is a growing threat to agriculture globally, with most substantial impacts expected in tropical smallholder systems such as cocoa farms in West Africa. Cocoa agroforestry is widely believed to enhance resilience to climatic extremes due to protection and a favourable microclimate under the shade trees. Morphological traits of many locally used shade tree species and their specific contribution to microclimate for climate-resilient cocoa production remain unclear. Therefore, aboveground morphology and sub canopy microclimate of eight common shade tree species were investigated in cocoa agroforestry systems in the Ahafo region, Ghana. Additionally, the growth of cocoa trees in three different distance zones to the shade tree stem was measured. The eight different shade tree species exhibited considerable variation in their impact on microclimate and cocoa growth. M. indica and M. excelsa allowed lowest light transmission, with the highest microclimatic buffering effect, i.e., reducing vapour pressure deficit and daily fluctuations of temperature and relative humidity. Cocoa trees around M. lucida and F. capensis were the highest in growth, characterized by height and stem diameter. However, a universally superior shade tree species could not be identified implying the need for shade tree diversity allowing various microclimatic conditions within an agroforestry system to spread risk of climate extremes. Cocoa tree growth was more affected by distance to the shade tree than by shade tree species, resulting in enhanced growth with distance to the stem. These findings provide a better understanding of species-related differences on cocoa growing conditions and climate change adaptation strategies.

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.

Agroforestry systems (AFS) can serve to decrease ecosystem carbon (C) losses caused by deforestation and inadequate soil management. Because of their shade tolerance, cacao plants are suitable to be grown in AFS, since they can be combined with other kinds of trees and shrubs. The potential for C sequestration in cacao farming systems depends on various factors, such as management practices, stand structure and plantation age. We compared conventionally and organically managed cacao monoculture systems (MCS) and AFS in Sara Ana (Bolivia) with respect to C stocks in plant biomass and to amounts of litterfall and pruning residues. The total aboveground C stocks of the AFS (26 Mg C ha−1) considerably exceeded those of the MCS (~7 Mg C ha−1), although the biomass of cacao trees was greater in the MCS compared to the AFS. Due to higher tree density, annual litterfall in the AFS (2.2 Mg C ha−1 year−1) substantially exceeded that in the MCS (1.2 Mg C ha−1 year−1). The amounts of C in pruning residues (2.6 Mg C ha−1 year−1 in MCS to 4.3 Mg C ha−1 year−1 in AFS) was more than twice those in the litterfall. Annual nitrogen (N) inputs to the soil through pruning residues of cacao and N-fixing trees were up to 10 times higher than the N inputs through external fertiliser application. We conclude that appropriate management of cacao AFS, involving the pruning of leguminous trees, will lead to increases in biomass, litter quantity and quality as well as soil C and N stocks. Thus, we recommend stimulating the expansion of well-managed AFS to improve soil fertility and enhance C sequestration in soils.