Agroforestry Systems最新文献

Low adoption of agroforestry and other sustainable agriculture practices presents a pressing issue for both policy makers and practitioners in Sub-Saharan Africa. The inefficiency of extension advisory services partly contributes to low adoption of these practices in this region. Using survey data collected from Mzimba and Dedza districts in Malawi, this study applies an Ordered Probit model to assess the effect of ICT-enabled knowledge acquisition on the adoption of multipurpose tree species (MPTS). The results show that radio and WhatsApp messenger are key ICT-based platforms facilitating MPTS adoption. On the other hand, community-based farmer advisors (CBFAs) are an important form of face-to-face extension approach for promoting the adoption of MPTS. From a gender perspective, the results indicate that women farmers might be more inclined to adopt MPTS than their male counterparts, although this effect is not statistically significant. The findings highlight the importance of strengthening ICT-enabled extension advisory services to complement in-person extension services in an era when the number of extension agents is dwindling and the available extension officers are constrained to reach millions of farmers. Additionally, there is a need to scale digital extension services by developing appropriate content suitable for specific digital platforms and the type of agroforestry practices being promoted.

Coffee, an important global commodity, is threatened by climate change. Agroforestry has been considered as one option to maintain or enhance coffee production. In this study, we use a machine learning ensemble consisting of MaxEnt, Random Forest and Boosted Regression Trees to assess climate change impacts on the suitability to grow Arabica coffee, Robusta coffee and bananas in Uganda by 2050. Based on this, the buffering potential of Cordia africana and Ficus natalensis, the two commonly used shading trees in agroforestry systems is assessed. Our robust models (AUC of 0.7–0.9) indicate temperature-related variables as relevant for Arabica coffee suitability, while precipitation-related variables determine Robusta coffee and banana suitability. Under current climatic conditions, only a quarter of the total land area is suitable for growing Arabica coffee, while over three-quarters are suitable for Robusta coffee and bananas. Our results suggest that climate change will reduce the area suitable to grow Arabica coffee, Robusta coffee and bananas by 20%, 9% and 3.5%, respectively, under SSP3-RCP7.0 by 2050. A shift in areas suitable for Arabica coffee to highlands might occur, leading to potential encroachment on protected areas. In our model, implementing agroforestry with up to 50% shading could partially offset suitable area losses for Robusta coffee—but not for Arabica coffee. The potential to produce valuable Arabica coffee thus decreases under climate change and cannot be averted by agroforestry. We conclude that the implementation and design of agroforestry must be based on species, elevation, and regional climate projections to avoid maladaptation.

Extreme climatic events such as droughts, floods, cyclones, and landslides have adversely affected a homegarden that consists of its inherited characteristics as a secondary forest along with alterations made by human. Households, as the major beneficiary of homegardens, have the responsibility to maintain the homegarden incorporating its structure and composition with functions of the household to make the homegarden resilient to adverse effects. To assess the current climate resilience level of a homegarden, data were collected through an in-depth survey from 435 homegardens in Hambantota, Jaffna, Matale, and Ratnapura districts in Sri Lanka. Climate Resilience Index (CRI) of homegarden was constructed based on absorptive and adaptive capacities using the 13 variables. The mean value of the CRI was 0.375 (± 0.005) which ranged from 0.019 to 0.616. As per the multiple regression analysis performed taking the CRI as the dependent variable, the constructed models were complex, and all the variables were required to determine the level of resilience of a homegarden. Based on the CRI values five categories of homegardens were identified as very low, low, moderate, high and very high resilient. Accordingly, key variables affecting the level of resilience of a homegarden were; application of soil and water conservation methods, requirement of soil conservation, presence of woody trees, above-ground biomass, number of canopy strata, experience in farming and technical knowledge on farming, species richness of tree were selected as resilient variables that indicate absorptive and adaptive capacities. The resilience level of a homegarden can be changed, by altering these variables together.

Graphical abstract

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.

The Owita agroecosystem is a unique peri-urban land-use system. Typically it is a narrow strip of land with vegetation located between lowland paddy fields and the uplands of the Wet zone in Sri Lanka. Despite its potential to develop as a sustainable agricultural ecosystem, it has largely been ignored, underutilized and lesser-known. The main objective of this study was to assess the present status of Owita agro-ecosystem, with a focus on its plant species diversity, socio-economic aspects and ecosystem services. The study identified and evaluated thirty-five Owita systems located in the Wet zone of Sri Lanka through conducting vegetation and socio-economic surveys. The study reported a total of 115 plant species belonging to 49 families and 99 genera, of which, the family Fabaceae was found to be the most dominant, with a total of 11 species. Field observations and farmer feedback revealed that Owita provides numerous environmental benefits in the peri-urban landscape, including flood control, biodiversity conservation, and temperature regulation in the surrounding areas. Apart from the ecosystem services, Owita opens up new business ventures for subsistence farmers in peri-urban areas, and products from the system possess high demand due to their freshness and minimal usage of agrochemicals. Although the traditional Owita agro-ecosystem is primarily an annual-based cropping system, findings of the present study indicate that, it has been gradually transformed into a perennial tree-based agroforestry-type cropping system where plant species are spatially arranged in three vertical layers. Thus, the Owita system can be considered as a promising and sustainable agroecosystem that provides numerous benefits to the subsistent farmers in peri-urban environments.

Tropical and subtropical regions have the largest potential area and climatic conditions for sustainably hosting silvopastoral systems focused on the production of wood and livestock in at least two “production modes”. These regions concentrate extensive areas with pastures, in which there is a great opportunity to match forestry production to the profile of regional production rather than competing for land use. This can be beneficial for both productive sectors since certification standards for both forestry and livestock encompass a wide range of economic, social, environmental, and technical management aspects, including people’s well-being and livelihoods. It could converge objectives for both businesses toward a central element and disruptive of an innovative bio-based economy. The “wood model” focuses on producing a greater volume of wood biomass. It requires a high tree-stocking rate (33–47%) into pastures. The “cattle model” integrates more pasture production with fewer trees (< 33% tree-stocking rate). This model requires larger spaces between trees to allow for thicker logs (sawn wood). Both models protect herds and forage. In the “wood model”, negative interactions occur with still young trees. Spacing between strips generates alleys; alleys need to have a width between 3.5 and 5 times the tree canopy depth. Wide alleys facilitate herding; cattle perceive alleys as open spaces without being spooked by the cowboy approximation. Parallel strips facilitate silvicultural and harvest tree operations, animal herding, uniformity of tree density, minimization of runoff surface, and soil erosion.

Carbon sequestration through tree-based systems has been well recognized due to its potential to mitigate climate change. The lack of site-specific and species-specific biomass estimation models is a challenge to accurately estimating forest biomass at local and regional scales. Agarwood (Aquilaria malaccensis) trees form an essential component of agroforestry systems in Assam and Tripura state of India. In this study, trees with stem girth range of 10–80 cm and stand age of < 10 to > 20 years old in smallholder agarwood stands classes were destructively harvested to develop biomass estimation models. Different allometric relationships were compared using either diameter alone or a compound variable, including diameter and height, to predict above ground biomass (AGB), below ground biomass (BGB) and total biomass (TB). Based on the model fit criteria (R², RMSE, AIC and BIC), the best models for estimating above ground, below ground and total biomass of the agarwood trees were lnAGB = − 3.13 + (0.89 × lnD²H), lnBGB = − 2.40 + (1.49 × lnD) and lnTB = 0.29 + (0.96 × lnAGB), respectively. Stand biomass in the study area showed a significant increase from 6.92 Mg ha⁻¹ in < 10 years old stands to 65.90 Mg ha⁻¹in > 20-year-old stands, and is proportionally related with the increase in tree density of the stands ranging from 930–4470 stems ha⁻¹. The continuous harvesting of various-sized trees and the re-plantation and regeneration of agarwood trees in the study area affected the increase in stand-level biomass and the distribution of biomass carbon across the size classes. The proper implementation of the Assam Agarwood Promotion Policy 2020 and similar policies of Tripura need to be supported to promote the cultivation and conservation of the species across the region.

Many studies point to the social and environmental benefits of agroforestry, also in temperate regions such as Flanders. Nevertheless, farmers do not yet see agroforestry as an equally valuable option alongside other farming systems because of the uncertain economic profitability and the current incompatibility of this system with existing market conditions. This paper has the aim to identify and evaluate – existing and hypothetical- economic incentives for agroforestry in Flanders. Data was collected over the period 2015—2021 through focus groups at conferences and in thematic living labs in Flanders with a broad range of stakeholders (e.g. farmers, processors, policy makers, researchers, etc.). The results were analysed qualitatively in Nvivo12 to make a classification of incentives and instruments in a first phase. In a second phase they were evaluated based on an adjusted SAF (Suitability, Acceptability and Feasibility) framework. Four types of incentives were identified: (1) government based; (2) payment for agroforestry products; (3) payment for ecosystem services; and (4) community based incentives. Currently, the highest potential is expected from payment for ecosystem services and the least potential from payment for products and community-based incentives due to a lack of consumer demand for agroforestry products specifically and the unfamiliarity of agroforestry to a broader public. At the end of the data collection period, a positive evolution was already observed in the development of these instruments. To accelerate this evolution, initiatives supporting awareness among a broader public and more insights into the preferences of a wide range of stakeholders is needed.

Silvopastoral systems combine forestry and grazing, potentially improving land use efficiency and animal welfare. However, livestock predation on trees is a challenge. To compare the predatory behavior of calves (Bos taurus × Bos indicus) grazing native grassland with different Eucalyptus grandis densities, 71 calves were randomly allocated at weaning (Day 0) to 3 treatments: (1) Full sun (0 trees/ha), (2) low tree density (160 trees/ha), and (3) high tree density (240 trees/ha). The live weight of the calves was measured monthly, and blood samples were collected once to evaluate serum minerals. Tree severity damage was assessed using a visual scale (0 = no damage to 4 = severe damage). Variables were analyzed using SAS mixed and proc freq procedures, being significant if P < 0.05. On Day 66, damage was found in 16% of trees, with significant differences (P < 0.05) in severe damage between low (6%) and high (3%) tree densities. Daily weight gain and serum profiles of Ca, P, K, Na, Cl, Fe and Cu were similar (P > 0.05) between treatments, but Cu was below reference values. At Day 66, all calves were fitted with nose plates, halting predatory behavior for 54 days. On Day 120 a second attack was observed only in high tree density (17%), most with severe damage (P < 0.01). Live weight, daily gain and stocking rate were similar between treatments. We concluded that weaned calves exhibited predatory behavior towards E. grandis, not associated with weight loss but with mild Cu deficiency. An oscillating nose plate design effectively stopped predatory behavior.

The expansion of Eucalyptus globules boundary plantations (EGBPs) along farm boundaries is considered to have effects on the yield of crops underneath them. We evaluated the orientation and root trenching effect of EGBP on barley yield and soil physicochemical properties in the Gummer District of Central Ethiopia. Two months before sowing, trenches were prepared on each side of the orientation of EGBP at distances of 0.5 m, 1 m, and 1.5 m using a split-split plot design with three replications. At a 1.5 m trench distance, the north-facing field showed 20.4% to 31.2% additional yield increment compared with the south-, east-, and west-facing fields. Additionally, 15.2% to 43% additional yield was observed as the field distance from the EGBP increased from 3 to 12 m. In comparison to un-trenched fields, trenched fields showed 31.9% to 73.4% additional yield variation. Regarding the soil physicochemical properties, the aspect of EGBP had no a significant effect. However, except for the texture, pH, and exchangeable K, the soil OM, TN, available P, and CEC status significantly differed among the trenches. On average, the root trench minimized the field distance effect of EGBP on barley yield by 24%. Tree root trenching is a potential tool for managing below-ground competition. Therefore, establishing a 0.5 m × 0.5 m trench at a 1.5 m distance from the EGBP is vital for maximizing barley yield and increasing land-use efficiency.