Impact of agroforestry interventions on soil carbon sequestration and biodiversity in smallholder farms: A case study in [region]

Project Abstract

This study evaluates the effect of integrated agroforestry interventions on soil carbon sequestration and biodiversity within smallholder farming systems in [region], employing a mixed-methods approach to capture biophysical and socio-economic dimensions over a four-year period. The research leverages a quasi-experimental design with matched treatment and control plots across representative farm types to quantify changes in soil organic carbon (SOC), soil microbial biomass, and aggregate stability, alongside floristic and faunal biodiversity indicators. Soil samples were collected at 0–15 cm, 15–30 cm, and 30–60 cm depths to assess SOC stocks, particulate organic carbon, and mineral-associated carbon fractions using standard Walkley-Black and dry combustion methods, complemented by soil respiration and enzyme activity assays to illuminate microbial functional dynamics. Biodiversity assessments encompassed plant species richness, canopy diversity, understorey vegetation structure, and pollinator and avifauna abundance, employing transects, plots, pitfall traps, and camera-based monitoring, with DNA metabarcoding applied to soil and leaf litter to resolve cryptic diversity. Agroforestry treatments included multipurpose parkland trees, alley-cropping with leguminous species, understorey cover crops, and silvopastoral configurations, integrated with enhanced soil fertility practices (organic amendments, composting, and targeted biochar applications) and water management strategies (mulching, terracing, and micro-spray systems). Data were analyzed using linear mixed-effects models to account for spatial clustering and repeated measures, structural equation modeling to examine causal pathways linking tree incorporation, litterfall, and SOC stabilization, and multivariate ordination (RDA/ NMDS) to detect shifts in biodiversity assemblages. The study also incorporates remote sensing-derived vegetation indices and soil moisture data to scale plot-level findings to landscape patterns and to evaluate resilience indicators under variable climatic conditions, including drought episodes. Economic analyses assessed costs and benefits of agroforestry adoption, discounting future carbon sequestration benefits and estimating ecosystem service values through willingness-to-pay and cost-benefit frameworks. Key findings indicate that agroforestry interventions substantially increase SOC stocks by enhancing litter input, root biomass, and mineral-associated carbon fractions, with the most pronounced gains observed in plots combining multipurpose trees with leguminous alley-cropping and soil amendments. Biodiversity outcomes revealed higher plant species richness, improved habitat heterogeneity, and elevated pollinator and bird activity in agroforestry plots relative to controls, contributing to improved pollination services and natural pest regulation. However, benefits were modulated by tree species selection, management intensity, and baseline soil fertility. The results highlight the potential of smallholder-led agroforestry to simultaneously advance climate-regenerative agriculture and biodiversity conservation, while delivering livelihood co-benefits through diversified production, enhanced soil health, and reduced vulnerability to climate variability. Policy implications emphasize the importance of inclusive extension services, incentive mechanisms for agroforestry adoption, and integration of agroforestry practices into national climate-smart agriculture strategies. The study identifies scalable pathways for practice and policy to optimize soil carbon sequestration and biodiversity outcomes in smallholder landscapes across [region], offering transferable insights for comparable agroecosystems.

Project Overview

What This Project Is About

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A straightforward study of how integrating trees and other woody plants into farming (agroforestry) affects soil health, carbon storage, and the variety of living things on small farms. It looks at practices like intercropping, shade trees, and hedgerows to see if they help store carbon in the soil and support more species.

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The Problem It Addresses

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Many small farms rely on practices that can deplete soil carbon and reduce biodiversity over time. There is a need to understand whether agroforestry can improve soil carbon levels and support more plants, insects, and birds without harming crop yields. This study fills that gap and guides farmers and policymakers.

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Objectives of the Project

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1. Assess changes in soil carbon stocks under agroforestry setups on smallholder farms.
2. Measure biodiversity indicators including plants, insects, and birds in agroforestry systems versus conventional farms.
3. Compare crop yields and farm performance between agroforestry and non-agroforestry practices.
4. Identify best-practice combinations of trees with crops for maximizing benefits.

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What You Will Do Step by Step

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1. Review existing literature and select a study region and farms for data collection.
2. Document farm practices and establish agroforestry treatments.
3. Collect soil samples and measure soil carbon and related properties.
4. Survey biodiversity indicators (flora and fauna) on each farm.
5. Record crop yields and farming inputs used.
6. Analyze data to compare carbon, biodiversity, and yields between treatments.
7. Interpret results to identify promising agroforestry configurations.
8. Prepare a concise report with practical recommendations for farmers.

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Expected Outcome

Clear evidence on whether agroforestry raises soil carbon and biodiversity while maintaining or improving yields, plus practical guidelines for farmers to adopt effective agroforestry practices.