Impact of Organic Mulches on Soil Health and Crop Yield in Smallholder Farms

Thesis Abstract

Smallholder farms are crucial for food security and livelihoods in developing regions, yet they face significant challenges in maintaining soil fertility and optimizing crop yields amidst resource constraints. Organic mulching has been advocated as an environmentally sustainable practice to enhance soil health, conserve moisture, and improve crop productivity; however, comprehensive empirical evidence specific to smallholder contexts remains limited. This study aims to evaluate the impact of various organic mulches on soil health parameters and crop yields, thereby providing actionable insights for smallholder farmers and policymakers. The specific objectives are to (1) assess changes in soil physical, chemical, and biological properties resultant from organic mulching, (2) compare crop yields across different mulching treatments, and (3) analyze the relationship between soil health improvements and crop productivity. The research adopts a quantitative, experimental field study design conducted over a single growing season in a representative smallholder farming community. The study population comprises 60 smallholder farmers practicing maize or vegetable cultivation within the region. A stratified random sampling technique was used to select 48 farms, divided equally into four treatment groups control (no mulch), crop residues, composted manure, and combined mulch (crop residues plus compost). Data collection instruments include soil sampling kits for laboratory analysis, yield measurement tools, structured questionnaires for contextual data, and field observation checklists. Soil samples are analyzed for physical properties (aggregate stability, soil porosity), chemical attributes (pH, organic matter, nutrient content—N, P, K), and biological indicators (microbial biomass, activity levels) utilizing standardized laboratory protocols. Crop yields are quantified through harvest measurements, expressed as weight per hectare. Data analysis involves descriptive statistics to summarize baseline conditions, followed by analysis of variance (ANOVA) to compare soil parameters and crop yields across treatment groups. Multiple regression analysis is employed to explore relationships between soil health indicators and crop productivity. The study also utilizes the Theory of Planned Behavior to interpret farmers' adoption patterns of organic mulching practices, providing a behavioral framework for extension strategies. Expected findings anticipate that organic mulching, especially the combined mulch treatment, will significantly improve soil physical, chemical, and biological properties relative to control conditions, leading to increased crop yields. It is projected that enhancements in soil organic matter and microbial activity will strongly correlate with yield gains, demonstrating the mediating role of soil health in productivity. These findings will provide quantitative evidence supporting the adoption of organic mulching among smallholder farmers as a sustainable intensification strategy. The study contributes to existing knowledge by offering a localized, empirical assessment of organic mulching effects in smallholder systems, bridging the gap between theoretical benefits and field realities. It provides a scientific basis for policy recommendations and technical guidelines tailored to resource-limited settings. Furthermore, it advances understanding of the mechanisms linking soil health improvements to crop performance, integrating soil science with behavioral insights. The main conclusion underscores the positive impact of organic mulches on soil health and crop yields, advocating for the promotion of integrated mulching practices within smallholder farming systems. Recommendations include capacity-building initiatives for farmers, development of context-specific mulching materials, and integration of organic mulching into sustainable agricultural policies. Future research should explore multi-season assessments, economic analyses of mulching practices, and the long-term sustainability of such interventions in diverse ecological zones.