Assessing the Impact of Organic Mulching on Soil Fertility and Crop Yield

Thesis Abstract

In the context of increasing concerns over sustainable agricultural productivity and environmental conservation, this study investigates the effects of organic mulching on soil fertility parameters and crop yields within smallholder farming systems. The persistent reliance on synthetic fertilizers often leads to soil degradation, reducing long-term productivity and necessitating alternative soil management practices such as organic mulching. The primary aim of this research was to evaluate the extent to which organic mulching influences soil chemical and physical properties and subsequent crop productivity, with specific objectives to quantify changes in soil organic matter content, nutrient levels (particularly nitrogen and phosphorus), soil moisture retention, and crop yield parameters across different crop types. Employing a mixed-methods approach, the study adopted a randomized complete block design (RCBD) field experiment conducted over two growing seasons at a representative agricultural research station with a population of 150 smallholder farmers in the region. A total of 60 plots, subdivided into treatments comprising various organic mulches—including rice straw, maize stalks, and composted manure—and a control with no mulch, were selected. Data collection involved the use of standardized soil sampling protocols, portable soil testers, and crop-specific yield measurements. The soil chemical properties were analyzed using atomic absorption spectrophotometry and colorimetric methods, while soil physical assessments employed gravimetric moisture analysis and bulk density measurements. Crop yields were recorded at harvest, and farmer interviews supplemented quantitative data with insights on management practices. Data analysis utilized descriptive statistics to summarize baseline conditions, followed by inferential statistical techniques such as ANOVA to test significant differences among treatment groups. Regression analysis was applied to determine the relationship between soil fertility parameters and crop yields. Additionally, factor analysis identified key soil traits influenced by organic mulching practices. The theoretical framework integrated the Theory of Resource-Based View to assess the adoption and sustained use of organic mulching practices, and the Soil Fertility Resilience model to explain how organic matter inputs improve soil health over time. It is anticipated that results will demonstrate significant improvements in soil organic matter, nutrient availability, and moisture retention in plots treated with organic mulches compared to controls, leading to higher crop yields by an average of 20-30%. The findings are expected to reveal that rice straw and composted manure are particularly effective in enhancing soil fertility and crop productivity in the studied context. Moreover, farmers’ qualitative responses are projected to affirm the practicality and acceptability of organic mulching techniques, fostering broader adoption. This research contributes to the existing body of knowledge by providing empirical evidence on the agronomic benefits of organic mulching in smallholder systems under tropical conditions, emphasizing its role in sustainable intensification strategies. It offers valuable insights into soil management practices that can rehabilitate degraded soils, reduce dependency on chemical inputs, and promote eco-efficient farming systems. The study concludes that organic mulching constitutes a viable, cost-effective intervention to boost soil health and crop yields, with policy implications for extension services and agricultural development programs. Recommendations include encouraging the integration of locally available organic residues into farming practices, promoting farmer education on mulching techniques, and advocating for policy support to enhance adoption rates. Further research is suggested to examine long-term impacts of organic mulching on soil microbial diversity, greenhouse gas emissions, and climate resilience of cropping systems. Overall, the study underscores the potential of organic mulching as an environmentally sustainable approach for improving soil fertility and ensuring food security in smallholder agriculture.