Comparative Analysis of Soil Fertility in Organic vs. Conventional Farming Systems

Thesis Abstract

The sustainability and productivity of agricultural systems are increasingly scrutinized in the context of environmental conservation and food security, necessitating comparative assessments of soil fertility under different farming paradigms. This study aims to evaluate and compare soil fertility parameters in organic and conventional farming systems, with specific objectives to analyze soil chemical properties, physical characteristics, biological activity, and nutrient cycling processes within selected farms. The research seeks to determine the extent to which these systems influence soil health, thereby informing sustainable agricultural practices. Adopting a comparative cross-sectional research design, the study was conducted across 20 farms (10 organic and 10 conventional) within the same agro-ecological zone to control for climatic and geological variability. The population comprised registered organic and conventional farmers practicing on plots ranging from 1 to 5 hectares. A stratified random sampling technique was employed to select farms, and within each farm, soil samples were collected from five representative points at depths of 0-15 cm and 15-30 cm, resulting in a total of 200 samples. Data collection instruments included standardized soil sampling kits, soil test analyzers for chemical and physical parameters, microbial activity assay kits, and farmer questionnaires covering management practices. The soil samples underwent laboratory analysis to determine chemical properties such as pH, organic carbon, total nitrogen, available phosphorus, and exchangeable cations, utilizing methods including pH meter readings, Walkley-Black method, Kjeldahl digestion, Olsen’s extraction, and flame photometry. Physical analyses involved texture assessment via hydrometer method and bulk density measurement. Biological activity was assessed through soil microbial biomass carbon (fumigation-extraction method) and enzymatic activity assays. Data collected from soil analyses were subjected to descriptive statistics, while inferential analysis involved Analysis of Variance (ANOVA) and multiple regression models to compare soil fertility indices and determine predictors of soil health under each system. The theoretical framework incorporated the Soil Fertility Concept (Sustainable Soil Use Theory) and the Ecological Niche Theory to interpret microbial and nutrient cycling differences. This investigation anticipates that organic systems will demonstrate significantly higher soil organic carbon, microbial biomass, and enzymatic activity, indicating enhanced biological fertility, whereas conventional systems may exhibit higher available nutrients but potentially lower biological activity. The analysis aims at elucidating the trade-offs and synergies within the two systems, contributing to a nuanced understanding of soil health dynamics. The findings are expected to fill existing knowledge gaps regarding the specific impacts of organic versus conventional practices on soil properties within smallholder and commercial farming contexts. The study’s contribution lies in providing a comprehensive, evidence-based assessment that links management practices to soil fertility outcomes, thus supporting policy formulation and extension services aimed at promoting sustainable agriculture. The main conclusion emphasizes that organic farming systems enhance biological and chemical aspects of soil fertility, although they may require longer periods to achieve nutrient parity with conventional systems. Based on these findings, recommendations include integrating organic amendments into conventional practices to improve soil biology, promoting organic methods among farmers, and encouraging policies that incentivize sustainable soil management. Future research should explore long-term impacts and scalability across different agro-ecological zones to bolster sustainable intensification efforts.