THE EFFECT OF SAROSATE (N-PHOSPHONOMETHYL GLYCINE) ON THE GROWTH AND SPORULATION OF COMMON SOIL FUNGI

THE EFFECT OF SAROSATE (N-PHOSPHONOMETHYL GLYCINE) ON THE GROWTH AND SPORULATION OF COMMON SOIL FUNGI

ABSTRACT
The impact of Sarosate (N-phosphonomethyl glycine), a widely used nonselective herbicide, on soil fungal communities was investigated to understand its effects on mycelial growth and sporulation. Three commonly occurring soil fungi—Aspergillus niger, Trichoderma sp., and Penicillium sp.—were cultured on Potato Dextrose Agar (PDA) supplemented with Sarosate at concentrations of 0%, 0.01%, 0.1%, 0.5%, and 1.0% (v/v) over a 96-hour period. Results indicated that while mycelial extension increased over time for all species, higher herbicide concentrations were associated with reduced growth rates. Despite the inhibitory effects on growth, sporulation occurred across all concentrations by 48 hours. These findings demonstrate that Sarosate exerts a concentration-dependent inhibitory effect on soil fungi but does not completely prevent fungal reproduction. The study highlights the need for careful herbicide management to preserve soil microbial diversity and maintain soil health in agricultural ecosystems.

CHAPTER ONE: 

INTRODUCTION

1.1 Background of the Study
Herbicides play a critical role in modern agriculture by controlling unwanted plant growth, thereby enhancing crop yield and productivity. Sarosate (N-phosphonomethyl glycine) is a non-selective herbicide extensively used worldwide due to its broad-spectrum weed-killing ability. While effective in weed management, herbicides can influence non-target organisms, including soil microorganisms that are vital for nutrient cycling, soil structure, and plant health. Soil fungi such as Aspergillus niger, Trichoderma sp., and Penicillium sp. are essential decomposers and contribute to organic matter breakdown, nitrogen cycling, and soil fertility. Understanding how herbicides affect these microbial populations is crucial for sustainable agricultural practices.

1.2 Statement of the Problem
Excessive or improper use of herbicides like Sarosate can disrupt soil microbial communities, potentially reducing soil fertility and ecological balance. There is limited research examining the direct effects of Sarosate on the growth and reproductive capacity of soil fungi in Nigerian agricultural contexts. This study addresses the knowledge gap by evaluating how different concentrations of Sarosate influence the mycelial growth and sporulation of key soil fungi.

1.3 Purpose of the Study
The primary objective of this study is to assess the effect of Sarosate on the growth and sporulation of selected soil fungi. Specifically, the study aims to:

1. Determine the concentration-dependent effects of Sarosate on mycelial extension of Aspergillus niger, Trichoderma sp., and Penicillium sp.
2. Examine the herbicide’s impact on fungal sporulation over a defined period.
3. Provide insights for sustainable herbicide application that safeguards beneficial soil microorganisms.

1.4 Significance of the Study
The study provides valuable data on the ecological impact of herbicide use, highlighting potential risks to soil microbial diversity. Findings from this research can inform farmers, agronomists, and policymakers about safe herbicide concentrations that minimize adverse effects on beneficial soil fungi. Additionally, the research contributes to a broader understanding of how chemical inputs influence soil ecosystem health, which is critical for sustainable agricultural development.

1.5 Scope of the Study
This research focuses on three common soil fungi—Aspergillus niger, Trichoderma sp., and Penicillium sp.—grown under controlled laboratory conditions on Potato Dextrose Agar supplemented with varying concentrations of Sarosate. The study measures mycelial growth and sporulation over a 96-hour period, providing insights into the herbicide’s inhibitory effects without extending to field-scale interactions.