ABSTRACT
Soil fauna play a critical role in soil transformation which is important implication for soil fertility. A study was conducted in Faculty of Agriculture, Department of Soil Science Experimental farm located at University of Benin in Edo state, Nigeria. This was aimed at determining the abundance and diversity of soil fauna in chemical treated soil farmland and untreated soil farmland.
Replicate soil samples were collected and quadrants thrown both in untreated and treated sites for period of six (6) months from July-September 2017 and December 2017 - February 2018 across two seasons (rainy and dry seasons) and the soil organisms are each extracted, identified and counted. Seventeen (17) Soil physico – chemical parameters were determine (in situ) soil pH, Organic carbon, Calcium, Magnesium, Sodium, Nitrogen, Phosphate, Hydrogen ion Concentration, Aluminium, Exchange Acidity, Cation Exchange Capacity, Effective Cation Exchange Capacity, Sand, Silt, Clay and Organic Matter.
Results showed that chemicals significantly affected total soil fauna abundances, with a reduction in treated soil site when compared to the untreated soil site. These are represented in the checklist of species encountered for innstance Isoptera sp (termitoidae) a family of termites presented the highest frequency of organisms encountered in untreated soil are more abundant and less abundant in the treated soil. The soil physico-chemical paraments results showed no significant difference across the four treatments (P > 0.05) and the species richness shows that abundance of soil fauna under treated soil site had negative effect as compared to untreated soil biomes which is the control site. Diversity index results suggests that abundance and diversity are critical to the conservation and dynamics of soil organic matter nutrient release and maintenance of physical properties that are essential for a sustained primary production. There is need to improve agricultural practices due to the fact that they affect soil organisms by altering their densities and the ratios of the different groups. Many invertebrates regulate nutrient cycling by feeding directly on plant materials and organic substrates.
