Faunal population as parameter for soil fertility assessment: a case of soil microarthropod study in South-Western Nigeria

The fertility of most tropical soils depends on the level of its organic matter which serves as the reservoir for most plant nutrients and food for organisms in the topsoil. Soil fauna plays a major role in the transformation processes by which plant nutrients are released from soil organic matter. Most of the soils in south-western Nigeria are dominated by low activity kaolinitic clay, generally low in plant nutrient buffering capacity, and easily depleted. As biological property of the soil, faunal population have not been greatly related to the chemical properties and explored as parameter in assessing the fertility of the soil. Though soil microarthropod populations are comparatively lower in tropical soils, the few studies on this group of soil fauna has demonstrated their significant influence on the rates of nutrient turnover. Studies aimed at determining relationships between microarthropod taxa and soil fertility parameters in south-western Nigeria reveal their potential in management of soil for sustainable crop production. In a study involving soils from eight different land-use management, microarthropod population correlated with soil organic carbon, available P and exchangeable cations, and nutrient uptake depending on their taxa. Results also indicated that microarthropod activity could influence P sorption characteristics of the topsoil.