Comparison of qualitative and quantitative approaches to soil quality assessment for agricultural purposes in South-western Nigeria

Abstract

There has been a major challenge on how to develop soil quality standards to assess changes which are practical and useful to farmers. This study assesses soil quality using qualitative and quantitative indicators and established the relationship between the two methods of assessment. Two locations (farmer’s fields) were chosen for the study in each of three states (Oyo, Osun and Ekiti) in south-western Nigeria. In each of the farmlands, soil quality was assessed qualitatively on the field using soil health cards for visual indicators produced by natural resources conservation services of United State Department of Agriculture, and quantitatively by laboratory analysis of measured properties. The values of indicators by each of the methods of assessment were separately integrated into quantitative index using soil management assessment framework. The relationship between qualitative and quantitative methods was established using correlation analysis at α0.05. Qualitative soil quality index ranged from 65 to 90%. Quantitatively, the indices ranged from 64 to 87%. Significant positive relationships (r = 0.64 to 0.93) exist between qualitative and quantitative methods. From the results, the two methods can be used interchangeably for soil quality assessment but where fund is limiting as with peasant farmers, the qualitative approach is preferable.