ABSTRACT

Soil quality indices of cultivated cassava/maize land (CML1) at AKADEP Centre, fallow land (FL2) at AKADEP Centre, and vegetable land use (VL3) at Nkap all in Ikot Ekpene LGA in Akwa Ibom State, Nigeria were evaluated. Composite soil samples (18 samples) were collected from 0-20cm, and 20-40cm soil depths across the three land use types and analyzed in the laboratory. The quality indices evaluated were, soil texture, bulk density, hydraulic conductivity, total porosity, soil pH(H₂O), electrical conductivity, organic carbon, available phosphorus, total Nitrogen, organic matter, exchangeable bases, exchangeable acidity, and total microbial count using standard laboratory methods. Results showed that in the surface soil, soil pH, electrical conductivity and base saturation of Vegetable land use were significantly higher (p <0.05) than that of Cassava/maize and Fallow land. Exchangeable acidity was significantly higher in Fallow land than in Cassava/maize and Vegetable. Soil texture of all land use types were Loamy sand except soil texture of fallow land (20-40cm) was sandy loam. Soil pH, exchangeable Ca and Mg, exchangeable acidity, ECEC, and base saturation were significantly higher (p<0.05) in Vegetable land use than in Cassava/maize land use and Fallow land use. The results obtained in microbial densities in the soil samples of the three land use types showed that total microbial population in the 0-20cm cassava/maize land use, fallow land, and vegetable land, were 21.45, 26.31 and 23.3cfu/g respectively. At 20-40cm soil depth, total microbial population was 17.3, 24.21 and 20.14cfu/g in cassava/maize, fallow and vegetable land use respectively. Based on the  MVIT model, VL3 had the highest soil quality rating of 54%  at both depths, followed by  CML1 (45.5%) and FL2 (45.5%). Generally, the three land use types were rated moderate (medium) in soil quality. Based on the SQI assigned model based on weighted values of variables, CML1 was rated best in  both 0-20cm and poor in  20-40cm soil depths. FL2 was rated fair in surface soil (0-20cm) and fair in subsurface soil (20-40cm), while VL3 was fair at both 0-20 cm depth and in subsurface soil (20-40cm). The SQI in VL3 was significantly higher than that of CML1 and FL2 because selected soil indicators were above critical levels as those indicators were enhanced through a good soil management routine.