Evaluating quality of soils formed on basement complex rocks in Kaduna State, northern Guinea savanna of Nigeria.

A few investigations have been done regarding the soil quality index (SQI) for various locations, soil types, and states. Still, little has been reported regarding SQI for both surface and control sections, especially for the Northern Guinea Savanna of Nigeria. Due to the subsurface property pedogenic influence on soil function, it is crucial to assess SQI using surface and subsurface properties as both properties influence soil productivity. We investigated the potentials of choosing a minimum data set for soil quality indicators and assess soil quality (SQ), using both surface and entire soil pedon data for the soils on the basement complexes. Both additive and weighted soil quality indices and different scoring methods (linear and non-linear) were used in evaluating SQ. Out of the twenty-three soil properties subjected to PCA, eight indicators (TEB, clay, silt, K, EA, EC, BD, and Fe) were selected as the minimum data set (MDS). There was not much difference in the calculated soil quality using the non-linear additive (SQI-NLA), linear additive (SQI-LA), linear weighted (SQI-LW), and non-linear weighted (SQI-NLW) for the soils as they were all rated low (SQI < 0.55). The estimated SQI for the control section had relatively higher values than the surface soil, thus suggesting the need to incorporate both surface and entire soil profile properties in assessing SQ as both are important in integrating the relationship between soil properties and management goals which eventually provides complete information that affects the production of crops.

Variation of soil properties under different landscape positions and land use in Hunkuyi, Northern Guinea savanna of Nigeria.

The food insecurity problem in developing countries has been linked to rapid rates of soil loss and decline in fertility in tropical environments which are characterized by insidious topography. This study was conducted to assess the relationship between topographic positions, land use, and soil characteristics. Three slope classes were considered with six pedons; two on each slope position were opened, described, sampled, and analysed for morphological and physicochemical properties. The results showed that the soils were deep to very deep with drainage improving from HK1 soils (very poorly drained) to HK3 (well-drained). The mean sand fraction ranged between 320 and 740 g kg-1, while bulk density had values between 1.20 and 1.80 M gm-3. The cation exchange capacity (CEC) of the soils with values from 5.6 to 10.4 cmol (+) kg-1 was generally lower on the surface than the subsurface soils. The different landscape positions alongside variation in land use substantially influence variations in soil properties of the study area. The influence of topography was noticed for sand values and soil reaction (pH) along the slope, as mean pH values were significantly (P ≤ 0.05) higher for HK1 compared with HK2 and HK3. Intensive cultivation of soils due to rainfed and irrigated land use on middle slope position (HK2) alongside its strong slope gradient resulted in significant variation in total exchangeable bases (TEB) ((P ≤ 0.05), base saturation (P ≤ 0.05), available P ((P ≤ 0.01), and exchangeable Ca and Mg (P ≤ 0.05).