Soil Characteristics in Semi-Arid Climate: A Case Study of a Northeastern Nigerian Plain of Low Relief

Abstract

This study was embarked upon to evaluate soil resources on a plain of low relief in a semi-arid area of northeastern Nigeria. Field work was accomplished first by delineation of study area based on soil type and then obtaining soil samples by auger drillings to a depth of at least 90cm. Three major soil mapping units were identified: Aeolian, alluvial, and seasonal inundated areas. The area is characterized by low rainfall and humidity with a mean of 883mm and 56% respectively. Vegetation distribution is low especially in the dry season when 88% of the landscape is without vegetation. A major problem identified in the study area is the prevalent nature of soil infertility. This has to do especially with low cation exchange capacity (< 4cmol/kg), organic matter contents (< 1.4%) and macro nutrients. These soils showed low levels of organic matter (<2%) and medium base saturation (45–50%). Cation exchange processes were also extremely low, being less than 5 cmol/kg. Moreover, the amounts of available phosphorus and nitrogen were quite low. Coupled with these is the poorly aggregated nature of the soil. Soil and water conservation measures recommended include conservation tillage complemented with biochar application.