Evaluation of Nutrient Status of Soils Under Parkia biglobosa for Sustainable Production and Climate Change Mitigation in Ogbomoso, South West, Nigeria

Abstract

The African locust bean (Parkia biglobosa) is a multi-purpose tree that is commonly retained on small-holder farms in the savanna region of West Africa. Nutrient status of soils under African locust bean was evaluated to ascertain the effects of the tree on soil physical and chemical properties and suggest management practices needed for an increased production and climate change mitigation. This study was carried out in Ogbomoso North, Orire and Surulere Local Government Areas of Oyo state, Nigeria. Nine villages in Ogbomoso North (Lautech farm, katangua, Amama), Orire (Fedegbo, Obamo, Olooru) and Surulere (Oloose, Iregba and Iresa) Local Government areas were randomly selected based on the predominance of farming occupation over other occupations in the local government areas. Soil samples were collected in triplicate with the aid of a soil auger. In each village, three farms planted each with Parkia biglobosa were sampled at the depth of 0-20cm with the use of soil auger for physical and chemical analysis in the laboratory. Organic carbon was variably low and medium between villages of the study area of parkia canopy. Micro nutrients such as Iron, copper, zinc and manganese were very high, exchangeable magnesium and potassium were high. Calcium is medium while nitrogen, phosphorus and sodium are low in soil under the tree canopy. The build-up of organic carbon under the tree was not substantial due to frequent cultivation that involved site burning that destroys plant litter that would have been converted into soil organic matter when allowed to decompose in situ. Furthermore, growth of parkia trees and seedlings will be retarded in areas with predominantly sandy soils and this should be taken into consideration in afforestation, community forestry and shelterbelt projects involving the establishment of parkia trees.