Potentials of Soils derived from Asu River Group and Asata Nkporo Shale for Arable Crop Production in Ebonyi State, Nigeria

Land capability classification (LCC), fertility capability classification (FCC) and land suitability evaluation of some soils of Ebonyi State were carried out for cassava, yam and maize cultivation. Land capability and fertility capability classes were obtained using the method of United State Development of Agriculture (USDA) while suitability evaluation was done using the Food and Agricultural Organization of the United Nations' (FAO) conventional method. Four (4) pedons were investigated, two from Akaeze (Asu river group) and two from Abakaliki (Asata nkporo shale) . Results of LCC showed that sites 1 and 2 (Asu river group) were classified as class II soils while sites 3 and 4 (Asata nkporo shale) were classified as class IV soils. According to FCC results, the major classes obtained were SM,g,k for site 1, A,g,k for site 2 and SA,e,k,r for sites 3 and 4 respectively. The results of land suitability evaluation showed that despite climatic factors and topography, there was no highly suitable (S1) land for maize, yam and cassava cultivation. Total nitrogen and organic carbon contents of pedons 1, 2 and 4 were marginally (S3) suitable for the production of yam and cassava while the nitrogen and organic carbon contents of pedon 3 were currently not suitable (N1) for yam and cassava cultivation. Soil texture, pH, ECEC and available phosphorus made the 4 sites moderately suitable (S2) for cassava and yam cultivation. Also,the acidic condition of the soils made all the sites moderately suitable for maize production. From the results of the aggregate suitability ratings, the major constraint for yam, cassava and maize cultivation in the sites was soil fertility (f) resulting from low organic carbon and total nitrogen contents of the soils. Though not optimum for the cultivation of the crops evaluated, the soils can still produce increased and sustainable crop yield if the appropriate husbandry practices are adopted, with particular reference to organic and nitrogen fertilizer application.