Soil Organic Carbon Stocking Ability of Some Soils Under Oil Palm (elaeis Guineensis Jacq.) and Rubber (hevea Brasiliensis Muell Arg.) Plantations in Edo State, Nigeria

This study evaluated soil organic carbon stock and its relationship with some soil microbial, physical and chemical properties. The soils were Alagba, Orlu, Ahiara and Kulfo series located in two (2) locations within Edo State namely; Nigeria Institute for Oil Palm Research (NIFOR), Benin City, (latitude 06.33’ to 06.47’N; longitude 05.37’E to 05.46’E) and Rubber Research Institute of Nigeria (RRIN), Benin City, (latitude 06.08’N to 06.11’N; longitude 05.34’E to 05.38’E). With the aid of soil maps, in each of the soil types, random auger samples were collected at a soil depth of 0-30 cm. Similarly, core samples were taken from the same point where auger boring were made. The results obtained from the study indicated that, there were significant differences among the various soil types and soil properties. The study revealed that, most of the soils were dominated by sand in Texture. The results further revealed that there were considerable variations among the soils in soil organic carbon stock contents. For example, NIFOR location had mean values ranging from 14.76 g/kg to 86.16 g/kg. While, that of RRIN ranged from 26.28 g/ kg to 104.6 g/kg. Total bacteria count ranged from 16.07 cfu/g x 103 (Kulfo soils) - 24.20 cfu/g x 103 (Alagba soils) and Total fungi count ranged from 10.00 cfu/g x 103 (Kulfo soils) - 15.00 cfu/g x 103 (Alagba soils) respectively as recorded for NIFOR soils (location 1). While, pH value ranged from 5.4 (Ahiara soils) - 6.2 (Orlu soils), Soil organic matter ranged from 38.38 g/kg (Kulfo soils) - 55.08 g/kg (Alagba soils). Total bacteria count ranged from 16.00 cfu/g x 103 (Ahiara soil) - 26.00 cfu/g x 103 (Alagba soil) and Total fungi count ranged from 10.00 cfu/g x 103 (Ahiara soil) - 22.00 cfu/g x 103 (Orlu soil) respectively as recorded for RRIN location.