EVALUATION OF CASHEW PLANTATION (Anarcadium occidentale L.) SOIL FOR PRODUCTIVITY AND CLIMATE CHANGE MITIGATION IN OGBOMOSO, SOUTH WEST NIGERIA

Abstract

Land use and soil management practices are the keys to improving the SOC of the soil and maintaining sustainable agricultural production. This research was conducted in Ogbomoso North, Orire and Surulere Local Government Areas of Oyo State to assess the soil organic carbon stock and other soil properties of Cashew (Anarcadium occidentale L.) under plantation crops. Three farms noted for cashew plantations were visited and in each village, three farms planted each with cashew (Anarcadium occidentale) were sampled at 0-20 cm depth for laboratory analysis of particle size, pH, C, N, P, EC and extractable micronutrients. The bulk densities at 0-5 cm, 5-10 cm and 10-15 cm depths were determined. Soil properties were analysed using descriptive statistics. The soil texture was sandy loam with soil pH ranging slightly acid to moderately acid (6.4 to 6.09). Irrespective of the local government areas, land use and OC (1.15 cmol kg-1), N (0.08 g kg-1), Na (0.74 cmol kg-1) and P (4.91 mg kg-1) were low. While Cu (7.68 mg kg-1), Fe (112.00 mg kg-1), Mn (154.5 mg kg-1), Ca (4.09 cmol kg-1) and K (0.233 cmol kg-1) were medium and Mg (1.35 cmol kg-1) were high. Total soil carbon (4011 kg C/ha) was very high. The bulk density ranged from 1.74 to 2.27 which were very high. In conclusion, most of the plantations were low in fertility, low carbon stocks which is assumed to be due to losses arising from continuous tillage practices and continuous cropping. The carbon storage status of land uses in the study area was low. Management practices like residue retention, use of organic fertilizer, green manuring, early harvesting and composting are recommended.