Assessment of organic carbon stock in cashew plantations (Anacardium occidentale L.) in Benin (West Africa)

Abstract

The present study aims to assess cashew plantations carbon sequestration potential following a climate gradient in Benin. The study was carried out in the Transitional, Sudano-Guinean and Sudanian zone, in the farmers’ cashew plantations. The study was carried out from March to October 2016 and six plantations of 15 years and Diameter at Breast Height (DBH) between 0- 20 and 20-40 cm were selected across the cashew growing areas. Allometric equations were used to assess carbon stock in the biomass and laboratory analyze to assess soil carbon stock. High carbon stock was recorded in the transitional zone (84.84± 4.06 t C /ha) against 63.14±3.78 t C /ha in the sudanian zone. In general, 78.9% of the carbon stock was found in the trunk of the trees against 19% and 2.1% respectively in the branches and in the leaves. Carbon sequestrated in the soil varied between 80.99 and 45.88% according to the zones. Temperature and the total carbon stock were significantly and negatively correlated (Pearson correlation coefficient r = - 0.903 and P < 0.05). A rise of the temperature causes the decrease of the stock of carbon in the cashew plantations. Cashew-based cropping systems can be considered as carbon well.