How much soil organic carbon is there in agricultural lands? A case study of a prime agricultural province in Southern Philippines.
Patricio J. H. P.
Author Affiliation: Department of Environmental Science, College of Forestry and Environmental Science, Central Mindanao University, University Town, Musuan, Bukidnon, Philippines.
AES Bioflux 6 : 194-208
Abstract : This paper is a synthesis of the study on the estimation of the actual contribution of major agricultural land use types in Bukidnon, an agricultural province in Southern Philippines, as soil carbon sink. Soil organic carbon sampling was done in plantations of corn, rice, sugarcane, pineapple, banana, rubber, cassava, coconut, coffee, and mango. Carbon saturation deficit of soils in these plantations was also determined. Among the 10 land use types examined, rubber and coconut plantations showed significantly the highest soil organic carbon sequestered amounting to 37.1 MgC ha-1 and 30.3 MgC ha-1, respectively while pineapple plantation had the least at 14.7 MgC ha-1. Overall, soil organic carbon sequestration in these agricultural land use types goes in the following order: rubber plantation (37.1 MgC ha-1) > coconut plantation (30.3 MgC ha-1) > rice plantation (22.7 MgC ha-1) > cassava plantation (22.3 MgC ha-1) > coffee plantation (20.0 MgC ha-1) > sugarcane plantation (19.8 MgC ha-1) > mango plantation (19.3 MgC ha-1) > banana plantation (18.3 MgC ha-1) > corn plantation (17.5 MgC ha-1) > pineapple plantation (14.7 MgC ha-1). Land use devoted for rubber plantation is basically soil carbon saturated with mean Corg/Cref ratio of 0.99 which is comparable to that of a natural forest while those areas utilized for pineapple, corn and sugarcane production had the greatest carbon saturation deficit. Results of this study need to be effectively communicated to various stakeholders especially policymakers to institutionalize interventions that are vital to maintain, if not further increase existing soil carbon stocks in such agricultural lands.