Effect of Intensive Vegetable Cultivation on Soil Organic Carbon Storage in Akwa Ibom State, Southeastern Nigeria

An empirical study was carried out to assess the effect of intensive vegetable cultivation on the amount of soil carbon stored in Abak, Onna, Uyo and Ikot Ekpene area of Akwa Ibom State, Southeastern Nigerian. The objectives of the study were to; assess the types of farming practices in the study area, characterize the physical and chemical properties of soils, quantify the amount and types of organic carbon stored as well as assessing the functional pool of soil organic carbon. Random and systematic sampling techniques were used for the collection of soil samples. Data was analyzed using descriptive and inferential statistics. The results showed that the average amount of soil carbon sequestered was similar among the study locations, ranging from 497.4 to Mgha-1 in Abak to 576.7 Mgha-1 in Uyo. The average amount of carbon stored in the uncultivated soil range from 417.3 Mgha-1 in Uyo to 799.0 Mgha-1 in Abak. On the average, the amount of carbon stored in the uncultivated soil was 575.6 Mgha-1 greater than 535.2 Mgha-1 in the cultivated area by about 7%. The results also showed that potential mineralized carbon (PMC) was also similar among the locations, ranging from 4.20 MgC02- C ha-1 in Uyo to 5.04 MgC02- C ha-1 in Ikot Ekpene cultivated area. In the uncultivated area, PMC range from 3.01 MgC02- C ha-1 in Onna to 5.24 MgC02- C ha-1 in Ikot Ekpene. Soil carbon storage can be improved by the application of organic manures and use of planted fallows in the cultivated areas.