Organic Carbon Distribution in Soils of Various Land-use Patterns in Eastern Hainan

Distribution characteristics of organic carbon (SOC) in soils from fields of 4 different land-use patterns (i.e., paddy field, abandoned land, orchard land, and rubber forest land) in eastern Hainan Island were studied. The results showed that the SOC contents in 0-30 cm layer of the soil ranked in the order of paddy field > abandoned land > orchard land > rubber forest land. There were significant differences on SOC accumulation among the soils that decreased gradually with increasing depth. The correlation analysis showed that SOC in the paddy field or the abandoned land was significantly affected by the makeup and pH of the soil, while that in the orchard land or the rubber forest land also affected by the makeup but not the pH. Thus, for a sustainable agricultural production and a desirable SOC reserve in soil, conservation measures in tillage, such as returning straws to the rice field after harvest and applying organic fertilizer on the land, should be implemented and enforced to warrant adequate soil fertility and available land for rice farming, as well as carbon sequestration capacity of the soil for the areas on the island.