第七届青年地学论坛

Recent and rapid expansion of rubber plantations requires understanding of their effects on soil physicochemical properties and soil quality. An ideal testbed for analyzing such land-use change and its impacts is Hainan Island, the largest tropical island in China which, in recent decades, has seen a dramatic expansion in the rubber industry. Based on fourteen soil physicochemical properties at two soil depths (0–20 and 20–40 cm) a comprehensive assessment index (CAISPP) was established employing principal component analysis to assess soil qualities under rubber plantations (monoculture and intercropping) and five additional land-use types (areca palm, eucalyptus and banana plantations, secondary forest, and tropical rainforest). The following results were obtained: (i) total porosity, ammoniacal nitrogen, total phosphorus, available phosphorus, and soil organic matter were vital soil physicochemical properties contributing to the comprehensive assessment index. (ii) The comprehensive assessment indices of rubber plantations were significantly lower than those of tropical rainforest and areca palm plantation. (iii) Intercropping improves most soil physicochemical properties in rubber plantations comparing monoculture and intercropped rubber plantations. (iv) Redundancy analysis demonstrated that land-use type interacted with climatic, geographical, and edaphic factors, and collectively explained about half of the variation in the soil physicochemical properties across the study area. Deteriorating soil quality by converting tropical rainforest to rubber plantations and other land-use types, provides another reason to protect tropical rainforests, especially on area limited islands like Hainan.

rubber plantations,soil physicochemical properties,a comprehensive assessment index