The Response of Organic Compositions of Hainan Latosols to Rubber Planting and Rubber Continuous Cropping

Key words: 
• Rubber plantation /
• Regeneration /
• Continuous cropping /
• Latosol soils /
• Organic compositions

Abstract: This study takes the latosols developed from granite parent material soil that under the natural secondary tropical rain forest,the first generation rubber plantation and the second generation rubber plantation in Hainan as the research object making scientific researches on the changes of soil organic compositions and migration in the soil. The results showed that the natural secondary forest in the 0- 20 cm soil layer,soil organic carbon and carbon content of each unit were significantly higher than the first generation and the second generation rubber plantation. Soil organic carbon,particulate organic carbon,humic acid and carbon black carbon content of the first generation rubber plantation were significantly higher than that of the second generation. The fulvic acid and GRSP carbon content of the second generation were decreased,but with the first generation had no significant difference. In the 20- 40 cm soil layer,the soil organic carbon and organic compositions of natural secondary forest and first generation rubber plantation were not significantly different. Organic carbon,particulate organic carbon,humic acid and carbon black carbon content of the natural forest soil were significantly higher than that of the second generation. The soil particulate organic carbon and Humin acid carbon content of first generation rubber plantation were significantly higher than the second generation rubber plantation but the difference of other organic compositions carbon content was not significant. With rubber planting and rubber continuous cropping,soil organic matter and the organic compositions were greatly reduced. At the same time,it had affected the distribution of organic components in the surface and subsurface. Natural secondary forest soil had obvious surface accumulation but the difference was not significantly in rubber plantation.