西双版纳橡胶农林复合系统土壤团聚体稳定性研究

Water-Stable Aggregation of Soil in Different Types of Rubber-Based Agroforestry Ecosystems in Xishuangbanna

研究西双版纳地区橡胶-云南大叶茶、橡胶-可可、橡胶-大叶千斤拔、橡胶-咖啡、橡胶-龙血树5种典型胶农复合生态系统及单层纯橡胶林、热带雨林土壤团聚体的稳定性特征、有机碳含量以及与土壤物理性质的关系。结果表明：与热带雨林相比，单层橡胶林〉5mm水稳定性团聚体和〉0．25 mm水稳定性团聚体均极显著降低，平均质量直径下降了103．20％，团聚体破坏率增加了3．6倍；除了橡胶-咖啡复合系统外，其余胶农复合系统〉5mm、〉0．25 mm水稳定性团聚体及MWD均大于单层橡胶林；与单层橡胶林相比，胶农复合系统能使0-10 cm土层有机碳含量增加5．30％-69．69％；团聚体中碳含量表现为，粒径越小，有机碳含量就越低；胶农复合系统不同样地间的土壤理化性质指标存在较大差异，其中土壤容重和土壤孔隙度均与〉0．25 mm和〉5 mm水稳定性团聚体及与MWD呈显著线性关系。综上所述，大面积单层纯橡胶林在改造为胶农（林）复合系统后，其土壤质量状况得到了明显的改善。

We measured the content and soil physicochemical properties of water-stable aggregates and the con- tent of organic carbon from five rubber-based （Hevea brasiliensis ） agroforestry ecosystems with different interplants （Camellia sinensis, Theobroma cacao, Flemingia macrophylla, Coffea arabica ,and Dracaena americana）, one rubber monoculture, and tropical rain forest in Xishuangbanna, southwest China. The results showed that when compared with tropical rain forest,the content of 〉5 mm and 〉0. 25 mm water-stable aggregates collected from rubber mono- culture signifi creased by 3. content, with cantly decreased, Meanwhile, the weight diameter （WMD） decreased by 103.20%, and PAD0.25 in- 6 times. When compared to rubber monocuhure, agroforestry ecosystems displayed higher levels of SOC the increased level in the range of 5.3% -69. 69%. As to the content of soil organic carbon in the ag- gregates, it was discovered that the smaller the aggregates were, the lower the soil organic carbon content was. Soil physicochemical properties （ e. g. , EC, bulk density and porosity） varied significantly among different sampling sites, whereas bulk density and porosity were both significantly related to the content of 〉 0. 25 mm and 〉 5 mm water-sta- ble aggregates and WMD. The above results showed that soil quality has been improved in rubber-based agroforestryecosystems in comparison to rubber monocultures.