尖峰岭自然保护区土壤性质空间异质性

选取尖峰岭热带林自然保护区水平和垂直两条样带10个主要的生态系统类型,研究了该地区土壤性质的空间异质性特征。结果表明水平样带0~20cm土壤有机碳、总氮、速效氮含量变异顺序为原始林>次生林>3种人工林;垂直样带0~20cm土壤有机碳、总氮、总磷含量表现为山地雨林原始林最高,向高海拔和低海拔两端逐渐降低的趋势,且差异达到显著水平。土壤速效养分有效氮和有效磷以及阳离子交换量表现出与其它养分指标不同的变化趋势,但在水平和垂直样带都表现出与pH值有很好的相关性。位于中、高海拔,人为干扰最轻的山地雨林原始林具有最好的土壤养分保持能力,土壤综合质量指数最高。在受干扰类型中天然次生林土壤综合质量指数最高。在海拔梯度上,常绿季雨林是最易受干扰也是对干扰最敏感的生态系统类型。表明热带森林原始林对维持土壤质量及天然林破坏后使其自然恢复为保持土壤质量具有重要意义。

Spatial heterogeneity of soil properties in Jianfengling Nature Reserve

In this paper, horizontal and vertical strips including ten types of ecosystems in Jianfengling Nature Reserve of Hainan Island were chosen to study the spatial heterogeneity of soil properties in this region. The results showed that on horizontal strip, the organic carbon, total nitrogen and available nitrogen contents in 0-20 cm soil layer ranked in the order of tropical mountain rain forest>natural secondary forest>Caribbean pine, Chinese fir and tea-oil camellia plantations. On vertical strip, the contents of organic carbon, total nitrogen and total phosphorus in 0-20 cm soil layer were the highest in tropical mountain rain forest, and had a decreasing trend towards higher and lower altitudes, with significant difference between test ecosystems. Soil available nitrogen, available phosphorus, and cation exchange capacity had different variation sequences with other soil properties, but significantly correlated with soil pH. The tropical mountain rain forest located at mid-high altitude with slight anthropogenic disturbance had the highest soil nutrient-holding capacity and integrated soil quality index. Among the disturbed forest types, natural secondary forest had the best integrated soil quality index. At altitude gradient, tropical evergreen monsoon forest was the most vulnerable and sensitive forest type. Soil quality maintenance would be of significance in protecting tropical original forest and promoting its natural restoration after destroyed.