喀斯特地区不同退耕类型对土壤碳氮的影响

为探讨不同退耕模式对喀斯特峰丛洼地土壤碳氮特征的影响,选取广西环江典型退耕类型样地进行有机碳、全氮特征研究,结果表明:不同退耕类型之间的土壤有机碳、全氮差异显著;各退耕类型土壤有机碳和全氮都表现出随土层加深而逐渐降低趋势;土壤有机碳和全氮线性拟合呈显著正相关.表明退耕还林(草)显著提高了土壤有机碳、氮,但在植被类型和人为活动的影响下土壤碳氮特征差异明显.

Effects of Different Types of Reforestation on Characteristics of SOC and TN in Karst Areas

To investigate the effects of different types of reforestation on the characteristics of soil organic carbon (SOC) and total nitrogen (TN) in karst peak-cluster depressions,SOC and TN concentrations of soil samples collected from seven typical types of returned farmland sites in Huanjiang County of Guangxi Autonomous Region were studied. The results showed that the contents of SOC and TN were both significantly different among the types of returned farmland,the surface soil SOC and TN contents of natural restoration were both highest while those of the cultivated land were lowest. SOC and TN contents tended to decrease with increasing soil depth. Linear regression revealed that SOC was in significant positive correlation with TN. Generally,SOC and TN contents increased dramatically by reforestation but showed obvious difference which was influenced by vegetation types and human disturbance.