漓江流域喀斯特森林土壤碳氮磷储量分布特征及其影响因素

以探明漓江流域喀斯特森林土壤的碳氮磷储量分布为目的，为保护漓江流域脆弱的喀斯特生态系统提供理论依据。在漓江上中下游各流域段的典型喀斯特森林共设置20 m×20 m的15块天然林样方，对森林植被进行每木检尺调查，采用五点采集法采集0—20,20—40 cm土层土壤，分析土壤碳氮磷储量空间分布情况及驱动因子作用途径，量化各类生物和非生物因子对区域喀斯特森林土壤养分储量分布格局形成的作用贡献。结果表明：(1)漓江流域喀斯特森林土壤碳氮磷储量平均分布表现为上游>下游>中游，在漓江流域喀斯特森林土壤中碳、氮、磷储量分别为55.8～192.0,3.1～14.8,6.0～12.0 kg/m²。在同一流域土壤中，0—20 cm土层碳氮含量均显著高于同流域20—40 cm土层，磷元素在漓江流域不同深度土层中未表现出显著差异。(2)碳储量与C/P、N/P、森林物种多样性Shannon-Wiener指数和Simpson指数均呈现出显著正相关关系；氮储量与C/P、N/P、Shannon-Wiener指数和Simpson指数均呈现显著正相关关系，与C/N呈现显著负相关关系；磷储...

Distribution Characteristics and Influencing Factors of Soil Carbon, Nitrogen and Phosphorus Storage in Karst Forest in the Lijiang River Basin

In order to explore the distribution of soil carbon, nitrogen and phosphorus storage in Karst forest in the Lijiang River Basin, and to provide a theoretical basis for protecting the fragile Karst ecosystem in the Lijiang River Basin, a total of 15 natural forest quadrats of 20 m × 20 m were set up in the typical Karst forests in the upper, middle and lower reaches of the Lijiang River, and the forest vegetation was surveyed for each tree. The 0-20, 20-40 cm soil layers were collected by five-point collection method to analyze the spatial distribution of soil carbon, nitrogen and phosphorus storage and driving factors, and to quantify the contribution of various biological and abiotic factors to the formation of soil nutrient storage pattern in karst forest. The results showed that: (1) The average distribution of soil carbon, nitrogen and phosphorus storage in the Karst forest in the Lijiang River Basin was upstream > downstream > midstream. In the Karst forest soil of the Lijiang River Basin, the storage of carbon, nitrogen and phosphorus was 55.8~192.0, 3.1~14.8, and 6.0~12.0 kg/m², respectively. The storage of carbon and nitrogen in 20 cm soil layer in the same watershed was significantly higher than that in 20-40 cm soil layer, while phosphorus storage did not show significant difference in the soil layers of different depth in the Lijiang River Basin. (2) Carbon storage showed a significant positive correlation with C/P, N/P, Shannon-Wiener index and Simpson index of forest species diversity; nitrogen storage had a significant positive correlation with C/P, N/P, Shannon Wiener index and Simpson index, while a significant negative correlation with C/N; the phosphorus storage had a significant negative correlation with C/N, and there was no significant correlation with forest species diversity. (3) The stoichiometric characteristics of Karst forest soil chemistry in the Lijiang River Basin were the direct driving factors driving the distribution of soil carbon, nitrogen and phosphorus storages, and the stoichiometric characteristics of deep soil were the most important direct driving factors. Secondly, forest species diversity played an important role in the immobilization and input of soil nutrients, directly affecting and driving the formation of soil carbon and nitrogen storage distribution pattern. The formation of phosphorus storage was not driven by the impact of forest vegetation conditions. In the Karst forest soil in the Lijiang River basin, the stoichiometric characteristics and the diversity of forest plants had played an important role in the formation and decomposition of soil carbon, nitrogen and phosphorus reserves. It is advocated to improve the water and fertilizer storage functions of forest soil in the Lijiang River Basin by improving the species diversity of forest vegetation in the Lijiang River Basin, while protecting the fragile karst forest ecosystem in the Lijiang River Basin.