The Influence of Different Vegetation Types on Soil C, N, P Content, and Their Stoichiometry in the Eastern Qilian Mountains' Binggou River Basin

Abstract

To investigate the impact of vegetation types on the ecological stoichiometry of soil carbon, nitrogen, and phosphorus, and to reveal the nutrient limitation and cycling patterns in the terrestrial ecosystem of a tributary, Quanshui River, in the upper reaches of the Shiyang River. The study focused on the marshland of Quanshui River, shrubland of Iris lacteal Pall and Potentilla fruticosa, and the forest of Picea crassifolia. The analysis covered the characteristics of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) content, and stoichiometric ratios in the 0-60cm soil depth across different vegetation types. The results indicated that: (1) In the 0-60cm soil layer, SOC was highest in shrubland, followed by forest and grassland. TN was highest in grassland, followed by forest and shrubland. In the 0-30cm soil layer, grassland exhibited significantly higher TP content compared to forest and shrubland. SOC, TN, and TP content in forest, grassland, and shrubland were higher in the 0-10cm layer compared to the 10-20cm layer. ( 2) Soil C:N, C:P, and N:P ratios were significantly influenced by different vegetation types. The C:N and C:P ratios were highest in shrubland, followed by forest and grassland. The N:P ratio was highest in grassland, followed by forest and shrubland. The vegetation growth in Quanshui River was found to be more limited by soil nitrogen than phosphorus. Therefore, based on the actual conditions of vegetation types, the rational application of nitrogen and phosphorus fertilizers is recommended to enhance nutrient retention in the soil and maintain ecological balance.