Ecological stoichiometry of leaf C, N and P of different vegetation types in the Dry-Hot Valley of the Jinsha River

The Dry-Hot Valley of the Jinsha River has a poor ecological environment and poor vegetation growth and development. It is of great significance to explore the ecological stoichiometric characteristics of C, N and P elements in the leaves of natural forests, artificial forests and savannahs in this region for the evaluation of vegetation restoration and ecological management benefits of the Dry-Hot Valley of the Jinsha River.

In January 2021, a total of 47 plots in the upper, middle and lower reaches of the Dry-Hot Valley of the Jinsha River were investigated in the field, and the samples were collected and analyzed in the laboratory. The C, N and P ecological stoichiometric characteristics and influencing factors of the leaves of natural forests, artificial forests and savannahs in the Dry-Hot Valley of the Jinsha River were compared.

(1) The contents of C, N and P elements in the leaves of natural forests, artificial forests and savannahs in the Dry-Hot Valley of Jinsha River were affected by soil and other environmental factors, and the contents of C, N and P elements in the leaves of plants were as follows: natural forests > artificial forests > savannahs.(2) The ratios of C/N and C/P in leaves were as follows: savannahs > artificial forests > natural forests, and the ratio of N/P in leaves was as follows: natural forests > artificial forests > savannahs. (3) The growth and development of natural forests, artificial forests and savannahs in the Dry-Hot Valley of the Jinsha River were all restricted by N and P elements, among which savannahs were the most restricted by N and P elements, while natural forests were the least restricted by N and P elements.

This study shows that the contents of C, N and P elements in natural forests, artificial forests and savannahs in the Dry-Hot Valley of the Jinsha River are influenced by environmental factors such as soil. Among them, the contents of C, N and P elements in the vegetation and soil of savannahs were the lowest, and the growth and development of vegetation were the most restricted by N and P elements. The contents of C, N and P elements in the vegetation and soil of artificial forests are effectively increased, and the growth and development of vegetation are gradually reduced by N and P elements. These results indicate that artificial afforestation has achieved good results in vegetation restoration and ecological environmental governance in the Dry-Hot Valley of the Jinsha River, and it can effectively improve vegetation restoration and ecological governance effects by increasing soil moisture and soil nutrient content.