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Soil nutrients have always been an important evaluation indicator of plant production and vegetation ecological environment. Soil nutrient conditions can be tested and analyzed with soil nutrient analyzers. In order to better analyze soil conditions, soil analyzers can be used for more intuitive and accurate analysis. Soil nutrients, trace elements and so on.
The total amount of soil nutrients represents the source and pool of soil nutrients and the potential level of supply of the nutrients, while the effective nutrients reflect the effectiveness of the use of vegetation, both of which comprehensively reflect the status of soil nutrients. There are significant differences in soil nutrient properties between different vegetation communities in the study area. Soil organic carbon can not only promote soil fertility and fertilizer supply capacity, but also enhance the formation of aggregate structure, improve soil water permeability, water storage capacity and ventilation, and improve soil buffering. The soil organic carbon in the study area has the changing trend of bare land<grassland<shrub=tree forest, and Luohaibo et al. have consistent research results on soil organic matter carbon trends of different vegetation communities in karst rocky desertification areas. Soil nitrogen is the most important and most abundant element in plant nutrition. It is mainly derived from animal and plant residues, biological nitrogen fixation and fertilizer application. Soil total N and alkali-hydrolyzed N under different vegetation communities in the study area have the changing trend of bare land<shrub<shrub<forest, of which the total nitrogen of the grass is only 38% of the soil of the Qiaolin, and the alkali nitrogen is Jolin’s 66%.
Soil phosphorus is also one of the important elements of plant growth. In many natural ecosystems, the growth and activity of plants and microorganisms are limited by phosphorus. The total phosphorus and available phosphorus in the study area showed that the forest and shrub were significantly higher than those in the grass and bare land. The total phosphorus in the grass was 41% of the soil in the forest, and the effective phosphorus was 80% in the forest. In the process of vegetation succession, soil and vegetation interact with each other. Soil nutrients not only affect the growth of vegetation, but also affect the structure of vegetation community. After changes in the structure and structure of vegetation communities, the quality and quantity of soil are provided through the litter and root residue. Different organic matter, thus affecting the status of soil nutrients. Due to the low productivity of grass vegetation, there are few litter and root remnants that are returned and available for decomposition, so the content of soil organic carbon and other nutrients is the lowest. In contrast, the biomass of vegetation covered by arbors and shrubs is large, the litter content in the soil is high, and with the decomposition of root residues and secretions, the nutrients are released and returned to the soil. Carbon, total nitrogen and other nutrients are high. At the same time, the ability of different vegetation communities to maintain soil nutrients is also inconsistent. Therefore, different vegetation communities affect soil nutrient content. On the whole, the soil nutrient content of forests and shrubs in the study area is significantly higher than that of the grass, while the vegetation communities are significantly higher than the bare land, and they are different from those of Liu Fang et al. and Si Bin et al. The results of soil nutrient characteristics under vegetation succession in the process of degradation and restoration of karst ecosystems are consistent.
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