Abstract:

The pH spatial distribution characteristics and its potential influencing factors were explored in Shiping County to provide a basis for the optimization and improvement of the soil. 226 soil samples were collected from 6 main tobacco-planting towns in Shiping County. The spatial distribution characteristics of pH and its possible intrinsic factors were analyzed. The results showed that soil pH showed obvious spatial difference in Shiping. The soil pH was low in the north and high in the south, high in the west and low in the east. And altitude had significant effects on soil pH. Organic matter, exchangeable calcium, available potassium and exchangeable magnesium had a significant positive relationship with pH, and the effective phosphorus, effective copper, and effective iron showed a significant negative correlation with soil pH. Based on this, the structural equation model of soil pH and significantly related nutrient factors was constructed. It was found that the exchangeable calcium had the most action sites, which not only directly affected soil pH, but also promoted the content of organic matter, available potassium and exchangeable magnesium to indirectly regulate soil pH. Effective copper and phosphorus played a direct negative role on pH, and effective iron indirectly affected soil pH by promoting effective copper content. Above all, the soil nutrient had positive or negative effects on soil pH. Changeable calcium had direct and indirect effects on soil pH. Organic matter and available potassium had positive effects on soil pH. Effective copper and phosphorus played a direct negative role on pH and effective iron indirectly affected soil pH. It could provide a reference for soil pH regulation.

Key words: soil pH, spatial distribution, altitude, soil type, soil nutrients