3.3 Effect of soil moisture and pH on SIC content
The relationship between SIC content and pH and soil moisture was evaluated by the linear regression method, as shown in Figure 5. In the 0-300 cm soil layer, SIC content showed a significant negative correlation with soil moisture (P < 0.001), while a significant positive correlation with pH (P < 0.05) was observed only in the deeper 200-300 cm soil layer. It showed that the degree of influence of soil pH on SIC varied with increasing soil depth, while soil moisture had a significant effect on SIC in all the different soil layers.