Study on the Carbon, Nitrogen and Phosphorus Stoichiometry of Typical Forest Soils and Its Water-holding Capacity in Southwest of Zhejiang Province

The eco-chemical characteristics research of forest soil carbon (C), nitrogen (N), and phosphorus (P) and the soil water-holding capacity exploration are helpful for mastering the differences in soil carbon, water and nutrient reservoirs of different forests, providing a foundation for forest construction and stand structure adjustment. In this study, with the typical broad-leaved forest, coniferous and broad-leaved mixed forest and coniferous forest in Shigu Mountain, Longyuan Forest Park, Longquan City, Zhejiang Province as the research objects, the samples are collected, the soil C, N, P content and soil water-holding performance are analyzed on the basis of investigation of forest stands. It is found that the diameter distribution of broad-leaved forest and coniferous broad-leaved mixed forest was positively skewed, while that of the coniferous forest was in an inverted “J” shape. The soil C, N, P content of the broad-leaved forest were significantly higher than those of the remaining (P<0.05). The differences in soil C/N, C/P, and N/P ratios among different forests weren’t significant (P>0.05), there were no significant differences in soil bulk density and total porosity of different forests (P>0.05). The field water-holding capacity, capillg capacity, actual water-holding capacity, and maximum water-holding capacity of the broad-leaved were 420.57, 03.31, 625.02, and 806.18 g kg^-1, respectively, all of which significantly higher than those of the others (P<0.05). There was a significant negative correlation between the soil C, N content and the bulk density (P<0.05), a significant positive correlation between the soil C, N content and the total porosity (P<0.05), and an extremely significant positive correlation among the soil C, N content, water-holding capacity, capillary water-holding capacity, actual water-holding capacity, and maximum water-holding (P<0.01). The significant positive correlation between soil P content and capillary water-holding capacity and actual water-holding capacity existed (P<0.05). In conclusion, forest soil with high C and N content still has excellent water-holding capacity, the proportion of broad-leaved tree can be appropriately increased in forest construction and stand reconstruction in the future.