天然次生林退化对黄土关键带土壤水分的影响——以蒙古栎为例

With the advance of ecological restoration and vegetation reconstruction, important progress has been made in the research on the relationship between plant growth and soil water at home and abroad. However, most of the existing research focuses on artificial vegetation or non-degraded natural vegetation, and the research on the change in deep soil water after the degradation of natural secondary forests and its mutual feedback relationship with vegetation is still insufficient. In this study, we compared degraded and non-degraded Quercus mongolica and farmland plots, we found that the root system of Quercus mongolica can extend to a depth of 1500 cm, with 95% of the root biomass is concentrated in the 0–600 cm soil layer. The soil water content (SWC) in the 0–600 cm profile ranged from 5.3% to 20.8%, with an average of 11.9%. There were significant differences in the mean SWC among the three treatments (p<0.001), both degraded and non-degraded plots showed excessive depletion of deep soil water resources, which intensified the drying of deep soil and the formation of dry soil layer. Although the soil water in the degraded plots has recovered to some extent, the degree of recovery is limited. The change in the relationship between root traits and SWC is the main reason for the difference in soil water in the root zone. The study can provide scientific reference for vegetation management and water resources regulation in the Loess Critical Zone and help build the ecological barrier in the Loess Critical Zone.