Evaluation of litter and soil water-holding capacity of typical forest stands in southern foot of Qinling Mountains

Existing studies on the water conservation function of forests in the Qinling region have primarily focused on regional-scale simulations, with limited attention paid to the differences and influencing factors of litter and soil water-holding capacities among different forest types at the stand scale. This has resulted in an unclear understanding of the functional mechanisms of the "Qinling Water Tower". In this study, based on field observations and plot investigations, we quantitatively compared the litter and soil water-holding characteristics of five dominant forest types within the Qinling Ecological Station. Correlation analysis was used to identify the key factors influencing water-holding capacity. The results showed that the total water-holding capacity of the litter and soil layers at the Qinling ecological station ranged from 296.74 to 414.74 t/hm², with the order being Picea wilsonii>Pinus tabuliformis>Quercus aliena var. acuteserrata>Pinus tabuliformis-Quercus aliena var. acuteserrata mixed forest>Betula albosinensis. Litter water absorption during the soaking phase exhibited three stages: rapid absorption (0~1 h), slow absorption (1~12 h), and saturation (>12 h). Meanwhile, the water loss rate during the static drainage phase remained relatively stable under the influence of environmental factors.Litter water-holding capacity primarily depended on litter storage, fresh weight, maximum water-holding capacity, slope, stand age, and stand density, while soil water-holding capacity was mainly influenced by soil non-capillary porosity, soil depth, and altitude. This study clarifies the differences in litter and soil water-holding capacities among different forest types and identifies their dominant influencing factors, providing a scientific basis for regional water conservation management.