State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2023 Jul;34(7):1862-1870. doi: 10.13287/j.1001-9332.202307.020.
Gully head is the main active part of gully erosion, which seriously affects the occurrence of gully headcut erosion. To investigate root distribution and soil physical and mechanical characteristics of typical vegetation gully head, we analyzed the infiltration, root distribution, physical and mechanical properties of soil-root complex of soil in different layers (0-1 m) in natural restoration gully head and artificial restoration gully head. The results showed that the variability of soil bulk and total porosity among different vegetation gully heads was low, with bulk density ranging from 1.10 to 1.37 g·cm and total porosity ranging from 48.3% to 58.4%. Infiltration index of different vegetation gully heads generally decreased with increasing soil depth. The infiltration rate of different soil layers in natural restoration gully head tended to stabilize in 20-30 min, while that of artificial restoration gully head tended to stabilize in 40 min. The infiltration capacity and average infiltration rate of artificial restoration gully head were generally higher than those of natural restoration gully head in all soil layers. Root length density, root surface area density, and average diameter all tended to decrease with increasing soil depth. Except for the 20-40 cm soil layer, root length density, root surface area density and average diameter of natural restoration gully head were all lower than those of artificial restoration gully head. Root system of both vegetation gully heads mainly consisted of 0-0.5 mm roots, accounting for 84.2%-93.6% of the total root length. In the vertical depth, with the increases of water content, the cohesion force decreased linearly with the deepening of soil layer, ranging from 0.42 to 22.67 kPa. The average cohesion force of artificial restoration gully head was higher than natural restoration gully head at each level of water content. The study revealed the effects of vegetation on the gully head cut erosion, which could provide scientific basis for the effective prevention and control of soil erosion in the region.
沟头是沟蚀发生的主要活跃部位，严重影响沟头溯源侵蚀的发生。为了研究典型植被沟头根分布及土壤物理力学特性，分析了自然恢复沟头和人工恢复沟头不同土层（0-1 m）土壤入渗、根分布、土壤-根系复合体物理力学性质。结果表明，不同植被沟头土壤容重和总孔隙度变化较小，容重在 1.10-1.37 g·cm之间，总孔隙度在 48.3%-58.4%之间。不同植被沟头的入渗指数随土壤深度的增加而普遍降低。自然恢复沟头各土层的入渗速率在 20-30 min 内趋于稳定，而人工恢复沟头在 40 min 内趋于稳定。各土层人工恢复沟头的入渗能力和平均入渗率普遍高于自然恢复沟头。根长密度、根表面积密度和平均直径均随土壤深度的增加而减小。除 20-40 cm 土层外，自然恢复沟头的根长密度、根表面积密度和平均直径均小于人工恢复沟头。两种植被沟头的根系系统主要由 0-0.5 mm 根组成，占总根长的 84.2%-93.6%。在垂直深度上，随着含水量的增加，土壤层的黏聚力随深度的增加呈线性下降，范围在 0.42-22.67 kPa 之间。在每个含水量水平上，人工恢复沟头的平均黏聚力均高于自然恢复沟头。本研究揭示了植被对沟头切蚀的影响，可为该地区土壤侵蚀的有效防治提供科学依据。
