Gu Kang-Min, Zhao Yun-Ge, Zhang Zi-Hui, Ji Jing-Yi, Guo Ya-Li
College of Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2022 Jul;33(7):1827-1834. doi: 10.13287/j.1001-9332.202207.010.
Water is the key factor for vegetation restoration in the Loess Plateau region. Biological soil crust (biocrust), a widely distributed soil surface cover, significantly affects soil infiltration. Disturbance would affect soil water infiltration of biocrust. The effects of different intensities of disturbance on soil water infiltration of biocrust are still unclear. By simulating the trampling disturbance of sheep, we examined the effects of disturbance intensity (10%, 20%, 30%, and 40%) estimated by the coverage of broken biocrust on the surface cover of biocrust slope in the Hegou catchment of Wuqi County, Shaanxi Province. Soil water infiltration under different intensities were measured by the linear source infiltration method. The influence mechanisms of disturbance on soil water infiltration of biocrust slope were investigated with a structural equation model and correlation analysis. Results showed that compared to that without disturbance, the coverage of cyanobacterial crust was increased by 33.6% at 10% of disturbance intensity, no difference at 20% of disturbance intensity, and decreased by 36.1% and 75.0% at 30% and 40% of disturbance intensities, respectively. Litter coverage was increased by 34.3% under 40% of disturbance intensity, while that of other treatments were not changed. Surface roughness was decreased by 22.3%, 11.1%, and 5.6% at 10%, 20%, and 30% of disturbance intensities, respectively, but increased by 8.2% at the 40% of disturbance intensity. The initial infiltration rate at 40% of disturbance intensity was 77.1% higher than that without disturbance, while other treatments had no significant difference at the initial infiltration rate. Furthermore, distur-bance did not affect the stable and average infiltration rate. Our results confirmed that disturbance mainly promoted the initial infiltration by reducing the coverage of cyanobacterial crust, increasing the coverage of litter, and changing soil roughness. This study would provide scientific basis for the management of biocrust of rehabilitated lands in the Loess Plateau region.
水分是黄土高原地区植被恢复的关键因素。生物土壤结皮作为一种广泛分布的土壤表面覆盖物，对土壤入渗有显著影响。扰动会影响生物土壤结皮的土壤水分入渗。不同强度扰动对生物土壤结皮土壤水分入渗的影响尚不清楚。通过模拟绵羊践踏扰动，我们研究了以破碎生物结皮覆盖率估算的扰动强度（10%、20%、30%和40%）对陕西省吴起县贺沟流域生物结皮坡面地表覆盖的影响。采用线源入渗法测定不同强度扰动下的土壤水分入渗。利用结构方程模型和相关分析研究了扰动对生物结皮坡面土壤水分入渗的影响机制。结果表明，与未扰动相比，扰动强度为10%时蓝藻结皮覆盖率增加了33.6%，扰动强度为20%时无差异，扰动强度为30%和40%时分别降低了36.1%和75.0%。扰动强度为40%时凋落物覆盖率增加了34.3%，而其他处理则无变化。扰动强度为10%、20%和30%时地表粗糙度分别降低了22.3%、11.1%和5.6%，但扰动强度为40%时增加了8.2%。扰动强度为40%时初始入渗率比未扰动时高77.1%，而其他处理的初始入渗率无显著差异。此外，扰动不影响稳定入渗率和平均入渗率。我们的研究结果证实，扰动主要通过降低蓝藻结皮覆盖率、增加凋落物覆盖率和改变土壤粗糙度来促进初始入渗。本研究将为黄土高原地区恢复土地生物结皮的管理提供科学依据。
