Wu Xianzhong, Wang Xing, Teng Yuan, Chen Dong, Wang Xudong, Ma Bing
College of Urban Environment, Lanzhou City University, Lanzhou 730070, China.
College of Forestry and Prataculture, Ningxia University, Yinchuan 750021, China.
Sci Total Environ. 2024 Nov 10;950:175145. doi: 10.1016/j.scitotenv.2024.175145. Epub 2024 Jul 31.
Deep soil drying is a physical soil phenomenon that has become increasingly characteristic to artificial afforestation on China's Loess Plateau. Current research is largely short of conclusive reports on soil moisture recovery following deep soil drying in afforested lands. In this study, a 10-m deep underground column was constructed at Pengyang Experimental Station in Ningxia. The CS650-CR1000 automatic soil moisture monitoring system and BLJW-4 small meteorological observation stations were used to respectively monitor soil moisture and meteorological conditions in the study area for the period 2014-2019. The local rainfall was classified and the characteristics of soil infiltration analyzed at both monthly and annual scales. The results showed that: i) Deep soil moisture recovery in the semi-arid Loess Plateau region depended mainly on 25-49.9 mm and >50 mm types of rainfall; together accounting for 35.44 % of the precipitation. ii) Deep soil moisture replenishment occurred mainly for the period from April to October. While this accounted for 30.13 % of the precipitation, evaporation loss accounted for 69.87 % of it. With increasing monthly rainfall (P), the variation in monthly infiltration depth (Z) was quadratic in shape - where Z = -0.0094 P + 3.7702 P (R = 0.9577). iii) At the annual scale, deep soil moisture replenishment was mainly driven by year-on-year infiltration water accumulation. This is because a single year precipitation infiltration was not enough to replenish deep soil moisture. The cumulative infiltration depth for 2014-2019 was 180, 260, 400, 700, 1000 > 1000 cm. It suggested that soil water infiltration and deep dry soil recovery occurred at different times under rainfed conditions in the semi-arid loess hills in China. This is key for in-depth studies of the hydrological process in dry soil regions.
深层土壤干燥是一种土壤物理现象，在中国黄土高原人工造林中已日益凸显。目前的研究在很大程度上缺乏关于造林地深层土壤干燥后土壤水分恢复的确凿报告。在本研究中，于宁夏彭阳试验站构建了一个10米深的地下柱状体。利用CS650 - CR1000自动土壤水分监测系统和BLJW - 4小型气象观测站，分别对2014 - 2019年研究区域内的土壤水分和气象条件进行监测。对当地降雨进行分类，并在月尺度和年尺度上分析土壤入渗特征。结果表明：i）半干旱黄土高原地区深层土壤水分恢复主要依赖于25 - 49.9毫米和大于50毫米的降雨类型；二者合计占降水量的35.44%。ii）深层土壤水分补给主要发生在4月至10月。虽然这部分占降水量的30.13%，但蒸发损失占其69.87%。随着月降雨量（P）增加，月入渗深度（Z）的变化呈二次函数关系——其中Z = -0.0094P² + 3.7702P（R = 0.9577）。iii）在年尺度上，深层土壤水分补给主要由逐年入渗积水驱动。这是因为单年降水量入渗不足以补给深层土壤水分。2014 - 2019年的累积入渗深度分别为180、260、400、700、1000、>1000厘米。这表明在中国半干旱黄土丘陵雨养条件下，土壤水分入渗和深层干土恢复发生在不同时期。这对于深入研究干旱土壤区域的水文过程至关重要。
