Temporal Variation in Preferential Water Flow during Natural Vegetation Restoration on Abandoned Farmland in the Loess Plateau of China

Abstract

The restoration of vegetation in abandoned farmlands is an effective approach to control soil erosion on the Chinese Loess Plateau. However, few studies have investigated the effect of natural restoration age on the infiltration patterns and preferential flow in soil layers. This study examined the effect of the temporal variations in the degree of preferential flow and their contribution on the total infiltration in abandoned farmlands restored with different vegetation communities. In total, four sites were investigated, namely site AF3, AF12, AF18 and AF25 of restoration age of 3, 12, 18 and 25 years, respectively. A traditional dye tracer experiment was adopted to visualize the water flow behavior in the four sites. A semi-variance analysis was conducted to interpret the spatial variability of the soil water induced by infiltration. The results showed that both the soil properties and the root systems improved with the increased natural restoration ages combined with the effect of the plant species. The degree of preferential flow from the lowest to the highest occurred in AF3, AF12, AF18 and AF25, which was mainly affected by the development of root systems. Also, the abundant lateral root and steeper slope may have caused the presence of lateral flow in AF18 and AF25. Meanwhile, the spatial variability of the soil water in the infiltration patterns through vertical soil profiles increased from AF3 to AF25. Compared to AF3, the infiltration volume through preferential pathways in AF12, AF18 and AF25 increased by 1.73 times, 1.94 times and 4.09 times, respectively. Therefore, the preferential flow was improved in abandoned farmland in the presence of natural vegetation restoration that can increase water storage in the deep soil layer and reduce surface runoff and erosion.

Complementarity Characteristics of Actual and Potential Evapotranspiration and Spatiotemporal Changes in Evapotranspiration Drought Index over Ningxia in the Upper Reaches of the Yellow River in China

“…This study showed that ET increased with the increase of soil water content in the irrigated area, which indicated that irrigation had a direct impact on AET in arid and semi-arid areas. This result was consistent with other studies [22].…”

“…Unlike other parametric tests, the Mann-Kendall test does not require samples to follow a certain distribution pattern and is disturbed by abnormal values; therefore, this method is more suitable for testing sequential variables. A Mann-Kendall test had been successfully used to test hydrological and meteorological time-series data for determining whether the data showed an upward or downward trend [22,23].…”

Preferential Flow and Preferential Path Characteristics of the Typical Forests in the Karst Region of Southwest China

“…Although soil profile staining images can visualise the basic morphological characteristics of preferential flow, specific characteristic parameters and statistical models are needed to quantify preferential flow when the overall development of preferential flow is to be assessed. The preferential flow morphological parameters obtained in this study showed that the DC of the karst region is lower than that of the northwest loess region [30], semi-arid grassland in northern China [31], and Three Gorges purple soil region [32]. This difference may be due to the fact that the soil in this study area is limestone red soil with a large water holding capacity but minimal available water and low saturated water conductivity [33,34]-conditions not conducive to the infiltration of water into deep layers.…”

Temporal and spatial changes of soil erosion under land use and land cover change based on Chinese soil loss equation in the typical watershed on the Loess Plateau

“…Cropland converted to grassland after abandonment increases soil moisture (An et al, 2017). At the same time, the migration of rural residents and increased urbanization have rapidly increased the amount of abandoned land in the past few years (Wang et al, 2011(Wang et al, , 2019. Due to the abovementioned reasons, an adjustment to the vegetation restoration planting structure transformed the spatial pattern of land use types, significantly increasing the grassland area.…”