Response of Preferential Soil Flow to Different Infiltration Rates and Vegetation Types in the Karst Region of Southwest China

Abstract

The widespread preferential flow phenomenon has an important impact on the water resource allocation of vegetation restoration in karst regions. In this study, four kinds of water infiltration experiments were conducted on six kinds of vegetation types (Pinus yunnanensis Franch. var. tenuifolia plantation forestlands, Eucalyptus robusta Smith plantation forestlands, Platycladus orientalis (L.) Francoptmxjjkmsc plantation forestlands, secondary forestlands, scrublands, and natural grasslands) separately to evaluate the effect of vegetation restoration on preferential flow in karst regions. The distribution of soil water infiltration was visualized via Brilliant Blue staining (290 images of soil vertical section staining) and data were processed via structural equation model (SEM). Results showed that 15–35 mm water accumulation was beneficial to the visualization of preferential flow. The experimental statement of a higher matrix flow in grassland than in plantations made it possible to draw conclusions of economic importance. Therefore, undergrowth of vegetation coverage in plantation forestlands should be increased. Experimentally analyzing the water-vegetation-soil interaction, shows an increase in vegetation coverage inhibits the development of matrix flow, an increase in soil erodibility may inhibit the development of preferential flow, and an increase in soil clay content may promote the deepening of matrix flow depth. The artificial forest can improve the soil structure and can effectively restore the degree of soil fragmentation; vegetation can be restored reasonably to prevent desertification in karst regions. Therefore, identifying and analyzing the structure characteristics of the soil macropore network under the conditions of natural vegetation communities and artificial vegetation communities in karst-geologic settings is an urgent study, which can provide a reference for improving the restoration measures of artificial forests and sustainable forestry development in karst desertification areas.

Preferential flow in the understory soil of Hippophae rhamnoides at different stump heights

“…The distribution of dye and the morphological characteristics of soil preferential flow reflect the evolving status and changing laws of preferential flow (Edith Allaire et al, 2011;Tobella et al, 2014). In this study, the characteristics of the soil preferential flow index showed that preferential flow occurred in the understory soils of H. rhamnoides in feldspathic sandstone areas, with dye area ratio generally decreasing with increasing soil depth (Figure 2); this is consistent with the findings of other studies (Kan et al, 2019;Kan et al, 2020). This occurred because the lower soils were compact, the moisture exchange between pores and the matrix was weaker than in the surface layer, and water flow always manifested as diverse macroporous flow (Luo Z. T. et al, 2019).…”

Influence of Paulownia fortunei (Seem.) Hemsl. roots on preferential flow in the red soil hilly region

“…To avoid the cutting process from impacting the soil structure, for each plate, a 5 cm buffer zone was left at the inner circle. The final data for each treatment were collected in a 0.5 × 0.5 m stained area in the centre of the quadrat, in which the quadrats were cut into five slices vertically with 10 cm spaces between them (Kan et al 2020), as shown in Figure 2. Calibrated frames were designed inside the soil profile to assist with the subsequent image correction process (Jiang et al 2017).…”

The Impact of Land Cover Density on the Water Infiltration Process in the Nyadeng Lake Area, Merabu Village Berau District, East Kalimantan

“…Crown thickness, crown area, and vegetation density affect the effectiveness of vegetation in mitigating runoff and erosion. The importance of vegetation can inhibit the saturated hydraulic conductivity of soil, suggesting that increasing the erodibility of soil can inhibit movement development, which in turn hinders the development of macropore flow [19].…”