Abstract
Textural layering of soil plays an important role in distributing and regulating resources for plants in many semiarid and arid landscapes. However, the spatial patterns of textural layering and the potential effects on soil hydrology and water regimes are poorly understood, especially in arid sandy soil environments like the desert-oasis ecotones in northwestern China. This work aims to determine the distribution of textural layered soils, analyze the effects of different soil-textural configurations on water regimes, and evaluate which factors affect soil water infiltration and retention characteristics in such a desert-oasis ecotone. We measured soil water content and mineral composition in 87 soil profiles distributed along three transects in the study area. Constant-head infiltration experiments were conducted at 9 of the soil profiles with different texture configurations. The results showed that textural layered soils were patchily but extensively distributed throughout the study area (with a combined surface area percentage of about 84%). Soil water content in the profiles ranged from 0.002 to 0.27 g/cm3 during the investigation period, and significantly and positively correlated with the thickness of a medium-textured (silt or silt loam) layer (p < 0.001). The occurrence of a medium-textured layer increased field capacity and wilting point and decreased available water-holding capacity in soil profiles. Burial depth of the medium-textured layer had no clear effects on water retention properties, but the layer thickness tended to. In textural layered soils, smaller water infiltration rate and cumulative infiltration, and shallower depths of wetting fronts were detected, compared with homogeneous sand profiles. The thickness and burial depth of medium-textured layers had obvious effects on infiltration, but the magnitude of the effects depended on soil texture configuration. The revealed patterns of soil textural layering and the potential effects on water regimes may provide new insight into the sustainable management of rainfed vegetation in the desert-oasis ecotones of arid northwestern China and other regions with similar environments around the world.
Highlights
Textural layered soils are soils with textural contrasts, or duplex soils with subsoil in which the clay content is at least one and a half times that of the overlying layer (Northcote, 1971)
We had evidence that textural layering increased field capacity (FC), wilting point (WP) and available water content (AWC) of the surface sand layers (Figure 5), indicating the possibility of high water-storage capacity. These results were likely related to the increases in silt and clay content and Total porosity (TP) of the surface sand layers and the thickness of the medium-textured layers, irrespective of the burial depth of those layers (Figure 10), because the thickness of the medium-textured layers is used as an indicator of silt and clay content, and increases in silt and clay content and TP can cause an increase in the abundance of small pore spaces where most water is retained (Sperry and Hacke, 2002)
Based on soil sampling and in-situ infiltration tests, this study examined the heterogeneity of textural layering soils and the effects of textural layering on soil water content, hydrological properties and processes
Summary
Textural layered soils are soils with textural contrasts, or duplex soils with subsoil in which the clay content is at least one and a half times that of the overlying layer (Northcote, 1971). These include abrupt textural-change soils (Hill and Parlange, 1972; Bockheim, 2016) characterized by a clear, abrupt, or sharp boundary between the surface and the underlying horizon, and soils with a considerable increase in clay content within a very short vertical distance (Hardie, et al, 2012; Bockheim and Hartemink, 2013). In China, similar textural layered soils have been found in the wind-water erosion crisscross region of the Loess Plateau (Zhang, et al, 2017a), and in the desert-oasis ecotone of northwestern China (Zhou, et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
