Spatiotemporal variability of soil-water characteristic curve model parameters of Lanzhou collapsible loess

Abstract

The spatiotemporal variation of the model parameters of the soil-water characteristic curve (SWCC) reflect the soil water holding capacity and soil pore distribution state. It is an integral part of interdisciplinary disciplines such as soil hydrodynamics and ecohydrology. The authors selected the optimal SWCC model for the Lanzhou collapsible loess, used classical statistics and geostatistics methods studied the spatiotemporal variability of the SWCC model parameters, and used the comprehensive comparison of the mean relative differences (MRD), standard deviations (SDRD) and an index of temporal stability (ITS) determined the representativeness measuring point. The results showed that the SWCC parameters α was medium variability in the 0–30 cm soil layer, n and θs were of low variability, the spatial distribution of the parameters of different soil layers was consistent. Migration direction prediction of θs was very similar in each layer, α, n and θs were all strongly significantly correlated positively. Moreover, the determination coefficient of representative measuring point 16 had the highest prediction accuracy for the measured values of SWCC. The results of this paper can be used as a simple method to predict SWCC and provide theoretical guidance for soil water management and soil collapse erosion monitoring in collapsible loess area. HIGHLIGHT Presented a study of the temporal stability and variability of SWCC in the Lanzhou collapsible loess, using the comprehensive comparison of the Mean relative differences (MRD), standard deviations (SDRD) and an index of temporal stability (ITS), and determined the representativeness measuring point.

The Impact of Vegetation Types on Soil Hydrological and Mechanical Properties in the Hilly Regions of Southern China: A Comparative Analysis

“…Compared with other soil types, the water-holding characteristics of red clay are generally considered to be poor, and the saturated water content is generally about 40% [78]. Among them, the saturated water content of surface horizons (depth < 30 cm) in yellow soil is usually measured at 40-50% (e.g., Tu et al [79], 40%; Wang et al [80], 45% and Zhao et al [81], 51%). The saturated water content of surface horizons of black soil in northeast China is usually about 45% [82].…”

Assessing the effects of agricultural waste returning on soil moisture characteristics

“…The soil water characteristic curve (SWC) reflects the relationship between soil suction and WHC. [10][11][12][13] It can be used to directly evaluate the improvement effect of agricultural waste returning on soil WHC and is an important parameter for studying and evaluating the soil WHC. [14][15][16][17][18] Prior studies have focused on SWC under different media such as gravel, 19 biochar, [20][21][22] and different soils, 23 showing that the SWC is mainly related to soil type and porosity.…”

“…The soil water characteristic curve (SWC) reflects the relationship between soil suction and WHC 10–13 . It can be used to directly evaluate the improvement effect of agricultural waste returning on soil WHC and is an important parameter for studying and evaluating the soil WHC 14–18 .…”