Spatio-temporal variability and temporal stability of water contents distributed within soil profiles at a hillslope scale

Abstract

a b s t r a c t a r t i c l e i n f oInformation about soil water content (SWC) within soil profiles in terms of its spatio-temporal variability and temporal stability is crucial when selecting appropriate soil water management practices. However, detailed profile distribution features for related indices are not clear on the Chinese Loess Plateau. This study aimed to investigate the depth dependency of spatio-temporal variability and temporal stability of SWC at the hillslope scale using an intensive sampling strategy for both horizontal and vertical directions as well as over time. The SWCs at 20 depths within 0-300 cm soil profiles were measured on 20 occasions between July 2008 and October 2010 at 91 locations on a hillslope on the Loess Plateau, China. Results showed that although the profile distributions of investigated statistical parameters differed greatly, they were all depth dependent. Based on both the spatio-temporal variability and the temporal stability characteristics using eight indices, the studied soil profile (0-300 cm) could be divided into three soil layers, i.e., 0-60, 60-160 and 160-300 cm, with a characteristic feature of "irregularly changing", "regularly changing", and "relatively constant", respectively. The deepest rainwater replenishment depth was approximately 160 cm. Therefore, choosing 200 cm as the sampling depth would be sufficient in similar areas. Such findings are useful for designing an optimal strategy for sampling and management of profile soil moisture.

Spatial and temporal variability of 0‐ to 5‐m soil–water storage at the watershed scale

“…In contrast, Gao et al () and Jia, Shao, Wei, and Wang () found that TS increased with depth in the 3‐m soil profile, and more time stable locations were identified in deeper layers. More recently, Gao, Shao, Peng, and She () separated a soil profile into “irregularly changing” (0–0.6 m), “regularly changing” (0.6–1.6 m), and “relatively constant” layers (1.6–3.0 m) according to different TS indices. Wang et al () partitioned a 21‐m soil profile into an active layer (0–2 m) and a relatively stable layer (2–21 m) based on the TS indicator.…”

Soil moisture temporal stability analysis for typical hilly and gully re-vegetated catchment in the Loess Plateau, China

“…A series of studies on the time stability of soil moisture in the northern Loess Plateau have been conducted for different purposes (Hu et al 2009(Hu et al , 2012Gao and Shao 2012;Jia and Shao 2013;Gao et al 2015). The earliest study was conducted by Hu et al (2009), who explored the effects of neutron probe calibration procedures on the identification of the most time stable location for mean soil moisture estimation.…”

“…Thereafter, they explored the impacts of soil depth, soil texture, and land use on the time stability of soil moisture (Hu et al 2010b) and compared the performance of seven time stability indices (Hu et al 2012). Recently, the time stability concept has been extended to an adjacent or distant area for the estimation of mean soil moisture, and has also been applied in diverse soil layers (Gao and Shao 2012;Jia and Shao 2013;Gao et al 2013Gao et al , 2015. However, nearly all these studies were concentrated in the transitional belt between loess and desert; studies conducted in typical hilly and gully areas of the Loess Plateau are rare.…”

Variations in Soil Water Content, Infiltration and Potential Recharge at Three Sites in a Mediterranean Mountainous Region of Baja California, Mexico

“…We also calculate that, on average, around 9.5% (~34.5 mm) of the accumulated precipitation may contribute to the recharge of the aquifer at the hillslope sites. Information about θ in a mountain block is essential for describing the dynamics and movement of water into the thin soil profile and its relation to potential groundwater recharge.scales [10] with substantial variations observed with soil depth [11][12][13]. For instance, θ in different soil layers is influenced by the productivity of terrestrial plants with varying rooting depths [14][15][16].Precipitation pulses are a first-order control on the seasonal variation of θ during the hydrological year, in particular for semiarid regions characterized by long periods of no rainfall [9,17,18].…”

“…scales [10] with substantial variations observed with soil depth [11][12][13]. For instance, θ in different soil layers is influenced by the productivity of terrestrial plants with varying rooting depths [14][15][16].…”