Soil moisture variability along transects over a well-developed gully in the Loess Plateau, China

Shao

Peng

et al. 2015

CATENA

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.

Section: Introductionmentioning

confidence: 95%

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

Shao

Peng

et al. 2015

CATENA

“…These studies have focused on the increase of evapotranspiration (ET) caused by vegetation recovery when the input processes were not sufficient. Soil moisture dynamics have received considerable attention in recent decades Gao et al, 2011;Hu et al, 2009). Previous studies have shown that infiltration processes can be more reliably captured by time series soil moisture content measurements using time domain reflectometry than by other methods (Jones et al, 2002;Wang et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Responses of soil moisture in different land cover types to rainfall events in a re-vegetation catchment area of the Loess Plateau, China

Wang

et al. 2013

CATENA

173

117

a b s t r a c t a r t i c l e i n f oImplementation of the Grain-for-Green project has resulted in significantly increased vegetative cover on the Loess Plateau of China during the past few decades. The plant communities influence soil moisture recharge and usage processes, particularly the input process, which is directly related to transformation of the limited precipitation into available soil water in the semi-arid Loess Plateau. A study to measure soil moisture dynamics of typical land cover types associated with precipitation events was conducted in a re-vegetated catchment area. Smart probes were inserted at 6 different depths below the ground surface under grass (Andropogon), subshrub (Artemisia scoparia), shrub (Spiraea pubescens), tree (Robinia pseudoacacia), and crop (Zea mays) vegetation to record volumetric soil moisture at 10-minute intervals for a period of 60 days during the growing season in 2011. The advance of the wetting front and total accumulated infiltrated water were measured. The rainfall events were sporadic with widely different intensities, and the soil moisture was replenished mainly by 3-4 heavy precipitation events during July and August. The mean soil moisture content profiles of the 5 vegetation types can be ordered as crop > grass > subshrub> tree> shrub and this relationship displayed time stability. The different land cover types clearly influenced the water infiltration and water input amounts in the re-vegetated area. The subshrub site showed the highest total infiltration amount (164 mm) with precipitation (227 mm) during the study period. The grass site had an infiltration amount of 156 mm. The tree site had a total precipitation of 154 mm and an infiltration amount of 97 mm. The infiltration amount was 136 mm for the shrub site and was the lowest (83 mm) for the crop site. Natural grasses displayed a rapid infiltration rate and the wetting front was able to reach a greater depth.

“…To facilitate the installation of the tubes, the relief at some sampling points was disturbed slightly. The TRIMETDR system has been shown to provide accurate soil moisture measurements in the Loess Plateau region after local calibration (Li et al 2005;Gao et al 2011).…”

Section: Site Descriptionmentioning

confidence: 99%

“…An understanding of the coupling responses between land cover types and soil moisture is essential to determine the impact of various land uses on hydrological, ecological, and biogeochemical processes at different spatiotemporal scales (Li 2011). Thus, the complex spatiotemporal patterns and variability of soil moisture content have been widely investigated, at various scales, by hydrologists and ecologists in recent decades Fu et al 2003;Hu et al 2009;Qiu et al 2001aQiu et al , b, 2003Western et al 2004;Gao et al 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Some studies have found increases in the standard deviation (SD) of soil moisture with reductions in the mean moisture content (Brocca et al 2007;Hupet and Vanclooster 2002), while others have found the opposite (Famiglietti et al 1998;Martinez-Fernandez and Ceballos 2003). Recent studies have found that the SD and mean moisture content display a convex upward relationship (Brocca et al 2010;Gao et al 2011).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Linking the soil moisture distribution pattern to dynamic processes along slope transects in the Loess Plateau, China

Wang

et al. 2015

Environ Monit Assess

Soil moisture pulses are a prerequisite for other land surface pulses at various spatiotemporal scales in arid and semi-arid areas. The temporal dynamics and profile variability of soil moisture in relation to land cover combinations were studied along five slopes transect on the Loess Plateau during the rainy season of 2011. Within the 3 months of the growing season coupled with the rainy season, all of the soil moisture was replenished in the area, proving that a type stability exists between different land cover soil moisture levels. Land cover combinations disturbed the trend determined by topography and increased soil moisture variability in space and time. The stability of soil moisture resulting from the dynamic processes could produce stable patterns on the slopes. The relationships between the mean soil moisture and vertical standard deviation (SD) and coefficient of variation (CV) were more complex, largely due to the fact that different land cover types had distinctive vertical patterns of soil moisture. The spatial SD of each layer had a positive correlation and the spatial CV exhibited a negative correlation with the increase in mean soil moisture. The soil moisture stability implies that sampling comparisons in this area can be conducted at different times to accurately compare different land use types.