Modeling and prediction of soil hydrologic processes require the identification of soil moisture spatial-temporal patterns and effective methods allowing the data observations to be used across different spatial and temporal scales. This work presents a methodology for the combination of spatially- and temporally-extensive soil moisture data obtained in the Shale Hills Critical Zone Observatory (CZO) from 2004 to 2010. The soil moisture data sets were decomposed into spatial Empirical Orthogonal Function (EOF) patterns, and their relationship with various geophysical parameters was examined to determine the dominant factors contributing to the profiled soil moisture variability. The EOF analyses indicated that one or two EOFs of soil moisture could explain 76-89% of data variation. The primary EOF pattern had high values clustered in the valley region, and conversely low values located in the sloped hills. We suggest a novel approach to integrate the spatially-extensive manually measured datasets with the temporally-extensive automated monitored datasets based on the EOF analyses. Given the data accessibility, the current data merging framework has provided the methodology for the coupling of the mapped and monitored soil moisture datasets, as well as the conceptual coupling of slow and fast pedologic and hydrologic functions. This successful coupling implies that a combination of different extensive moisture data has provided interesting insights into our understanding of hydrological processes at multiple scales.
The widespread construction of photovoltaic (PV) power stations within northwest China poses an environmental threat because of severe wind erosion and land degradation attributed to unique wind control issues caused by the power stations. In this study, various engineering (E), plant (V), and biocrust (B) treatments were evaluated for their effectiveness in the reduction of wind erosion. The placement of solar panels with wide wind inlets and narrow wind outlets caused wind velocity reductions at the inlet that sharply increased at the outlet and formed distinct zones of deflation, direct shear abrasion (DSA), and deposition. The engineering treatments reduced the wind velocities and sand transport rates, in comparison to the control with E4 (DSA zone + a gravel/deposition zone + red clay) being the most effective with an 87% reduction in the total sand transport rate. Both plant treatments V1 (Sedum aizoon L.) and V2 (Pennisetum alopecuroides (L.) Spreng) increased the aerodynamic roughness, and decreased the sand transport rates and the sand erosion-deposition budget under or between the solar panels. Treatment B2 (moss crust) decreased the sand transport rate and sand erosion-deposition budget under the solar panels in comparison to the control. All the treatments had effects on reducing wind erosion, and we strongly recommend the use of moss crust, gravel mulch, and red clay mulch in the deflation zones, DSA zones, and deposition zones, respectively, to control the severe wind erosion at these PV power stations located in sandy areas.