Variations in Global Soil Moisture During the Past Decades: Climate or Human Causes?

Abstract

In particular, rootzone soil water availability is more critical than surface water availability. This is because vegetation roots can extend downward to tens or even hundreds of centimeters to absorb water and nutrients from the soil (Hirschi et al., 2014;Yang et al., 2022). Therefore, it is important to investigate the variation patterns of both surface and rootzone SM across the globe, which could be expected to boost the understanding of Earth-surface system evolution processes.A host of studies have analyzed the spatial-temporal variability of SM and achieved meaningful findings. The multi-satellite derived surface SM was considered to explore its global fluctuation from 1988 to 2010. The data set displayed a negative trend over 73% of the covered region (Dorigo et al., 2012). Feng and Zhang (2015) utilized the European Space Agency Climate Change Initiative SM data set to examine the widely accepted "dry gets drier, wet gets wetter" (DGDWGW) evolution pattern. The result showed that this cognition was overestimated, and that only 15.12% of the trends followed the DGDWGW mode. Besides, they detected a significant "drier in dry, wetter in wet" (DIDWIW) trend, which focused on the moisture trends and can capture their spatial patterns in detail. Despite promising findings, uncertainties caused by prevalent gap regions, inability to detect dense vegetation, and the features of each spaceborne sensor should be fully considered before further processes. In comparison, the reanalysis SM products could break through the limitation of spaceborne signal derived data, and achieve complete coverage SM with definite physical meaning. The European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-Analysis (ERA-Land) SM products was applied to global trend investigations during 1988-2010, and revealed a significant and dominant (more than 70%) falling trend of surface SM,

Macro- and micro-plastics change soil physical properties: a systematic review

“…It might cause a reduction in water content at FC due to the modification in pore size, pore distribution, and induced water repellency in soil (Wang et al 2020, Cramer et al 2022, Shafea et al 2023a. These pointscale changes in agrosystems, where the most abundant residual plastics were reported, could be reflected during the regional drying trend of soil moisture on soil surface and in the root zone (Liu et al 2023).…”