Spatiotemporal characteristics and temporal stability of soil water in an alpine meadow on the northern Tibetan Plateau

摘要

The spatiotemporal characteristics of soil water content (SWC) have a significant influence on vegetation degradation and growth in alpine meadow ecosystems. The spatiotemporal variability and temporal stability (TS) of SWC, however, have rarely been studied on the northern Tibetan Plateau owing to the rugged and hostile sampling environment. The objective of this study was to analyze the spatiotemporal variability and the TS of SWC in various layers of the soil, to a depth of 50?cm in a 33.5 hm~(2) plot, with the data obtained from 113 measuring locations collected on 22 sampling occasions during the growing seasons of 2015 and 2016. The SWC was moderately variable both in time (two consecutive growing seasons) and horizontal space (plot). The variabilities, however, did not vary consistently with increasing depth for the various dominant influencing factors. The SWC in the undeveloped, shallow, and stony alpine meadow soil was temporally stable; TS did not depend on depth due to disturbances by grass roots and stones. The best representative location of TS at each depth could be determined, and all accurately estimated the field mean SWC. Vegetation coverage, soil organic carbon, gravel and stone contents, and saturated hydraulic conductivity were the main factors influencing TS. This study provides useful information for the management of alpine meadows and provides an effective method for studying SWC at a hectometre scale on the Tibetan Plateau.