Abstract
Drought and shortages of soil water are becoming extremely severe due to global climate change. A better understanding of the relationship between vegetation type and soil-moisture conditions is crucial for conserving soil water in forests and for maintaining a favorable hydrological balance in semiarid areas, such as the Saihanwula National Nature Reserve in Inner Mongolia, China. We investigated the temporal dynamics of soil moisture in this reserve to a depth of 40 cm under three types of vegetation during a period of rainwater recharge. Rainwater from most rainfalls recharged the soil water poorly below 40 cm, and the rainfall threshold for increasing the moisture content of surface soil for the three vegetations was in the order: artificial Larix spp. (AL) > Quercus mongolica (QM) > unused grassland (UG). QM had the highest mean soil moisture content (21.13%) during the monitoring period, followed by UG (16.52%) and AL (14.55%); and the lowest coefficient of variation (CV 9.6-12.5%), followed by UG (CV 10.9-18.7%) and AL (CV 13.9-21.0%). QM soil had a higher nutrient content and higher soil porosities, which were likely responsible for the higher ability of this cover to retain soil water. The relatively smaller QM trees were able to maintain soil moisture better in the study area.
Highlights
Soil moisture in semiarid areas plays an important role in ecological hydrological processes, including evapotranspiration, infiltration, runoff, and erosion [1, 2]
The soil-moisture content (SMC) throughout the 40-cm depth was generally higher for Quercus mongolica (QM) than for the other two covers
The maximum soil moisture was higher for QM (26.9%) and artificial Larix spp. (AL) (23.4%) than for unused grassland (UG) (22.7%)
Summary
Soil moisture in semiarid areas plays an important role in ecological hydrological processes, including evapotranspiration, infiltration, runoff, and erosion [1, 2]. Maintaining a high level of soil-moisture content (SMC) can improve the capacity of ecological systems to conserve water [3, 4]. Variations in soil moisture can be highly influenced by plant-soil interactions [5]. The type of vegetation is often associated with specific soil properties and different community structures and architectures, variation in vegetation can be a major influence on the pattern of soil moisture [6]. Some research has suggested that soil and water conservation in ecosystems could be improved by increasing forest cover. More recent studies have suggested that forests with high coverage may not be the best option for PLOS ONE | DOI:10.1371/journal.pone.0118964. More recent studies have suggested that forests with high coverage may not be the best option for PLOS ONE | DOI:10.1371/journal.pone.0118964 March 17, 2015
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