[Rainfall effects on the sap flow of Hedysarum scoparium.].

In arid and semi-arid areas, plant physiological responses to water availability depend largely on the intensity and frequency of rain events. Knowledge on the responses of xerophytic plants to rain events is important for predicting the structure and functioning of dryland ecosystems under changing climate. The sap flow of Hedysarum scoparium in the Mu Us Sand Land was continuously measured during the growing season of 2012 and 2013.

Patterns and possible mechanisms of soil CO2 uptake in sandy soil.

It has been reported that soils in drylands can absorb CO2, although the patterns and mechanisms of such a process remain under debate. To address this, we investigated the relationships between soil CO2 flux and meteorological factors and soil properties in Northwest China to reveal the reasons for "anomalous" soil CO2 flux in a desert ecosystem. Soil CO2 flux increased significantly and exponentially with surficial turbulence at the diel scale under dry conditions (P<0.

Effect of vegetation rehabilitation on soil carbon and its fractions in Mu Us Desert, northwest China.

Although vegetation rehabilitation on semi-arid and arid regions may enhance soil carbon sequestration, its effects on soil carbon fractions remain uncertain. We carried out a study after planting Artemisia ordosica (AO, 17 years), Astragalus mongolicum (AM, 5 years), and Salix psammophila (SP, 16 years) on shifting sand land (SL) in the Mu Us Desert, northwest China. We measured total soil carbon (TSC) and its components, soil inorganic carbon (SIC) and soil organic carbon (SOC), as well as the light and heavy fractions within soil organic carbon (LF-SOC and HF-SOC), under the SL and shrublands at depths of 100 cm.

Fractal scaling of particle size distribution and relationships with topsoil properties affected by biological soil crusts.

Background: Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions.

Methodology/principal Findings: To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well.

Influence of disturbance on soil respiration in biologically crusted soil during the dry season.

Soil respiration (Rs) is a major pathway for carbon cycling and is a complex process involving abiotic and biotic factors. Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. In desert ecosystems, soils are protected from surface disturbance by BSCs, but it is unknown whether Rs is affected by disturbance of this crust layer.