Yang Y.-F.,Xinjiang Institute of Ecology and Geography |
Yang Y.-F.,University of Chinese Academy of Sciences |
Yang Y.-F.,National Fukang Desert Ecosystem Field science Observation and Research Station |
Zhou H.-F.,Xinjiang Institute of Ecology and Geography |
And 3 more authors.
Chinese Journal of Applied Ecology | Year: 2011
To understand the dynamic variations of soil moisture in the root zone of original Haloxylon ammodendron land is of significance for further understanding the interactions between hydrological processes and vegetations in the Gurbantunggut Desert. By using TDR probes system, this paper measured the volumetric soil moisture content in H. ammodendron land in the southern edge of Gurbantunggut Desert, and analyzed the spatiotemporal distribution of soil moisture in the root zone of H. ammodendron in August 2007 -July 2008. There existed ' wet island' effect in H. ammodendron root zone. The 0-60 cm soil water storage in the root zone was 1. 49 times of that in bare land. Such a difference was greater in summer than in spring and after rainfall than before rainfall. The soil moisture content in the Desert was the richest in spring after snow melting and the lowest in winter, and its annual variation could be divided into three periods, i. e. , quick supplement-consumption period in spring (from March to May) , slow consumption period in summer and autumn (from June to September) , and stable period in winter (form October to next February). Based on wavelet analysis, the soil moisture variation in H. ammodendron root zone and bare land had a short cycle of 43 and 40 days and a long cycle of 110 and 103 days, respectively. The relatively rich soil moisture content in H. ammodendron root zone could be mainly due to the stem flow water collection, tree canopy shading, and the better water percolating capacity in root zone.
Zhou H.,Xinjiang Institute of Ecology and Geography |
Zhou H.,National Fukang Desert Ecosystem Field science Observation and Research Station |
Xiao Z.,Xinjiang Institute of Ecology and Geography |
Xiao Z.,University of Chinese Academy of Sciences |
And 5 more authors.
Shuikexue Jinzhan/Advances in Water Science | Year: 2013
Understanding of the temporal and spatial variation of soil moisture in sand dunes is a fundamental part of exploring the ecological and hydrological pattern of desert ecosystem. The temporal and spatial variation of soil moisture is analyzed using neutron probe soil water data collected from the Gurbantunggut Desert in central Eurasia. Results show that the spatial variation of soil moisture in different locations over sand dunes exhibits high level of consistency over time. Vertically, the variation behaves differently with soil layers. In the top layer of the soil (0-1 m), the volumetric soil moisture content has the highest value at the top, following by the hill, and the driest value is found at the foot. The opposite is true for the sub-layer of the soil (1-2 m), where the highest value occurs at the foot, following by the hill, and the smallest value is found at the top. The variation of soil moisture exhibits significant seasonality and has a strong vertical structure. The soil moisture is the richest in spring, but changes most rapidly during the season. The values of the coefficient of variation (CV) in soil moisture for the layers of 0-40 cm, 40-140 cm and 140-200 cm are 13.56%, 5.35% and 0.8%, respectively, which correspond well to the source of soil water, the evaporation loss and the distribution of shrub roots in different soil layers. The vertical variation of soil moisture is greater than that in the horizontal ones. The vegetation covers and topography have strong influences on the spatial distribution of soil moisture. There exists a water-rich region in the Haloxylon ammodendron root-zone and the foot of sand dunes.
Zhou H.-F.,Xi'an University of Technology |
Zhou H.-F.,Xinjiang Institute of Ecology and Geography |
Zhou H.-F.,National Fukang Desert Ecosystem Field science Observation and Research Station |
Zhou B.-J.,Yuxi Investigation and Design Institute of Water Resources and Electrical Engineering and Architecture |
Dai Q.,Chongqing University
Shuikexue Jinzhan/Advances in Water Science | Year: 2010
There are long winter seasons with stable snow cover and frequently rime phenomena in the Gurbantunggut Desert in China. Based on the rime observations from November 2007 to March 2008 at the experimental sites on the southern margin of the Gurbantunggut Desert, we find that the average water equivalent of rime condensation on desert shrub crowns is 5.8 mm, about 5 times more than that on snow surfaces, and accounts for 21.8% of the total winter precipitation. The values of rime-fall on plants on the top and foot of longitudinal dunes are 3.8 mm and 9.1 mm respectively, which amount to 14.4% and 34.3% of the total winter precipitation, respectively. The rime condensation provides an important moisture input to the shrub cover regions of the Gurbantunggut Dsert during the winter seasons. The maximum wind speed for rime formation is usually less than 3 m/s. The most frequent temperature for rime formation range between -15°C and -20°C, which accounts for 24.3% of the total rime events. The rime-fall significantly reduces when the air temperature falls below -30°C. The rime days are 41% of the rime days occurred in winter when the maximum relative humidity is less than 80%. Low temperatures, high humilities, and low wind speeds, as well as the small diameter of the Haloxylon ammodendron crown branches and needle-like leaves are the important reasons for rime formation and condensation on desert shrubs over the Gurbantunggut Desert.