Transpiration from three dominant shrub species in a desert-oasis ecotone of arid regions of Northwestern China

2016 ◽  
Vol 30 (25) ◽  
pp. 4841-4854 ◽  
Author(s):  
Xibin Ji ◽  
Wenzhi Zhao ◽  
Ersi Kang ◽  
Bowen Jin ◽  
Shiqin Xu
Keyword(s):  
Arid Regions ◽  
Northwestern China ◽  
Shrub Species ◽  
Desert Oasis

Effects of textural layering on water regimes in sandy soils in a desert-oasis ecotone, Northwestern China

2021 ◽  
Author(s):  
Chengpeng Sun ◽  
Wenzhi Zhao ◽  
Hu Liu ◽  
Yongyong Zhang ◽  
Hong Zhou
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Infiltration ◽  
Northwestern China ◽  
Soil Profiles ◽  
Burial Depth ◽  
Layered Soils ◽  
Water Regimes ◽  
Desert Oasis

<p>Textural layering of soil plays an important role in distributing and regulating resources for plants in many semiarid and arid landscapes. However, the spatial patterns of textural layering and the potential effects on soil hydrology and water regimes are poorly understood, especially in arid sandy soil environments like the desert-oasis ecotones in northwestern China. This work aims to determine the distribution of textural layered soils, analyze the effects of different soil-textural configurations on water regimes, and evaluate which factors affect soil water infiltration and retention characteristics in such a desert-oasis ecotone. We measured soil water content and mineral composition in 87 soil profiles distributed along 3 transects in the study area. Constant-head infiltration experiments were conducted at 9 of the soil profiles with different texture configurations. The results showed that textural layered soils were patchily but extensively distributed throughout the study area (with a combined surface area percentage of about 84%). Soil water content in the profiles ranged from 0.002 to 0.27 g/cm<sup>3</sup> during the investigation period, and significantly and positively correlated with the thickness of a medium-textured (silt or silt loam) layer (<em>P</em> < 0.001). The occurrence of a medium-textured layer increased field capacity (FC) and wilting point (WP), and decreased available water-holding capacity in soil profiles. Burial depth of the medium-textured layer had no clear effects on water retention properties, but the layer thickness tended to. In textural layered soils, smaller water infiltration rate and cumulative infiltration, and shallower depths of wetting fronts were detected, compared with homogeneous sand profiles. The thickness and burial depth of medium-textured layers had obvious effects on infiltration, but the magnitude of the effects depended on soil texture configuration. The revealed patterns of soil textural layering and the potential effects on water regimes may provide new insight into the sustainable management of rainfed vegetation in the desert-oasis ecotones of arid northwestern China and other regions with similar environments around the world.</p>

scholarly journals Atmospheric Optical Turbulence Profile Measurement and Model Improvement over Arid and Semi-arid regions

2021 ◽  
Author(s):  
Hao Yang ◽  
Zhiyuan Fang ◽  
Cheng Li ◽  
Xu Deng ◽  
Kunming Xing ◽  
...  
Keyword(s):  
Observational Data ◽  
Arid Regions ◽  
Northwestern China ◽  
Profile Measurement ◽  
Height Distribution ◽  
Optical Turbulence ◽  
Different Seasons ◽  
Combined Action ◽  
Model Improvement ◽  
Improved Model

Abstract. From August 4th to 30th, 2020 and from November 27th to December 25th, 2020, a self-developed radiosonde balloon system was used to observe high-altitude atmospheric optical turbulence at three sites in northwestern China, and an improved model based on the observational data was established. Through comparative analysis of the observational data and the improved model, the distribution characteristics of atmospheric optical turbulence under the combined action of different meteorological parameters and different landform features in different seasons were obtained. The improved model can show the variation of the detailed characteristics of turbulence with the height distribution, and the degree of correlation with the measured values is above 0.82. The improved model can provide a theoretical basis and supporting data for turbulence estimation and forecasting in northwestern China.

scholarly journals Environmental Drivers for Cambial Reactivation of Qilian Junipers (Juniperus przewalskii) in a Semi-Arid Region of Northwestern China

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Qiao Zeng ◽  
Sergio Rossi ◽  
Bao Yang ◽  
Chun Qin ◽  
Gang Li
Keyword(s):  
Soil Moisture ◽  
Water Availability ◽  
Arid Regions ◽  
High Elevation ◽  
Northwestern China ◽  
Environmental Drivers ◽  
Limiting Factor ◽  
Severe Drought ◽  
Cambial Reactivation ◽  
Semi Arid

Although cambial reactivation is considered to be strongly dependent on temperature, the importance of water availability at the onset of xylogenesis in semi-arid regions still lacks sufficient evidences. In order to explore how environmental factors influence the initiation of cambial activity and wood formation, we monitored weekly cambial phenology in Qilian juniper (Juniperus przewalskii) from a semi-arid high-elevation region of northwestern China. We collected microcores from 12 trees at two elevations during the growing seasons in 2013 and 2014, testing the hypothesis that rainfall limits cambial reactivation in spring. Cambium was reactivated from late April to mid-May, and completed cell division from late July to early August, lasting 70–100 days. Both sites suffered from severe drought from January to April 2013, receiving < 1 mm of rain in April. In contrast, rainfall from January to April 2014 was 5–6 times higher than that in 2013. However, cambial reactivation in 2014 was delayed by 10 days. In spring, soil moisture gradually increased with warming temperatures, reaching 0.15 m3/m3 before the onset of xylogenesis, which may have ensured water availability for tree growth during the rainless period. We were unable to confirm the hypothesis that rainfall is a limiting factor of cambial reactivation. Our results highlight the importance of soil moisture in semi-arid regions, which better describe the environmental conditions that are favorable for cambial reactivation in water-limited ecosystems.

scholarly journals Effects of Textural Layering on Water Regimes in Sandy Soils in a Desert-Oasis Ecotone, Northwestern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Chengpeng Sun ◽  
Wenzhi Zhao ◽  
Hu Liu ◽  
Yongyong Zhang ◽  
Hong Zhou
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Infiltration ◽  
Northwestern China ◽  
Soil Profiles ◽  
Burial Depth ◽  
Layered Soils ◽  
Water Regimes ◽  
Desert Oasis

Textural layering of soil plays an important role in distributing and regulating resources for plants in many semiarid and arid landscapes. However, the spatial patterns of textural layering and the potential effects on soil hydrology and water regimes are poorly understood, especially in arid sandy soil environments like the desert-oasis ecotones in northwestern China. This work aims to determine the distribution of textural layered soils, analyze the effects of different soil-textural configurations on water regimes, and evaluate which factors affect soil water infiltration and retention characteristics in such a desert-oasis ecotone. We measured soil water content and mineral composition in 87 soil profiles distributed along three transects in the study area. Constant-head infiltration experiments were conducted at 9 of the soil profiles with different texture configurations. The results showed that textural layered soils were patchily but extensively distributed throughout the study area (with a combined surface area percentage of about 84%). Soil water content in the profiles ranged from 0.002 to 0.27 g/cm3 during the investigation period, and significantly and positively correlated with the thickness of a medium-textured (silt or silt loam) layer (p &lt; 0.001). The occurrence of a medium-textured layer increased field capacity and wilting point and decreased available water-holding capacity in soil profiles. Burial depth of the medium-textured layer had no clear effects on water retention properties, but the layer thickness tended to. In textural layered soils, smaller water infiltration rate and cumulative infiltration, and shallower depths of wetting fronts were detected, compared with homogeneous sand profiles. The thickness and burial depth of medium-textured layers had obvious effects on infiltration, but the magnitude of the effects depended on soil texture configuration. The revealed patterns of soil textural layering and the potential effects on water regimes may provide new insight into the sustainable management of rainfed vegetation in the desert-oasis ecotones of arid northwestern China and other regions with similar environments around the world.

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