Vertical variations and transport mechanism of soil moisture in response to vegetation restoration on the Loess Plateau of China

2021 ◽  
Author(s):  
Dexun Qiu ◽  
Peng Gao ◽  
Xingmin Mu ◽  
Baili Zhao
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Transport Mechanism ◽  
Vegetation Restoration ◽  
The Loess Plateau ◽  
Vertical Variations

Stochastic soil moisture dynamic modelling: a case study in the Loess Plateau, China

2018 ◽  
Vol 109 (3-4) ◽  
pp. 437-444
Author(s):  
Cong WANG ◽  
Shuai WANG ◽  
Bojie FU ◽  
Lu ZHANG ◽  
Nan LU ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Loess Plateau ◽  
Hydrological Cycle ◽  
Dynamic Modelling ◽  
Vegetation Restoration ◽  
Balance Model ◽  
Rainfall Regime ◽  
The Loess Plateau ◽  
Dry Period

ABSTRACTSoil moisture is a key factor in the ecohydrological cycle in water-limited ecosystems, and it integrates the effects of climate, soil, and vegetation. The water balance and the hydrological cycle are significantly important for vegetation restoration in water-limited regions, and these dynamics are still poorly understood. In this study, the soil moisture and water balance were modelled with the stochastic soil water balance model in the Loess Plateau, China. This model was verified by monitoring soil moisture data of black locust plantations in the Yangjuangou catchment in the Loess Plateau. The influences of a rainfall regime change on soil moisture and water balance were also explored. Three meteorological stations were selected (Yulin, Yan'an, and Luochuan) along the precipitation gradient to detect the effects of rainfall spatial variability on the soil moisture and water balance. The results showed that soil moisture tended to be more frequent at low levels with decreasing precipitation, and the ratio of evapotranspiration under stress in response to rainfall also changed from 74.0% in Yulin to 52.3% in Luochuan. In addition, the effects of a temporal change in rainfall regime on soil moisture and water balance were explored at Yan'an. The soil moisture probability density function moved to high soil moisture in the wet period compared to the dry period of Yan'an, and the evapotranspiration under stress increased from 59.5% to 72% from the wet period to the dry period. The results of this study prove the applicability of the stochastic model in the Loess Plateau and reveal its potential for guiding the vegetation restoration in the next stage.

scholarly journals Vertical variations of soil moisture in response to vegetation restoration on the Loess Plateau of China

2020 ◽  
Author(s):  
dexun Qiu ◽  
Peng Gao ◽  
Xingmin Mu ◽  
Baili ZHao
Keyword(s):  
Soil Moisture ◽  
Vertical Distribution ◽  
Loess Plateau ◽  
Preferential Flow ◽  
Soil Depth ◽  
Stable State ◽  
Vegetation Restoration ◽  
Vegetation Types ◽  
The Loess Plateau ◽  
Main Mode

Soil moisture is essential for vegetation restoration in arid and semi-arid regions. Ascertaining the vertical distribution and transportation of soil moisture under different vegetation restoration types has a profound impact on the ecological construction. In this study, the soil moisture at a depth of 500 cm for four typical vegetation types, including R. pseudoacacia (forestland), C. korshinskii (shrubland), S. bungeana (abandoned land), and corn (cropland) were investigated and compared in the Zhifanggou watershed of Loess plateau, China. Additionally, hydrogen and oxygen stable isotopes were detected to identify and reflect the characteristics of soil water. The results showed vertical distribution and transportation of soil moisture have different variations under different vegetation types. Depth-averaged soil moisture under S. bungeana and corn increased along the profile as a whole, while C. korshinskii and R. pseudoacacia showing a trend of weakly increasing and relatively stable state after an obvious decreasing trend (0–40 cm). The mean soil moisture under R. pseudoacacia is lower than other types, especially in deeper layers. In addition, it was observed that the longer vegetation age, the lower mean soil moisture, while this phenomenon was unobvious in S. bungeana. Planting arbor species such as R. pseudoacacia intensified the decline of soil moisture in the Loess Plateau, this limited the growth of arbor species in turn. The capacity of evaporation fractionation of soil moisture followed the sequence: corn > S. bungeana > R. pseudoacacia > C. korshinskii. Profiles of δ18O values of soil moisture under different vegetation types are quite different. On the whole, the δ18O values varied greatly in upper soil layers and tend to be consistent with the increase of soil depth. We estimate that piston flow is the main mode of precipitation infiltration, and the occurrence of preferential flow is related to vegetation types. These results are expected to help improve the understanding of the response of deep soil moisture to vegetation restoration and inform practices for sustainable water management.

scholarly journals Quantifying the Responses of Evapotranspiration and Its Components to Vegetation Restoration and Climate Change on the Loess Plateau of China

2021 ◽  
Vol 13 (12) ◽  
pp. 2358
Author(s):  
Linjing Qiu ◽  
Yiping Wu ◽  
Zhaoyang Shi ◽  
Yuting Chen ◽  
Fubo Zhao
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Dominant Role ◽  
Vegetation Restoration ◽  
Vegetation Coverage ◽  
Ecological Planning ◽  
The Loess Plateau ◽  
Canopy Interception ◽  
Community Land Model ◽  
Spatiotemporal Trends

Quantitatively identifying the influences of vegetation restoration (VR) on water resources is crucial to ecological planning. Although vegetation coverage has improved on the Loess Plateau (LP) of China since the implementation of VR policy, the way vegetation dynamics influences regional evapotranspiration (ET) remains controversial. In this study, we first investigate long-term spatiotemporal trends of total ET (TET) components, including ground evaporation (GE) and canopy ET (CET, sum of canopy interception and canopy transpiration) based on the GLEAM-ET dataset. The ET changes are attributed to VR on the LP from 2000 to 2015 and these results are quantitatively evaluated here using the Community Land Model (CLM). Finally, the relative contributions of VR and climate change to ET are identified by combining climate scenarios and VR scenarios. The results show that the positive effect of VR on CET is offset by the negative effect of VR on GE, which results in a weak variation in TET at an annual scale and an increased TET is only shown in summer. Regardless of the representative concentration pathway (RCP4.5 or RCP8.5), differences resulted from the responses of TET to different vegetation conditions ranging from −3.7 to −1.2 mm, while climate change from RCP4.5 to RCP8.5 caused an increase in TET ranging from 0.1 to 65.3 mm. These findings imply that climate change might play a dominant role in ET variability on the LP, and this work emphasizes the importance of comprehensively considering the interactions among climate factors to assess the relative contributions of VR and climate change to ET.

Long-term vegetation restoration promotes the stability of the soil micro-food web in the Loess Plateau in North-west China

CATENA ◽  
2021 ◽  
Vol 202 ◽  
pp. 105293
Author(s):  
Yang Wu ◽  
WenJing Chen ◽  
Wulan Entemake ◽  
Jie Wang ◽  
HongFei Liu ◽  
...  
Keyword(s):  
Food Web ◽  
Loess Plateau ◽  
Vegetation Restoration ◽  
The Loess Plateau ◽  
West China ◽  
North West ◽  
The Stability

scholarly journals Effects of Vegetation Restoration on Soil Erosion on the Loess Plateau: A Case Study in the Ansai Watershed

2021 ◽  
Vol 18 (12) ◽  
pp. 6266
Author(s):  
Hui Wei ◽  
Wenwu Zhao ◽  
Han Wang
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
Loess Plateau ◽  
Water Conservation ◽  
Large Scale ◽  
Land Use Changes ◽  
Vegetation Restoration ◽  
The Loess Plateau ◽  
Local Soil ◽  
Erosion Environment

Large-scale vegetation restoration greatly changed the soil erosion environment in the Loess Plateau since the implementation of the “Grain for Green Project” (GGP) in 1999. Evaluating the effects of vegetation restoration on soil erosion is significant to local soil and water conservation and vegetation construction. Taking the Ansai Watershed as the case area, this study calculated the soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration, using the Chinese Soil Loess Equation (CSLE), based on rainfall and soil data, remote sensing images and socio-economic data. The effect of vegetation restoration on soil erosion was evaluated by comparing the average annual soil erosion modulus under two scenarios among 16 years. The results showed: (1) vegetation restoration significantly changed the local land use, characterized by the conversion of farmland to grassland, arboreal land, and shrub land. From 2000 to 2015, the area of arboreal land, shrub land, and grassland increased from 19.46 km2, 19.43 km2, and 719.49 km2 to 99.26 km2, 75.97 km2, and 1084.24 km2; while the farmland area decreased from 547.90 km2 to 34.35 km2; (2) the average annual soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration was 114.44 t/(hm²·a) and 78.42 t/(hm²·a), respectively, with an average annual reduction of 4.81 × 106 t of soil erosion amount thanks to the vegetation restoration; (3) the dominant soil erosion intensity changed from “severe and light erosion” to “moderate and light erosion”, vegetation restoration greatly improved the soil erosion environment in the study area; (4) areas with increased erosion and decreased erosion were alternately distributed, accounting for 48% and 52% of the total land area, and mainly distributed in the northwest and southeast of the watershed, respectively. Irrational land use changes in local areas (such as the conversion of farmland and grassland into construction land, etc.) and the ineffective implementation of vegetation restoration are the main reasons leading to the existence of areas with increased erosion.

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