scholarly journals Soil Water Movement Changes Associated with Revegetation on the Loess Plateau of China

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 731 ◽  
Author(s):  
Haocheng Ke ◽  
Peng Li ◽  
Zhanbin Li ◽  
Peng Shi ◽  
Jingming Hou
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Large Scale ◽  
Plant Density ◽  
Water Movement ◽  
Temporal Distribution ◽  
Semiarid Region ◽  
The Loess Plateau ◽  
Vegetation Growth ◽  
Soil Water Movement

Soil water is the limitation factors in the semiarid region for vegetation growth. With the large scale “Grain for Green” implementation on the Loess Plateau of China, an amount of sloping cropland was converted to forestland, shrubland, and grassland. The spatial and temporal distribution of soil water was changed. However, the effect of revegetation on soil water movement is still unclear. In this study, we analyze the stable isotopes changes in precipitation and soil water in sloping cropland, forestland, shrubland, and grassland to trace the movement of moisture in soil. The results showed that δ18O in shallow layers (<20 cm depth) of sloping cropland, forestland, shrubland, and grassland were −3.54‰, −2.68‰, −4.00‰, and −3.16‰, respectively. The δ18O in these layers were higher than that in the lower layers, indicating that evaporation was mainly from the shallow layers. The δ18O for the soil water in the unsaturated zone in the grassland, shrubland, and forestland of the temporal variability decreases with depth and approaches a minimum value at 160 cm, 180 cm, and 200 cm, respectively, suggesting that the soil water is relatively stable many months or even longer. Precipitation was infiltrated with piston and preferential modes, and infiltration demonstrated obvious mixing. Present study demonstrated the δ18O was more sensitive than the soil water content for tracing the maximum infiltration depth of event water and recharge mechanisms. Consequently, we suggested that the land user management such as type, plant density should be considered in the revegetation.

scholarly journals Soil Freeze-Thaw and Water Transport Characteristics Under Different Vegetation Types in Seasonal Freeze-Thaw Areas of the Loess Plateau

2021 ◽  
Vol 9 ◽  
Author(s):  
Lanfeng Bo ◽  
Zhanbin Li ◽  
Peng Li ◽  
Guoche Xu ◽  
Lie Xiao ◽  
...  
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Water Movement ◽  
Vegetation Types ◽  
The Loess Plateau ◽  
Freezing And Thawing ◽  
Freezing Period ◽  
Thawing Processes ◽  
Semi Arid ◽  
Soil Water Movement

In the arid and semi-arid regions of the Loess Plateau, seasonal freezing and thawing influence soil water movement, and water movement directly influences vegetation growth. However, currently, research with regard to freezing and thawing processes under various vegetation types and the mechanism of soil water movement is lacking. Therefore, the present study explored soil water migration characteristics of two typical vegetation types [arbor land (AL) and shrub land (SL)] on the Loess Plateau during seasonal freezing and thawing processes using bare land (BL) as a control. We used field measured data for hourly soil temperature (ST) and soil water content (SWC) at a depth of 100 cm below the soil surface from November 2017 to March 2018. Freezing and thawing process was divided into three stages based on ST change (initial freezing period, stable freezing period, and thawing period). Compared with previous studies in this area, ST is lower than expected, and SWC migration characteristics are also different. The results revealed that: 1) the maximum freezing depth of AL and SL was 60 cm, which was 30 cm less than that of BL. The freezing date of each soil layer in BL was the earliest and average ST value was the lowest. BL had the highest degree of freezing. The freezing of all soil layers in AL occurred at a later date than that of SL. ST and the minimum soil freezing temperatures were higher than those of SL, and the capacity of AL to resist freezing was higher; 2) the SWCs in AL and BL at depths of 0–10 cm and 10–30 cm decreased, whereas SWCs of AL and BL at a depth of 60 cm increased by 152 and 146%, respectively. The SWCs of SL at soil depths of 0–10 cm, 10–30 cm, and 30–60 cm increased by 46.3, 78.4 and 205%, respectively. The amount and distribution of soil moisture in SL were optimum when compared to those of AL and BL. The results of the present study could provide a scientific basis for vegetation restoration in arid and semi-arid areas of the Loess Plateau.

scholarly journals Effects of revegetation on soil moisture under different precipitation gradients in the Loess Plateau, China

2016 ◽  
Vol 48 (5) ◽  
pp. 1378-1390 ◽  
Author(s):  
Fei Tian ◽  
Xiaoming Feng ◽  
Lu Zhang ◽  
Bojie Fu ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
Loess Plateau ◽  
Large Scale ◽  
Tree Planting ◽  
Mean Annual Precipitation ◽  
Soil Water Deficit ◽  
The Loess Plateau ◽  
Soil Desiccation

Revegetation can alter catchment water balance and result in soil desiccation. Large-scale revegetation took place in the Loess Plateau of China to control soil erosion and improve environmental conditions. However, the dynamic nature of soil moisture in response to revegetation under different climatic conditions is still unclear mainly due to lack of long-term in situ observations. To overcome this challenge, a biophysically based ecohydrological model (WAVES) was used to examine the effects of revegetation on soil moisture. Results showed that trees consume more water (100% of precipitation) than shrub (97.6%) and grass (98.3%), and therefore are more likely to result in soil desiccation. No runoff occurred under the tree scenario, while for shrub and grass, runoff accounted for 2.4% and 1.7% of precipitation, respectively. In areas with mean annual precipitation (MAP) less than 400 mm, tree planting resulted in soil water deficit, while in areas with MAP exceeding 600 mm, no soil water deficit occurred. Within this MAP range (400 &lt; MAP &lt; 600 mm), this could lead to soil water deficit during dry years. Extending this analysis to the entire Loess Plateau, 40% of the region will face reduced soil moisture when converting cropland to trees.

scholarly journals A Land Surface Water Deficit Model for an Arid and Semiarid Region: Impact of Desertification on the Water Deficit Status in the Loess Plateau, China

1999 ◽  
Vol 12 (1) ◽  
pp. 244-257 ◽  
Author(s):  
Qinxue Wang ◽  
Hidenori Takahashi
Keyword(s):  
Surface Water ◽  
Water Deficit ◽  
Loess Plateau ◽  
Land Surface ◽  
Large Scale ◽  
Semiarid Region ◽  
The Loess Plateau ◽  
Deficit Model ◽  
Land Surface Water ◽  
Arid And Semiarid

Abstract A land surface water deficit model was developed for a large-scale heterogeneous arid and semiarid area with various soil, vegetation, and land use types, and used to simulate seasonal and spatial variability in potential (E0) and actual (Ea) evapotranspiration and an index of water deficit (WDI). Comparisons with the results of other commonly used models and natural vegetation conditions suggest that this model can give an estimate of the success for large-scale regional studies. By using the model, the authors estimated E0, Ea, and WDI in a grid cell of 0.25° lat × 0.25° long over the Loess Plateau, China. Finally, the sensitivities of the model to both a vegetation parameter and an assumed desertification case were simulated, and several highly sensitive areas were found to be the risk regions to desertification.

Soil water balance dynamics under plastic mulching in dryland rainfed agroecosystem across the Loess Plateau

2021 ◽  
Vol 312 ◽  
pp. 107354 ◽  
Author(s):  
Ai-Tian Ren ◽  
Rui Zhou ◽  
Fei Mo ◽  
Shu-Tong Liu ◽  
Ji-Yuan Li ◽  
...  
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Loess Plateau ◽  
Soil Water Balance ◽  
The Loess Plateau ◽  
Plastic Mulching ◽  
Balance Dynamics

scholarly journals Contributions of Vegetation Greening and Climate Change to Evapotranspiration Trend after Large-Scale Vegetation Restoration on the Loess Plateau, China

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1755
Author(s):  
Shuo Wang ◽  
Chenfeng Cui ◽  
Qin Dai
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Large Scale ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Potential Evapotranspiration ◽  
Development Trend ◽  
Future Trend ◽  
Natural Ecosystem ◽  
The Loess Plateau

Since the early 2000s, the vegetation cover of the Loess Plateau (LP) has increased significantly, which has been fully recorded. However, the effects on relevant eco-hydrological processes are still unclear. Here, we made an investigation on the changes of actual evapotranspiration (ETa) during 2000–2018 and connected them with vegetation greening and climate change in the LP, based on the remote sensing data with correlation and attribution analysis. Results identified that the average annual ETa on the LP exhibited an obvious increasing trend with the value of 9.11 mm yr−1, and the annual ETa trend was dominated by the changes of ETa in the third quarter (July, August, and September). The future trend of ETa was predicted by the Hurst exponent. Partial correlation analysis indicated that annual ETa variations in 87.8% regions of the LP were controlled by vegetation greening. Multiple regression analysis suggested that the relative contributions of potential evapotranspiration (ETp), precipitation, and normalized difference vegetation index (NDVI), to the trend of ETa were 5.7%, −26.3%, and 61.4%, separately. Vegetation greening has a close relationship with the Grain for Green (GFG) project and acts as an essential driver for the long-term development trend of water consumption on the LP. In this research, the potential conflicts of water demanding between the natural ecosystem and social-economic system in the LP were highlighted, which were caused by the fast vegetation expansion.

Changes in rainfall partitioning and its effect on soil water replenishment after the conversion of croplands into apple orchards on the Loess Plateau

2021 ◽  
Vol 312 ◽  
pp. 107342
Author(s):  
Rui Zhang ◽  
Di Wang ◽  
Ziqi Yang ◽  
Katsutoshi Seki ◽  
Manmohanjit Singh ◽  
...  
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Apple Orchards ◽  
The Loess Plateau

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.

scholarly journals A Weighted-Time-Lag Method to Detect Lag Vegetation Response to Climate Variation: A Case Study in Loess Plateau, China, 1982–2013

2021 ◽  
Vol 13 (5) ◽  
pp. 923
Author(s):  
Qianqian Sun ◽  
Chao Liu ◽  
Tianyang Chen ◽  
Anbing Zhang
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Time Lag ◽  
New Method ◽  
Climate Factors ◽  
The Loess Plateau ◽  
Climate Conditions ◽  
Vegetation Growth ◽  
Lag Effect

Vegetation fluctuation is sensitive to climate change, and this response exhibits a time lag. Traditionally, scholars estimated this lag effect by considering the immediate prior lag (e.g., where vegetation in the current month is impacted by the climate in a certain prior month) or the lag accumulation (e.g., where vegetation in the current month is impacted by the last several months). The essence of these two methods is that vegetation growth is impacted by climate conditions in the prior period or several consecutive previous periods, which fails to consider the different impacts coming from each of those prior periods. Therefore, this study proposed a new approach, the weighted time-lag method, in detecting the lag effect of climate conditions coming from different prior periods. Essentially, the new method is a generalized extension of the lag-accumulation method. However, the new method detects how many prior periods need to be considered and, most importantly, the differentiated climate impact on vegetation growth in each of the determined prior periods. We tested the performance of the new method in the Loess Plateau by comparing various lag detection methods by using the linear model between the climate factors and the normalized difference vegetation index (NDVI). The case study confirmed four main findings: (1) the response of vegetation growth exhibits time lag to both precipitation and temperature; (2) there are apparent differences in the time lag effect detected by various methods, but the weighted time-lag method produced the highest determination coefficient (R2) in the linear model and provided the most specific lag pattern over the determined prior periods; (3) the vegetation growth is most sensitive to climate factors in the current month and the last month in the Loess Plateau but reflects a varied of responses to other prior months; and (4) the impact of temperature on vegetation growth is higher than that of precipitation. The new method provides a much more precise detection of the lag effect of climate change on vegetation growth and makes a smart decision about soil conservation and ecological restoration after severe climate events, such as long-lasting drought or flooding.

Modeling Soil Water Movement in Pedostructure

2006 ◽  
Author(s):  
Rabi H. Mohtar ◽  
Erik Braudeau
Keyword(s):  
Soil Water ◽  
Water Movement ◽  
Soil Water Movement
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