scholarly journals Influence of Landscape Pattern Changes on Runoff and Sediment in the Dali River Watershed on the Loess Plateau of China

Land ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 180
Author(s):  
Yan Zhang ◽  
Zhilei Bi ◽  
Xin Zhang ◽  
Yang Yu
Keyword(s):  
Loess Plateau ◽  
Landscape Pattern ◽  
Large Scale ◽  
Landscape Planning ◽  
Significant Negative Correlation ◽  
Shape Index ◽  
Annual Runoff ◽  
The Loess Plateau ◽  
River Watershed ◽  
Watershed Land Use

The large-scale Grain for Green project on the Loess Plateau of China significantly changes the regional landscape pattern, which has a profound impact on runoff and sediment process. The relationship between landscape pattern and runoff and sediment in the Dali River watershed is established. Cropland and grassland areas in the watershed show a downward trend, whereas the woodland and building land increases continuously. The Number of Patches (NP), Patch Density (PD) and Landscape Diversity (SHDI), Landscape Division Index (DIVISION) increase significantly. The Largest Patch Index (LPI) and Landscape Shape Index (LSI) show overall change in the rising and falling rule. The Contagion Index (CONTAG) and Cohesion Index (COHESION) first increase, then decrease. A decreasing trend is shown by runoff and sediment. The annual runoff in 2010 was 29.76% less than in 1960, and the annual sediment load was 84.87% less. NP, PD, COHESION, DIVISION and SHDI have a significant negative correlation with runoff and sediment, and CONTAG and runoff sediment are positively related. This study could provide theoretical support for guiding watershed land use and landscape planning to effectively reduce runoff and sediment transport.

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.

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 Effects of climatic variability and human activity on runoff in the Loess Plateau of China

2013 ◽  
Vol 89 (02) ◽  
pp. 153-161 ◽  
Author(s):  
Yang Zhao ◽  
Xinxiao Yu
Keyword(s):  
Soil Water ◽  
Loess Plateau ◽  
Water Conservation ◽  
Human Activities ◽  
Climatic Variability ◽  
Land Use Changes ◽  
Annual Runoff ◽  
Central China ◽  
Vegetative Cover ◽  
The Loess Plateau

The Loess Plateau in north-central China has a long history of human activities. As a result of climate change, deforestation and sparse vegetative cover, the region suffers from water shortages and severe soil erosion, significantly influencing efforts for sustainable social development. In order to understand the impacts of climatic variability and human activities on runoff and other hydrological factors in this region, the Luoyugou catchment and its paired catchments (Qiaozidong and Qiaozixi) were selected. Statistical analysis indicated precipitation did not vary significantly whereas the annual runoff decreased from 1986 to 2008, with an abrupt change in 1994. Actual evapotranspiration (AET) increased slightly but not significantly. A comparison of runoff in the paired catchments showed land use changes reduced runoff by more than 38% under the same rainfall conditions. Human activities were the strongest contributor to changes in runoff and AET, at 67% and 90% respectively, while the remaining contributor was climate variation. The influence of various human activities on runoff is quite different, and soil-water conservation initiatives have a greater impact on runoff (about 41%). Thus, human activities were the primary reason for the reduction in runoff in the study catchment compared to climate. Greater emphasis should be given to afforestation and soil-water conservation measures.

scholarly journals Hydrologic feasibility of artificial forestation in the semi-arid Loess Plateau of China

2011 ◽  
Vol 15 (8) ◽  
pp. 2519-2530 ◽  
Author(s):  
T. T. Jin ◽  
B. J. Fu ◽  
G. H. Liu ◽  
Z. Wang
Keyword(s):  
Loess Plateau ◽  
Large Scale ◽  
Regional Scale ◽  
Negative Relationship ◽  
Northern Region ◽  
Shaanxi Province ◽  
Stand Age ◽  
Mean Annual Precipitation ◽  
The Loess Plateau ◽  
Semi Arid

Abstract. Hydrologic viability, in terms of moisture availability, is fundamental to ecosystem sustainability in arid and semi-arid regions. In this study, we examine the spatial distribution and after-planting variations of soil moisture content (SMC) in black locust tree (Robinia pseudoacacia L.) plantings in the Loess Plateau of China at a regional scale. Thirty sites (5 to 45 yr old) were selected, spanning an area of 300 km by 190 km in the northern region of the Shaanxi Province. The SMC was measured to a depth of 100 cm at intervals of 10 cm. Geographical, topographic and vegetation information was recorded, and soil organic matter was evaluated. The results show that, at the regional scale, SMC spatial variability was most highly correlated with rainfall. The negative relationship between the SMC at a depth of 20–50 cm and the stand age was stronger than at other depths, although this relationship was not significant at a 5 % level. Watershed analysis shows that the after-planting SMC variation differed depending upon precipitation. The SMC of plantings in areas receiving sufficient precipitation (e.g., mean annual precipitation (MAP) of 617 mm) may increase with stand age due to improvements in soil water-holding capacity and water-retention abilities after planting. For areas experiencing water shortages (e.g., MAP = 509 mm), evapotranspiration may cause planting soils to dry within the first 20 yr of growth. It is expected that, as arid and semi-arid plantings age, evapotranspiration will decrease, and the soil profile may gradually recover. In extremely dry areas (e.g., MAP = 352 mm), the variation in after-planting SMC with stand age was found to be negligible. The MAP can be used as an index to divide the study area into different ecological regions. Afforestation may sequentially exert positive, negative and negligible effects on SMCs with a decrease in the MAP. Therefore, future restoration measures should correspond to the local climate conditions, and the MAP should be a major consideration for the Loess Plateau. Large-scale and long-term research on the effects of restoration projects on SMCs is needed to support more effective restoration policies. The interaction between afforestation and local environmental conditions, particularly water availability to plants, should be taken into account in afforestation campaigns in arid and semi-arid areas.

Effects of large-scale re-vegetation on soil desiccation in the Loess Plateau: problems and perspectives

2019 ◽  
Vol 39 (20) ◽  
Author(s):  
杨磊 YANG Lei ◽  
张子豪 ZHANG Zihao ◽  
李宗善 LI Zongshan
Keyword(s):  
Loess Plateau ◽  
Large Scale ◽  
The Loess Plateau ◽  
Soil Desiccation

Large-scale spatial interpolation of soil pH across the Loess Plateau, China

2012 ◽  
Vol 69 (8) ◽  
pp. 2731-2741 ◽  
Author(s):  
Zhi Peng Liu ◽  
Ming An Shao ◽  
Yun Qiang Wang
Keyword(s):  
Loess Plateau ◽  
Soil Ph ◽  
Spatial Interpolation ◽  
Large Scale ◽  
The Loess Plateau

scholarly journals Influence of Check Dams on Flood and Erosion Dynamic Processes of a Small Watershed in the Loss Plateau

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 834 ◽  
Author(s):  
Shuilong Yuan ◽  
Zhanbin Li ◽  
Peng Li ◽  
Guoce Xu ◽  
Haidong Gao ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Water Conservation ◽  
Large Scale ◽  
Dynamic Processes ◽  
Outlet Section ◽  
Small Watershed ◽  
The Loess Plateau ◽  
Flood Peak ◽  
Check Dams ◽  
Flood Volume

As an important soil and water conservation engineering measure, check dams have been constructed on a large scale in the Loess Plateau of China. However, their effects on runoff and sediment processes in the basin are still unclear. In this study, the hydrodynamic processes of the Wangmaogou watershed located in the Loess Plateau were simulated, and the influence of check dams on the flood and erosion dynamic processes in this watershed were also evaluated. The results showed that the check dams obviously reduced the flood peak and flood volume and mitigated the flood process. After the dam system was completed, the flood peak and flood volume were reduced by 65.34% and 58.67%, respectively. The erosion dynamic distribution of the main channel in the small watershed was changed to different extents by the different dam type combinations, and the erosion dynamic parameters of the channel decreased most after the dam system was completed, when the velocity and runoff shear stress of the outlet section were reduced by 10.69% and 31.08%, respectively. Additionally, the benefits of sediment reduction were most obvious after the check dam system was completed, with the sediment discharge in the watershed being reduced by 83.92%. The results of this study would provide specific implications for construction and management of check dams in the Loess plateau.

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