Large‐scale Afforestation over the Loess Plateau in China Contributes to the Local Warming Trend

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.

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

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18126266 ◽

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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Effects of large-scale climate anomalies on trends in seasonal precipitation over the Loess Plateau of China from 1961 to 2016

Ecological Indicators ◽

10.1016/j.ecolind.2019.105643 ◽

2019 ◽

Vol 107 ◽

pp. 105643 ◽

Cited By ~ 4

Author(s):

Xuhu Wang ◽

Baitian Wang ◽

Xianying Xu

Keyword(s):

Loess Plateau ◽

Large Scale ◽

Seasonal Precipitation ◽

The Loess Plateau ◽

Climate Anomalies

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

Hydrology and Earth System Sciences ◽

10.5194/hess-15-2519-2011 ◽

2011 ◽

Vol 15 (8) ◽

pp. 2519-2530 ◽

Cited By ~ 53

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.

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

Acta Ecologica Sinica ◽

10.5846/stxb201909041842 ◽

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

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

Environmental Earth Sciences ◽

10.1007/s12665-012-2095-z ◽

2012 ◽

Vol 69 (8) ◽

pp. 2731-2741 ◽

Cited By ~ 35

Author(s):

Zhi Peng Liu ◽

Ming An Shao ◽

Yun Qiang Wang

Keyword(s):

Loess Plateau ◽

Soil Ph ◽

Spatial Interpolation ◽

Large Scale ◽

The Loess Plateau

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

Water ◽

10.3390/w11040834 ◽

2019 ◽

Vol 11 (4) ◽

pp. 834 ◽

Cited By ~ 4

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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The effects of restoration on vegetation trends: spatiotemporal variability and influencing factors

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691018000518 ◽

2018 ◽

Vol 109 (3-4) ◽

pp. 473-481 ◽

Cited By ~ 1

Author(s):

Kun ZHANG ◽

Yihe LÜ ◽

Bojie FU ◽

Ting LI

Keyword(s):

Spatial Distribution ◽

Loess Plateau ◽

Vegetation Cover ◽

Large Scale ◽

Vegetation Change ◽

Linear Process ◽

Spatiotemporal Variability ◽

Ecological Change ◽

The Loess Plateau ◽

Aid Decision

ABSTRACTSince the ‘Grain to Green Program' was launched in 1999 in the Loess Plateau, China, the processes and patterns of ecological change have become important. Through the use of the fractional vegetation cover (FVC) index, this study examines the spatial distribution and temporal change of vegetation cover in the Loess Plateau during 2000–2014. Over this period more than 60% of the Loess Plateau has remained with little vegetation cover (FVC <30%). The spatial distribution pattern shows an overall increase from the NW to SE. Temporally, the vegetation cover exhibits a general trend of improvement. In 2000–2005, 2000–2010 and 2000–2014, the percentages of restored vegetation (vegetation with significantly increased FVC, P<0.05) were 2, 21 and 52%, respectively. The rate of vegetation cover restoration was highly variable among different bioclimatic zones. The expansion of restored vegetation was greater in the N of the Loess Plateau than in the south. Both human restoration activities and climatic fluctuation influenced the vegetation cover change. The ‘Grain to Green Program' emphasised vegetation restoration. Regional precipitation also had clear effects on vegetation cover. The results of this study reveal that vegetation change shows a non-linear process in response to climate and ecological restoration measures, and that the change gradually emerges over time. This study highlights the importance of considering the spatiotemporal variability in vegetation cover during the implementation of restoration programs, which could aid decision-making for the effective and sustainable management of large-scale restoration programs.

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Effect of Ecological Construction Engineering on Vegetation Restoration: A Case Study of the Loess Plateau

Remote Sensing ◽

10.3390/rs13081407 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1407

Author(s):

Lina Xiu ◽

Xiaojun Yao ◽

Mengdie Chen ◽

Changzhen Yan

Keyword(s):

Ecological Restoration ◽

Loess Plateau ◽

Large Scale ◽

Structural Changes ◽

Ecological Engineering ◽

Vegetation Restoration ◽

The Loess Plateau ◽

Large Area ◽

Forest Protection ◽

Ecological Construction

Since the 1980s, with rapid economic development and increased attention given to ecological protection, China has launched a series of ecological-restoration programs to restore the local environment through afforestation and natural forest protection. The evaluation of vegetation restoration is an important part of evaluating the effectiveness of ecological restoration. The Loess Plateau is an area where ecological problems are concentrated, and it is a key area of ecological construction in China. This paper takes the Loess Plateau as the research area, using remote sensing and geographic information technology combined with ecosystem structural changes and an improved residual model to study vegetation restoration. The following main conclusions were drawn: (1) From 1990 to 2000, the farmland area increased by 3084.81 km2, resulting in the encroachment of a large area of grassland and shrubland. (2) With the implementation of ecological engineering, the area of returning farmland to forest and grassland reached 18,001.88 km2; in this period, the NDVI of vegetation increased rapidly, and the area that increased comprised 91.90% of the total area, of which the area of significant increase reached 65.78%. The quality of vegetation was restored to a great extent, and ecological engineering played a major role in this stage. (3) Under the background of large-scale implementation of ecological restoration, the urban area of the Loess Plateau continues to expand.

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

Water ◽

10.3390/w11040731 ◽

2019 ◽

Vol 11 (4) ◽

pp. 731 ◽

Cited By ~ 3

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.

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