scholarly journals Spatial variations of deep soil moisture and the influencing factors in the Loess Plateau, China

2016 ◽  
Author(s):  
X. N. Fang ◽  
W. W. Zhao ◽  
L. X. Wang ◽  
Q. Feng ◽  
J. Y. Ding ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Variation ◽  
Influencing Factors ◽  
Loess Plateau ◽  
Rapid Change ◽  
Spatial Variations ◽  
Native Vegetation ◽  
Watershed Scale ◽  
Deep Soil ◽  
Soil Layers

Abstract. Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the spatial variations of deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focused on analyzing the spatial variation and factors influencing soil moisture content (SMC) in (0–500 cm) soil layers based on a soil moisture survey of the Ansai watershed, Yanan, Shannxi province. Our results can be divided into four main findings. (1) At the watershed scale, the higher spatial variation of deep SMC occurred at 0–20 cm, 120–140 cm and 480–500 cm in the vertical direction. At a comparable depth but in the horizontal direction, the spatial variation of deep SMC under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The deep SMC in native vegetation and human-managed vegetation was significantly higher than that of introduced vegetation, and different degrees of soil desiccation occurred under all introduced vegetation types. (3) Taking the SMC condition of native vegetation as a reference for local control, soil could be divided into four layers: I) shallow rapid change layer (0–60 cm); II) main rainfall infiltration layer (60–220 cm); III) transition layer (220–400 cm); and IV) stable layer (400–500 cm). Positive and significant correlations existed between SMC at layers II, III and IV, and the correlations of the neighboring layer ranges were clearly stronger than that of nonadjacent depth ranges, although the SMC at shallow rapid change layer I showed a disconnect (i.e., no correlations) with those at the three other soil depth layers. (4) The influencing factors of deep SMC at the watershed scale varied with land management types. The main local controls of SMC variation were soil particle composition and annual average rainfall; human agricultural management measures can alter soil buck density, which contributes to higher deep SMC. In introduced vegetation, plant growth conditions, planting density, and litter water holding traits showed significant relationships with deep SMC. The results of this study are of practical significance for vegetation restoration strategies and the sustainability of restored ecosystems.

scholarly journals Variations of deep soil moisture under different vegetation types and influencing factors in a watershed of the Loess Plateau, China

2016 ◽  
Vol 20 (8) ◽  
pp. 3309-3323 ◽  
Author(s):  
Xuening Fang ◽  
Wenwu Zhao ◽  
Lixin Wang ◽  
Qiang Feng ◽  
Jingyi Ding ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Influencing Factors ◽  
Loess Plateau ◽  
Vegetation Restoration ◽  
Native Vegetation ◽  
Watershed Scale ◽  
Vegetation Types ◽  
Deep Soil ◽  
Soil Layers ◽  
Management Measures

Abstract. Soil moisture in deep soil layers is a relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the variations in deep soil moisture and its influencing factors at a moderate watershed scale is important to ensure the sustainability of vegetation restoration efforts. In this study, we focus on analyzing the variations and factors that influence the deep soil moisture (DSM) in 80–500 cm soil layers based on a soil moisture survey of the Ansai watershed in Yan'an in Shanxi Province. Our results can be divided into four main findings. (1) At the watershed scale, higher variations in the DSM occurred at 120–140 and 480–500 cm in the vertical direction. At the comparable depths, the variation in the DSM under native vegetation was much lower than that in human-managed vegetation and introduced vegetation. (2) The DSM in native vegetation and human-managed vegetation was significantly higher than that in introduced vegetation, and different degrees of soil desiccation occurred under all the introduced vegetation types. Caragana korshinskii and black locust caused the most serious desiccation. (3) Taking the DSM conditions of native vegetation as a reference, the DSM in this watershed could be divided into three layers: (i) a rainfall transpiration layer (80–220 cm); (ii) a transition layer (220–400 cm); and (iii) a stable layer (400–500 cm). (4) The factors influencing DSM at the watershed scale varied with vegetation types. The main local controls of the DSM variations were the soil particle composition and mean annual rainfall; human agricultural management measures can alter the soil bulk density, which contributes to higher DSM in farmland and apple orchards. The plant growth conditions, planting density, and litter water holding capacity of introduced vegetation showed significant relationships with the DSM. The results of this study are of practical significance for vegetation restoration strategies, especially for the choice of vegetation types, planting zones, and proper human management measures.

scholarly journals Spatial variations of shallow and deep soil moisture in the semi-arid Loess Plateau, China

2012 ◽  
Vol 16 (9) ◽  
pp. 3199-3217 ◽  
Author(s):  
L. Yang ◽  
W. Wei ◽  
L. Chen ◽  
F. Jia ◽  
B. Mo
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Sampling Site ◽  
Spatial Variations ◽  
Slope Position ◽  
Slope Aspect ◽  
Deep Soil ◽  
Soil Layers ◽  
Vegetation Growth ◽  
Semi Arid

Abstract. Soil moisture in deep soil layers is an important relatively stable water resource for vegetation growth in the semi-arid Loess Plateau of China. Characterizing the spatial variations of deep soil moisture with respect to the topographic conditions has significant importance for vegetation restoration. In this study, we focused on analyzing the spatial variations and factors influencing soil moisture content (SMC) in shallow (0–2 m) and deep (2–8 m) soil layers, based on soil moisture observations in the Longtan watershed, Dingxi, Gansu province. The vegetation type of each sampling site for each comparison is same and varies by different positions, gradients, or aspects. The following discoveries were captured: (1) in comparison with shallow SMC, slope position and slope aspect may affect shallow soil moisture more than deep layers, while slope gradient affects both shallow and deep soil moisture significantly. This indicates that a great difference in deep soil hydrological processes between shallow and deep soil moisture remains that can be attributed to the introduced vegetation and topography. (2) A clear negative relationship exists between vegetation growth condition and deep soil moisture, which indicates that plants under different growing conditions may differ in consuming soil moisture, thus causing higher spatial variations in deep soil moisture. (3) The dynamic role of slope position and slope aspect on deep soil moisture has been changed due to large-scale plantation in semi-arid environment. Consequently, vegetation growth conditions and slope gradients may become the key factors dominating the spatial variations in deep soil moisture.

scholarly journals Spatial variation of shallow and deep soil moisture in the semi-arid loess hilly area, China

2012 ◽  
Vol 9 (4) ◽  
pp. 4553-4586 ◽  
Author(s):  
L. Yang ◽  
W. Wei ◽  
L. Chen ◽  
F. Jia ◽  
B. Mo
Keyword(s):  
Soil Moisture ◽  
Spatial Variation ◽  
Growth Condition ◽  
Slope Position ◽  
Slope Aspect ◽  
Slope Gradient ◽  
Deep Soil ◽  
Soil Layers ◽  
Vegetation Growth ◽  
Semi Arid

Abstract. Soil moisture in deep soil layers is the only relatively stable water resource for introduced vegetation in the semi-arid Loess Plateau of China. Characterizing the spatial variation of deep soil moisture is significant for vegetation restoration with respect to the topographic conditions. In this study, we focused on analyzing the spatial variations and influencing factors of soil moisture content (SMC) in shallow (0–2 m) and deep (2–8 m) soil layers based on soil moisture observation in the Longtan watershed. The vegetation type of each sampling site for each comparison is same, while varies with slope position, slope gradient, or slope aspect. The following results are found: (1) compared with shallow SMC, slope position and slope aspect may affect shallow soil moisture more, rather than deep layers. Slope gradient however, affect both shallow and deep soil moisture significantly. It indicates that high difference of deep soil hydrological processes between shallow and deep soil moisture remains, which can be attributed to the introduced vegetation and topography. (2) The vegetation growth condition has significant negative relation with deep soil moisture. This result indicates that plants under different growth conditions may consume soil moisture differently, thus causing higher spatial variation of deep soil moisture. (3) The dynamic role of slope position and slope aspect on deep SMC has been changed by introduced vegetation in semi-arid environment. Consequently, vegetation growth condition and slope gradient may be the major factor contributing to the spatial variation of deep soil moisture.

Soil moisture dynamics under Caragana korshinskii shrubs of different ages in Wuzhai County on the Loess Plateau, China

2018 ◽  
Vol 109 (3-4) ◽  
pp. 387-396 ◽  
Author(s):  
Haibin LIANG ◽  
Yayong XUE ◽  
Jianwei SHI ◽  
Zongshan LI ◽  
Guohua LIU ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Growing Season ◽  
Deep Soil ◽  
Soil Moisture Dynamics ◽  
Soil Layers ◽  
Caragana Korshinskii ◽  
Hilly Region ◽  
Different Ages ◽  
Moisture Dynamics

ABSTRACTSoil moisture is a key factor affecting vegetation growth and survival in arid and semi-arid regions. Knowledge of deep soil moisture dynamics is very important for guiding vegetation restoration and for improving land management practices on the water-limited Loess Plateau. Temporal changes and vertical variations in deep soil moisture (at soil depths of 0–600cm) combined with soil moisture availability were monitored in situ under Caragana korshinskii shrubs of different ages (named CK-10a, CK-20a and CK-35a) in the Loess hilly region during the growing season of 2013. The soil moisture content (SMC) under C. korshinskii shrubs of different ages was highly consistent with the seasonal precipitation variations and generally decreased as follows: CK-10a>CK-20a>abandoned land>CK-35a. The SMC varied greatly over time during the growing season (P<0.01), decreasing from April to May and then slowly increasing with some fluctuation from June to October. The SMC drastically decreased with depth from 0–300cm and then gradually increased with some fluctuation from 300–600cm. A critical turning point and transition zone connecting the shallow and deep soil moisture occurred at 200–300cm. Therefore, the soil profile was divided into active, secondary active and relatively steady soil layers in terms of soil moisture. The SMC fluctuated at depths of 0–100cm and 300–400cm and was relatively stable in the deeper soil layers. The amount of available soil moisture gradually decreased as the forest stand age increased, especially at CK-35a, where most of the soil moisture was unavailable for plant use. In addition, our study indicates that a large-scale restoration strategy with pure shrubland or woodland may not be suitable for soil moisture recovery in arid environments.

Soil moisture dynamics under Caragana korshinskii shrubs of different ages in Wuzhai County on the Loess Plateau, China

2020 ◽  
Author(s):  
Zongshan Li ◽  
Haibin Liang
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Growing Season ◽  
Deep Soil ◽  
Soil Moisture Dynamics ◽  
Soil Layers ◽  
Caragana Korshinskii ◽  
Hilly Region ◽  
Different Ages ◽  
Moisture Dynamics

&lt;p&gt;Soil moisture is a key factor affecting vegetation growth and survival in arid and semi-arid regions. Knowledge of deep soil moisture dynamics is very important for guiding vegetation restoration and for improving land management practices on the water-limited Loess Plateau. Temporal changes and vertical variations in deep soil moisture (at soil depths of 0&amp;#8211;600 cm) combined with soil moisture availability were monitored in situ under &lt;em&gt;Caragana korshinskii&lt;/em&gt; shrubs of different ages (named CK-10a, CK-20a and CK-35a) in the Loess hilly region during the growing season of 2013. The soil moisture content (SMC) under &lt;em&gt;C. korshinskii&lt;/em&gt; shrubs of different ages was highly consistent with the seasonal precipitation variations and generally decreased as follows: CK-10a &gt; CK-20a &gt; abandoned land &gt; CK-35a. The SMC varied greatly over time during the growing season (P &lt; 0.01), decreasing from April to May and then slowly increasing with some fluctuation from June to October. The SMC drastically decreased with depth from 0&amp;#8211;300 cm and then gradually increased with some fluctuation from 300&amp;#8211;600 cm. A critical turning point and transition zone connecting the shallow and deep soil moisture occurred at 200&amp;#8211;300 cm. Therefore, the soil profile was divided into active, secondary active and relatively steady soil layers in terms of soil moisture. The SMC fluctuated at depths of 0&amp;#8211;100 cm and 300&amp;#8211;400 cm and was relatively stable in the deeper soil layers. The amount of available soil moisture gradually decreased as the forest stand age increased, especially at CK-35a, where most of the soil moisture was unavailable for plant use. In addition, our study indicates that a large-scale restoration strategy with pure shrubland or woodland may not be suitable for soil moisture recovery in arid environments.&lt;/p&gt;

Seasonal variation of deep soil moisture under different land uses on the semi-arid Loess Plateau of China

2018 ◽  
Vol 19 (3) ◽  
pp. 1179-1189 ◽  
Author(s):  
Bowei Yu ◽  
Gaohuan Liu ◽  
Qingsheng Liu ◽  
Chong Huang ◽  
He Li ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Seasonal Variation ◽  
Loess Plateau ◽  
Land Uses ◽  
Deep Soil ◽  
Semi Arid

scholarly journals Effects of two typical revegetation methods on soil moisture in the semi-arid Loess Plateau, China

2019 ◽  
Vol 50 (5) ◽  
pp. 1453-1462
Author(s):  
Qian Zhao ◽  
Lei Yang ◽  
Xin Wang ◽  
Runcheng Bi ◽  
Qindi Zhang
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Temporal Variations ◽  
Chinese Loess Plateau ◽  
Deep Soil ◽  
Chinese Loess ◽  
Soil Desiccation ◽  
Native Grasslands ◽  
First Choice ◽  
Natural Revegetation

Abstract Understanding the effects of vegetation on soil moisture is vital to the ecosystem restoration in water-restricted areas. For this study, the effects of introduced revegetation and natural revegetation on soil water (0–1.8 m) were investigated in the Chinese Loess Plateau, which was based on an in situ vegetation removal experiment and two years of soil moisture monitoring. The results indicated that under introduced revegetation, pasture grassland had lower soil moisture but higher temporal variations over the growing season. Compared with abandoned farmlands and native grasslands under natural revegetation, pasture grasslands revealed greater negative effects on deep soil moisture (1–1.8 m), which was difficult to recover following soil desiccation. In contrast, for abandoned farmlands and native grasslands, the surface soil moisture (0–0.4 m) was mainly impacted, which was easily replenished through rainfall events. These outcomes implied that natural revegetation, rather than introduced revegetation, should be the first choice in water-limited regions toward the rehabilitation of degraded ecosystems.

Impact of revegetation of the Loess Plateau of China on the regional growing season water balance

2020 ◽  
Author(s):  
Weidong Guo ◽  
Andrew Pitman ◽  
Jun Ge ◽  
Beilei Zan ◽  
Congbin Fu
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Wrf Model ◽  
Growing Season ◽  
Weather Research And Forecasting ◽  
The Loess Plateau ◽  
Deep Soil ◽  
Bare Land ◽  
Biophysical Changes ◽  
The Impact

&lt;p&gt;To resolve a series of ecological and environmental problems over the Loess Plateau, the was initiated at the end of 1990s. Following the conversion of croplands and bare land on hillslopes to forests, the Loess Plateau has displayed a significant greening trend with soil erosion being reduced. However, the GFGP has also affected the hydrology of the Loess Plateau which has raised questions whether the GFGP should be continued in the future. We investigated the impact of revegetation on the hydrology of the Loess Plateau using high resolution simulations and multiple realisations with the Weather Research and Forecasting (WRF) model. Results suggests that land cover change since the launch of the GFGP has reduced runoff and soil moisture due to enhanced evapotranspiration. Further revegetation associated with the GFGP policy is likely to increase evapotranspiration further, and thereby reduce runoff and soil moisture. The increase in evapotranspiration is associated with biophysical changes, including deeper roots that deplete deep soil moisture stores. However, despite the increase in evapotranspiration our results show no impact on rainfall. Our study cautions against further revegetation over the Loess Plateau given the reduction in water available for agriculture and human settlements, without any significant compensation from rainfall.&lt;/p&gt;

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