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

<p>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 0–600 cm) combined with soil moisture availability were monitored in situ under <em>Caragana korshinskii</em> 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 <em>C. korshinskii</em> 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 0–300 cm and then gradually increased with some fluctuation from 300–600 cm. A critical turning point and transition zone connecting the shallow and deep soil moisture occurred at 200–300 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 0–100 cm and 300–400 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.</p>

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.

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.

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;

scholarly journals The effects of stemflow on redistributing precipitation and infiltration around shrubs

2018 ◽  
Vol 66 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Dong Li ◽  
Deng Wang ◽  
Zening Wu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
Soil Depth ◽  
Rainfall Threshold ◽  
Chinese Loess Plateau ◽  
Wetting Front ◽  
Deep Soil ◽  
Soil Layers ◽  
Chinese Loess ◽  
Caragana Korshinskii

Abstract The experiments of stemflow of two semiarid shrubs (Caragana korshinskii and Hippophae rhamnoides) and its effect on soil water enhancement were conducted from 1st May to 30th September of 2009-2013 in the Chinese Loess Plateau. Stemflow values in C. korshinskii and H. rhamnoides averaged 6.7% and 2.4% of total rainfall. The rainfall threshold for stemflow generation was 0.5 and 2.5 mm for C. korshinskii and H. rhamnoides. When rainfall was less than 17.0 mm, the funnelling ratios were highly variable, however, stable funnelling ratios were found for rainfall greater than 17.0 mm for C. korshinskii. The funnelling ratios of H. rhamnoides first increased until a threshold value of 10.0 mm and then the funnelling ratios begin stabilize. The wetting front depths in the area around stem was 1.4-6.7 and 1.3-2.9 times deeper than area outside the canopy for C. korshinskii and H. rhamnoides. Soil moisture at soil depth 0-200 cm was 25.6% and 23.4% higher in soil around stem than that outside canopy for C. korshinskii and H. rhamnoides. The wetting front advanced to depths of 120 and 100 cm in the area around stem and to depths of 50 cm in the area outside the canopy for C. korshinskii and H. rhamnoides suggested that more rain water can be conserved into the deep soil layers through shrub stemflow. Soil moisture was enhanced in the area outside the shrub canopy, only when rainfall depth is > 4.7 and 5.1 mm, which is an effective rainfall for the area for C. korshinskii and H. rhamnoides. While for the area around stem of C. korshinskii and H. rhamnoides, the corresponding threshold values are 3.2 and 4.3 mm. These results confirmed that stemflow has a positive effect on soil moisture balance of the root zone and the enhancement in soil moisture of deeper soil layers.

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 Comparison of Soil Moisture Dynamics in Fixed Dune and Sandy Grassland on Korqin Sandy Land

2021 ◽  
Vol 293 ◽  
pp. 01013
Author(s):  
Shuxia Yao ◽  
Chuancheng Zhao
Keyword(s):  
Soil Moisture ◽  
Soil Depth ◽  
Spatial Dynamics ◽  
Growing Season ◽  
Observation Data ◽  
Sandy Land ◽  
Soil Layers ◽  
Semi Arid Region ◽  
Moisture Dynamics ◽  
Sandy Grassland

Based on the fixed-point observation data of soil moisture in different soil layers (0~150 cm) of fixed dunes and sandy grassland in the semi-arid region of Horqin Sandy Land, in the growing season (May to September) from 2005 to 2014, we conducted a comparative study on the seasonal, inter-annual, and spatial dynamics of soil moisture in the two types of sandy land. The results revealed that: (1) in the growing season, the soil moisture in sandy grassland was significantly higher than that in fixed dunes, and the multi-year average soil moisture in both types of sandy land was higher in July than in other months; (2) from 2005 to 2014, the average soil moisture in both types of sandy land was relatively high in 2010, and the average soil moisture in sandy grassland increased gradually with each year; specifically, there was a significant increase in soil moisture in June, while the average soil moisture in fixed dunes did not show an obvious increase; (3) the soil moisture in fixed dunes and sandy grassland generally showed a trend of “first increase, then decrease, and finally increase again”, with the increase in soil depth, and this change was more obvious for sandy grassland.

scholarly journals The Joint Effects of Precipitation Gradient and Afforestation on Soil Moisture across the Loess Plateau of China

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 285 ◽  
Author(s):  
Qindi Zhang ◽  
Wei Wei ◽  
Liding Chen ◽  
Lei Yang
Keyword(s):  
Soil Moisture ◽  
Loess Plateau ◽  
Regional Scale ◽  
Mean Annual Precipitation ◽  
Precipitation Gradient ◽  
Vegetation Types ◽  
The Loess Plateau ◽  
Deep Soil ◽  
Ecological Regions ◽  
Caragana Korshinskii

Understanding the dependence of soil moisture changes following afforestation on the precipitation gradient and afforested vegetation types is crucial for improving ongoing afforestation projects, and to guide future restoration strategies in water-limited regions. For this study, we characterized afforestation-induced changes in soil moisture at depths of 0–3.0 m across a precipitation gradient in the semi-arid Loess Plateau of China. A paired experiment was conducted across 15 sites, where native grasslands served as the baseline hydrology. The results showed that korshinsk peashrub (Caragana korshinskii Kom.), sea buckthorn (Hippophae rhamnoides L.), and black locust (Robinia pseudoacacia L.) afforestation caused an overall strong decline in soil moisture content at depths of below 2.2 m. The degree of soil moisture decline at the regional scale did not vary between different afforested vegetation types but was contingent on precipitation. With decreasing precipitation gradients, afforestation increased the cost of deep soil moisture. Precipitation restrictions began to appear at mean annual precipitation (MAP) = 520 mm, and were intensified at MAP = 380 mm, which could be employed to divide the Loess Plateau into different ecological regions. Because of this, different strategies should be assigned in future restoration practices to these ecological regions to align with localized precipitation conditions. It will likely be prudent to encourage afforestation in areas with MAP of more than 520 mm, while advocating alternative grassland restoration in areas with MAP of less than 380 mm.

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 Soil moisture and evapotranspiration of different land cover types in the Loess Plateau, China

2012 ◽  
Vol 16 (8) ◽  
pp. 2883-2892 ◽  
Author(s):  
S. Wang ◽  
B. J. Fu ◽  
G. Y. Gao ◽  
X. L. Yao ◽  
J. Zhou
Keyword(s):  
Soil Moisture ◽  
Land Cover ◽  
Loess Plateau ◽  
Vegetation Type ◽  
The Other ◽  
Plantation Forest ◽  
The Loess Plateau ◽  
Soil Moisture Dynamics ◽  
Land Cover Types ◽  
Moisture Dynamics

Abstract. We studied the impacts of re-vegetation on soil moisture dynamics and evapotranspiration (ET) of five land cover types in the Loess Plateau in northern China. Soil moisture and temperature variations under grass (Andropogon), subshrub (Artemisia scoparia), shrub (Spiraea pubescens), plantation forest (Robinia pseudoacacia), and crop (Zea mays) vegetation were continuously monitored during the growing season of 2011. There were more than 10 soil moisture pulses during the period of data collection. Surface soil moisture of all of the land cover types showed an increasing trend in the rainy season. Soil moisture under the corn crop was consistently higher than the other surfaces. Grass and subshrubs showed an intermediate moisture level. Grass had slightly higher readings than those of subshrub most of the time. Shrubs and plantation forests were characterized by lower soil moisture readings, with the shrub levels consistently being slightly higher than those of the forests. Despite the greater post-rainfall loss of moisture under subshrub and grass vegetation than forests and shrubs, subshrub and grass sites exhibit a higher soil moisture content due to their greater soil retention capacity in the dry period. The daily ET trends of the forests and shrub sites were similar and were more stable than those of the other types. Soils under subshrubs acquired and retained soil moisture resources more efficiently than the other cover types, with a competitive advantage in the long term, representing an adaptive vegetation type in the study watershed. The interactions between vegetation and soil moisture dynamics contribute to structure and function of the ecosystems studied.

Soil moisture dynamics of different land-cover types in the blacksoil regions of China

2009 ◽  
Vol 17 (2) ◽  
pp. 256-260 ◽  
Author(s):  
Feng WANG ◽  
Shu-Qi WANG ◽  
Xiao-Zeng HAN ◽  
Feng-Xian WANG ◽  
Ke-Qiang ZHANG
Keyword(s):  
Soil Moisture ◽  
Land Cover ◽  
Soil Moisture Dynamics ◽  
Land Cover Types ◽  
Moisture Dynamics
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