Heat and water balances of the bare soil surface and the potential distribution of vegetation in the Loess Plateau, China

The understanding of the structure of the spatial variability of soil surface hydraulic properties on steep slopes is important for modeling infiltration and runoff processes. The objective of this study was to investigate the spatial variability of these properties on a steep slope of the Loess Plateau in northwest China. A 9600 m² area was systematically sampled in a grid of 106 points spaced 10 m x 10 m. Hydraulic properties were determined with a disc infiltrometer under multiple pressure heads (-15, -9, -6, -3, 0 cm) at each sample point. Classical and geo-statistical methods were used for data analysis. The results indicated that the variation of Gardner's a and hydraulic conductivities at all applied pressure heads was moderate and the heterogeneity for hydraulic conductivities increased as the applied pressure head increased. Along the slope, hydraulic conductivities generally decreased downwards, while the Gardner's a fluctuated slightly. The Gardner's a of the shaded aspect of the slope was greater than that of the sunny aspect. The hydraulic conductivities of the shaded aspect were greater at higher pressure heads as compared to the sunny aspect, but lower than those of the sunny aspect at lower pressure heads. Correlation analysis showed a negative correlation between hydraulic conductivity and soil organic matter and clay (<0.01 mm) contents. Hydraulic conductivities at pressure heads of -3, -6, -9, -15 cm varied across the slope and their spatial dependence increased as the pressure head declined. The heterogeneity and spatial dependence of hydraulic properties were larger for the areas with shaded aspect as compared to the sunny aspect, however, as pressure decreased they showed a progressively increasing spatial structure, and their spatial structure behaved increasingly similar in both the shaded and sunny aspects.

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Soil water storage and winter wheat productivity affected by soil surface management and precipitation in dryland of the Loess Plateau, China

Agricultural Water Management ◽

10.1016/j.agwat.2016.03.005 ◽

2016 ◽

Vol 171 ◽

pp. 1-9 ◽

Cited By ~ 30

Author(s):

Gang He ◽

Zhaohui Wang ◽

Fucui Li ◽

Jian Dai ◽

Qiang Li ◽

...

Keyword(s):

Winter Wheat ◽

Soil Water ◽

Loess Plateau ◽

Water Storage ◽

Soil Surface ◽

Soil Water Storage ◽

The Loess Plateau

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Variation in soil surface roughness under different land uses in a small watershed on the Loess Plateau, China

CATENA ◽

10.1016/j.catena.2020.104465 ◽

2020 ◽

Vol 188 ◽

pp. 104465 ◽

Cited By ~ 1

Author(s):

Ping-zong Zhu ◽

Guang-hui Zhang ◽

Bao-jun Zhang ◽

Hong-xiao Wang

Keyword(s):

Surface Roughness ◽

Loess Plateau ◽

Soil Surface ◽

Land Uses ◽

Small Watershed ◽

The Loess Plateau ◽

Soil Surface Roughness

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Effects of litter cover on partitioning of natural rainfall for plantation Pinus tabulaeformis forest in the Loess Plateau of China

10.5194/egusphere-egu21-7695 ◽

2021 ◽

Author(s):

Yongsheng Cui ◽

Chengzhong Pan ◽

Geng Zhang ◽

Zhanwei Sun ◽

Fuxing Wang

Keyword(s):

Loess Plateau ◽

Surface Runoff ◽

Rainy Season ◽

Soil Layer ◽

Bare Soil ◽

Pinus Tabulaeformis ◽

Soil Water Storage ◽

The Loess Plateau ◽

Light Rain ◽

Litter Cover

&#160; &#160; &#160; Litter accumulates yearly since vegetations were widely planted for reforestation, and it plays an important role in hydrologic cycling. There is little information on the effects of litter on re-allocation of rainfall processes. Eight runoff plots were established in the Pinus tabulaeformis stand with four litter (needle-leaf) masses (0, 0.6, 1.2, 1.8 kg/m2), and the surface runoff (R), evaporation (E), infiltration and soil moisture dynamics were measured throughout the mainly rainy season from August 4 to September 28 in the Loess Plateau. The results showed that, soil evaporation mainly occurred in daytime for bare soil, and decreased with increasing litter masses, and litter cover is prone to hinder the heat and water exchange between soil and atmosphere, especially for the soil layer 0~5 cm. Litter cover greatly decreased surface runoff, and it may hinder infiltration at the beginning of rainy season, but increasing soil water storage (SWS) with deeper infiltration depth for the long run, especially for the litter masses 1.2 and 1.8 kg/m2. With the litter covered, the ratio of R to precipitation (P) was less than 10%, no matter it was heavy rain or light rain. However, the proportion of R was amplified when the rainfall was intense for the bare soil. And the ratio of E to P was always below 10% for all treatments, except for light rainfall. With the increased litter masses, the proportion of R and E all decreased, and the SWS/P has well nonlinear positive relationship with litter masses, and it was proved that more than a half of rainfall was stored even for bare soil. This study may helpful to better understanding the effects of litter on hydrological response, and promotes practical measurements to the management of precipitation in a forest stand view.

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Vegetation Restoration Alleviated the Soil Surface Organic Carbon Redistribution in the Hillslope Scale on the Loess Plateau, China

Frontiers in Environmental Science ◽

10.3389/fenvs.2020.614761 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yipeng Liang ◽

Xiang Li ◽

Tonggang Zha ◽

Xiaoxia Zhang

Keyword(s):

Spatial Distribution ◽

Soil Erosion ◽

Organic Carbon ◽

Loess Plateau ◽

Effective Means ◽

Soil Surface ◽

Vegetation Restoration ◽

The Loess Plateau ◽

Loess Slope ◽

Carbon Redistribution

The redistribution of soil organic carbon (SOC) in response to soil erosion along the loess slope, China, plays an important role in understanding the mechanisms that underlie SOC’s spatial distribution and turnover. Consequently, SOC redistribution is key to understanding the global carbon cycle. Vegetation restoration has been identified as an effective method to alleviate soil erosion on the Loess Plateau; however, little research has addressed vegetation restoration’s effect on the SOC redistribution processes, particularly SOC’s spatial distribution and stability. This study quantified the SOC stock and pool distribution on slopes along geomorphic gradients in naturally regenerating forests (NF) and an artificial black locust plantation (BP) and used a corn field as a control (CK). The following results were obtained: 1) vegetation restoration, particularly NF, slowed the migration of SOC and reduced the heterogeneity of its distribution effectively. The topsoil SOC ratios of the sedimentary area to the stable area were 109%, 143%, and 210% for NF, BP, and CK, respectively; 2) during migration, vegetation restoration decreased the loss of labile organic carbon by alleviating the loss of dissolved organic carbon (DOC) and easily oxidized organic carbon (EOC). The DOC/SOC in the BP and NF increased significantly and was 13.14 and 17.57 times higher, respectively, than that in the CK (p < 0.05), while the EOC/SOC in the BP and NF was slightly higher than that in the CK. A relevant schematic diagram of SOC cycle patterns and redistribution along the loess slope was drawn under vegetation restoration. The results suggest that vegetation restoration in the loess slope, NF in particular, is an effective means to alleviate the redistribution and spatial heterogeneity of SOC and reduce soil erosion.

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Soil erodibility affected by vegetation restoration on steep gully slopes on the Loess Plateau of China

Soil Research ◽

10.1071/sr18129 ◽

2018 ◽

Vol 56 (7) ◽

pp. 712 ◽

Cited By ~ 3

Author(s):

Bao-jun Zhang ◽

Guang-hui Zhang ◽

Han-yue Yang ◽

Hao Wang ◽

Ning-ning Li

Keyword(s):

Loess Plateau ◽

Mass Density ◽

Organic Matter Content ◽

Aggregate Stability ◽

Soil Surface ◽

Matter Content ◽

Vegetation Restoration ◽

Soil Erodibility ◽

The Loess Plateau ◽

The Mean

Vegetation restoration influences near soil-surface characteristics and thus likely affects soil erodibility. This study was performed to quantify the effects of vegetation restoration on soil erodibility on steep gully slopes, and to identify the potential influencing factors on the Loess Plateau. Three shrub and four grass types distributed on different gully slopes were selected, and six erodibility indicators and an integrated erodibility index (IEI) were applied to indirectly evaluate the effects of vegetation restoration on soil erodibility. The former included the soil erodibility K factor, aggregate stability (the mean weight diameter, MWD, and the mean number of drop impacts, MND), saturated hydraulic conductivity (Ks), cohesion (Coh), and penetration resistance (PR), and the latter was calculated using these indicators and a weighted integration method. The results showed that vegetation restoration on steep gully slopes was effective in reducing soil erodibility on the Loess Plateau, and grasses seemed more effective than shrubs. Compared with the control, the K of vegetation-restored gully slopes decreased by 4.1–24.0%, and MWD, MND, Ks, Coh, and PR increased by 64.0–284.3, 51.4–269.5, 100.5–417.4, 10.1–172.2, and 63.3–278.9% respectively. Consequently, the IEI of the vegetation-restored gully slopes declined by 33.1–81.9%, and the mean reduction percentage of the four grasses was 1.5 times that of the three shrubs. The variation in soil erodibility was closely related to the changes in the soil organic matter content and root mass density with vegetation restoration. The results will help in understanding the soil conservation mechanisms of vegetation restoration on steep gully slopes.

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