Ecosystem service trade-offs and their influencing factors: A case study in the Loess Plateau of China

Steep gully slopes are widespread and have been recognized as the main sediment source on the Loess Plateau. Different vegetation growth may lead to the differences in soil properties and plant roots, and thus likely affects soil resistance to flowing water erosion, reflected by rill erodibility and critical shear stress. However, few studies have been conducted to evaluate this effect on steep gully slopes on the Loess Plateau of China. This study was performed to investigate the effects of vegetation growth on soil resistance to flowing water erosion on steep gully slopes, and quantify the main potential influencing factors on the Loess Plateau. Three typical shrub communities and four typical grass communities that distributed on different gully slopes were selected. 240 undisturbed soil samples were collected from these seven gully slope lands and one slope farmland (control), and were subjected to detachment by overland flow under six different shear stresses (6.64 to 17.85 Pa). The results showed that the mean detachment capacity of slope farmland was 6.9 to 47.8 times greater than those of steep gully slopes covered with different plant communities. The rill erodibilities of steep gully slopes covered with different plant communities reduced greatly by 77.0% to 95.1% compared to the control slope. The critical shear stress of slope farmland (2.72 Pa) was only 57.2% and 39.6% of that of shrubland (4.76 Pa) and grassland (6.88 Pa). Both shrub and grass communities were effective in reducing soil detachment capacity and rill erodibility, and increasing critical shear stress on steep gully slopes. But the effects were more obvious for the grass communities. The differences in rill erodibility between slope farmland and gully slope lands were mainly explained by the changes in root mass density (82.4%). Plant roots had strong direct effects on increasing soil cohesion (0.78), organic matter content (0.56), and water stable aggregation (0.92). Rill erodibility was negatively related to root mass density as an exponential function (p

Soil resistance to flowing water erosion of seven typical plant communities on steep gully slopes on the Loess Plateau of China

Revegetation induced change in soil erodibility as influenced by slope situation on the Loess Plateau

Temporal variations in soil erodibility indicators of vegetation-restored steep gully slopes on the Loess Plateau of China

Landscape patches influencing hillslope erosion processes and flow hydrodynamics

Effects of landscape positions on soil resistance to rill erosion in a small catchment on the Loess Plateau

The knowledge of soil resistance to runoff (reflected by rill erodibility, K r , and critical shear stress, τ c ) of steep croplands from laboratory flume experiments and their influencing factors are unclear at a larger scale. Therefore, the disturbed soil samples (representing the freshly tilled steep croplands) of 36 soil types were collected from eastern China and scoured under different flow shear stresses to investigate the spatial variations in K r and τ c and their influencing factors. The results showed that the soil “Argi-Udic Ferrosols” had the lowest K r , while the soil “Aqui-Sandic Primosols” had the highest K r . The K r values of the 36 soil types showed a high spatial variability. The mean K r of the northwest Loess Plateau was significantly greater than that of the other five secondary water erosion regions. Soil texture with moderate clay and sand content had the highest K r . τ c showed moderate spatial variability, and no obvious correlation was detected with soil types, the six secondary water erosion regions, or soil textures. K r was significantly correlated with the measured soil physical and chemical properties. No significant correlation was found between τ c and measured soil properties. K r could be satisfactorily estimated by the silt content, sand content, the geometric mean particle diameter of the soil ( D g ), cation exchange capacity ( CEC ) and soil organic matter ( SOM ) ( R 2  = 0.70).

Soil resistance to runoff on steep croplands in Eastern China

Landscape position may impact soil detachment capacity (Dc) by overland flow through the imposing influences on soil properties and plant roots. Nonetheless, little knowledge existed with regard to the response of Dc to landscape position. Therefore, this study was conducted to detect the response of Dc to landscape positions and identify the primary influencing factors in hilly and gully regions of the Loess Plateau. 540 undisturbed soil samples taken from six landscape positions were subjected to scour in a hydraulic flume to determine Dc. The results demonstrated that Dc of the top ridge was the maximum (1.13 kg m−2 s−1), while Dc of the footslope was the minimum (0.0026 kg m−2 s−1). The landscape positions significantly influenced Dc, presenting a regularly decreasing trend from the top to the bottom. Dc increased with stream power (ω) by a power function. Power function was better than linear function for predicting of Dc. The partial least square regression analysis showed that soil organic matter, water stable aggregate (WSA), root mass density (RMD), and soil cohesion (Coh) dominated the variations in Dc. Significant negative relationships were detected between these primary factors and Dc. Landscape position affected Coh, WSA and RMD, which in turn controlled the regular change of Dc with landscape position. Dc of six landscape positions could be satisfactorily estimated by ω, WSA, and RMD (r2 = 0.81; NSE = 0.81). The results are helpful to understand the vertical changes in soil erosion intensity in small watershed scale.

Qian-hong Ma

Papers

Effects of landscape positions on soil resistance to rill erosion in a small catchment on the Loess Plateau

Soil resistance to runoff on steep croplands in Eastern China

Response of soil detachment capacity to landscape positions in hilly and gully regions of the Loess Plateau