| Seasonal dynamics of soil critical shear stress in soybean and potato farmlands in the loess plateau |
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| DOI：10.7606/j.issn.1000-7601.2018.01.07 |
| Key Words: loess areas soil critical shear stress seasonal dynamics root growth |
| Author Name | Affiliation | | YU Yao-chuang | College of Geography and Environment, Baoji Arts & Sci. University, Baoji Shaanxi 721013, China
Key Laboratory of Disaster Monitoring and Mechanism Simulating of Shaanxi Province, Baoji Shaanxi 721013, China | | WANG Chang-yan | College of Geography and Environment, Baoji Arts & Sci. University, Baoji Shaanxi 721013, China
Key Laboratory of Disaster Monitoring and Mechanism Simulating of Shaanxi Province, Baoji Shaanxi 721013, China |
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| Abstract: |
| In order to provide reference data for establishing the soil erosion process model in the loess plateau. The research take soybean and potato farmlands in the hilly region of the Loess Plateau as a target. The scouring experiments in a laboratory flume to simulate soil detachment by concentrated flow was conducted under the different condition of six flow shear stress (τ=5.71～17.18 Pa). Based on data of soil detachment capacity and flow shear stress, and combined the famous soil erosion process WEPP model, the seasonal dynamics of soil critical shear stress were discussed for soybean and potato farmlands during the crop growing season. Results showed that the seasonal dynamics of soil critical shear stress under soybean and potato farmlands in loess areas increased significantly during the whole growing season (P＜0.05). During the growing season, soil critical shear stress for soybean fluctuated over time with a pattern of double peak curve. τc values varied from 1.66 Pa to 5.37 Pa, with a mean value of 3.34 Pa. The minimum and maximum values of soil critical shear stress for soybean appeared in the seeding stage and harvesting stage, respectively. Soil critical shear stress for potato displayed similar a pattern of the seasonal variation f. τc values varied from 1.06 Pa to 5.26 Pa, with a mean value of 3.12 Pa. The minimum and maximum values of soil critical shear stress for potato occurred in the squaring stage and blooming stage, respectively. Positive relations were detected between soil critical shear stress and soil cohesion, bulk density, content of water-stable aggregates, and root weight density. Among them, soil bulk density and root weight density were important factors affecting seasonal dynamic of soil critical shear stress. Seasonal dynamics of soil critical shear stress under soybean and potato farmlands could well be simulated with soil bulk density and root weight density (R2＞0.50，NSE＞0.50). |
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