Relationship between soil surface roughness and hydraulic roughness coefficient on sloping farmland

Water Science and Engineering

Fa-qi Wu¹  Zi-cheng Zheng²  Shu-qin He² 

[1] College of Resources and Environment, Northwest A&F University, Yangling 712100, P. R. China;College of Resources and Environment, Sichuan Agricultural University, Chengdu 611130, P. R. China;

关键词: soil hydraulics;    sloping farmland;    soil erosion;    soil surface roughness;    hydraulic roughness coefficient;    Reynolds number;    tillage practice;   

DOI  :  10.3882/j.issn.1674-2370.2012.02.007

来源: DOAJ

【 摘 要 】

The soil surface roughness and hydraulic roughness coefficient are important hydraulic resistance characteristic parameters. Precisely estimating the hydraulic roughness coefficient is important to understanding mechanisms of overland flow. Four tillage practices, including cropland raking, artificial hoeing, artificial digging, and straight slopes, were considered based on the local agricultural conditions to simulate different values of soil surface roughness in the Loess Plateau. The objective of this study was to investigate the relationship between the soil surface roughness and hydraulic roughness coefficient on sloping farmland using artificial rainfall simulation. On a slope with a gradient of 10°, a significant logarithmic function was developed between the soil surface roughness and Manning's roughness coefficient, and an exponential function was derived to describe the relationship between the soil surface roughness and Reynolds number. On the slope with a gradient of 15°, a significant power function was developed to reflect the relationship between the soil surface roughness and Manning's roughness coefficient, and a linear function was derived to relate the soil surface roughness to the Reynolds number. These findings can provide alternative ways to estimate the hydraulic roughness coefficient for different types of soil surface roughness.

【 授权许可】

Unknown