Effects of Biological Soil Crusts' Coverage on Slope Runoff and the CN Value of SCS-CN Model in Hilly Loess Plateau Region[J]. 2021, 35(1): 132-137.
DOI:
Effects of Biological Soil Crusts' Coverage on Slope Runoff and the CN Value of SCS-CN Model in Hilly Loess Plateau Region[J]. 2021, 35(1): 132-137. DOI: 10.13870/j.cnki.stbcxb.2021.01.019.
Effects of Biological Soil Crusts' Coverage on Slope Runoff and the CN Value of SCS-CN Model in Hilly Loess Plateau Region
Runoff yield from revegetated grasslands with different coverage of biocrust was measured by simulating rainfall in the study. Meanwhile
the relationship between biocrust coverage and CN value of SCS-CN model was analyzed. The results showed that: (1) Under a 90 mm/h rainfall intensity
the initial runoff yield time decreased against the increase of biocrust coverage
and the initial runoff time with low biocrust coverage (0~20%) was 1.64 and 2.46 times of that with medium biocrust coverage (40%~60%) and high biocrust coverage (80%~100%)
respectively. (2) In the first 15 minutes of rainfall
biocrusts with high coverage promoted runoff yield co
mpared with medium and low biocrust coverage. After 15 minutes
high biocrust coverage inhibited runoff yield compared with medium and low biocrust coverage. After 45 minutes of rainfall
runoff coefficient of each treatment tended to be stable. (3) There was a significant negative correlation between biocrust coverage and runoff depth
and runoff depth decreased in the form of logarithmic function with the increase of biocrust coverage (y=-13.87ln x+73.515
R
2
=0.761 4). (4) By adjusting CN value
SCS-CN model could be suitable for runoff estimation from biocrustal slope
and there was a significant negative correlation between biocrust coverage and CN value
the relational expression is that CN=-0.2672×C
BSC
+79.0166
R
2
=0.680 0. In which
C
BSC
was the percentage coverage of biocrust. In this study
the influence of biocrust on the parameters of runoff model was revealed
which was of great significance to the establishment of hydrological model considering biological crust.