ZHANG Meng1, LI Dongjie2, ZHOU Yue1. Effects of Rainfall Intensity and Slope Gradient on Soil Erosion, Nitrogen and Potassium Loss on Loess Slope[J]. 2018, 32(1): 85-90.
ZHANG Meng1, LI Dongjie2, ZHOU Yue1. Effects of Rainfall Intensity and Slope Gradient on Soil Erosion, Nitrogen and Potassium Loss on Loess Slope[J]. 2018, 32(1): 85-90. DOI: 10.13870/j.cnki.stbcxb.2018.01.014.
This study explored the effects of rainfall intensity and slope gradient on soil erosion and nutrient loss under two rainfall intensities (50 and 75 mm/h) and four slope gradients (5°
10°
15° and 20°) through simulated rainfall experiments. The results were as follows: (1) When the rainfall intensity increased from 50 mm/h to 75 mm/h on the same slope
the runoff yield time was advanced by 2.75 ~ 4.79 min. (2) On the same slope
with the increasing of rainfall intensity
the cumulative runoff and cumulative sediment yield increased by 12.53 ~ 15.80 mm/m2 and 0.47 ~ 3.61 kg/m2
respectively
and the increase ranges were 1.24 ~ 1.31 times and 0.77 ~ 2.90 times
respectively; there was a critical slope gradient in the process of slope erosion
and it was about 15°. (3) The loss of nitrogen in the runoff was dominant
and the amount of nitrogen loss in sediment was low
which accounted only for 1.4% ~ 9.7% of total nitrogen loss in runoff; when the slope gradient was low
the loss of phosphorus was mainly caused by runoff loss
while with the increasing of the slope gradient
it was mainly caused by sediment loss. (4) The concentration of total nitrogen loss in runoff had obvious linear positive correlation with runoff intensity
and there was a significant positive linear correlation between total nitrogen and total phosphorus loss and sediment yield rate.