Seasonal discrepancy of ephemeral gully erosion in Northeast China with black soils

Ephemeral gully erosion can be a major sediment source serving as main conduits to convey runoff and sediment from most farmland.Ephemeral gully erosion is similar to but differ from both rill and classical gully erosion.But ephemeral gully erosion is often overlooked,and it is also not estimated with rill-interrill erosion prediction models such as the Revised Universal Soil Loss Equation.Soil erosion is increasingly severe in Northeast China with black soils,in which ephemeral gully erosion is an important type of water erosion.However,the existing literature indicated that little research on ephemeral gully erosion has been done in this area.In this paper,ephemeral gully erosion was investigated in spring and summer of 2005 in black soil regions of two small catchments on Heshan Farm of Heilongjiang Province.The aim of the study was to present the characteristics of ephemeral gullies and their seasonal discrepancies and controlling factors.The results show that soil losses due to ephemeral gully erosion fluctuate along the slope,and the high erosivity belts alternate with the low belt.There are also great differences in the morphology,the erosion intensity and controlling factors of ephemeral gully erosion between spring and summer.Ephemeral gully erosion in spring is mainly resulted from snow storm and is significantly influenced by freeze-thaw and snowmelt runoff.Ephemeral gully erosion in spring is slightly severer than that in summer.Ephemeral gully erosion was caused by storm.Compared with that in spring,ephemeral gullies in summer were shorter and shallower,but wider due to the storm characterized by high intensity and low duration.Furthermore,the depth and distribution of ephemeral gully are significantly influenced by tillage practice and crop type,especially in summer.