典型黑土区小流域浅沟侵蚀季节差异分析

通过2005年对黑龙江鹤山农场两个小流域进行定位观测,研究了典型黑土区浅沟侵蚀特征及其季节差异,并对作物类型和耕作措施对浅沟侵蚀的影响进行了分析。结果表明,两流域年浅沟侵蚀量达285.9 m³ km^-2和290.8 m³ km^-2,仅浅沟侵蚀量就超过了黑土区的土壤允许侵蚀量。浅沟侵蚀量呈现出沿坡面波动的变化,沿坡面向下存在浅沟侵蚀的强弱交替带。春夏浅沟侵蚀在侵蚀强度、浅沟形态及主要影响因素3个方面存在差异,春季浅沟侵蚀受融雪、冻融影响显著,侵蚀较夏季严重;与春季相比,夏季浅沟长度变短、宽度变大、深度变浅,浅沟体积与长度的相关性较春季差,这与夏季暴雨历时短、雨强大以及植被盖度大有关。耕作措施和作物类型影响浅沟侵蚀深度和浅沟分布,尤其在夏季比较明显。

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.