东北漫岗黑土区春季冻融期浅沟侵蚀

浅沟侵蚀是东北漫岗黑土区农耕地上常见的水蚀类型,往往对坡耕地造成严重的破坏。2005年春季,通过对两个小流域浅沟侵蚀的调查测量,发现该区浅沟侵蚀相当严重,两流域分别形成浅沟14条、16条,浅沟总长度分别达3 269 m、2 146 m,浅沟密度分别为908 m/km2、766 m/km2,侵蚀深度分别为0.17 mm、0.16 mm,侵蚀模数分别达181.8 t/km2、173.6 t/km2。2005年春季两流域浅沟侵蚀期的径流深分别是6.8 mm、7.7 mm。分析表明,研究区在春季表层土壤解冻、地表裸露和存在季节性冻土层的条件下,春季融雪及强降水易造成强烈的浅沟侵蚀。在分布上,浅沟一般位于坡面的中下部,而且多发育在瓦背状坡面的集流水路上。另外,耕作措施对浅沟的形成和发展也有重要影响。

Ephemeral Gully Erosion during the Spring Freeze-thawing Period in Black Soil Rolling-hill Regions of Northeast

Ephemeral gully erosion is a common type of water erosion in black soil rolling-hill regions of Northeast,and is responsible for heavy damage to agricultural land.A field survey in the spring 2005 in the two small watersheds was conducted to investigate ephemeral gully erosion in freeze-thawing period in this area.There are 14 and 16 ephemeral gullies respectively in the two watersheds,with the total length 3 269 m and 2 146 m respectively.The result shows that ephemeral gully erosion has caused significant soil losses,181.8 t/km~(2)and 173.6 t/km~(2)respectively or 0.17 mm and 0.16 mm respectively,channel density 908 m/km~(2) and 766 m/km~(2) respectively.In late spring,the combination of frozen subsoil,bare surface cover and thawing topsoil facilitated ephemeral gully growth.In general,ephemeral gullies began approximately one second or two third of the way down the slope from the slope top,and developed on the concave slope.On the other hand, the result shows that tillage practices had significant influence on the forming and development of ephemeral gully.