摘要
京郊农用地土壤风蚀而发生的起沙起尘是造成北京市大气环境中、重度污染的重要原因之一。为有效地防治北京郊区农业用地的起沙起尘,在2003年和2004年对京郊不同土地利用类型地表粗糙度和起沙情况进行了多次重复的野外观测。地表粗糙度观测结果表明,不同土地利用类型地表粗糙度明显不同,即使是同一地类,地表状况不同,粗糙度也有很大差异,这为通过调整土地利用结构来防止起沙起尘提供了依据。在2 m高风速为8.6m/s时,玉米低留茬地上观测到的输沙率高达0.597 kg/(m.h),表明在大风条件下,留荐高度过低时防风蚀作用不明显。依据上述风沙观测结果,结合北京市土地资源特点和利用现状,提出调整土地利用结构,完善平原区防护林体系,全面实行保护性耕作,硬化乡间道路等控制京郊农地起沙起尘的措施。
Blown sand-dust caused by wind erosion of farmland is one of important factor that forms serious air polluting in Beijing. The sources of sand-dust during sand blowing weather mainly come from Beijing outskirts. For effectively control blown sand-dust of farmland in Beijing outskirts, repeating fields observation of aerodynamic roughness length and the cases of blowing sand on different land use type were conducted during 2003 and 2004 year. The aerodynamic roughness length is a very important parameter to describe aerodynamic characteristics above land surface. Its value is higher and blowing sand is more difficult, so it can well and truly demonstrate the ability of land surface to resist wind erosion. Wind erosion can be controlled effectively by improving the value of aerodynamic roughness length. The observation results of surface aerodynamic roughness length indicate that each land use type has its own aerodynamic roughness length. In other words, different land use type has different aerodynamic roughness length. According to these results, adjusting land use structure is a way to control blowing sand--dust caused by soil wind erosion. When wind velocity at 2 m heights is 8. 6m/s, the observed rate of sand drift on corn land covered with residue is 0. 597 kg/（m ~ h）, which indicates that when the height of corn residue is very low, its function to control wind erosion is negligible under strong wind. Based on these observation results and Beijing land resource characteristics and its present use, some controlling blown sand-dust measures are put forward such as adjusting land use structure, perfecting windbreak system of plain area, entirely implementing conservation tillage and paving rural roads.
出处
《水土保持研究》
CSCD
北大核心
2007年第2期1-3,共3页
Research of Soil and Water Conservation
基金
北京市科技项目(H020620270120
H020720110330)资助
关键词
农田风蚀
起沙起尘
防治措施
北京郊区
wind erosion of farmland
blown sand-dust
control measurement
Beijing outskirts
