退耕地青海云杉人工林土壤抗冲性试验研究.doc

退耕地青海云杉人工林土壤抗冲性试验研究 Ξ退耕地青海云杉人工林土壤抗冲性试验研究 胡建忠 , 周心澄 , 李文忠 , 张春霞 ()北京林业大学 水土保持学院 ,水土保持与荒漠化防治教育部重点实验室 , 北京 100083 摘要 : 青海云杉为青海省大通县的顶极植物群落树种 ,是当地退耕还林的主要树种 。通过研究退耕地青海云杉 人工林的土壤抗冲性 ,对于科学指导当地生产实践 、制定退耕还林方案等十分必要 。三因素三水平的正交试验结 果表明 ,土层 、坡度 、流量对抗冲性的影响依次增强 ,以流量对抗冲性的影响最大 。 < 1 mm 根数是影响土壤抗冲 性的主要生物因素 , < 1 mm 根数越多 ,土壤抗冲性越强 。青海云杉人工林根系为表层聚积 、下层骤减的分布类() 型 。表土层 0,20 cm为根系密集分布层 , < 1 mm 根数占 98. 88 % ,根长占 91. 37 % ,该层根系对土壤颗粒的网络 () 粘结作用最好 ,抗冲性最强 ,其平均值达到 0. 830 min/ g ,为中层 0. 201 min/ g抗冲性的 4 倍 。退耕还林还草工作 中 ,应重视对在表土层中密集分布须根类型植物的应用 。 关键词 : 土壤抗冲性 ; 正交试验 ; 根系 ; 退耕还林地 ; 青海云杉 () 中图分类号 : S157. 1 文献标识码 :A 文章编号 :100922242 20040620006205 Experiment on Soil Anti2scoura bility of Artif icial Picea crassif oli a Forest in Reha bilitation Lands HU J ian2zhong , ZHOU Xin2cheng , L I Wen2zhong , ZHANG Chun2xia ( College of Soil and Water Conservation , Beijing Forestry University , Key L aboratory of Soil and Water Conservation )and Desertif ication Combating of the Ministry of Education , Beijing 100083 Abstract : Picea crassif oli a is a species of climax community in Datong county , Qinghai province , and is used as the main afforestaion species in the project of converting from cropland into forest lands and grasslands. It is very important to study the soil anti2scourability of Picea crassif oli a in the rehabilitation lands for directing practice and making layout of the con2 version from croplands into forest lands and grasslands. The orthogonality experiment with three factors and three levels shows that runoff is the first important factor which influences the anti2scourability greatly , then comes slope and soil layers. The number of less than 1 mm roots are the main biological factor which seems to have a same trend with anti2scourability. The more the numer of less than 1 mm roots , the stronger the anti2scourability. The roots of Picea crassif oli a distribute (more in the top soil layer and sharp less in the under soil layers. The number of less than 1 mm in the top soil layer