农田休闲期不同保护性耕作措施的防风效应研究

摘要/Abstract

摘要： 保护性耕作是旱作农田土壤风蚀防治的必要措施\.通过野外试验,对深松、浅耕、翻耕覆盖、免耕油菜低茬和高茬、免耕小麦低茬和高茬等7种保护性耕作措施和传统翻耕、草地两种对照下0～4 m的风流场进行了观测,对各种下垫面上空气动力学粗糙度、摩阻速度、风速绝对脉动强度和相对脉动强度进行对比分析。结果显示,不同保护性耕作措施降低风的侵蚀力,防治土壤风蚀的机制不同。留茬主要通过增加地表空气动力学粗糙度和摩阻速度,利用作物残茬和秸秆等粗糙元分解风对地表的剪切应力,降低风蚀强度。而深松、浅耕、翻耕覆盖等措施在增加地表粗糙度和摩阻速度上效果不如留茬,但近地表0\^05 m处风速脉动较弱,相同风速下对地表的剪切应力较小,土壤风蚀速率降低。此外,作物残茬、秸秆和牧草等粗糙元的高度、密度及直立性均对下垫面的空气动力学粗糙度、摩阻速度及风速脉动有一定影响。

关键词: 保护性耕作, 空气动力学粗糙度, 风速脉动, 土壤风蚀

Abstract:

Conservation tillage is essential for soil wind erosion control in the semi-arid area, whereas more studies are needed on the mechanism of different conservation tillage measures to prevent wind erosion. Through field test, we observed wind profiles of 0 to 4 m under seven kinds of conservation tillage, i.e. subsoil tillage, shallow ploughing, stalk mulch after ploughing, no till with tall rape stubbles, no till with short rape stubbles, no till with tall wheat stubbles, no till with short wheat stubbles, and conventional tillage and pasture for comparison. Five items of aerodynamic roughness, friction velocity, and absolute and relative fluctuation intensity of wind velocity were analyzed comparatively on all the underlying surfaces. The results indicated that remnant stubble could reduce soil erosion by reducing near surface wind shear stress. In addition, the height, density and perpendicularity of remnant stubble, straws and grass had influence on aerodynamic roughness and wind velocity fluctuation on different underlying surfaces.

Key words: conservation tillage, aerodynamic roughness, wind velocity fluctuation, soil wind erosion

中图分类号:

X169＋S157.1

刘目兴;;刘连友;*;王静爱;严平;;杨秀春;;祁兴芬;宋阳;;胡霞;. 农田休闲期不同保护性耕作措施的防风效应研究[J]. 中国沙漠, 2007, 27(1): 46-51.

LIU Mu-xing;;LIU Lian-you;;WANG Jing-ai;YAN Ping;;YANG Xiu-chun;;QI Xing-fen;SONG Yang;;HU Xia;. Wind-breaking Effect of Various Conservation Tillage Measures during Fallow Period of Cropland[J]. JOURNAL OF DESERT RESEARCH, 2007, 27(1): 46-51.

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