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保护性耕作对农田土壤风蚀影响的风洞实验研究
范清成
Subtype博士
2011-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword土壤风蚀 保护性耕作 风洞模拟
Abstract

土壤风蚀是干旱、半干旱以及部分半湿润地区土地沙漠化与沙尘暴灾害的首要环节,也是世界上许多国家和地区的主要环境问题之一。保护性耕作能够有效的减少农田土壤风蚀。本试验通过选取黄土高原具有代表性的三种土壤类型进行室内风蚀模拟试验,分析不同耕作措施对土壤风蚀的影响,结果表明:
1)小麦留茬和小麦秸秆覆盖与裸土对照相比均能减少土壤风蚀,三种土壤类型中小麦留茬20cm高度和小麦秸秆全覆盖量4210kg/hm2两种处理下的土壤风蚀速率最低,减蚀率最高;垄作防风蚀效应则受到垄向的影响,垄向与风向垂直能够减少风蚀,垄向与风向平行则加剧风蚀。同一风速下三种土壤类型的风蚀速率随着留茬高度的升高而降低,随着秸秆覆盖量的增加而降低。
2)裸土对照风蚀速率与风速呈显著性线性相关,不同保护性耕作方式下的土壤风蚀速率与风速都呈现显著性幂函数关系。
3)三种土壤类型其中小麦秸秆覆盖处理4210 kg/hm2下的距风洞底面0-60cm总输沙量最小,其次是小麦20cm留茬,垄作在风速<8m/s时总输沙量小于裸土对照,>8m/s时输沙量则大于裸土对照。同一风速下总输沙量随着覆盖量的增加而减少,随着留茬高度的增加而减少。
垄作(垄向与风向垂直时)输沙量主要集中在45-60cm高度,而其它处理方式下的输沙量主要集中在0-15cm。0-15cm高度的输沙量比例随着风速的增加而升高,随着留茬高度的增加而降低,随着秸秆覆盖量的增加而降低。
4)三种土壤类型的风蚀速率顺序风沙土>黄绵土>塿土,不同保护性耕作措施下的减蚀率塿土>黄绵土>风沙土,并随着风速的增加而降低。
秸秆覆盖4210kg/hm2处理下0-15cm输沙率风沙土>黄绵土>塿土,但此时0-15cm输沙率较小,风蚀危害较轻。20cm留茬处理下风沙土0-15cm输沙量比例则随着风速增加而降低,0-15cm输沙率则是黄绵土>风沙土>塿土。土壤风蚀是干旱、半干旱以及部分半湿润地区土地沙漠化与沙尘暴灾害的首要环节,也是世界上许多国家和地区的主要环境问题之一。保护性耕作能够有效的减少农田土壤风蚀。本试验通过选取黄土高原具有代表性的三种土壤类型进行室内风蚀模拟试验,分析不同耕作措施对土壤风蚀的影响,结果表明:
1)小麦留茬和小麦秸秆覆盖与裸土对照相比均能减少土壤风蚀,三种土壤类型中小麦留茬20cm高度和小麦秸秆全覆盖量4210kg/hm2两种处理下的土壤风蚀速率最低,减蚀率最高;垄作防风蚀效应则受到垄向的影响,垄向与风向垂直能够减少风蚀,垄向与风向平行则加剧风蚀。同一风速下三种土壤类型的风蚀速率随着留茬高度的升高而降低,随着秸秆覆盖量的增加而降低。
2)裸土对照风蚀速率与风速呈显著性线性相关,不同保护性耕作方式下的土壤风蚀速率与风速都呈现显著性幂函数关系。
3)三种土壤类型其中小麦秸秆覆盖处理4210 kg/hm2下的距风洞底面0-60cm总输沙量最小,其次是小麦20cm留茬,垄作在风速<8m/s时总输沙量小于裸土对照,>8m/s时输沙量则大于裸土对照。同一风速下总输沙量随着覆盖量的增加而减少,随着留茬高度的增加而减少。
垄作(垄向与风向垂直时)输沙量主要集中在45-60cm高度,而其它处理方式下的输沙量主要集中在0-15cm。0-15cm高度的输沙量比例随着风速的增加而升高,随着留茬高度的增加而降低,随着秸秆覆盖量的增加而降低。
4)三种土壤类型的风蚀速率顺序风沙土>黄绵土>塿土,不同保护性耕作措施下的减蚀率塿土>黄绵土>风沙土,并随着风速的增加而降低。
秸秆覆盖4210kg/hm2处理下0-15cm输沙率风沙土>黄绵土>塿土,但此时0-15cm输沙率较小,风蚀危害较轻。20cm留茬处理下风沙土0-15cm输沙量比例则随着风速增加而降低,0-15cm输沙率则是黄绵土>风沙土>塿土。

Other Abstract

Soil wind erosion is the important influence factor on land desertification and sand storm in arid, semi-arid and some semi-humid area, which is the primary environment problem of the most countries in the world. Conservation tillage could reduce soil wind erosion effectively. The effect of different conservation tillage treatments, which were straw mulch, stubble and ridge, on the factors of soil wind erosion under three kind of soil of the Loess Plateau was studied through sand wind tunnel. The results summed up as below:
1) Wheat straw mulch and stubble could reduce soil wind erosion rate compared to the control, the rate of soil wind erosion under stubble with 20cm high and straw mulch with 4210kg/hm2 were the lowest of all conservation treatments, and the reduction erosion rate were the highest. The ridge tillage could reduce rate of soil wind erosion in low wind velocity, which was in the vertical direction of wind, the rate of soil wind erosion under ridge tillage with the same direction as the wind is higher than other treatments, even exceed the control when the wind velocity is higher. In the same wind velocity the rate of soil wind erosion decreased with straw mulch weight increasing, while the height of stubble increasing, rate of soil wind erosion deceased.
2) Under conservation tillage treatments, the rate of soil wind erosion had a power function to wind velocity, while the soil wind erosion of the control had a significantly linear correlation to wind velocity.  3) In the height of 0~60cm, the total volume of sand transport under straw mulch with 4210kg/hm2 was the least, the second is stubble with 20cm high. In the same wind velocity the total volume of sand transport decreased with straw mulch weight increasing, while the height of stubble increasing, the total volume of sand transport deceased. The total volume of sand transport of ridge was more than the control when the wind velocity exceed 8 meter per second.
The volume of sand transport of ridge which was in the vertical direction of wind concentrate in the height of 45~60cm, the sand of other treatments including the control mostly concentrate in the height of 0~15cm. The sand transport percent in the 0~15cm increased with wind velocity increasing. It also decreased with height of stubble decreasing, while sand transport percent decreased with straw mulch increasing.
4) The magnitude order of soil wind erosion with three types of soil were as follow: aeolian sand soil > loessal soil > lou soil, and the order of reduction erosion rate with conservation treatments were as fellow: lou soil > loessal soil > aeolian soil, while the reduction erosion rate decreased with wind velocity increasing.
Under the straw mulch with 4210kg/hm2 treatments, the order of sediment transport rate in the height of 0~15cm were as follow: aeolian sand soil > loessal soil > lou soil, while the value of sediment transport was too lower to cause serious wind erosion harm. Under the stubble with 20cm high, the sand transport percent of aeolian sand soil in the 0~15cm decreased with wind velocity increasing. the order of sediment transport rate in the height of 0~15cm were as follow: loessal soil > aeolian sand soil > lou soil.
The order of soil wind erosion under ridge treatment with in the vertical direction of wind were as follow: aeolian sand soil > lou soil > loessal soil, the reduction erosion rate of loessal soil was higher than the others. The sediment transport rate of aeolian sand soil in 0~15cm was lower than others, result from the sand transport percent was lower than 45~60cm.
Key Words:conservation tillage; soil wind erosion; wind tunnel simulation

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8876
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
范清成. 保护性耕作对农田土壤风蚀影响的风洞实验研究[D]. 北京. 中国科学院研究生院,2011.
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