【作者】 张国瑞；

【导师】 赵士杰；

【作者基本信息】 内蒙古农业大学 ， 农业机械化工程， 2007， 硕士

【摘要】 本文对内蒙古武川县保护性耕作试验区的传统耕作农田和保护性耕作农田土壤颗粒的机械组成进行了分析,计算了土壤颗粒的分形维数,对土壤颗粒的分形特征进行了研究。同时对传统耕作农田和保护性耕作农田的原状土样进行了风蚀风洞试验,计算出在不同风速吹蚀后表层土壤颗粒的分形维数,研究了两种农田土壤颗粒分形维数和粒度组成随风速的变化规律。结果表明,土壤颗粒的分形维数与土壤的粒级组成密切相关,因而可以利用土壤颗粒的分形维数代替土壤的机械组成,作为一项定量指标来评价农田土壤的风蚀程度;保护性耕作农田土壤颗粒的分形维数要大于传统耕作农田土壤颗粒的分形维数,而且在土壤表层,保护性耕作农田土壤颗粒的分形维数明显高于传统耕作农田,则表明该地区保护性耕作农田的土壤状况要好于传统耕作农田的土壤状况;在相同风速吹蚀下,传统耕作农田分形维数的变化趋势大于保护性耕作农田分形维数的变化趋势,则表明实施保护性耕作和留茬覆盖对于减少农田土壤风蚀具有明显作用。更多还原

【Abstract】 In the text, the mechanical constitution of traditional cultived farmland soil granule and protective cultived farmland soil granule was analysed, the fractal dimension of soil grain was computed,and the fractal features of soil granule was researched. At the same time, the soil’s erosion experiment of traditional cultived farmland soil and protective cultived farmland soil was done in wind tunnel, after blowing in different speed wind,the fractal dimension of soil granule in surface was got, the fractal dimension of two kinds of farmland soil granule and the changing regulation which is made up of granularity in different wind speed were researched. According to the result, the fractal dimension of soil granule is correlated closely with the constitution of soil granularity degree, so we can replace the mechanical constitution of soil with the fractal dimension of soil granule, it can be used to evaluate the soil’s erosion degree of farmland soil as a quantitative norm; the fractal dimension of protective cultived farmland soil granule is bigger than the fractal dimension of traditional cultived farmland soil granule, and in the surface of soil, the fractal dimension of protective cultived farmland soil granule is obviously bigger than the fractal dimension of traditional cultived farmland soil granule, it demonstrates that the condition of protective cultived farmland soil is better than the condition of traditional cultived farmland soil; sufferred blowing in the same speed wind,the changing tendency of the traditional cultived farmland’s fractal dimension is faster than the changing tendency of the protective cultived farmland’s fractal dimension,it proves that executing protective cultivation and leaving stubbles to cover field can reduce the effect of wind erosion for the farmland soil.更多还原