试析农田风蚀土壤的颗粒分形特征研究

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1、内蒙古农业大学硕士学位论文农田风蚀土壤的颗粒分形特征研究姓名：张国瑞申请学位级别：硕士专业：农业机械化工程指导教师：赵士杰20070601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

2、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。关键词：土壤风蚀；土壤颗粒：分形维数；风蚀风洞TheReseachofCultivedLandSoil’SGrannieFractalFeatureAbstractIntlletext．themech

3、anicalconstitutionoftraditionaleultivedfarmlandsoilgranuleandprotectivecukivedfarmlandsoilgranulewasanalysed,thefraetaldimensionofsoilgrainwascomputed，andthefractalfeaturesofsoilgranulewasresearched．Atthesalnetime,thesoil’serosionexperimentoftraditionalcuhivedfarmlandsoilandprotectiveeultiv

4、edfarmlandsoilwasdoneinwindtunnel，afterblowingindifferentspeedwind，thefractaIdimensionofsoilgranuleinsurfacewasgot．thefractaldimensionoftwokindsoffarmlandsoilgranuleandthechangingregulationwhichismadeupofgranularityindifferentwindspeedwereresearched．Accordingtotheresult，thefractaldimensiono

5、fsoilgranuleiscorrelatedcloselywiththeconstitutionofsoilgranularitydegree，SOwecanreplacethemechanicalconstitutionofsoilwiththefractaldimensionofsoilgranule．itcanbeusedtoevaluatethesoil’Serosiondegreeoffarmlandsoilasaquantitativenorm；thefractaldimensionofprotectivecultivedfarmlandsoilgranule

6、isbiggerthanthefractaldimensionoftraditionalcultivedfarmlandsoilgranule．andinthesurfaceofsoil．thefractaldimensionofprotectivecultivedfarmlandsoilgranuleisobviouslybiggerthanthefTactaldimensionoftradhionalcuhivedfarmlandsoilgranule．itdemonstratesthattheconditionofprotectiveeultivedfarmlandso

7、iliSbetterthantheconditionoftraditionalcultivedfarmlandsoil；sufferredblowinginthesamespeedwind．thechangingtendencyofthetraditionalcultivedfarmland’sfi'aetaldimensionisfasterthanthechangingtendencyoftheprotectivecultivedfarmland’Sfractaldimension,itproves