耕作土壤地表不平度的分形特性

Fractal Behavior of Tillage Soil Surface Roughness

利用激光式不平度测试仪测定犁耕耕地、圆盘耙耙地和驱动耙耙地地表的不平度,测定沿着3个方向进行,即平行、倾斜和垂直方向。通过对各种分形计算方法进行比较,对每一种地表不平度的RMS高度和分形维数进行了分析。结果表明:RMS高度和各种地表的相关性不如分形维数明显,而且两者间存在一定的关系。最后提出利用地表不平度指数可以较好地表征随机地面的特性,地表不平度指数越大,地表不平度越大。

Using a laser profiler, the surface height variation trace of three types of tillage soil profilesploughed, harrowed and rolled surface were obtained. In order to acquire the different direction profiles of every tillage type, the profiles at 0, 45 and 90 degrees with respect to the tillage direction were measured. With these data, the ranges of root mean square height and fractal dimension were estimated, compared with root mean square height, fractal dimension have been well related with tillage soil surface. Two soil surfaces may present different characteristics with same fractal dimension and different root mean square height. So the complex behavior of different tillage soil profiles could be well described by using surface roughness exponent with combination the fractal dimension and root mean square height. The higher surface roughness parameter is, the more roughness of soil surface would be.