黑土区玉米地作物信息多重分形与多尺度相关特征研究

为揭示黑土区玉米地作物信息的时空变异机理,在东北农业大学香坊实验基地选取48 m×48 m区域,利用多重分形和联合多重分形理论,研究作物信息的多重分形特征、不同时间作物信息以及不同作物信息之间的多尺度相关特征。结果表明,黑土区玉米叶绿素含量的多重分形特征不明显,茎粗和株高的多重分形特征较明显。随时间变化,造成叶绿素含量、茎粗空间变异的局部信息有所差异,引起株高空间变异的局部信息一致,叶绿素含量、茎粗、株高的空间变异性分别先降后增、先降后增、逐渐减弱。单一尺度和多尺度上,不同时间叶绿素含量之间、茎粗之间、株高之间的相关程度均有明显差异;叶绿素含量之间、茎粗之间的相关程度排序均有所差异,株高之间的相关程度排序相同。随时间变化,单一尺度和多尺度上不同作物信息之间的相关程度均有明显差异,且相关程度均逐渐降低。与单一尺度相比,多尺度上,叶绿素含量之间、茎粗之间、不同作物信息之间的相关程度增大,株高之间的相关程度有增有降。

Multifractal and Multi-scale Correlation Characteristics of Crop Information of Corn Field in Black Soil Region

Quantitative expression of spatial and temporal variability of crop information is an important step to realize distributed control of water and soil resources in precise agriculture. In order to reveal spatial and temporal variability of crop information in corn field in black soil region, multifractal characteristics of crop information, multi-scale correlations between crop information of different sampling dates and the ones between different crop information were studied with multifractal and joint multifractal methods based on the results of experiments in 48m×48m field in Xiangfang Experimental Base of Northeast Agricultural University. The results showed that multifractal characteristic of corn chlorophyll content was not obvious, and stem diameter and plant height had obvious multifractal characteristics. As sampling date changed, the local information that caused spatial variability of chlorophyll content and stem diameter were different, the ones that caused spatial variability of plant height were the same, spatial variability intensity of chlorophyll content and stem diameter was firstly decreased and then increased, and that of plant height was reduced gradually. At the single scale and multi-scale, when sampling date was different, correlation degrees between chlorophyll contents were different, there was difference in correlation degrees between stem diameters, and correlation degrees between plant heights were different; there was difference in sorting of correlation degree of chlorophyll content, stem diameter and plant height. As sampling date changed, correlation degrees between different crop information at the single scale and multi scale were different, which were decreased gradually. Compared with research results at the single scale, the correlation degrees between chlorophyll contents were increased, the ones between stem diameters were enhanced, the ones between different crop information were augmented, and correlation degrees between plant heights were sometimes increased or decreased at multi-scale.