Abstract: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 multiscale 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.
