[Effects of alternate subsurface drip irrigation on yield and water use efficiency of spring maize.].

The experiment was conducted using automatic rain shelter to study the effect of precisely controlled water quota of alternate subsurface drip irrigation (ASDI) on spring maize yield and water use efficiency (WUE). The results showed that jointing to heading stage and heading to hilling stage were the key stages of water requirement for spring maize under ASDI. In particular, both the water consumption percentage and diurnal water consumption in these two stages were higher than in other stages and were more sensitive to water deficit stress.

[Fractal theory and its application in the analysis of soil spatial variability: a review].

Soil has spatial variability in its attributes. The analysis of soil spatial variability is of significance for soil management. This paper summarized the fractal theory and its application in spatial analysis of soil variability, with the focus on the utilization of moment method in calculating the fractal dimension of soil attributes, the multi-fractal analysis of soil spatial variability, and the scaling up of soil attributes based on multi-fractal parameters.

[Fractal characteristics of visible spectra across a hilly area].

The spectral characteristic of remotely sensed image is mainly the results of integrative effects on spectrum from heterogeneous ground reflectors. Investigating its spatial distribution characteristics may be helpful for image interpreting and modeling based on remote sensing technique. In the present study, spatial heterogeneity of remotely sensed multispectral TM image across a hilly area in late October was studied by the combination of statistical method and multifractal analysis.