The Study On Apple Canopy Structure And Regularity Of Light Distribution In Loess Plateau

This research was studied in hilly area and yuan in Loess Plateau. The canopy characteristics and the relative light radiation were studied by the plant canopy hemispherical photographs system. The results are as follows:1. The canopies of three kinds of ages were all the major axis level elliptic type, and the MLA was 16-20°. Along with the ages increasing, the proportion of visible sky decreased. The LAI, LAI between the plants and LAI between the rows were increasing. The ISF, DSF and GSF were reducing. The captured diffuse, direct and total radiations were increasing.2. The canopies of the three kinds of shapes were all the major axis level elliptic type, and the MLA was 14-34°. The proportion of visible sky of the open center shape was the smallest, and the disperse lamination shape was the biggest. The ranking of the LAI, LAI between the plants and LAI between the rows of different kinds of shapes trees was the spindle shape> the disperse lamination shape> the open center shape. The ranking of the captured radiation of different kinds shapes was the disperse lamination shape>the spindle shape> the open center shape. The ISF, DSF and GSF of the open center shape were the biggest in the three kinds of trees. The ISF and GSF of the spindle shape were bigger than the disperse lamination shape, but its DSF was smaller than the disperse lamination shape.3. The ELADP of the three kinds of pruning intensity were all the major axis level elliptic type. The MLA changed little. Along with the pruning intensity increasing, the basal diameter and the height below the branches were increasing. The height of the canopy, the diameter below canopy and the branches numbers were reducing. The proportion of visible sky, the ISF, DSF and GSF were increasing. The LAI, the captured diffuse, direct and total radiation were reducing.4. The proportion of visible sky, ISF, DSF and GSF had the same change tendency along with the month changing. They were all reducing from May to August, and had the minimum value in August, but they were increasing from August to September. And the LAI, the captured diffuse, direct and total radiation had the opposition tendency. Those were increasing from May to August, and had the maximum value in August, but they were reducing from August to September. The mild and moderate degree pruning intensities were less amplitude of fluctuation, but the heavy degree was the most amplitude of fluctuation.5. The correlation analysis of the canopy characteristics showed that: the proportion of visible sky was negatively correlated with the LAI, the captured diffuse, direct and total radiation, but was positively correlated with the ISF, DSF and GSF. The LAI was negatively correlated with the ISF, DSF and GSF, but was positively correlated with the captured diffuse, direct and total radiation. The ELADP was negatively correlated with MLA. The ISF was positively correlated with the DSF and GSF, but was negatively correlated with the captured diffuse, direct and total radiation. The DSF was positively correlated with the GSF, but was negatively correlated with the captured diffuse, direct and total radiation. The GSF was negatively correlated with the captured diffuse, direct and total radiation. The captured diffuse radiation was positively correlated with the captured direct and total radiation. And the captured direct radiation was positively correlated with the captured total radiation.