Effects of Silver-Grey Reflex Mulching on the Microclimate and the Physiological Properties of Apple Tree

Silver-grey reflex film was used for ground-covering in Apple orchard on July 18 and August 5 in 1993～1994 to explore its ecological and physiological effects.Results of the experiment showed:①Muching with silver-grey reflex film could obviously increase the re- flected light intensity in the inner parts of apple canopy.The temperature of apple canopy was increased in day time and decreased at night by the mulching,so that the temperature differ- ences between day and night was raised up to 2.3 higher than in the case of non-mulching. Compared with the control,the humidity of apple canopy in the mulching treatment was lower and the humidity changes during day and night was higher in the mulching treatment.② mulching could increase the soil temperature in day time,thus increased the root activity up to 24.6%～35.2% in comparison with the control.Only half month after the mulching with the reflex film,the leaf content of leaf chlorophyll and net photosynthetic rate significantly in- creased.③The content of soluble sugar,soluble solids and the coloring index of fruits picked from the inner part of apple canopy,the rate of full-coloring fruits per tree were significantly increased by mulching with silver-grey reflex film,but there were little difference on the acidi- ty,VC content and fruit firmness in comparison with the control.The increased range of the soluble sugar content was higher in the plot mulched on July 18 than that on August 5,but the coloring effects of the later showed better than that of the former.