摘要： 为了探讨不同树形模式条件下果园光照的变化规律,系统比较叶幕结构对太阳辐射吸收光谱、不同光质比例以及光质强度的差异,为中国苹果树形改造提供依据,以开心树形和小冠树形苹果树为试材进行了研究.试验结果表明:太阳辐射透过苹果叶幕时,辐射光谱发生了不均匀消减:在530～50 nm和72～703 nm波长内,形成了辐射快速消减区,其消减速率明显高于相对应叶幕辐射消减的平均值;而在738～74 nm波长之间,形成了辐射消减的惰性区,其消减速率明显低于相对应叶幕的平均值.受叶幕结构的影响,在开心形叶幕层中因吸收截获率较低,因而透射率较高.而小冠形树则相反,叶幕层的透射率较低.不同叶幕层的光谱构成中,PAR(400～700 nm)、紫外辐射(U,300～380 nm)、红外及远红外辐射(R/FR,780～1 010 nm)所占的比例不同.从树冠表面到内膛叶幕,PAR比例依次递减,U,R/FR的比例依次递增,开心树形叶幕中PAR的递减速率较慢.不同波长辐射在叶幕层内的消减速率不同.拟合回归方程表明,太阳总辐射(300～1 010 nm)和PAR透过叶幕时,其消减速率呈指数函数,而U,R/FR透过叶幕层时,则以多项式或对数形式递减.由于开心树形叶幕透射率较高,树冠不同部位的PAR分别高于小冠树形处理,因而有利于苹果树的光合作用.
关键词:
叶幕,
太阳辐射,
光质,
微区光环境
Abstract: Solar radiation (300 - 1 010 nm),photo synthetically active radiation (PAR,380 - 720 nm),ultraviolet radiation (U,300 - 380 nm),infrared radiation (R/ FR,780 - 1 010 nm),transmission rate of solar direct radiation and diffused radiation of apple ( Malus domestica Borhk. cv. Fuji) were measured under the field with the center2open and small canopy trepanning system at Beijing from 2004 to 2007. The result showed that :when solar radiation passed through canopy,radiation spectrum changed greatly.At 530 - 560 nm and 738 - 746 nm,the radiation reduced significantly,and at 738 - 746 nm,the radiation reduced slowly. The ratio of transmission of center2open trepanning system was higher than that of small canopy trepanning system. The ratio of PAR,U and R/ FR radiation were different in different canopy. From surface to inner of the canopy,the ratio of PAR was decreased and the ratio of U and R/ FR radiation were increased. The intensity of PAR,U and R/ FR radiation decreased from surface to inner of the canopy. The intensity of solar radiation, PAR,U and R/ FR radiation were different in different canopy. Fitting equations showed that,when solar radiation and PAR passed through canopy,their radiant intensity decreased in the way of exponential function ;and when U and R/ FR passed through canopy,their radiant intensity decreased in the way of logarithmic function or polynomial function.
Key words:
Canopy,
Solar radiation,
Light quality,
Microlight environment
中图分类号:
牛自勉, 张文和, 王建新. 苹果开心树形叶幕太阳辐射吸收规律研究[J]. 华北农学报, 2009, 24(4): 212-217. doi: 10.7668/hbnxb.2009.04.043.
NIU Zi-mian, ZHANG Wen-he, WANG Jian-xin. Study of Solar Radiation and Its Transmission and Diffusion in the Center-open System of Apple[J]. ACTA AGRICULTURAE BOREALI-SINICA, 2009, 24(4): 212-217. doi: 10.7668/hbnxb.2009.04.043.