Abstract: In this paper, the particulates density on the leaves of washed- and unwashed Platycladus orientalis, Sabina chinensis, Pinus tabulaeformis and Picea koraiensis in Beijing was measured within a month of spring, and was compared day by day with the weather data and the microconfiguration of test species’ leaf epidermis. The results showed that the particulates density on conifers leaves changed with the alternative appearance of rainy, windy and dusty weather in spring, and in most cases, had a lower value than in wintertime. Parts of the particulates were firmly adhered to the leaf epidermis, and could not be removed by medium intensity (15 mm) precipitation. Five or six class strong wind could not reduce the particulates density. Compared with the local dust, extraneous dust made the particulates density on leaves increased greatly. The grooves between vertebral heaves on the leaf epidermis of P. orientalis and S. chinensis could hold many small particulates deeply and firmly, making them hard to be removed by precipitation and wind. The leaf epidermis of P. tabulaeformis was smooth and sticky, and thus, had a small and easily saturated capacity of holding particulates. The particulates loosely adhered to its leaf surface were prone to be removed. The wider grooves around the stomas of P. koraiensis leaf epidermis were in favor of retaining larger size particulates, and hence, could effectively capture larger size extraneous dust.

Key words: Continuous and alternate cropping, Soybean, Rhizospheric soil, Organic compounds, GC-MS analysis, Allelopathy