Abstract: In July-September 2005, a 24 hours synchronous observation was conducted on the air temperature, relative humidity and wind speed in the urban center, urban lake, suburb, and urban forest of Nanjing City, aimed to investigate the effects of the diurnal variation patterns of these microclimatic factors on the human comfort degree in these habitats. The results indicated that in all testhabitats, air temperature was the lowest at 4:00, and the highest at 13:00-14:00. Urban forest had the lowest mean air temperature, while urban center had the highest one. The air temperature in urban center and urban lake increased rapidly at 17:00, and that in urban center and suburb had a larger diurnal variation range. The relative humidity in the four habitats was the highest at 0:00-5:00, and the lowest at 16:00-17:00. Urban forest had the highest humidity, while urban center had the lowest one. Wind speed and its variation range in urban forest and suburb were bigger at daytime than at night, and the wind speed decreased at 11:00-12:00. There existed a weak ‘heat island effect’ in Nanjing, with a diurnal difference of mean air emperature less than 0.5℃ between urban center and suburb. The human comfort degree at daytime in Nanjing was always higher in urban forest than in urban center and suburb.

Key words: Zinc lignosulfonate, Inorganic Zn fertilizer, Corn