A RESEARCH ON THE AREAL DIFFERENTIATION RULES OF RICE CHALKINESS FORMATION IN CHINA
中国稻米垩白形成的地域分异规律之研究

On the basis of experiments with 19 rice varieties and many sowing datas in 13 placs of the whole country, the meteorologic ecological base of rice chalkiness formation has been analysed in this paper. Results show that the temperature condition in the 15 days after rice full heading stage is a leading factor affecting rice chalkiness. In order to know the average daily temperture of the 15 days after full heading that is demanded by the formation of different meteorologic chalkiness area (that is, the change of chalkiness area caused by meteorologic condition), the temperature demanded by 3 kinds of the miteroioogic chalkiness area is determined by a linear planning model as follows:meteorologic chalkiness area: < 5medium japanica:early indica:medium indica:The areal differentiation of meteorologic chalkiness in rice growing areas with different rice farming systems has been analysed by using the above indices. Results show that from north to south the rice meteorolgic chalkiness varies from small to big with the change of average daily temperature of the 15 days after rice full heading. The rice growing areas of the meteorologic chalkiness area of <5% include areas on the north of the Huaihe River, the Yungui plateau, and on the north of the Sichuan basin. Those of 5-10% include the Sichuan basin, southern Yunnan province and the areas from the south of the Huanhe River to the south of the Yangtze River along this river. Those of 10-20% (only the early rice of the double-cropping rice is concerned) include the areas on the east of the Yungui plateau and on the south of the Yangtze River.