【摘要】 <正> 一、前言 柑桔是一种经济价值很高的栽培植物,在我国亚热带山区亩产一万斤鲜果之例,时有见闻。 我国是世界上栽培柑桔最早的国家(章文才,1975),长期以来累积了极为丰富的栽培经验。不但如此,我国还具有宽广的可供栽培的生态环境。众所周知,柑桔是一种典型的亚热带植物,而我国的亚热带幅员辽阔,北起北纬33°30′附近(例如甘肃省的武都县),南到北纬22°30′(例如广西的灵山县)之间,有许多地点都种有柑桔。但是我国目前柑桔的生产水平都是很低的,全国每人每年平均分配不到一斤鲜果,而日本每人约60斤,美国每人约更多还原

【Abstract】 Four main ecoclimatic factors, viz. temperature, rainfall, light and wind in. subtropical China were investigated. The frost damage caused by low temperature in winter is the only factor restricting Citrus growing. The indices of minimum temperature of light, middle and heavy frost damage for cultivars of different resistance to frost (Citrus unshiu Marc, and C. sinensis Osb.) are discussed. It was found that the indices are quite different both for different types of weather and for different cultivars. Two basic types of frost weather may be classified, i. e. the radiational (calm and clean-sky frost) and the advect- ional (windy and overcast-sky frost).Yellow shoot disease is a very dangerous disease of Citrus in subtropical China. Minimum temperature below a certain level seems to be the main factor which may restrict the infection (occurrence). This disease never occurs wherever the mean of minimum temperatures of each year for a period of 20 years or longer below-4℃; it seldom occurs where temperature is between-2℃ and -4℃; and it may frequently occur in regions where temperature is higher than-2℃;Regionalization of frost-proof Citrus cultivation can be made into three grades according to scales of regions, i. e. for the whole subtropical China, for a certain province (such as Hunan Province) and for a certain county (Hunshan County) are studied. Local climate for a small scale region, such as a county, or even a commune, the influence of topography on minimum temperature and wind speed are discussed in detail. Four types of the surrounding topography are studied according to their influences on minimum temperature and wind speed for both radiational and advectional weathers.更多还原