甜橙的氮素营养与施肥（综述）

NITROGEN NUTRITION AND FERTILIZATION FOR ORANGE PLANTS(Citrus sinensis Osbeck):A REVIEW

A review is made on the major results from the studies on N nutritionand fertilization for orange plants,including N distribution in orangeplants,N deficiency symptoms,the seasonal patterns of N uptake and leaf Ncontent,and the correlation among N application rates,leaf N concentrat-ions and fruit yield.According to the specific situations in Sichuan orangegrowing and the results of the author's work,emphasis is placed on thediscussion of the effects of N rates on fruit yield and quality and thetiming of N application.It is argued that although N in citrus nutrition iswell documented,accurate data remain insufficient for the determining theoptimum parameters of N fertilization in orange orchards and furtherstudy and improvement are needed.