柑桔、龙眼、荔枝系福建三大亚热带果树,近年来(1980—1987年),其平均年产占全省果树总产的56.4％,足见上述树种在福建果树生产中具有举足轻重的作用。然而,三大果树中,除柑桔外,龙眼、荔枝仍处于低产水平,且三者都较普遍存在不稳产和品质较低的现象。实践表明,加强果园土壤管理,特别是提高科学施肥水平,是当今实现果树高产、稳产、优质的关键,而应用叶片营养诊断技术,则是指导合理施肥行之有 Citrus, longan and litchi are the three major sub-tropical fruit trees in Fujian Province. In recent years (1980-1987), the average annual output of these citrus fruits is 56.4% of the total fruit trees in Fujian province. This shows that these tree species play an important role in the production of fruit trees in Fujian Province. However, among the three fruit trees, in addition to citrus, longan and lychee are still at low-yielding levels, and the three are more commonly unstable and yielding lower quality. Practice shows that to strengthen orchard soil management, especially to improve the level of scientific fertilization is the key to achieve high yield, stable yield and high quality of fruit trees. The application of leaf nutrition diagnosis technology is to guide the rational fertilization