(1)选择最佳施肥时机苹果根系一年有3次生长吸收活动高峰期,分别在早春萌芽前后(3月下旬至4月中下旬),春梢停长后(5月下旬至6月上中旬)和秋梢停长后(8月下旬至落叶)。3次根系活动高峰期正是果树开花坐果、花芽分化与果实发育、树体贮藏养分需要大量营养元素的时期。①弱树衰老树,施肥目的是促进枝叶生长,恢复树势,施肥应在新梢旺长前(萌芽前后或开化前后)和秋季进行,以氮肥为 (1) Choose the best time for fertilizer application Apple root growth and absorption peak of three times a year, respectively, before and after sprouting in early spring (late March to mid-April late), spring shoot long stop (late May to June Mid) and autumn shoot long stop (late August to the leaves). 3 times the peak of root activity is the fruit flowering and fruiting, flower bud differentiation and fruit development, tree storage of nutrients need a large number of nutrients during the period. ① weak tree aging trees, the purpose of fertilization is to promote the growth of branches and leaves, restore the tree vigor, fertilization should be long in front of the new shoots (before or after germination or before and after the opening) and autumn, with nitrogen as