关键词: 苹果, 一次和分次施肥, ¹⁵N–尿素, 吸收, 分配, 利用

Abstract: The characteristics of absorption，distribution and utilization of eight-year-old‘Gala’apple（Malus domestica/Malus hupehensis）under the treatment of once and split fertilization were studied. The results were as follows：At the fruit maturity stage，Ndff values in different organs were obviously different，and Ndff values of the organs were generally higher in split fertilization than once fertilization. However，the Ndff value of fruits and roots in split fertilization was lower than that of once fertilization at the new shoot growing stage and the fruit rapid-swelling stage. At the fruit maturity stage，the distribution ratio 15N in reproductive organs was the highest，while vegetative and storage organs were in lower level，but there were no significantly difference between the two treatments. The ratio of 15N utilization in split fertilization was 32.2%，which was obviously higher than that of once fertilization（23.34%）.

Key words: apple, once and split fertilization, ¹⁵N-urea, absorption, distribution, utilization