综述了甜橙对氮肥的响应、甜橙氮平衡、甜橙氮储存和转运等过程,以加深对甜橙氮肥施用中所涉及过程的理解.成年甜橙树含氮量一般为1 ～2 kg/株,其中30％ ～ 60％集中在1年生部分(叶片和果实),300 kg/(hm2·年)足以保证良好的甜橙产量和橘树生长.15N标记施肥试验表明,甜橙最高的氮吸收率出现在坐果期,冬季氮吸收率非常低.春季树体从土壤中吸收的氮较少,老组织中贮藏氮对春天新梢和新叶的生长和开花起着非常重要的作用.相比于充足的氮肥供应,在较低的氮肥投入情况下,新梢和新叶的氮大多来自于贮藏氮.土壤有机质和成年树贮藏氮对植株生长点生长起着非常重要的作用.因此,当年的施肥是为了维持甜橙树可持续生长,而不是提高当年的果实产量.%The response of orange to nitrogen, nitrogen balance, nitrogen storage and transmission were reviewed, so as to increase our understanding of the processes involved. Mature orange citrus trees contain 1-2 kg/tree, 30% -60% of which is in the annual parts (leaves and fruits). 300 kg/hm2 applied annually is sufficient to sustain good citrus yield and tree development. Experiments with "N fertilizer applications showed that the highest N-uptake rate occurred during fruit set period and that in winter the uptake was very low. N reserves in the older tissues played an important part in the development of new leaves and flowers in the spring, when the uptake from the soil was still low. It was confirmed that the nitrogen contained in the soil organic matter and in the mature trees plays an important part in the regulation of N supply to the growing parts of the tree. More N is derived from these parts when low N fertilization is lower than abundant supply. The purpose of fertilization is to ensure sustainable growth of orange trees, not to improve the fruit yield.
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