Objective] The aim was to determine the reasonable nitrogen application amount on citrus.[Method] With Newhall navel orange as the tested variety, setting up 4 treatments namely no nitrogen fertilizer ( CK), nitrogen application amount of 0.315, 0.450, 0.585 kg/plant, the agronomic traits, yield, fruit commodity, economic benefit of citrus under various nitrogen application quantities were studied. [ Result] The nitrogen fertilizer could enhance agronomic traits, increase average fruit number per plant, average single fruit weight, fruit lon-gitudinal diameter and transverse diameter by 44.6-66.2 fruits, 13.7-27.3 g, 1.9-3.7 mm, 2.9-4.0 mm, respectively;increase the yield of citrus by the growth rate of 21.94%-57.99%; weight of top grade fruit and first grade fruit was significantly increased by amplification of 14.93%-27.62% and 38.91%-42.58%; fruit quality and economic benefits were declined with increasing of nitrogen application amount. [Conclusion] Considering agronomic characters, yield, commodity and economic benefit of citrus, the appropriate nitrogen application quanti-ty is 0.450 kg/plant.%[目的]明确柑橘合理的施氮量。[方法]以纽荷尔脐橙为供试品种，设4个处理，分别为不施氮肥（CK）、施氮量0．315、0．450、0．585 kg／株，研究不同氮肥施用量对柑橘农艺性状、产量、果实商品性、经济效益的影响。[结果]氮肥可提高柑橘农艺性状，使平均单株果数增加44．6～66．2个，平均单果重增加13．7～27．3 g，果实纵径和横径分别增大1．9～3．7、2．9～4．0 mm；可提高柑橘产量，增产率为21．94％～57．99％；特等果和一等果重量明显增大，增幅分别为14．93％～27．62％、38．91％～42．58％；随着施氮量的增大，果实品质和经济效益反而有所下降。[结论]综合柑橘的农艺性状、产量、商品性及经济效益，适宜的施氮量为0．450 kg／株。
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