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作 者 ：袁伟玲 王晴芳 袁尚勇 甘彩霞 崔 磊 张嘉炜 梅时勇

期 刊 ：植物营养与肥料学报 2014年 20卷 3期 页码：696-701

关键词：萝卜；施氮量；基追比例；氮素吸收；分配；

Keywords:radish, nitrogen application, basal to dressing ratio, nitrogen uptake, distribution,

摘 要 ：运用¹⁵N示踪法研究了大田条件下不同氮肥用量与施肥方式对萝卜氮素吸收、分配及肉质根产量的影响。试验设置3个氮水平（0、 60和120 kg/hm²）和两种基追肥比例［基肥∶破肚期肥料∶膨大期肥料=50%∶20%∶30%（A）和30%∶20%∶50%（B）］，共5个处理，依次记作 N0、N60A、N60B、N120A、N120B。结果表明，在施N 0120 kg/hm²范围内，随氮施用量的增加，萝卜吸收的肥料氮素、土壤氮素数量及肥料氮在土壤中的残留量显著增加，氮素的吸收利用率和土壤残留率显著下降，氮素损失率显著增加。当氮用量为120 kg/hm² 时， N120A和N120B处理萝卜吸收的肥料氮素、土壤氮素及肥料氮在土壤中的残留量分别为30.50、 53.64、 14.88 kg/hm²和35.56、 56.61、 17.81 kg/hm²，采收期肉质根产量分别为67.6 t/hm²和72.5 t/hm²，比对应的低氮处理（N60A和N60B）分别增加64.07%和66.67%，且N120B处理萝卜氮素吸收利用率显著提高。因此，适量施氮并增加肉质根膨大期的施氮比例，可有效提高氮肥利用率，显著增加萝卜肉质根产量。在本试验条件下，施氮量为120 kg/hm²， 按照基肥∶破肚期肥料∶膨大期肥料比例30%∶20%∶50%进行施肥，是兼顾产量和氮肥利用效率的最佳氮肥运筹方式。

Abstract:A field experiment was conducted to study the effect of nitrogen application rates and methods on the uptake and distribution of N by radish using ¹⁵N isotope tracing method. Three N rates (0,  60 and 120 kg/ha) and two application proportions of basal∶15 d after seeding∶30 d after seeding［50%∶20%∶30%(A) and 30%∶20%∶30%(B)］were designed with total of five treatments reordered as N0,  N60A,  N60B,  N120A and N120B,  respectively. The result showed that the nitrogen absorbed from  fertilizer and soil by radish，the residual N amount in the soil were increased significantly，the absorption and utilization rate and soil residual rate were decreased as consequence,  although the N loss rate still increased with the nitrogen application rate increased from 0 to 120 kg/ha. At the application rate of 120 kg/ha,  the nitrogen absorption was 30.50 kg/ha from the fertilizer and 53.64 kg/ha from soil,  and the residual N amount in soil was 14.88 kg/ha with the treatment of N120A,  the N absorption was 35.56 kg/ha from fertilizer and 56.61 kg/ha from soil and the residual N amount in soil was 17.81 kg/ha with the treatment of N120B. The root yield for the treatments of N120A and N120B were 67.6 t/ha and 72.5 t/ha,  respectively,  64.07% and 66.67% higher than those for treatment N60A and N60B. The highest nitrogen use efficiency was obtained in the treatment of N120B. Therefore,  appropriate nitrogen application with increasing topdressing nitrogen ratio in later growth stage could increase root yield of radish and the nitrogen use efficiency. The recommended N application rate for radish in the studied area is N 120 kg/ha  with application ratio of 30% for basal,  20% for 15 d after seeding and 50% for 30 d after seeding.

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