氮肥用量对萝卜肉质根产量及氮素吸收利用的影响

目的]研究氮肥用量对萝卜肉质根产量、养分含量和累积量及氮肥利用率的影响,可为萝卜的合理施肥与科学利用提供理论依据。方法]通过小区试验,研究了氮肥用量(0、40、80、120和160 kg N/hm2,分别记作N0、N40、N80、N120、N160)对萝卜肉质根产量、养分含量、累积量及氮肥利用率的影响。结果]在0~160 kg N/hm2的范围内,施用氮肥可显著提高萝卜肉质根产量和养分累积量,以施氮120 kg N/hm2为最高,肉质根产量达到6.42×104kg/hm2,氮、磷、钾累积量分别达到68.15、11.78和87.18 kg/hm2;施氮可以提高萝卜肉质根和茎叶中的氮素含量。合理氮肥用量能促进萝卜植株的生长,但氮肥农学利用率、偏生产力和表观利用率均随施氮量的增加而显著下降。结论]在试验条件下,施氮量为120 kg/hm2是兼顾产量和氮肥利用效率的最佳氮肥运筹方式。

Effects of Nitrogen Application on Yield and Nitrogen Uptake and Utilization of Radish

Objective ] The effects of nitrogen application on yield, nutrient contents and accumulations, nitrogen uptake and utilization of the radish were studied to provide the theoretical clue for the proper fertilizer management and utilization. Method] Plot experiments were conducted to study the effects of nitrogen application（0 ,dO ,80,120 and 160 kg N/hm2, which were expressed as N0, N40, N80, N120 and N x60 ,respectively）on root yield, nutrient contents and accumulations, and N use efficiency of radish. Result ] The yield of the root and nutrient contents and accumula- tions of the radish were significantly increased with the increasing nitrogen application from 0 to 160 kg N/hm2. With 120 kg N/hm2, the root yield, N ,P, K accumulations were 6.42 x 104 ,68.15,11.78 and 87.18 kg/hm2, respectively. The nitrogen content of the stem and leaf were in- creasing with the increasing application of the nitrogen. However,with the increasing N application, N agronomic use efficiency, partial factor pro- ductivity and apparent recovery efficiency of the radish decreased significantly. Conclusion] As far as yield and environmental benefits were con- cerned,the most appropriate nitrogen fertilizer application recommended was 120 kg N/hm2 in this study.