【摘要】 对宁夏灌淤旱耕人为土氮(N)肥与大白菜产量及菜体和土体中硝酸盐累积的关系进行了田间试验研究。结果表明,在设计范围内,银川平原复种大白菜的产量及净菜率与施N量成正比;施N肥增加大白菜硝酸盐含量;复种大白菜的最高产量施N量为448.5㎏/hm2,最佳产量施N量为427.5㎏/hm2;大白菜外叶硝酸盐含量高于内叶,内叶硝酸盐含量随施N肥量的增加而增加,外叶硝酸盐含量在高施N时,随生育期延长而增加;施用N肥明显增加土体各土层中的硝态N含量。更多还原

【Abstract】 A study on influence of nitrogen on cabbage growth and nitrate accumulation was conducted by means of field experiments in Guanyu Soil. The results showed that nitrogen could increase growth and net yield rate of cabbage and nitrate accumulation in cabbage leaves. The nitrogen fertilizer application rate of 448.5㎏/hm2 brought about the highest yield and the rate of 427.5㎏/hm2 was the optimum for cabbage in double cropping. Nitrate content was higher in outer leaves than in inner leaves. The nitrate content in the inner leaves increased with the nitrogen application rate whilein the outer leaves it increased with the time of growth under a high nitrogen application rate. Nitrogen application increased significantly nitrate contents in all the layers in the profiler.更多还原