氮肥品种及施肥方式对小白菜产量与品质的影响

氮肥在农业生产中起着重要的作用,但是氮肥的大量施用不仅造成养分比例失调及环境污染,而且会限制产量的提高和品质的改善。针对广东蔬菜氮肥施用不合理的现象,在田间试验条件下研究了不同氮肥品种和不同底追比对小白菜产量和营养品质的影响,旨在为华南地区的蔬菜施用氮肥提供参考。试验结果表明,施氮极显著提高了小白菜的生物量和产量,亦增加了硝酸盐的累积量,其中尿素处理增产效果最好,蔬菜专用肥(磷铵 尿素)处理小白菜硝酸盐累积量最低,其次是碳酸氢铵和氯化铵处理。各氮肥处理间Vc和可溶性糖含量差异达到极显著水平,其中蔬菜专用肥处理含量最高;不同底、追肥处理间产量和Vc含量的差异达到显著或极显著水平,而可溶性糖含量差异未达到显著水平。除底肥70%、追肥30%的处理外,其余处理均极显著提高了硝酸盐含量。在本试验条件下,蔬菜专用肥既可以提高小白菜产量,又可以明显改善小白菜营养品质与卫生品质,如果以尿素为氮源,底肥70%、追肥30%是兼顾产量和品质的优化处理。

Effects of different nitrogen fertilizers and fertilization patterns on yield and quality of Brassica chinensis

Nitrogen fertilizer plays an important role in agriculture, but surplus fertilization not only caused environment pollution but also restrict the yield and quality. So it is an urgent problem to enhance the yield and the quality. The aim of the paper is to study the effects of nitrogen fertilizers and basal-/top-dressing ratio on yield and quality of pakchoi cabbage (Brassica campestris L. ssp. Chinensis (L.) Makino) to be aimed at the question of surplus fertilizer, moreover to provide the theoretical base for rational fertilization for pakchoi cabbage in South China. The method of field experiment was adopted to study the different nitrogen and fertilization patterns on the yield and quality. The results showed that applying with N fertilizer could increase the yield and increment of urea was higher than others. Applying N fertilizer could result in nitrate accumulation, however nitrate accumulation of special fertilizer treatment was the lowest, followed with ammonium bicarbonate and ammonium chloride. There were significant differences of vitamin and soluble sugar content between these nitrogen fertilizer treatments that had identical N rate, and contents of vitamin and sugar were remarkably higher in the treatment applying with special fertilizer for vegetable. With identical N applying, yield and vitamin content were different significantly among treatment with the rate of different base top dressing, however there was no difference in the content of soluble sugar. Compared with CK, when base fertilizer was 70% and dress fertilizer was 30% nitrate contents were decreased, however nitrate contents of other treatments were increased significantly. Under the field fertility of this experiment, the treatment, which was base 70% and dress 30% with the applying urea, was the optimal treatment taking account of yield and quality. Applying with special fertilizer for vegetables could not only improve yield but also reduce nitrate accumulation in the pakchoi cabbage.