氮素对甘蓝产量、硝酸盐含量及氮吸收量的影响

为了保证蔬菜食用安全,研究了不同施氮量对甘蓝产量、硝酸盐含量和氮吸收量的影响。结果表明,氮肥是提高甘蓝产量的主要影响因子,各处理与N1处理比较,可增产9.2%以上,特别是处理N3,N4,N6,N7分别增产23.7%,20.9%,13.9%,34.8%;外叶硝酸盐含量是内叶(可食部分)的3倍左右,外叶和内叶(可食部分)中硝酸盐含量均随着施氮量的增加呈增加趋势,甘蓝结球可食部分可以生吃,外叶部分硝酸盐含量较高,只能熟食;施N为162 kg/hm2是甘蓝最佳施氮量,可食部分中氮吸收量远远高于外叶,处理N7可食部分氮累积量最高;处理N1,N2氮素施用量表现为亏缺,其他处理氮素施用量都表现为盈余,并且随着施氮量的增加氮的盈余量增多(处理N7除外);耕层土壤(0～20 cm)硝酸盐含量高于20～40 cm土层土壤,各土层中硝酸盐含量不稳定。

Effects of Nitrogen on Cabbage Yield, Nitrate Content and Nitrogen Uptake

Study on cabbage yield,nitrate content and nitrogen uptake in different nitrogen applications was conducted to ensure the safety of vegetables.The results showed that nitrogen played a key role on cabbage yield improvment.Comparing to N1 treatment,the yields in other treatments could be improved by above 9.2%;as for N3,N4,N6,N7 treatments,it increased 23.7%,20.9%,13.9%,34.8% respectively;and the net incomes of them were promoted.The nitrate content in cabbage leaf and cabbage head was increased with the nitrogen application and the nitrate content in cabbage leaf was 3 times higher than that in cabbage head.Therefore,the cabbage head could be eaten raw,but the cabbage leaf must be eaten cooked.Based on this study,the optimum nitrogen application on cabbage was 162kg/hm2.The nitrogen uptake in cabbage head was much higher than that in cabbage leaf.Compared with the other treatments,the nitrogen accumulation in cabbage head of N7 was the highest.For N1 and N2,the nitrogen applications were deficit for cabbage planting,while other treatments surplus(except N7).Besides,with the increase of nitrogen application,the surplus amounts increased.Nitrate content was higher in topsoil(0～20 cm)than in the 20～40 cm soil layer,nitrate content was destabilizing in other soil layers.