氮肥、土壤肥力和采收期对小白菜体内硝酸盐含量的影响  

Influence of Nitrogen Rates, Soil Fertility and Harvest Time on Nitrate in Chinese Cabbage

作　　者：王正银[1] 李会合[1] 李宝珍[1] 叶学见[1] 孙彭寿 戴亨林 向天常 

机构地区：[1]西南农业大学资源环境学院,重庆400716 [2]重庆市农业局土肥站,重庆400020

出　　处：《中国农业科学》2003年第9期1057-1064,共8页Scientia Agricultura Sinica

基　　金：重庆市科委攻关资助项目 ( 2 0 0 0- 62 0 8)

摘　　要：在田间条件下研究了土壤肥力、氮肥施用量、采收时期、光照对小白菜生物量、硝酸盐累积和营养品质的影响。结果表明 ,不同氮水平下小白菜生物量与生长天数呈极显著直线回归关系 ,不同收获期的施氮处理与小白菜生物量呈极显著二次抛物线关系。施氮 2 2 5kg·ha-1可使小白菜获得最高产量 ,而经济最佳施氮量为 15 0kg·ha-1处理。中、低肥力土壤无氮肥处理的小白菜硝酸盐含量分别为 2 16 0± 72 8和 10 4 9± 799mg·kg-1,施氮 75 0～30 0kg·ha-1使 2种土壤的小白菜硝酸盐含量提高 2 3.5 %～ 30 .1%和 14 0 .5 %～ 185 .1% ;小白菜生长天数与硝酸盐累积量呈极显著直线关系 ,中肥力土壤上植株硝酸盐累积速率 (b值 )为低肥力土壤的 3.2 1～ 4 .4 9倍 ,并以施氮 2 2 5kg·ha-1的累积量为最大。施氮量与小白菜硝酸盐累积量之间呈显著二次回归关系 ,硝酸盐最大累积速率 (b1值 )出现在 4 0d(中肥力土壤 )和 4 5d(低肥力土壤 )。连续阴天后 ,光照 2d ,小白菜硝酸盐含量降低 10 .5 %～ 2 5 .5 %。施氮明显降低小白菜Vc含量和低肥力土壤上小白菜可溶性糖及氨基酸含量 ,延后采收明显提高小白菜Vc、可溶性糖和氨基酸含量。A field experiment was conducted to study the effects of soil fertility, nitrogen fertilizer rates, harvest time and natural lighting on the biomass, nitrate accumulation and nutritive quality of Chinese cabbage. Results showed that there was a significant linear regression between growth day and biomass of Chinese cabbage at different nitrogen levels, and a significant quadratic regression between nitrogen rates and biomass of Chinese cabbage at different harvest time. The maximum yield of Chinese cabbage could be obtained at the N rate of 225 kg·ha -1 on two soil fertility but the optimum yield response to nitrogen fertilizer appeared at the 150 kg N·ha -1 treatment. The average contents of nitrate in Chinese cabbage were 2 160±728 and 1 049±799 mg·kg -1 respectively for no nitrogen fertilizer treatment, and the nitrate contents increased by 23.5%-30.1% and 140.5%-185.1% respectively by applying nitrogen (N) 75-300 kg·ha -1 under medium and low fertility soil conditions. A significant linear was found between the days of growth and nitrate accumulation of Chinese cabbage in two fertility soils. The accumulation rate of nitrate (b value) was increased by 3.21-4.49 times on medium fertility soil as compared with the low fertility soil. The maximum nitrate content appeared at the 225 kg N·ha -1 treatment. A significant quadratic regression existed between nitrogen rates and nitrate accumulation at different harvest time and the maximum rate of nitrate accumulation (b value) appeared at the 40th day on medium fertility soil and at the 45th day on low fertility soil, respectively. The nitrate content of Chinese cabbage was decreased by 10.5%-25.5% after continuous two sunny days. Applying nitrogen fertilizer could obviously reduce the Vc content of Chinese cabbage on two fertility soils and the content of soluble sugar and amino acid in Chinese cabbage on low fertility soil. The contents of Vc, soluble sugar and amino acid in Chinese cabbage were obviously increased by postponing harvest.

关 键 词：氮肥 土壤肥力 采收期 小白菜 硝酸盐 含量 影响因素 

分 类 号：S634[农业科学—蔬菜学]