氮肥对菘蓝生长及氮素吸收的影响

Effects of N Fertilization on Growth and N Content of Isatis indigotica

研究不同氮素用量对不同生长期菘蓝叶、根产量及其氮素吸收量和土壤硝态氮的影响,为氮素的合理施用提供依据。采用田间小区试验方法,调查菘蓝(Isatis indigotica Fort.)不同生长期根(板蓝根)和叶(大青叶)干质量,并测定叶、根氮素含量和收获期土壤硝态氮。结果表明:施氮量在0～375kg/hm2,大青叶产量随着氮肥用量的增加而增加;当施氮量为150kg/hm2时,板蓝根产量、根冠比、植株氮素吸收量及产值达到最高值,超过150kg/hm2时开始下降。同时,随着施氮量的增加,60～100cm的土壤硝态氮含量相应增加,从而对环境污染的风险明显增大。综合大青叶、板蓝根产量及其氮素吸收量、根冠比、0～100cm土壤硝态氮的结果可知,氮的合理用量为150kg/hm2。

The objective is to study the effect of different amount N fertilizer on the yields of folium and root, nutrient content and soil nitrate in different growth of Isatis indigotica. The field plot experiment was conducted to determine the yields of folium and root, nutrient content and soil nitrate in different growth stages of Isatis indigotica. Result showed that the folium yields of Isatis indigotica increased with the increase of N application at the range of 0-375 kg/hm2, When the amount N exceeded 150 kg/hm2, the root yields,root/shoot ratio, plant nitrogen absorption and output value decreased. Meanwhile, the increasing amount of N application caused nitrate increase in 60-100 cm soil, and the risk of environment contamination increased too. Thus, the appropriate amount of N ap- plication was 150 kg/hm2.