冬小麦—夏玉米轮作周期内碱解氮、硝态氮时空变化及施氮安全值的研究

Study on Change of Alkali Hydrolysable N and NO_3^-N Content in Soil With Time and Space and Secure Use of Nitrogen Amount in the Wheat-maize Rotating System

利用 3年 6季氮肥试验研究了冬小麦—夏玉米轮作制度下 ,冀东褐土剖面碱解氮、NO-3 -N含量时空迁移变化和土壤氮素安全值指标。结果表明 ,土壤碱解氮自上而下依次递减 ,NO-3 -N呈“V”字型变化 ,二者均与施肥水平及植株生长状况密切相关 ,在 2 0～ 40cm区域出现碱解氮亏缺区 ,N2处理较为明显。N2处理的地下水NO-3 -N含量已超标 ,建议高产条件下土壤环境投氮安全值为 42 0～ 450kghm- 2

A 3-year’s N fertilizer experiment was conduced in drab soil in the Northeast of Hebei province to study the changes of Alkali hydrolysable N and NO - 3-N content,and the secure amount of fertilizing nitrogen in crop growimg period in wheat-maize rotating system. The results showed that the Alkali hydrolysable N content tended to decrease.Alkali hydrolysable N was deficient from 20cm to 40cm in soil section, especially that of N2 treatment. NO - 3-N content of N2 treatment in ground water exceeded secure criterion, so suitable amount of nitrogen was 420-450 kg ha -1 .