肥料氮的淋溶深度对肥效的影响

在人工模拟土柱中,用~(15)N示踪方法,研究了麦田追施尿素之后,随灌溉水淋溶到不同深度层次中的肥料氮对小麦的有效性及其再分布规律。结果表明,肥料氮的淋溶深度对其有效性确有一定影响,在0～40cm内,这一影响不显著,而在达到40cm以下时,肥料氮的利用率降低7.22％～12.36％,肥效下降13.99％～22.49％,达极显著水平。植株吸收肥料氮的比例随着淋溶深度的加深而有所降低。淋溶到土体深处的肥料氮的再分布能力很弱。肥料氮的损失率与利用率成反相关。

EFFECTS OF LEACHING DEPTH OF FERTILIZER-N ON ITS EFFICIENCY

The efficiency on wheat and the redistribution of the topdressed urea-N which had been leached to difierent depths of the soil by irrigation were studied on simulated soil columns using 15N tracing technique.The results showed that within 0~40cm the effect of the leaching depth of topdressed urea-N on its efficiency was not significant.When it was leached to a depth below 40 cm,the utilization rate of the leached urea-N decreased by 7.23%~12.36% and the efficiency of the N decreased by 13.99%~22.49%.The ratio of the fertilizer-N in wheat plant reduced with the depth of the leaching of urea-N.The redistribution ability of the leached fertilizer-N in deep osil was very weak.The loss rate of the fertilizer-N was inversely correlated with its ultilization rate.