北京潮土NO3—N在土体中的移动特点及其淋失动态

利用养分渗滤池研究了北京潮土地区春小麦夏玉米连作期间NO3N在土壤剖面中移动的时空动态。结果表明,NO3N的移动同降雨、灌水以及整个土壤系统中的水分状况密切相关。在春小麦期间只有个别处理在020cm和20-40cm中有显著移动,而夏玉米期间在0130cm的土体中NO3N发生了波浪式的移动。淋失量同当时的降雨量线性相关。130cm深处NO3N含量在淋失高峰期可达10mgN.L-1以上。此外,NO3N的移动同尿素施用量的多少有着密切关系,而尿素、硝铵和硫铵等肥料品种之间差异则不明显。15N示踪结果表明,在春小麦前期尿素中的酰胺态氮或NH4N在0-20cm土层中直接移动,而来自肥料的NO3N在4060cm处移动;夏玉米生长期间,在60cm以下深处有大量来自尿素和硝铵等残留标记氮的NO3N移动。

THE MOVEMENT AND LEACHING LOSS OF NO3-N IN PROFILE OF CHAO SOIL IN BEIJING

In lysimeters the NO₃-N change in Chao soil profile was observed during spring wheat and summer corn growing period in Beijing. The results of common chemical analysis indicated that the NO₃-N movement was coresponded with the water condition. During spring wheat growth period the marked movement occrued only from 0-20cm to 20-40cm with certain experimental treatments. However, NO₃-N moved down in the profile like "a wave " during summer corn period, thus it brought up leaching loss of NO₃-N out of 130cm soil body. With ¹⁵N stable istope techenlque the directed movement of NH₄-N and/or (NH₂)₂CO-N was observed in short distance in early stage of spring wheat growth period, and NO₃-N derived from fertilizers might moved down to deeper horizon expecially during later stage and in the treatment with NH₄NO₃.During summer corn period the residual labelled N could moved down in increasing rate with urea treatment or to much dooper with NH₄NO₃ treatment.