鸭梨不同施氮期肥料氮的平衡及其效应

以3年生初结果的鸭梨/杜梨为试材,用~(15)N示踪技术探讨了秋施、春施及夏施肥料氮在土壤-植物中的平衡及其效应。结果表明,肥料氮损失量与植株吸收量之比表现为夏施>秋施>春施;肥料氮利用率以春施最高,秋施次之,夏施最低。肥料氮在植株体内的分配基本上随生长中心的转移而转移,无果中、短枝有优先累积肥料氮的效应。以秋施肥料氮的分配与植株生长节奏最吻合,并能刺激生长势弱的植株吸收利用肥料氮。显示出秋施氮对植株的效应最好。

THE EFFECT OF FERTILIZER-N APPLIED At DIFFERENT TIME TO "YALI" PEAR

The effect of N applied at different time to "yali" pear was studied by using 15N-label>led urea as a tracer.The results were as follows:The ratio of fertilizer-N lost to utilized was in an order of summer application>autumn application>spring application,but the fertili zer-N utilization efficiency was in the reverse order.The distribution of %NDFF in plant parts was changed with the translocation of growth centre,and the spurs could accumulate more NDFF.The distribution direction of fertilizer-N applied at autumn coincided well with the growth rhythm,and could stimulate the tree of poor growth vigor to absorb more fertilizer-N.It was concluded that the autumm application fertilizer to "yali" pear has the best effect.