ABSTRACT

A field micro-plot experiment with nitrogen isotope (¹⁵ N) labelling was performed to study the impacts of the timing of aside-dressed Napplication on urea-¹⁵ N in amaize-soil system. The treatments comprised three application timings, each of which consisted of the identical total rate of N, i.e. 280kg ha⁻¹. In all treatments, 40% of the Nwas used theday prior to sowing, and the rest was used either at the jointing stage (V6) (N1), at the bell stage (V12) (N2) or at the tasselling stage (VT) (N3). The results indicated that the grain yields increased in both the N1 and N2 treatments compared with the N3 treatment. Asplit application of Nat the bell stage significantly raised the percentage of Nderived from fertilizer N(Ndff) compared to the two other side-dressed Napplication timings. The ¹⁵ N recovery efficiencies for the N2 and N1 treatments were 10% greater than the N3 treatment. The possible Nlosses in the N2 treatment were lower than those in the other treatments. Therefore, Nside-dressing at the bell stage is an alternative and sustainable management strategy for maize production and NUE in spring maize cropping systems.

摘要

进行了氮同位素（¹⁵  N）标记的田间微小区试验，研究了 在玉米-土壤系统中，旁施氮肥的时间对尿素- ¹⁵ N 的影响。处理包括三个施用时间，每个时间由相同的氮总量组成，即280kg ha ^-1. 在所有处理中，40% 的 N 在播种前一天使用，其余的用于拔节期 (V6) (N1)、钟形期 (V12) (N2) 或抽穗期 (VT) (N3)。结果表明，与N3处理相比，N1和N2处理的籽粒产量均有所增加。与其他两种侧施施氮时间相比，在钟形阶段分批施用 Nat 显着提高了源自肥料 N(Ndff) 的 N 的百分比。在 ¹⁵ N2 和 N1 处理的氮回收效率比 N3 处理高 10%。N2 处理的可能 Nlosses 低于其他处理。因此，在铃期施肥是春玉米种植系统中玉米生产和 NUE 的替代和可持续管理策略。