Influence of single applications of nitrogen on white clover nitrogen fixation in autumn and winter dairy pastures in south‐west Victoria, Australia
作者:
F.R. McKenzie,
J.L. Jacobs,
P. Riffkin,
G. Kearney,
期刊:
African Journal of Range & Forage Science
(Taylor Available online 1998)
卷期:
Volume 15,
issue 1-2
页码: 1-6
ISSN:1022-0119
年代: 1998
DOI:10.1080/10220119.1998.9647933
出版商: Taylor & Francis Group
关键词: Dry matter yield;Lolium perenneL;perennial ryegrass;Trifolium repensL;species composition
数据来源: Taylor
摘要:
Effects of nitrogen (N) (0, 15, 30, 45 and 60 kg N ha−1) applied at five different times during autumn and early winter on the N fixation ofTrifolium repensL. (white clover) inLolium perenneL. (perennial ryegrass) / white clover pastures were examined (Experiment 1). Effects of applying different N fertilisers (e.g. urea and ammonium nitrate) at 45 kg N ha−1in autumn, with and without phosphorus (P), potassium (K) and sulphur (S) on N fixation were also tested (Experiment 2). In Experiment 1, percentage N derived from the atmosphere (percent Ndfa) by white clover varied between 87% and 91% in the period after (24 to 36 days) N application. Increasing rates of N and time of application did not influence percent Ndfa. The amount of N fixed by white clover ranged from 0.8 to 3.7 kg N ha−1in the period after N application. Increasing rates of applied N produced a significant (P<0.05) linear increase in the amount of N fixed. In Experiment 2, percent Ndfa and amount of N fixed (1.9 to 4.1 kg N ha−1) were unaffected by different N fertilisers, with and without P, K and S, in the period after (37 days) fertiliser application. For both experiments, fertiliser N increased dry matter yield while having no effect on white clover composition. It is concluded that single applications of N during the autumn and early winter benefit pasture growth without adversely affecting white clover N fixation or clover composition. This finding, however, will require further investigation.
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