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The effect of nitrogen in cattle slurry and mineral fertilizers on nitrogen fixation by white clover
Author(s) -
NESHEIM L.,
BOLLER B. C.,
LEHMANN J.,
WALTHER U.
Publication year - 1990
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/j.1365-2494.1990.tb02186.x
Subject(s) - slurry , agronomy , nitrogen , fertilizer , human fertilization , dry matter , zoology , perennial plant , chemistry , nitrogen fixation , biology , environmental science , organic chemistry , environmental engineering
The influence of N in slurry or in mineral fertilizers on herbage yield and nitrogen fixation by white clover grown in mixed swards was investigated. Two levels of N in cattle slurry were compared with a range of mineral N fertilization. The percentage of N derived from symbiosis (% Nsym) was measured by the 15 N‐isotope dilution method. The measurements were made in spring 1987 in two 4‐year‐old field trials, and included two out of five harvests. The % N sym was approximately 90% without N fertilization. It decreased in response to both mineral N and N in slurry but did not fall below 63%. The sum of two harvests revealed that 51·2 kg N ha −1 were fixed in the absence of N fertilization. With 75 kg mineral N ha −1 or 50 m 3 cattle slurry ha −1 , the yield of fixed N decreased to 17·2 and 24·9 kg ha −1 , respectively. When compared on the basis of the fertilizer effect on dry matter yield and N concentration of perennial ryegrass, the decrease in yield of N fixed due to treatment with cattle slurry was less than that due to mineral N fertilizer. This was owing to the smaller extent of the depression in the proportion of white clover in the sward when the same amount of N was applied in cattle slurry, as compared with mineral fertilizer, although % N sym responded similarly to both types of N fertilization.