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In vitro total and methane gas production as influenced by rate of nitrogen application, season of harvest and perennial ryegrass cultivar
Author(s) -
Lovett D. K.,
Bortolozzo A.,
Conaghan P.,
O'Kiely P.,
O'Mara F. P.
Publication year - 2004
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.1365-2494.2004.00421.x
Subject(s) - lolium perenne , perennial plant , dry matter , nitrogen , agronomy , cultivar , organic matter , forage , chemistry , fermentation , fertilizer , zoology , biology , food science , organic chemistry
The effects of rate of inorganic nitrogen (N) fertilization (0, 80 or 160 kg N ha −1 per regrowth), season of harvest (regrowths 1, 2 and 3) and perennial ryegrass ( Lolium perenne L.) cultivar [classified as having either a normal or elevated water soluble carbohydrate (WSC) concentration genotype] on in vitro gas production and digestibility were assessed. Increased N fertilizer application significantly decreased total gas production (TGP), methane (CH 4 ) production and organic matter digestibility (OMD). The results suggest that the decreases in TGP and CH 4 production were associated with a restriction in organic matter (OM) fermentation and an altered crude protein (CP) to structural carbohydrate ratio rather than a modification in the stoichiometry of fermentation. Season of harvest only significantly ( P < 0·05) altered in vitro OMD and CH 4 production at 8 h, despite altering the chemical composition of the herbage. Cultivar effects on all measured in vitro parameters were not significant presumably because the elevated WSC concentration trait was not expressed strongly in the study.