Higher Fatty Acid Composition of Immature Forages as Affected by N Fertilization

Mayland, H.F. and Molloy, L.F. and Collie, T.W. (1976) Higher Fatty Acid Composition of Immature Forages as Affected by N Fertilization. Agronomy Journal. 68(6):979-982.

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Abstract

High levels of both N and total higher fatty acids
(HFA) in forage have been associated with increasing the
grass tetany hazard to grazing cattle. The objective of this
study was to determine the relationship between forage
N, total HFA, and HFA species distribution in several
forages.

Forage N, HFA, HFA species concentration, and total
chlorophyll were determined in immature vegetative
growth of Agropyron desertorum (Fisch.) Schult., Cynodon
dactylon L., Lolium perenne L., Trifolium repens L.,
and Triticum aestivum L. established with soil fertility
levels up to 500 ppm N in the growth chamber. Forage
HFA concentrations were positively and linearly related
to forage N levels, but regression coefficients were not the
same for all species. The HFA concentrations were as
high as 16 mmol COOH/100g DM at 6% total N in first
cutting Lolium perenne L. The relative HFA species distribution
was the same within a given forage, even though
total N concentrations ranged from 2 to 6%. The mean
HFA specie concentrations (determined by gas-liquid-chromatography
relative to mean total HFA concentrations
determined by titration) when expressed as percent
for the grasses were: C14:0 — 2%, C16:0 — 13%, C16:1
— 1%, C18:0 plus C18:1 — 1%, C18:2 — 11%, and C18:3
— 67%. The total HFA concentrations were positively
correlated with chlorophyll a + b concentrations which
was expected, since the HFA of green plants is largely
associated with chloroplast membrane.

Item Type:	Article
NWISRL Publication Number:	0356
Subjects:	Irrigated crops > Grass forage > Chemistry Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:51
Last Modified:	13 Feb 2017 23:19
Item ID:	306
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/306