Soil factors affecting magnesium availability in plant-animal systems: A review

Mayland, H.F. and Wilkinson, S.R. (1989) Soil factors affecting magnesium availability in plant-animal systems: A review. Journal of Animal Science. 67:3437-3444.

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Abstract

Soils provide the support, water and most of the nutrient elements, including Mg,
needed for plant growth. Magnesium uptake by plants depends largely on the amount,
concentration and activity of Mg in the soil solution and the capacity of the soil to
replenish Mg in the soil solution. The availability of Mg depends on the activity or
proportion of Mg relative to soluble and exchangeable amounts of K, Ca, Na, Al and Mn.
In humid regions, Mg losses from leaching are often greatest from agroecosystems
receiving heavy N fertilization. Cool-season grasses produce nearly maximum growth at
herbage concentrations of 1 to 1.5 g Mg/kg, 25 g K/kg and 30 g N/kg of dry matter. At
these concentrations of N and K, herbage should contain about 2.5 g Mg/kg to avoid
inducing hypomagnesemic grass tetany in ruminants. To increase herbage Mg concentration
to this level often requires, except on sandy soils, an uneconomically large addition of
Mg fertilizer. Adjusting soil conditions to produce grasses with a low-tetany potential may
not always be possible physically. The risk of tetany can be reduced by a judicious
program of well-timed N, K and Mg fertilizer applications. However, direct Mg
supplementation of grazing ruminants is considered more cost-effective than is Mg
fertilization to prevent grass tetany.

Item Type:	Article
NWISRL Publication Number:	0693
Subjects:	Animal Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:53
Last Modified:	03 Jan 2017 18:15
Item ID:	527
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/527