Effect of Temperature and Coating Thickness on the Release of Urea from Resin-Coated Granules

Brown, M.J. and Luebs, R.E. and Pratt, P.F. (1966) Effect of Temperature and Coating Thickness on the Release of Urea from Resin-Coated Granules. Agronomy Journal. 58:175-178.

PDF 51.pdf Download (243kB)

Abstract

Resin coatings are very effective in controlling the
availability of N from applied urea in moist soil. In
leaching studies, 94% of the noncoated urea was recovered
in 1 day, compared to a 49% recovery of the
N from coated urea (13.2% resin) in 4 weeks of intermittent
leaching.

Release rates are controlled by the thickness of the
coating and the temperature of the medium. Coatings
averaging 13.2% resin markedly decreased release of
urea, compared to coatings of 9.0% resin. In the range
beween 5 to 35C, increased release of urea accompanied
increases in temperature. After 4 weeks of incubation and
intermittent leaching totaling 20 inches of water, 25 and
67% of the added N were leached from soil at 5 and
35C, respectively. Increasing the temperature 10C was
approximately equivalent to doubling the release time
within a 16-week period. Increasing the temperature increases
expansion of the capsule and the surface area
through which diffusion must take place. This effect is
probably supplemental to the effect of temperature on
the diffusion phenomena per se. Approximately 99% of
the capsules were recovered intact after incubation for 16
weeks at four temperatures between 5 and 35C.

Item Type:	Article
NWISRL Publication Number:	0051
Subjects:	Mass Import - unclassified
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:52
Last Modified:	13 Jan 2017 23:26
Item ID:	412
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/412