Progress Report Series No. 65
AGRICU LTU RAL EXPERIMENT
of The Alabama Polytechnic 
Institute
. . . .. . E. V. SMITH, Director . .
Urea-Formaldehyde Fertilizer As A Source of
Nitrogen for 1-0 Loblolly Pine Nursery Stock
JACK T. MAY, Forester
HENRY G. POSEY, Assistant Forester
REPEATED NITROGEN topdressings of pine
seedlings (Pinus taeda L.) has been a stand-
ard practice in forest nurseries. These topdress-
ings are expensive, but nitrogen must be available
throughout the growing season for rapid growth
of seedlings. A fertilizer material that gradually
releases nitrogen during the growing season could
eliminate the repeated nitrogen applications, thus
saving labor and expense.
A recently-developed product, urea-formalde-
hyde,' has been tested since 1955 by the Agricul-
tural Experiment Station of the Alabama Poly-
technic Institute to determine its usefulness as a
fertilizer material and its ability to release nitro-
gen over a long period.
Urea-formaldehyde is a type of plastic that has
many of the favorable characteristics of organic
nitrogen (Lunt and Sciaroni
2
). It contains 38 per
cent nitrogen that is released over a prolonged
period. About 25 per cent of the nitrogen is in
the form of a readily soluble fraction consisting
of unreacted urea and urea-formaldehyde poly-
mers of low molecular weight. Nitrification of
the soluble urea-formaldehyde is about as rapid
as that of ammonium sulfate. The other 75 per
cent of the nitrogen is in a slowly available form
referred to as water-insoluble nitrogen. In labora-
tory tests 55 to 60 per cent of the water-insoluble
nitrogen was nitrified in about 6 months (Kralo-
vec and Morgan
3
). Under field conditions the
rate of nitrification may be increased or decreased
as a result of differences in soil type, pH buffer
capacity, microbiological activity, plant nutrient
content, and climatic conditions.
PROCEDURE
Five nitrogen treatments replicated 4 times in
a randomized block design comprised the investi-
gation. Dimensions of individual plots were 4
feet by 50 feet. During the first week in April,
1955, all plots received uniform applications of
400 pounds of 48 per cent concentrated super-
phosphate, 200 pounds of 60 per cent muriate of
potash, and 15 tons of sawdust per acre, prior to
sowing.
The five nitrogen treatments applied prior to
sowing were:
1. No nitrogen.
2. Urea-formaldehyde fertilizer-217 pounds
per acre (82 pounds nitrogen).
3. Urea-formaldehyde fertilizer-435 pounds
per acre (165 pounds nitrogen).
4. Urea-formaldehyde fertilizer-653 pounds
per acre (248 pounds nitrogen).
5. Check plots received the standard nursery
treatment for 1955, 1,141 pounds of ammonium
nitrate (376 pounds nitrogen) per acre in eight
applications: 200 pounds prior to sowing; May 31,
100 pounds; June 19, 115 pounds; July 3, 168
pounds; July 15, 168 pounds; August 1, 140
pounds; August 16, 140 pounds; and September 1,
110 pounds.
All presowing applications of fertilizers were
thoroughly disked into the seedbed with a Seaman
Tiller. Postsowing applications of ammonium
nitrate were made through the overhead irriga-
tion system.
RESULTS
Preliminary results of the tests indicate that
it is feasible to use a fertilizer material for lob-
lolly pine seedlings in the nursery that gradually
releases available nitrogen throughout the grow-
ing season. A single application of urea-formalde-
hyde prior to sowing of loblolly pine seed in 1955
resulted in seedlings Whose heights were equal to
'Furnished by E. I. DuPont de Nemours and Company under the trade name Uramite.
2
Lunt, 0. R. and Sciaroni, R. H. 1955. Synthetic Fertilizer Tested. Agricultural Newsletter, Vol. 23, No. 5: 93-94.
Kralovec, R. D. and Morgan, W. A. 1954. Urea-Formaldehyde :Fertilizers. Agricultural 
and Food Chemistry, Vol. 2,
No. 2: 92-95.
I 1
i \~
EFFECT OF NITROGEN TREATMENT ON GROWTH OF LOBLOLLY PINE SEEDLINGS,
APRIL 12 - SEPTEMBER 12, 1955, AUBURN, ALABAMA
Nitrogen treatment per acre Seedling height
Pre-seeding Post-seeding Total Block 1 Block 2 Block 3 Block 4 Average
Pounds Pounds Pounds Inches Inches Inches Inches Inches
0 0 0 2.97 3.15 3.57 3.71 3.35
82 0 82 4.33 3.32 4.95 4.61 4.30
165 0 165 5.80 4.35 6.17 5.85 5.54
248 0 248 7.12 5.19 6.25 6.68 6.31
66 310 376 6.42 5.83 6.29 6.33 6.22
those grown with repeated topdressings of am-
monium nitrate. Given in the table are average
heights attained by the seedlings resulting from
the various treatments during the period April 12
to September 12, 1955.
CONCLUSIONS
1. A urea-formaldehyde fertilizer compound
resulted in loblolly pine seedling heights directly
proportional to the amounts applied.
2. In 1955 a single application of 632 pounds
per acre of urea-formaldehyde (248 pounds of N)
prior to sowing resulted in seedling heights equal
to those of seedlings receiving 1,141 pounds per
acre of ammonium nitrate (376 pounds of N) in
eight applications.
3. Results to date indicate that under conditions
similar to those prevailing in 1955 the use of urea-
formaldehyde fertilizer compound may eliminate
the need for periodic nitrogen applications during
the growing season.