THE INTERACTION OF CORN HYBRIDS WITH STARTER FERTILIZER
IN RELATION TO CORN YIELD, LODGING AND DRY DOWN'/
I. D. Teare, D. L. Wright, and B. T. Kidd"/
1/Contribution from the Inst. of Food and Agric. Sci. Florida Exp. Stn., Univ.
of Florida, and the North Florida Res. and Educ. Ctr., Quincy, FL 32351.
Research Report NF 87-7.
'/Research Scholar/Scientist of Agronomy, Professor of Agronomy and Biologist
Scientist II, University of Florida, North Florida Res. and Educ. Ctr.,
Quincy, FL 32351.
The temperature differential at time of planting undoubtedly contributes
to the differences in N and P uptake by corn. In the lower coastal plains,
optimum corn planting dates range from late February to mid-March (Ball, 1981;
Wright, Teare and Kidd, 1987). During this period, the soil temperature
fluctuates widely and is often low for several consecutive days. As planting
date is moved earlier to take advantage of the increased yield potential one
can expect greater responses from starter fertilizer containing N and P.
Slower than normal growth with low soil temperatures is probably due to a
combination of poor root growth (Knoll, et. al., 1964; Beauchamp and Lathwell,
1967) and low nutrient availability (Ketcheson, 1968; Reyes, et. al., 1977).
Poor seedling growth resulting from low nutrient availability in cold soils
can occur irrespective of residual soil fertility levels (Touchton and
Hargrove, 1983). Placing small amounts of soluble fertilizers in close prox-
imity to the seed at planting, commonly referred to as starter fertilizer
applications, will help alleviate the detrimental effects of cool weather on
early corn growth (Bates, et al., 1966; Ketcheson, 1968).
Nutrients used in starter fertilizer studies have consisted of various
N-P-K combinations, but a strict definable starter fertilizer combination does
not exist. Both N and P are considered to be primary ingredients in starter
fertilizers because of slow mineralization of organic to inorganic N (Cassman
and Munns, 1980) and slow release of solid to solution-phase-P (Arambarri, P.,
and 0. Talibudeen, 1959; Wallingford, W., 1978).
The objectives of this study were to determine if a starter fertilizer
containing N and P would improve growth, yield, dry-down and reduce lodging in
high yield corn in the subtropics and to determine how various hybrids would
interact with starter fertilizer.
MATERIALS AND METHODS
The study was planted March 28, 1985 and March 24, 1986 at the North
Florida Research and Education Center at Quincy, Florida, in a conventional
seedbed [Norfolk sandy loam soil (fine-loamy, siliceous thermic Typic
Paleudult)] using the plow-layer management system for high yield irrigated
corn (Wright and Rhoads, 1980). The area was fertilized 2-25-85 and 3-3-86
with 1.12 Mg ha~ of 5-10-15. Ammonium polyphosphate (10-34-0) was applied on
the surface of the row at planting at 94 L ha- as the starter fertilizer.
Zinc, Mn, Cu, and B chelates were applied to all plots at 7 L ha-. Dual (1.7
L ha~1) and Aatrex (1.7 L ha~1) were applied on March 29, 1985 and April 14,
1986. Rows were 7 m long and trimmed to 6.1 m for harvest. Corn was irri-
gated whenever tensiometers placed at 0.15 m level indicated 0.02 MPa. A 25%
N solution with 3% S was applied in a band near the row on April 18, 1985 and
April 24, 1986 at 140 kg N ha-. Paraquat was applied as a directed spray for
weed control on May 8 both years at 1.2 L ha- plus X-77. Another 112 kg N
ha1 was injected through the irrigation system with 1.12 kg ha1 of B on May
13 both years. Corn plants were thinned around the first of April each year
to 12150 plants ha-1. Orthene was applied at 1.12 kg ha1 through the irri-
gation system about June 20 for stink bug control each year.
Grain moisture was determined on 2 ears per hybrid per replication at
random twice weekly from July 14 until a grain moisture content below 25% was
recorded. The ears from each plot were placed in plastic bags stored in the
shade until all plots were harvested and then shelled and moisture measured
with a Burrows model 700 digital moisture computer.
Grain yields were harvested from the two center rows (6.1 m long) and
corrected to 15.5% moisture.
Lodging scores were calculated by counting the numbers of leaning or
horizontal stalks and dividing by the number of stalks per row x 100.
Arambarri, P., and 0. Talibudeen. 1959b. Factors influencing the
isotopically exchangeable phosphate in soils. Part III. The effect of
temperature in some calcareous soils. Plant Soil 11:364-376.
Ball, D. M. 1981. Alabama 1981 production guide for non-irrigated corn for
grain. Alabama Cooperative Extension Service, Auburn University, Auburn,
Bates, T. E., M. H. Miller, and D. Singh. 1966. Fertilizer placed with corn
seed reexamined. Crops Soils 18:20.
Beauchamp, E. G., and D. J. Lathwell. 1967. Root-zone temperature effects on
the early development of maize. Plant Soil 26:224-234.
Cassman, K. G., and D. N. Munns. 1980. Nitrogen mineralization as affected
by soil moisture, temperature, and depth. Soil Sci. Soc. Am. J.
Ketcheson, J. W. 1968. Effect of controlled air and soil temperature and
starter fertilizer on growth and nutrient composition of corn (Zea mays
L.). Soil Sci. Soc. Am. Proc. 32:531-534.
Knoll, H. A., D. J. Lathwell, and N. C. Brady. 1964. The influence of
root-zone temperature on the growth and nutrient composition of corn (Zea
mays L.). Soil Sci. Soc. Am. Proc. 28:400-403.
Reyes, D. M., L. H. Stolzy, and C. K. Labanauskas. 1977. Temperature and
oxygen effects in soil on nutrient uptake in jojoba seedlings. Agron. J.
Touchton, J. T., and W. L. Hargrove. 1983. Grain sorghum response to starter
fertilizers. Better Crops Plant Food 67:1-3.
Wallingford, W. 1978. Phosphorus in starter fertilizer. In Phosphorus for
Agriculture, p. 62-79. Potash/Phosphate Institute, Atlanta, GA.
Wright, D. L., I. D. Teare, and B. T. Kidd. 1987. Phenological events of
corn in relation to time of planting. Research Report No. NF 87-3 from
North Florida Res. and Educ. Ctr., Quincy, FL, Univ. of Florida, Agr. Exp.
Wright, D. L., and F. M. Rhoads. 1980. Management practices for 300 bushel
corn. Fla. Coop. Ext. Ser., Agronomy Facts 108:1-7.