Comparative Growth And Yield Of Cotton Planted At Various Densities And Configurations

Published online April 11, 2006

Comparative Growth and Yield of Cotton Planted at Various Densities
and Configurations
Jonathan D. Siebert,* Alexander M. Stewart, and B. Rogers Leonard
disease control have resulted in increased at-planting
variable costs. These variable costs may be offset
through reduced seeding rates. In addition, seed-specific
in-furrow application systems currentlyunder development may result in pesticide savings of approximately
50% (Wilkerson et al., 2004). Reduced seeding rates
may also have other management implications. For example, Leigh et al. (1974) reported higher numbers of
Lygus spp. with increased plant populations. Formerly
secondary pests of cotton, Lygus spp. now require multiple insecticide applications per season to achieve adequatecontrol in the South and southeastern Cotton Belt
(Williams, 2005). Thus, reduced seeding rates may have
implications beyond simply saving seed.
Several researchers have concluded that seed cotton
yield and plant density are unrelated (Ray et al., 1959;
Hawkins and Peacock, 1973; Baker, 1976; Buxton et al.,
1977; Jones and Wells, 1998; Bednarz et al., 2000;
Franklin et al., 2000). Otherresearchers, however, have
observed reduced yields with extremely high or low
plant densities (Hawkins and Peacock, 1971; Bridge
et al., 1973; Smith et al., 1979).
Interestingly, no one has ever investigated the interaction of plant population and seeding configuration on
cotton lint yield. Many producers have adopted hill-drop
seeding in an attempt to combat emergence problems in
soils proneto crusting and achieve uniform plant spacing.
Advances in crop planting equipment have improved the
precision of seed placement and seeding rate. Some
researchers have concluded that uniform seed placement
is more important in maximizing yield potential than
seeding rate (Lee, 1968; Wanjura, 1980). The objective
of these studies was to evaluate plant population and
seeding configurationson cotton growth, development,
and yield in an effort to isolate a specific combination to
minimize seed use without sacrificing yield and to identify
any potential management variations that may exist with
cotton grown at these divergent densities.

Reproduced from Agronomy Journal. Published by American Society of Agronomy. All copyrights reserved.

ABSTRACT
Cotton (Gossypium hirsutumL.) lint yield stability across a range
of plant populations, coupled with expensive transgenic cotton seed,
makes reduced seeding rates an attractive cost-saving option. Studies
evaluated plant populations and seeding configurations in an effort to:
(i) isolate a specific combination that minimizes seed use without
sacrificing yield, and (ii) identify potential growth and developmentchanges associated with cotton grown at these densities. Cotton
planted in studies conducted during 2003 and 2004 on a Norwood silt
loam (fine-silty, mixed, calcareous, thermic Typic Udifluvent) were
hand thinned to densities ranging from 33 978 to 152 833 plants ha21 in
both hill-drop and drill-seeded configurations (96.5-cm row widths).
Plant height, main-stem nodes per plant, maturity, bollretention by
position, lint yield, and fiber quality were all evaluated. No seeding
configuration 3 plant population interaction occurred for variables
other than yield. A positive relationship existed between plant population and plant height; however, main-stem nodes per plant, days
after planting to peak bloom, and boll retention were inversely related
to plant density. Lint yield washighest for 152 883 plants ha21 (1465 kg
ha21) planted in a hill-drop configuration with three plants per 20-cm
hill spacing, and was not reduced until population was lowered to
33 975 (30.5-cm plant spacing, 1263 kg ha21) and 50 958 (three plants
per hill, 60-cm hill spacing, 1177 kg ha21) plants ha21. Treatments did
not influence fiber properties. Reduced seeding rates appear to be a
viable...