Canopy Characteristics of Narrow‐Row Cotton as Influenced by Plant Density¹

Abstract

The optimum plant density for narrow‐row cotton (Gossypium hirsutum L.) is influenced by the lint yield response to plant density as well as other crop characteristics affecting crop management. This study was conducted to quantify the effect of population density on many of these characteristics. Three experiments were conducted with narrow‐row cotton in population densities ranging from 7.1 to 22.9 plants/m2. In August plants were harvested at ground level and morphological measurements were made. At the end of the growing season lint yield was determined. There were no statistical effects of plant density on lint yield or boll and fiber properties. Population pressure increased plant height when plants were young, while the effect on older plants was inconsistent. The morphological measurements showed (a) each five plants/m2 increase in, plant population decreased the number of mainstem nodes by one, (b) each eight plants/m2 increase in population decreased the number of monopodial branches per plant by one, (c) each 11 plants/m2 increase in population density raised the lowest sympodial branch with a boll by one node. In addition increasing density from about seven to 30 plants/m2 reduced the percentage of bolls supported by monopodial branches in a curvilinear manner from 25 to 0. Increasing plant density, also increased leaf area density, especially in the central portion of the plant canopy. Considered with their probable influence on harvesting efficiency, incidence of diseases and insects, and chemical defoliation, these data should help in predicting the optimum population for narrow‐row cotton. For these studies the optimum appears to be between 10 and 15 plants/m2.

Comparative Growth and Yield of Cotton Planted at Various Densities and Configurations

“…3). Buxton et al (1977) and Kerby et al (1990a, 1990b) noted that increasing plant density decreased the number of main‐stem nodes per plant.…”

“…In our study, the higher number of bolls per plant associated with lower plant densities may be related to LAI (leaf area index), PPFD (photosynthetic photon flux density), or efficiency of solar radiation utilization. Buxton et al (1977) noted that increases in cotton plant density increased LAI; however, those plants also exhibited a lower photosynthetic rate per unit leaf area due to mutual shading (Pegelow et al, 1977). Previous work showed LAI required to maximize PPFD interception (>90%) was obtained by cotton canopies by 83 d after planting regardless of row spacing or plant density, but the efficiency of PPFD interception per unit leaf area was greater at low plant densities (Heitholt, 1994).…”

“…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). Other researchers, however, have observed reduced yields with extremely high or low plant densities (Hawkins and Peacock, 1971; Bridge et al, 1973; Smith et al, 1979).…”

Manipulation of dry matter accumulation and partitioning with plant density in relation to yield stability of cotton under intensive management

“…As plant density increased, the mean net assimilation rate decreased, resulting to reduced fruiting site production, fruit retention, and boll weight. Although smaller individual plant and boll were produced at higher plant populations, more sympodia number, total nodes and total bolls per ground area were achieved than at lower plant density under extensive farming (Nichols et al, 2004;Buston et al, 1977). These combined effects show that cotton yield could be stabilized across a range of plant densities under extensive management through manipulation of boll occurrence and boll weight (Bednarz et al, 2000(Bednarz et al, , 2005(Bednarz et al, , 2006Jost and Cothren, 2000;Jones and Wells, 1998;El-Shinnawy and Ghaly, 1985;Fowler and Ray, 1977;Baker, 1976).…”

Densely Planted Okra for Destructive Harvest: II. Effects on Plant Architecture

“…Plant population density can be an important factor in shaping plants for efficient mechanical harvest (Buxton et al, 1977;Kahn et al, 1997;Marshall, 1984). Relatively dense plantings of other crops where the fruits are produced on upright plants, such as cotton (Gossypium hirsutum L.) (Buxton et al, 1977), pepper (Capsicum annuum L.) (Kahn et al, 1997), and tomato (Lycopersicon esculentum Mill.) (Zahara, 1970), promoted mechanical harvest through favorable changes in plant morphology.…”