Vegetative‐fruiting Development and N Concentrations of a Dwarf Determinate Cotton Cultivar

Abstract

AbstractThe lack of information needed to verify a nitrogen submodel for a cotton (Gossypium hirsutum L.) plant simulation model suggested the need to measure the effect of N level on a broad spectrum of vegetative and fruiting development characteristics in a single field study. The effect on plant N accumulation and growth of 0, 90, and 180 kg N/ha applied to Amarillo loam soil, Aridic Paleustalfs, was measured on the cultivar ‘Paymaster Dwarf’ grown in 25 and 100‐cm rows. Increasing soil N application rate from 0 to 90 kg/ha increased per plant dry matter production in 100 but not in 25‐cm rows. Application of soil N increased plant N concentrations in leaves‐petiole‐squares and bur fractions. Plant N concentration was unaffected by row spacing. Stem, leaves‐petioles‐squares, and bur fractions decreased in N concentration from first square to maturity, while seed N concentration increased between peak bloom and maturity. The time of fruiting was unaffected by N application rate but there was a trend of increasing per plant square and boll numbers at higher application rates. Peak boll shedding showed two peaks in 25‐cm rows where soil N was applied compared to a single peak for 100‐cm rows. Collectively, the data describe plant‐N status and dry weight at three stages of growth and fruiting weekly for two row spacing and population levels.