Nitrogen Effects on Boll Production of Field‐Grown Cotton

Nitrogen is an essential nutrient for cotton (Gossypium hirsutum L.) that affects plant growth, fruiting, and yield. This study was conducted to determine N effects on the development of harvestable bolls (HB) at fruiting sites among reproductive branches (sympodia). Field experiments were conducted from 1987 through 1990 on Commerce silt loam (fine-silty, mixed, thermic, nonacid, aeric Fluvaquent) to evaluate responses to preplant N rates of 0, 28, 56, 84, 112, 140, and 168 kg ha −1 , and to split applications of 56 + 56 kg N ha −1 . Increasing N decreased HB production at Sympodia 5 through 10, and increased HB at Sympodia 12 through 25. At Sympodia 5 through 10, production of HB at Fruiting Site 1 (first position on sympodial branch) decreased from 49% of fruiting sites at the 0 N rate, to 36% of fruiting sites, with N fertilization of 168 kg ha −1 []