Agroclimatology - Interactive effects of carbon dioxide and nitrogen nutrition on cotton growth, development, yield, and fiber quality

The consequences of elevated carbon dioxide concentrations ([CO2]) and N nutrition on cotton (Gossypium hirsutum L.) growth, development, yield, and fiber quality were determined. Cotton cultivar NuCOTN 33B was grown in sunlit controlled environment chambers at three levels of [CO2] (180, 360, and 720 mumol mol(-1)) and two levels of N [continuous N throughout the plant growth period (N+) and N withheld from flowering to harvest (N-)]. Leaf N concentration decreased with increasing [CO2] under both N treatments. These low leaf N concentrations did not decrease the effect of elevated [CO2] in producing higher lint yields at both N treatments, the response being highest for plants grown at elevated [CO2] and N+ conditions. Fiber quality was not significantly affected by [CO2], but the leaf N concentrations, which varied with [CO2], had either a positive or a negative influence on most of the fiber quality parameters. Leaf N during boll maturation period had significant positive correlations with mean fiber length (r(2) = 0.63), fine fiber fraction (r(2) = 0.67), and immature fiber fraction (r(2) = 0.65) and negative correlations With mean fiber diameter (r(2) = 0.61), short fiber content (r(2) = 0.50), fiber cross-sectional area (r(2) = 0.76), average circularity (r(2) = 0.74), and micronafis (r(2) = 0.65). It is inferred that future elevated [CO2] Will not have any deleterious effects on fiber quality and yield if N is optimum. The developed algorithms, if incorporated into process-level crop model, will be useful to optimize cotton production and fiber quality.