Effect of Nitrogen Fertilizer Applications and Pix Treatments on Cotton Growth and Development

Thein Han, J.T. Cothren, and F.M. Hons


High N rates, though necessary to optimize cotton yield potential, may under certain environmental conditions lead to excessive vegetative growth and subsequent decreases in cotton yield. Pix (1,1-dimethylpiperidinium chloride), a cotton growth regulant, suppresses vegetative growth of cotton and often increases lint yield. The objectives of this study were 1) to compare the effects of early-season, multiple applications to an early-bloom, single application of Pix on cotton growth and yield, 2) to determine the responses of cotton to N rates and time of application, and 3) to investigate the possible interactions of Pix treatment, N rates, and time of application on lint yield, N uptake, and other agronomic characteristics (plant height, light interception, and chlorophyll content) of cotton. The experimental design was a three-way factorial with two qualitative factors (Pix application and N application timing) and one quantitative factor with a zero level (N rate). The experiment was arranged as a split plot randomized complete block with four replications. The main plots were Pix application treatments, and the subplots were the N rate by N application timing combinations. The three Pix treatments were 1) control 2) early-season, multiple application (four treatments of 2 oz/ac, beginning at pinhead square), and 3) an early-bloom, single application of 8 oz/ac. Nitrogen was applied either preplant or split (one half preplant and one half at pinhead square). The five N rates were 0, 40, 80, 120, and 160 lb N/ac. Plant height, light interception, chlorophyll content (per gram fresh weight and per unit leaf area), and N uptake were measured 90 days after emergence. At harvest, lint yield, lint yield per unit of fertilizer N, and seed N content were determined.

Reprinted from 1990 Proceedings: Beltwide Cotton Production Research Conferences pp. 654 - 655
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998