Fertilizer N Effects on Cotton Growth and Fruiting Patterns

D.J. Boquet


 
ABSTRACT

The optimal level of nitrogen (N) for cotton is a difficult compromise between fertilizer rates that avoid insufficiency and rates that cause yield loss due to N induced excessive plant growth, delayed harvest and boll rot. In order to determine optimal N rates and characterize desirable and undesirable effects of fertilizer N, the effects of N levels on individual plant growth and yield were studied in field experiments during 1987 and 1988. The number, location, and fate of fruiting sites, and boll weight for each fruiting site were determined for cotton plants fertilized with N rates of 0, 28, 56, 84, 112, 140, and 168 kg/ha. Effect of N rate on plant architecture and the relationship of N rate to harvest efficiency were also determined. Fertilizer N increased the number of fruiting sites per plant, increased boll retention at no. 2 and 3 sympodial branch fruiting sites, and increased total fruiting sites on monopodial branches. The effect of N rate on boll retention and boll weight varied with location on the plant and with year. At rates of N above 84 kg/ha the beneficial effects of N were increasingly negated by excessive plant size, delayed maturity, decreased seedcotton weight of bolls on number 4 through 10 sympodial branches, increased boll rot, and decreased harvest efficiency.



Reprinted from Proceedings: 1989 Beltwide Cotton Research Conferences pp. 489 - 491
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998