About
  PDF
Full Text
(755 K)

Interaction of Nitrogen Rates and Mepiquat Chloride for Cotton Following Corn in Rotation

M.W. Ebelhar and J.O. Ware


ABSTRACT

Interest in higher nitrogen (N) rates for cotton in combination with plant growth regulators for cotton continues along with a renewed interest in crop rotations, especially rotations involving corn. Higher N rates for corn production could potentially lead to the buildup and carryover of N in the soil profile. This carryover could be exhibited as excess vegetative growth in subsequent cotton crops. A 4x2x2 factorial combination of N rates (60, 90, 120, and 150 lb/A), N application systems (preplant [PP] and preplant +sidedress [PP+SD]), and plant growth regulator (with and without PGR) was evaluated over a 3-year period (1999-2001) in the Mississippi Delta. Total lint yield in 1999 ranged from 1351 to 1544 lb/A with the highest numerical yield observed where 150 lb N/A was applied along with PIX Plus® plant growth regulator. When averaged across all other factors, PGR treatments were higher (34 lb/A, 2.4%) compared to the UTC. In 2000, there was no response to increasing N rates nor to N application systems but a significant increase in lint yields when PIX Plus was applied (91 lb lint/A, 8.8%). In 2001, there was also no yield response to increasing N rates with respect to total lint. At the first harvest in 2001, there was a significant reduction in lint yield with increasing N rates. However, the reverse was true with the second harvest. When the two harvests were added together, there was no difference between N rates. This occurrence suggests a delay in maturity which has been experienced in previous years with increasing N rates. In 2001, adverse weather conditions during boll development greatly limited the final yields due in part to the presence of boll rot. General field observations during the growing seasons would not suggest excessive growth of cotton following corn in a corn/cotton rotation. However, results from this study showed no significant response to increasing N rates above 60 lb/A in two of three years. Only in 1999, did 90 lb N/A produce higher yields than 60 lb N/A. PIX Plus plant growth regulator provided a significant yield increase in both years that could be measured.





[Main TOC] | [TOC] | [TOC by Section] | [Search] | [Help]
Previous Page [Previous] [Next] Next Page

Document last modified May 20, 2002