Cotton Production Affected by Row Profile and N Rates
- C. H. Harris and
- C. Wayne Smith
Cotton (Gossypium hirsutum L.) production in the Delta of Arkansas requires 150+ days from planting to final harvest. The evolved system for growing cotton includes planting on raised beds with N applied preplant into or under the bed. Maturity delays and associated yield reductions in recent years may have been related to this system. A study was initiated in 1975 to compare four genotypes grown in flat or bedded seedbeds with twice the recommended rate of N and half the recommended rate in order to evaluate the role of salts on seedcotton yield and earliness. The four genotypes represented a range of genetic maturity. A split-block, split-plot arrangement of a randomized complete block was utilized and the test site was Calloway silt loam, a fine-silty mixed, thermic alfisol, located on the Cotton Branch Experiment Station, Marianna, Ark.
Observations confirmed the surface drainage advantage of raised seedbeds. Otherwise, row profile contrasts had no effect on yield during any year, and we found no evidence that nitrate salts became concentrated in raised seedbeds, discounting the suggestion that increase in these salts resulted from the raised beds and thus directly delayed maturity.
The 134 kg/ha rate of N resulted in higher seedcotton yields than did 34 kg/ha but also delayed maturity as indicated by percent first pick, regardless of row profile. Aborted terminals were shown not to be the cause of delayed maturity with the high rate of N. Genotypes responded to the effects of contour and N equally as indicated by the lack of significant interactions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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