Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2016
Publication Date: 3/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5598221
Citation: Watts, D.B., Runion, G.B., Balkcom, K.S. 2017. Nitrogen fertilizer sources and tillage effects on cotton growth, yield, and fiber quality. Field Crops Research. 201:184-191.
Interpretive Summary: Urea-ammonium sulfate (UAS) is being marketed as an alternative fertilizer source due to increased restriction on ammonium nitrate use. Thus, a study was conducted to determine if this fertilizer source would provide equal or higher cotton yield and fiber quality under conservation and conventional tillage compared to urea and ammonium sulfate (AS), which are traditional fertilizer sources. Tillage had little influence on plant growth, while UAS and AS produced the greatest biomass in two of the three years evaluated. Urea-ammonium sulfate and AS also increased cotton lint yield two of the three years. Both tillage and fertilizer has minimal influence on cotton fiber quality. Results from this study suggest that UAS can be used as an alternative fertilizer for cotton production. However, more studies are needed to determine the long-term influence of UAS on soil acidity compared to urea and AS.
Technical Abstract: Interest in urea-ammonium sulfate (UAS) as a N fertilizer is increasing due, in part, to increased restriction on ammonium nitrate. This has resulted in UAS being marketed as an alternative fertilizer source; however, UAS has not been widely tested. A cotton (Gossypium hirsutum L.) field study was conducted in Central Alabama from 2009 to 2011 on a Coastal Plain soil (Marvyn loamy sand; fine-loamy, kaolinitic, thermic Typic Kanhapludult) comparing UAS to two common granular fertilizers [urea, ammonia sulfate (AS)] under both conservation and conventional tillage systems. The overall objective was to determine the influence of UAS on cotton growth parameters, yield, and fiber quality. Cotton was fertilized with 101 kg N ha-1 urea, AS, or UAS 5 to 6 wk after planting each year. Plant growth characteristics were evaluated 3 to 4 wk before defoliation, and cotton yield and fiber quality were determined on the machine-harvested lint. Tillage had little influence on plant growth, while UAS and/or AS tended to produce the largest number of bolls and largest aboveground, root, and total biomass in 2009 and 2011. Lint yield was also influenced by fertilizer source in 2009 and 2011, with UAS and AS producing significantly higher yields. Both tillage and fertilizer source had minimal influence on cotton fiber quality. Our results suggest that UAS produces similar or greater yields than urea and is comparable to AS. However, more research is needed to determine the long-term influence of UAS on soil acidity and N loss compared to urea and AS.