|BARNES, EDWARD - Cotton, Inc|
|Delhom, Christopher - Chris|
Submitted to: Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2013
Publication Date: 1/15/2014
Citation: Sui, R., Byler, R.K., Fisher, D.K., Barnes, E.M., Delhom, C.D. 2014. Effect of supplemental irrigation and graded levels of nitrogen on cotton yield and quality. Journal of Agricultural Science. 6(2):119-131.
Interpretive Summary: Cotton producers in the Mid-South have become increasingly reliant on supplemental irrigation to ensure the yield and quality. Water-stress in cotton plants can limit plant growth and productivity, resulting in reduction of yield. Under-fertilization and over-fertilization with nitrogen (N) can negatively affect the desired growth pattern of cotton plants, and thus degrade fiber quality and reduce yield. Research to optimize crop water and nutrient management is necessary for high yield and quality. USDA ARS Scientists at Crop production Systems Research Unit, Stoneville, MS, working with their collaborators, conducted experiments for two years investigating the effects of supplemental irrigation and N fertilization on yield and fiber quality in cotton. It was found that supplemental irrigation increased cotton yield by 14%. Cotton fiber length showed improvements with irrigation. Irrigated cotton had lower short fiber index than the non-irrigated. As the leaf N content reached a sufficient level, over-application of N would not be beneficial to cotton fiber quality while possibly degrading some fiber properties such as the nep content and color grade. Results obtained from this study can be used for optimization of water and nutrient management in cotton production.
Technical Abstract: Effects of supplemental irrigation and nitrogen (N) fertilization on cotton yield and fiber quality were investigated in the Mississippi Delta in 2011 and 2012. Cotton was planted in 48 experimental plots with irrigation as main treatment unit and N application rate as subunit. Supplemental irrigation was conducted based on crop evapotranspiration and soil-water sensor measurements. Cotton yield was determined using a load-cell scale equipped in a boll buggy. Cotton samples were collected and ginned, and the fiber quality was evaluated. Statistical analyses on the effects of irrigation and nitrogen on the yield and fiber quality indicated that irrigation increased cotton yield by 14%. Leaf N content varied in a range of 3.27% to 5.86% with an average of 4.34% at early bloom stage. Yield showed a positive linear correlation with leaf N content in both the irrigated plots (r2=0.46) and the non-irrigated plots (r2=0.36). Irrigation improved fiber quality, including all fiber length parameters. Micronaire decreased, and neps and yellowness increased with the increase of leaf N under inrrigated and non-irrigated conditions. Excessive application of N would not be beneficial to fiber quality and could possibly create negative impact on some properties of cotton fibers such as nep content and color grade.