Location: Sugarcane ResearchTitle: Effect of foliar application of glyphosate and cobalt on sugarcane yields and quality Author
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/2017
Publication Date: 6/14/2017
Citation: Da Silva, D.P., Richard, K.A., King, B.G., Johnson, R.M. 2017. Effect of foliar application of glyphosate and cobalt on sugarcane yields and quality [abstract]. Journal of the American Society of Sugar Cane Technologists. 37:39-40.
Technical Abstract: Sugarcane is one of the principal crops of the world, and is used in the production of sugar, alcohol and clean energy. In many sugarcane producing regions of the world selected herbicides, insecticides and fungicides are being evaluated for their potential bioactivator effects on sugarcane yields. The potential bioactivator effects of glyphosate have not been reported in Louisiana. In addition, the effects of foliar cobalt applications on sugarcane yields have also not been reported. The objective of this work was to determine the influence of foliar applications of glyphosate and cobalt, applied alone and in combination, on sugarcane productivity. The experiment was conducted in a 3rd ratoon field of HoCP 96-540 and was designed as a randomized complete block design with 4 replications and a plot size of 3 rows (5.5 m) by 12 m. The nine treatments were: 1) Control, 2) Keylate Cobalt 0.6 l/ha, 3) Keylate Cobalt 1.2 l/ha, 4) Keylate Cobalt 1.8 l/ha, 5) Keylate Cobalt 2.4 l/ha, 6) Glyphosate 0.19 l/ha, 7) Glyphosate 0.19l/ha + Keylate Cobalt 0.6 l/ha, 8) Glyphosate 0.19 l/ha + Keylate Cobalt 1.2 l/ha, and 9) Glyphosate 0.19 l/ha + Keylate Cobalt 1.8 l/ha. Treatments were applied 90 days before the plots were harvested. Sugarcane productivity was measured by determining the number of stalks of cane per hectare, tons cane/hectare, theoretical recoverable sugar, and sugar yield per hectare. Sugar quality was estimated by conducting a pre-breaker/press analysis of a subsample of the harvested stalks and determining the levels of fiber, purity, brix (percent soluble solids), and sucrose. Cobalt application increased cane (8-17%) and sugar (14-17%) yields when compared with the control, although the results were not significantly different (P=0.05). When low levels of glyphosate were applied to the plots, yields were significantly decreased, with cane yields decreasing by 50% and sugar yields by 60%, when compared to the control. However, when cobalt was combined with glyphosate, the effects on yields were decreased, with the high rate of cobalt increasing both cane and sugar yields to levels nearly equivalent to the untreated control. These results would suggest that foliar applications of cobalt may increase sugarcane yields when cobalt is applied alone. Glyphosate did not appear to have any bioactivator benefits and actually decreased sugarcane yields; however, cobalt appeared to mitigate these effects suggesting that cobalt may have a role in helping plants to manage external stress sources.