Location: Sugarcane ResearchTitle: Effect of potassium fertilizer application on the yield and quality of current sugarcane varieties in Louisiana
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/2017
Publication Date: 6/14/2017
Citation: Johnson, R.M. 2017. Effect of potassium fertilizer application on the yield and quality of current sugarcane varieties in Louisiana [abstract]. Journal of the American Society of Sugar Cane Technologists. 37:53.
Technical Abstract: For many sugarcane producers in Louisiana the only fertilizer that is routinely applied to their crop is nitrogen that is side-dressed in the spring. This is due, primarily to the high cost of potassium and phosphorus fertilizers. Recent cooperative research conducted between the USDA/ARS Sugarcane Research Unit and the LSU AgCenter has demonstrated that the yield benefits due to phosphorus fertilizer are small; thus justifying the omission of phosphorus. However, the yield benefits due to potassium fertilizer in Louisiana sugarcane has not been reported in over 30 years. Preliminary research conducted by the USDA/ARS, Sugarcane Research Unit has suggested that potassium fertilizer application may have positive cane and sugar yield benefits with current varieties. The objective of this study was to evaluate the effects of potassium fertilizer on the cane and sugar yields of plant and stubble fields of HoCP 96-540 and L01-299 on light and heavy soil in Louisiana. A series of experiments was conducted on light (silt loams) and heavy soils (silty clay loams and clays) on plant-cane and stubble fields of HoCP 96-540 and L01-299. All of the sites selected for the studies tested medium, low or very low for potassium. Five potassium rates were applied to each field ranging from 0 to 160 lbs K2O/A. All plots were harvested with a chopper harvester and weigh wagon equipped with a billet-sampler to collect samples for juice quality analysis. In 2014, in plant-cane L 01-299, a trend showed an increase in cane and sugar yields in both light and heavy soils with applied potassium, although it was not significant (P=0.05). The trend was more pronounced in heavy soils. In plant-cane HoCP 96-540, trends (not significant P=0.05) were also observed showing increases in both cane and sugar yield with applied potassium. In 2015, in first-stubble fields of L 01-299 a trend showed an increase in sugar yields with applied potassium in both light and heavy soils; the trend was significant for sugar yields in the heavy soil test (P=0.05). In first-stubble fields of HoCP 96-540, a trend showing an increase in cane and sugar yield was observed in the light soil test; there was not a trend evident in the heavy soil test. In 2016, in second-stubble fields of L 01-299, a trend showing an increase in cane and sugar yield was observed in the light soil test; this trend was significant for cane yields (P=0.05) and sugar yields (P=0.15). There was not a trend evident in either cane or sugar yields for the heavy soil test. In second stubble fields HoCP 96-540 a trend showed an increase in both cane and sugar yields with potassium in light and heavy soil tests; however, this trend was not significant (P=0.05). Soil samples that were collected in before and after potassium application to determine residual potassium showed an increase in potassium levels in the majority of studies. Results from these studies demonstrate that increases in both cane and sugar yields can be achieved with potassium fertilizer application in both plant-cane and ratoon fields of two of the major Louisiana sugarcane varieties in both light and heavy soils. Louisiana sugarcane producers that have eliminated potassium from their soil fertility programs may experience decreases in their cane and sugar yields as potassium levels fall to limiting levels. Further research should be conducted to confirm and expand the results of these studies to more varieties and soil types.