The application of manganese (Mn) has long been one of those things that superintendents do, just as a sort of “safety” application. Interestingly, very little research has examined the impact of applied manganese, be it for improved color or disease suppression, which are usually the two supposed reasons for applying manganese.
A key paper exploring manganese fertilization was authored by Joseph Heckman, Ph.D., and colleagues at Rutgers, who examined rates and timing of manganese application for the suppression of foliar symptoms of take-all patch disease [Gaeumannomyces graminis (Sacc.) Arx. & D. Olivier var. avenae (E.M. Turner) Dennis].
In the study, manganese was applied at different rates and times of year throughout a two-year period on a Penncross/Penneagle creeping bentgrass fairway that had natural infection of take-all patch. Rates of manganese were 0, 0.05, 0.09, 0.14 and 0.18 pound Mn/1,000 square feet (0, 2.25, 4.50, 6.75 and 9.00 kilograms/hectare), with the manganese applied only once to each experimental plot throughout the study. These rates were applied on the first of the month in April or October in 1998, 1999 and 2000.
The manganese source was manganese sulfate, applied in a solution to deliver 0.9 gallon/1,000 square feet (374 liters/hectare), with irrigation withheld for 24 hours after application. It was noted that summer application was avoided because previous work with summer application had resulted in foliar injury.
The application of manganese reduced the severity of take-all patch, and this happened in every year of the study. The lowest rate of manganese (0.05 pound/1,000 square feet) was usually as effective in suppressing manganese as the higher rates. However, when disease pressure was high or soil test manganese was low (<21 milligrams/kilogram Mehlich-3 extractable Mn), a higher rate of manganese (6.75 kilograms Mn/hectare) was needed for more effective control.
Timing of the manganese application was also important. In general, more recent application of manganese was more effective in suppressing foliar symptoms of take-all patch. When the manganese fertilizer had been applied a year or more before, suppression of foliar symptoms of take-all was not as effective. This was thought to be partly a result of clipping removal, as the foliar-applied manganese was removed with collected clippings.
It was also noted that the disease organism oxidizes manganese, altering the form(s) available for plant uptake. Thus, reapplication of foliar manganese may be needed for effective suppression of take-all patch.
Typically, application of any rate of manganese reduced severity of take-all patch by 20% compared with the untreated control plots. For example, in May 2000, the percent of the area infested with take-all patch was reduced from 37% to 16%. The authors recommended that manganese could be applied at 0.05 pound Mn/1,000 square feet every 12 to 18 months to maintain suppression of foliar symptoms of take-all patch on creeping bentgrass.
Source: Heckman, J.R., B.B. Clarke and J.A. Murphy. 2003. Optimizing manganese fertilization for the suppression of take-all patch disease on creeping bentgrass. Crop Science 43:1395-1398.
Heckman, J.R., I.A. Thompson and D.M. Huber. 2020. Manganese and plant disease. In: L.E. Datnoff, W.H. Elmer and D.M. Huber, editors. Mineral nutrition and plant disease. APS Press, St. Paul, Minn. (In press)
Hill, W.J., J.R. Heckman, B.B. Clarke and J.A. Murphy. 1999. Take-all patch suppression in creeping bentgrass with manganese and copper. HortScience 34:891-892.
Editor’s note: Read all of Beth Guertal’s recent Verdure columns.
Beth Guertal, Ph.D., is the Rowe Professor of Soil Fertility in the Department of Crop, Soil and Environmental Sciences at Auburn University in Auburn, Ala., and past president of the Crop Science Society of America. She is a 22-year member of GCSAA.