Wisconsin Turf study
Deicer Effects on Kentucky Bluegrass Turf
Wayne R. Kussow
Department of Soil Science
PURPOSE
The purpose of the study was to observe the effects of several deicing products on turfgrass. The study was initiated in mid-March, by which time the turf was free of snow and ice, and in a semi-dormant state.
EXPERIMENTAL METHODS
Quantities of the deicers corresponding to the recommended and twice the recommended single-time application rates were dissolved as completely as possible in 5L water and applied with a sprinkling can to duplicate 3 ft x 3 ft. areas of the turf. This volume of water approximates that from a 1/4-inch ice sheet. The turfgrass was the visually inspected over a 50-day period and rated for any damage observed and color development.
RESULTS
None of the deicing treatments caused foliage burn. Early in the study, when the soil was subject to freeze-thaw cycles, some soil heaving was observed in the NaCl and KCl treatments (Table 1). This did not seem to have a negative impact on turf quality.
The making deicer effect on the turfgrass was some delay in color development (Table 1). This was most noticeable during the April 18 to 22 period. The least impact on turfgrass was observed when MgCl2 was applied, while Safe Step was most detrimental deicer, but the reduced color development would not have been noticeable without side-by-side comparisons with the other treatments.
Soil samples were collected to a 6-inch depth in each plot in mid-May and analyzed for exchangeable cations and soluble salts. The type of deicer applied understandably determined which exchangeable cations and soluble salts. The type of deicer applied understandably determined which exchangeable cations and soluble salts. The type of deicer applied understandably determined which exchangeable cations were most strongly affected. Application of NaCl, at the 2X rate in particular, elevated exchangeable Na to a level (Table 2) where some concern has to be shown for loss of soil structure stability. Safe Step at the 2x rate resulted in exchangeable Na elevation to the same level as with NaCl at the 1X rate. Application of NaCl, at the 2X rate in particular, elevated exchangeable Na to a level (Table 2) where some concern has to be shown for loss of soil structure stability. Safe Step at the 2X rate resulted in exchangeable Na elevation to the same level as with NaCl at the 1X rate. Application of KCl and Safe Step resulted in very high concentrations of exchangeable K. Had this occurred in an acid soil with low Mf levels, the potential could exist for inducement of a Mg deficiency in the turfgrass.
Soluble salt levels (soil conductivity) were elevated by all of the deicers (Table 2). For turfgrass, only the values of 5.6 and 6.5 mmhos cm-1 observed by all of the deicers (Table 2). For turfgrass, only the values of 5.6 and 6.5 mmhos cm-1 for the 2X rates of NaCl and KCl, respectively, are of some concern. Had we experienced dry weather, a negative impact on the turfgrass could have developed. Of greater concern is the effect these soluble salt levels could have on other plants in landscaped areas. As an example, roses are severely damaged at conductivities of 4 mmhos cm-1.
SUMMARY AND CONCLUSIONS
Under the conditions in which the study was conducted, none of the deicers resulted in discernible tip or leaf burn in the Kentucky bluegrass. Some delay in color development was observed, the greatest amount being at the 2X rates of KCl and Safe Step. The effect of Sate Step on turfgrass color was short-lived and disappeared by early May, while the effect of KCl was still evident at that time.
Safe Step at 2X rate and NaCl at both the 1X and 2X rates increased soil exchangeable Na levels to the point where there is some concern about dispersion of the soil colloids. Only the 2X NaCl and KCl rates resulted in soluble salt levels where some injury to the most salt-sensitive turfgrasses could occur. These products and Safe Step produced soil conductivities of 4.0 and above. The amounts of soluble salts associated with these conductivities are sufficient to cause severe damage in salt-sensitive landscape plants.
The logic that KCl is preferable to NaCl as a deicer because K is an essential plant nutrient was not supported by this study. Extensive use of KCl has the potential of inducing plant damage through nutrient imbalances and/or excessive amounts of soluble salts.