Soil Amendment by Ca- and Mg-Silicates and Perennial Ryegrass Wear Resistance

By Derek Pruyne, MS Agronomy ’14; Max Schlossberg, Assoc. Prof. Turfgrass Nutrition; and Wakar Uddin, Prof. Turfgrass Pathology; Center for Turfgrass Science, Pennsylvania State Univ.

While not recognized as a plant essential nutrient, silicon (Si) accumulates in epidermal and vascular tissue of grasses. A field study of ‘CrossOver’ Ca/ Mg-silicate (SiO 3 ) pelletized soil conditioner/liming agent (Harsco Minerals Intl., Sarver, PA) was conducted on a neutral perennial ryegrass field within the J. Valentine Turfgrass Research Center (University Park, PA). Plots were trafficked weekly by a dedicated wear simulator, June through Sept. Multispectral radiometric canopy quality measures, clipping yield, clipping/tissue composition, soil pH, and plant-available soil Si levels from the 0–3" and 3–6" depths were regularly collected over the two-year study. Similar multiyear field experiments, employing identical products and methods on creeping bentgrass fairways and putting greens, were inconclusive. However, perennial ryegrass plots under intense wear/ traffic and treated annually by granular application of Ca/ Mg-silicates at 25 or 50 lbs per 1000 ft 2 , showed significantly improved mean canopy quality relative to adjacent plots receiving equal Ca and Mg as lime. This improved canopy density and color coincided with acetic-acid-extractable soil Si levels >70 ppm in the 0–3" soil depth. Further field trials are being initiated on perennial ryegrass and turf-type tall fescue to confirm these results and identify a critical leaf Si concentration for improved wear tolerance.