Using elemental sulfur to optimize/lower soil ph of bentgrass putting greens
Open Access
- Author:
- Pruyne, Derek Thomas
- Graduate Program:
- Agronomy
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 11, 2014
- Committee Members:
- Maxim J Schlossberg, Thesis Advisor/Co-Advisor
Andrew Scott Mc Nitt, Thesis Advisor/Co-Advisor
John Earl Watson, Thesis Advisor/Co-Advisor
Armen Ricardo Kemanian, Thesis Advisor/Co-Advisor - Keywords:
- elemental sulfur
calcareous sand
black layer
creeping bentgrass
putting greens - Abstract:
- Soil pH highly influences nutrient availability and root growth during both establishment and maintenance of creeping bentgrass (Agrostis stolonifera L.) putting greens (PGs). The optimal 1:1 soil pH range for creeping bentgrass is 5.5–6.5, yet PG rootzones containing even modest amounts of calcareous sand are often buffered to higher pH values. Furthermore, topdressing sand and/or irrigation water inputs are common sources of added alkalinity. Supraoptimal pH levels have been shown to increase turfgrass disease susceptibility while limiting nutrient availability, root growth, and stress tolerance. The objective of this research was to quantify growth and nutritional status responses of bentgrass PGs to method and/or rate of a single elemental sulfur (So) application. In Sept. 2012, pelletized or flowable So was applied to two internally-drained Penn A-series PGs at rates of 0, 195, 390, 586 kg So ha–1 (0, 4, 8, or 12 lbs So 1000 ft2). Response variables measured over the 2013 season were: clipping yield, canopy color and density, soil pH (by 3 rootzone depth segments), soil extractable nutrients, leaf nutrient content, specific root length, and root length density. Soil pH reductions observed within the surface 5-cm and 5 to 15-cm rootzone depths were highly correlated to So rate. Other response variables significantly influenced by linear So rate include leaf nutrient concentrations (Ca, K, Mg, S, Cu, and Fe) and canopy density. While canopy color, determined by dark green color index (DGCI), was not influenced by linear So rate, there was a significant effect of application method. Several of the described experimental variables measured proved statistically significant; however, observed differences were often marginal. Nutrient levels of all treated and untreated plots remained within the sufficiency range of creeping bentgrass. The most notable nutritional difference was that of leaf Mn concentrations. Mean leaf Mn increased approximately 20-40% in treated plots. Despite frequent visual inspection of the sand rootzone in the months following application, no evidence of black layer (precipitated manganous- or ferrous-sulfide) was observed.