Turfgrass Growth and Water Use in Gypsum-Treated Ultisols M.J. Schlossberg Penn State University
Turfgrass and the SE US Bermudagrass and Tall Fescue dominate the landscape of the US Southern Piedmont (GA, AL, and the Carolinas)
Turfgrass and the SE US Interestingly: • Bermudagrass and Tall Fescue are the two turfgrasses recognized for generating the most deeply-extending root systems of ALL turfgrass species.
Soil chemical or soil physical problem? Turf-type tall fescue roots Gypsum Control 0-3.5 ” 3.6-7 ” 7-11 ”
Treatment Options??? • Lime • Agricultural grade limestone is an effective ameliorant of soil acidity • Commonly incorporated at establishment for production of cotton, soybean, corn, peanuts, etc. • INCORPORATE is the key word, effective treatment of soil acidity with lime requires tillage into the soil profile
How Do Turf Managers Like Incorporating Lime? They don’t. Turfgrasses are perennial in nature and establishment is not only uncommon, but dreaded! So how can managers ameliorate the effects of acidity without plowing the lawn?
Gypsum • Many attributes: • More soluble than agricultural lime • Doesn’t require tillage or coring • Doesn’t raise pH of the surface soil • This can cause soil structure and turf disease problems • Provides sulfate (SO4), the plant essential nutrient form of sulfur
ZnO2 paint Fescue columns (33cm)
Tall fescue root growth column study c c b b b b a a a
Greenhouse Experiment Objectives 1. Construct columns which represent soil profiles indigenous to the SE US. 2. Analyze leachate to confirm calcium sulfate penetration of subsoil, displacement of Al, and/or other soil chemistry alterations. 3. Use installed instrumentation to monitor water extraction from acidic subsoil by roots, by depth. 4. Simulate drought periods repetitively; mimicking rain patterns, while promoting deep rooting in columns 5. Analyze columns to assess root architecture and calcium saturation of CEC by soil depth.
ExperimentalDesign Acidic B Horizon Clay pH w(1:1) 4.9 Exch. Acid 3.9 meq/100g Mehlich III (M3) exchangeable: Phosphorus (P) 2.0 lbs/A Potassium (K) 0.04 meq Magnesium (Mg) 0.25 meq Calcium (Ca) 0.65 meq Total CEC: 4.84 meq 8 cm 54 cm
ExperimentalDesign Acidic B Horizon Clay pH w(1:1) 4.9 Exch. Acid 3.9 meq/100g Mehlich III (M3) exchangeable: Phosphorus (P) 2.0 lbs/A Potassium (K) 0.04 meq Magnesium (Mg) 0.25 meq Calcium (Ca) 0.65 meq Total CEC: 4.84 meq
ExperimentalDesign Treatments (5): • Synthetic/FGD Gypsum (Southern Co.) • Tech. Grade Gypsum (CaSO4•2H2O) • Calcium Chloride (CaCl2•2H2O) • Calcitic Lime (100% CCE) • Control 90 columns total; 60 Bermudagrass (‘Princess’ or ‘Sultan’) and 30 turf-type Tall Fescue ‘Rebel’ Half of each instrumented for real-time soil moisture, three replications of six
ExperimentalDesign The Southern Co. SynGyp, is generated by a ‘wet’ spray-dryer scrubbing process, and contains 23.3% Ca by mass (+/- 0.65), and has a calcium carbonate equivalency of 2.7% (+/- 0.14). Trace element and heavy metal analysis show few impurities
ExperimentalDesign The Southern Co. SynGyp is 23.3% Ca by mass (+/- 0.65), and has a calcium carbonate equivalency of 2.7% (+/- 0.14). Trace element and heavy metal analysis show few impurities Application Rates Treatment lbs/Acre (Ca) Lime 4,332 (1,735) FGD and TG Gypsum 13,796 (3,224) CaCl2 11,825 (3,224)
ExperimentalDesign The Southern Co. SynGyp is 23.3% Ca by mass (+/- 0.65), and has a calcium carbonate equivalency of 2.7% (+/- 0.14). Trace element and heavy metal analysis show few impurities Application Rates Treatment Mg/ha (Ca) Lime 4.86 (1.94) FGD and TG Gypsum 15.46 (3.61) CaCl2 13.25 (3.61)
Cultural Methods TF columns mowed every 9±3 days @ 3” height No signs/symptoms of pest activity observed over the 2-year study, hence no pesticides were applied (tall fescue is good like that) When >half the TF columns showed stunted growth & leaf firing, all were irrigated with 4” in 1” pulses over 24 hours (every 20-35 days) Post-estab: ¼ lb N & K2O / 1000 ft2 / month
Cultural Methods Bermudagrass columns mowed every 7±3 days @ 1.4” height Insect activity was chemically controlled when necessary When >half the bermuda columns showed stunted growth/dormancy, all were irrigated with 4” in 1” pulses over 24 hours (every 30-50 days) Post-estab: ¾ lb N & K2O / 1000 ft2 / month
Leaf/shoot biomass production(generally analogous with quality/vigor)
Tall Fescue H2O-use by depth over (14) 10-35 d dry down periods cm water / day