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Investigation of Soil Amendments for Use in USGA Putting Greens. T.W. Shaddox. Problem Assessment. Droughts from 1997 to 2000 have brought about consumptive use permits for many superintendents Superintendents have less water to maintain the same quality turfgrass. Case Study.
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Investigation of Soil Amendments for Use in USGA Putting Greens T.W. Shaddox
Problem Assessment • Droughts from 1997 to 2000 have brought about consumptive use permits for many superintendents • Superintendents have less water to maintain the same quality turfgrass
Case Study • Colbert Hills GC – Manhattan, KS (Fry, 2002) • 120 million gallons year-1 = 374 acre feet • 374 / 365 days ≈ 1 acre foot day-1 • 1 acre foot / 150 acres = 0.08 inches day-1 !!
Problem Assessment • Greens receive 2-3 X more N than Fairways • Greens typically receive daily irrigation • Low nutrient retention in sand-based greens • 27% of applied P may leach (Shuman, 2001) • 56% of applied N may leach (Snyder, 1984)
Surfactant • HDTMA CH3(CH2)15N(CH3)3
26-28 Å Sorption Process
Objective:To determine the influence of soil amendments and incorporation method on water use efficiency (WUE) of Tifdwarf bermudagrass Ho: Soil amendments and incorporation method do not increase Tifdwarf WUE above sand:peat
Objective:To determine the influence of surfactant-modified amendments (SMSAs) on N and P leaching in a simulated USGA putting green Ho: SMSAs do not reduce N and P leaching in USGA putting greens
Materials and Methods Water Use
Methods • All pots in each study were maintained at 90% pot capacity • Sprigged with Tifdwarf • Pots were havested and weighed weekly for 18 weeks • WUE = dry matter / applied water • Turf Quality taken weekly (1 to 9) • 10 trts 4 reps RCBD • Duncans MRT α = 0.05
Incorporation Method Mixed Profile (85:15) • Aerification (50:50) • 9 Cores • 4 Cores Sand + Amendment Sand + Peat
Materials and Methods N and P leaching
PUMP H2O 30 cm 5 cm 2.54 cm Materials and Methods • Columns • Pb = 1.5 g cm-3 • pH = 7.1 • Injection Solution • pH = 2.5 • NO3-N = 2300 ppm • NH4-N = 2480 ppm • P = 4400 ppm • 10 mL Pump H2O 30 cm Sand/Peat Treatment Layer 5 cm 2.5 cm
Materials and Methods • Treatments: • Sand • Sand/Peat • Ecosand • Soil Master • Profile • HDTMA Ecosand • HDTMA Soil Master • HDTMA Profile • Treatment = 8 • Rep = 3 • Duncans MRT α = 0.05
Results Water Use
Turf Quality Full Incorporation a minimum acceptable quality b b c c c c d d e CV = 4.3
Turf Quality 9 Tine Aerification minimum acceptable quality a b bc bc cd de de de ef f CV = 1.9
Turf Quality 4 Tine Aerification minimum acceptable quality a b bc bc bcd d d cd d d CV = 1.8
WUE Full Incorporation a a ab ab b b c c d d CV = 6.8
WUE 9 Tine Aerification a b bc bc bc bc bc bc c c CV = 8.3
WUE 4 Tine Aerification a b b b b b b b b b CV = 9.2
WUE by Incorporation Method CV = 3.5
WUE Summary • Only CCs and Fe Humate increased turf quality • Individually, PAW and CEC are not good indicators of an amendment’s influence on WUE • Fe Humate, CCs, and diatomaceous earths increased WUE above peat • Fe Humate produced the greatest increase in WUE • Amendment influence was decreased after aerification
WUE Conclusion • WUE • Reject Ho and conclude: • Calcined clays, Diat. Earths, smectite, and Fe Humate increased Tifdwarf WUE above sand:peat • Quality • Reject Ho and conclude: • Calcined clays and Fe Humate increased Tifdwarf quality above sand:peat
Practical Implications • When WUE and turf quality are of concern, calcined clays and fe humate are plausible options to peat
Results N and P Leaching
NO3--N Breakthrough Curves Sand Sand/Peat HDTMA-Soil Master AEC = 11.3 Soil Master HDTMA-Profile AEC = 9.7 Profile HDTMA-Clinoptilolite AEC = 4.1 Clinoptilolite
Total NO3-N Leached CV = 9.8 Columns with same letter are not significantly different according to DMRT > 0.05
NH4+-N Breakthrough Curves Sand Sand/Peat HDTMA-Soil Master AEC = 11.3 Soil Master HDTMA-Profile AEC = 9.7 Profile HDTMA-Clinoptilolite AEC = 4.1 Clinoptilolite
Total NH4-N Leached CV = 12.9 Columns with same letter are not significantly different according to DMRT > 0.05
P Breakthrough Curves Sand Sand/Peat HDTMA-Soil Master AEC = 11.3 Soil Master HDTMA-Profile AEC = 9.7 Profile HDTMA-Clinoptilolite AEC = 4.1 Clinoptilolite
Total Phosphorous Leached CV = 6.9 Columns with same letter are not significantly different according to DMRT > 0.05
Leaching Summary • Uncoated amendments: • did not retard or decrease NO3- leaching • eliminated NH4+ leaching • retarded but did not decrease P leaching. • SMSAs reduced NO3-, NH4+, and P leaching
Leaching Conclusion • Reject Ho and conclude: • SMSAs reduce N and P leaching
Future Research • Long-term influence on leaching and stability • Microbial degradation • Influence on turf growth
Acknowledgments • Committee • Jerry Sartain (Chair) • Donald Graetz • Peter Nkedi-Kizza • James Bonczek • Grady Miller • SWSD Grad Students • E. Brown, R. Snyder, K. Makris • Lab Personnel • Ed Hopwood, Nahid Varshovi, Shawron Weingarten, Brian Owens, Martin Sandquist • Florida Turfgrass Association