What kind of soils produce the best turf today? Micah Woods Chief Scientist Asian Turfgrass Center www.asianturfgrass.com November 6, 2019 

1. Which data will we look at? 2. How will we look at the data? 3. Implications for pH, OM, K, P, Ca, Mg, salinity, micronutrients, and N 

Which data will we look at? 

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GSS kit, good performing turf 

GSS sample locations, 2013 to 2016 

Samples collected from good performing turf 

How will we look at the data? 

Golf scores as an example Ile aux Cerfs Golf Club, Mauritius 

87 92 86 81 87 83 86 91 86 84 82 84 86 88 90 92 18 hole score 10 random golf scores 

82 84 86 88 90 92 18 hole score Dotplot of 10 random golf scores 

0 1 2 3 80 82 84 86 88 90 92 18 hole score count bin width = 1 Histogram of 10 random golf scores 

0 1 2 3 4 5 80 82 84 86 88 90 92 94 18 hole score count bin width = 3 Histogram of 10 random golf scores 

87 92 86 81 87 83 86 91 86 84 88 86 81 84 87 86 87 80 88 81 81 89 87 89 75 81 86 85 87 81 90 82 83 84 87 94 84 92 81 85 88 93 80 83 82 81 92 85 79 89 81 83 87 80 96 79 83 82 87 84 86 82 85 89 88 87 81 76 86 84 91 82 84 81 74 78 84 81 83 91 88 87 91 84 86 88 83 87 87 87 86 89 81 78 82 78 91 89 90 83 74 76 78 80 82 84 86 88 90 92 94 96 18 hole score 100 random golf scores 

74 76 78 80 82 84 86 88 90 92 94 96 18 hole score Dotplot of 100 random golf scores 

0 5 10 74 76 78 80 82 84 86 88 90 92 94 96 18 hole score count bin width = 1 Histogram of 100 random golf scores 

0 10 20 30 74 76 78 80 82 84 86 88 90 92 94 96 98 18 hole score count bin width = 3 Histogram of 100 random golf scores 

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Implications for pH, OM, K, P, Ca, Mg, etc. 

median: 6.5 min: 4.6, max: 8.2 0 5 10 15 20 25 5 6 7 8 Soil pH in 1:1 H2O count pH 

median: 1.76 min: 0.17, max: 10.15 0 5 10 15 20 0.0 2.5 5.0 7.5 10.0 Soil organic ma er percent by weight count OM, all samples Loss on ignition at 360 C 

median: 1.44 min: 0.17, max: 4.69 0.0 2.5 5.0 7.5 10.0 0 1 2 3 4 Soil organic ma er percent by weight count OM, pu ing green samples Loss on ignition at 360 C 

▶ Soil organic matter is about 5% N. From 1 to 4% of that N is expected to become plant available each year. ▶ That gives an estimate of about 0.4 lbs N/1000 ft2 expected release each year from the top 4 inches of soil for each 1% of soil organic matter. ▶ With the average OM in putting green soils, N release is expected to be about 0.6 lbs N/1000 ft2. 

median: 60 min: 10, max: 296 0 5 10 15 20 25 0 100 200 300 Soil K in ppm count Potassium Mehlich 3 extraction 

median: 60 min: 10, max: 296 86 percent below 0 5 10 15 20 25 0 100 200 300 Soil K in ppm count Potassium Mehlich 3 extraction 

Soil K about 60 ppm 

median: 68 min: 6, max: 450 38 percent below 0 10 20 30 0 100 200 300 400 Soil P in ppm count Phosphorus Mehlich 3 extraction 

median: 585.5 min: 125, max: 2844 58 percent below 0 5 10 15 20 0 1000 2000 3000 Soil Ca in ppm count Calcium Mehlich 3 extraction, calcareous samples removed 

median: 74 min: 23, max: 516 79 percent below 0 10 20 30 0 100 200 300 400 500 Soil Mg in ppm count Magnesium Mehlich 3 extraction 

median: 0.66 min: 0.5, max: 1.5 100 percent below 0 10 20 30 40 0.0 0.5 1.0 1.5 2.0 Soil salinity (EC) in dS/m count Soil salinity saturated paste equivalent from 1:2 soil:water 

median: 6.7 min: 0, max: 26 98 percent below 0 5 10 15 20 25 0 10 20 Nitrate + ammonium in ppm count Available nitrogen 

Micronutrient median values • Iron: 198 ppm • Manganese: 27 ppm • Zinc: 6 ppm • Copper: 3 ppm • Boron: 0.4 ppm 

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