Fields we want Fields we don’t want (The difference due ... · The nature and properties of soil,...

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Basic Soil Physics forSports Turf and Golf Courses

Dr. Phil Busey, CCA, CPAgphil@philbusey.com

forFlorida Turfgrass Association Regional Turf

Seminars at Jacaranda Country Club 15 Jan 2019and Lake Worth Polish American Club 16 Jan 2019

by

Fields we want Fields we don’t want

(The difference duelargely to base soil)

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DCBA

SOIL TEXTURE (SIZE DISTRIBUTION OF PARTICLES)

Phil Busey, turf@ufl.edu

Separates Particles diameters:Gravel > 2 mmVery coarse sand > 1 mmCoarse sand > 0.5 mmMedium sand > 0.25 mmFine sand > 0.10 mmVery fine sand > 0.05 mmSilt >0.002 mmClay < 0.002 mm

phil@philbusey.com

USDA system from: Brady and Weil. 2008. The nature and properties of soil, 14th  edition. 

} Total fines

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SOIL PARTICLE SIZE DISTRIBUTION,SOIL PORE SIZE, AND SOIL WATER

Phil Busey, turf@ufl.eduphil@philbusey.com

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SpectrumFieldScoutTRD 300

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ULTIMATELY

Phil Busey, turf@ufl.eduphil@philbusey.com

• A healthy soil allows roots to breath and get water• Fines conspire and dominate; amending with sand 

to improve drainage is generally futile• Soil is very, very complicated and there are major 

myths and major mistakes• Terms infiltration, percolation, and leaching, have 

different and specific meanings• Drainage may mean somewhat different things• Ultimately, soil physics is about water and strength

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SOIL TEXTURE (SIZE DISTRIBUTION OF PARTICLES)

Phil Busey, turf@ufl.edu

Separates Particles diameters:Gravel > 2 mmVery coarse sand > 1 mmCoarse sand > 0.5 mmMedium sand > 0.25 mmFine sand > 0.10 mmVery fine sand > 0.05 mmSilt >0.002 mmClay < 0.002 mm

phil@philbusey.com

USDA system from: Brady and Weil. 2008. The nature and properties of soil, 14th  edition. 

} Total fines

SOIL PHYSICAL FACTORS – 2 BIGGIES

Phil Busey, turf@ufl.edu

Soil particle size Sand, silt, clay, and sand sieve classesUSGA root zones coarse + medium sand > 60%Fines (very fine sand + silt + clay) < 10%

Organic matter Can improves soil structure (floccules) and increase nutrient and moisture retention, stabilityCan also impede percolation; should be below about 3% by weightUsing quality peat with bulk density less than 0.15, about 1.5% by weight or 7.5% to 15% by volume may be suitable

phil@philbusey.com

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VARIATION IN ORGANIC MATTER SOURCES

Phil Busey, turf@ufl.edu

OM content % If amended in new root zone, USGA specifications require minimum 85%

Fiber content Not often measured. Correlates with OM content. Higher values, e.g., >67% (fibric), considered more valuable; hemic is suitable and higher bulk density; sapric (muck) undesirable.

Bulk density Determines the effective mixing ratio, dry weight divided by volume; tends to be inversely correlated with organic matter content

Other considerations

Organic matter sources can be quite variable; compost may have larger particles which may be more desirable in some cases inorganic soil amendments also have desirable characteristics

phil@philbusey.com

COMPARISON OF 4 SOILS

Phil Busey, turf@ufl.eduphil@philbusey.com

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AppearanceSOIL PHYSICS AND HEALTHY TURF

Phil Busey, turf@ufl.eduphil@philbusey.com

Turf Soil

Particle size A B C D

Sand (%) 96.9 92.1 81.4 69.4

Silt (%) 2.6 6.2 15.2 22.8

Clay (%) 0.5 1.1 2.7 6.6

DCBA

3.2% 12.9%

0.8 % 2.5%

Organic matter

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< 1 < 1

5.6 3.0

Saturated hydraulicconductivity (inches/hour) MORE SOIL PHYSICAL ANALYSIS

Phil Busey, turf@ufl.eduphil@philbusey.com

• Texture (sand, silt, clay particle sizes, including sand sieve sizes)

• Porosity (macro or air‐filled vs. micropores)• Organic matter (very complex)• Bulk density• Hydraulic conductivity  ‐ how easily water 

flows through soil pores (if saturated, Ksat)

SOIL PHYSICS AND HEALTHY TURF

Phil Busey, turf@ufl.eduphil@philbusey.com

Sample Location A B C D Goal

Saturated conductivity (in/hr) 5.6 3 < 1.0 < 1.0 > 3

Moisture retention (%) 22 30.4 29.8 57.6 14 to 20

Air filled pore space (%) 4.6 2.5 9.3 2.7 18 to 25

Bulk density (g/cc) 1.59 1.43 1.33 0.95 1.2 to 1.6

Organic matter (%) 0.8 2.5 3.2 12.9 < 3

Very fine sand + Silt + Clay 20.5 33.9 38.3 45.2 < 25

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CAN WE SPECIFY THE RIGHT SOIL MIX?

Phil Busey, turf@ufl.edu

“So although it is difficult to surmise a precise rule of organic amendment incorporation to achieve the benchmark CP (capillary porosity) value it generally appears that 10% to 20% by volume of sphagnum peat or quality compost and 5% to 10% of a reed-sedge peat is appropriate for most root zone sands.”

McCoy, Edward L. 2013. Commercial amendments for sand-based root zones: Review and interpretation. HortTechnol. 23:803-813.

phil@philbusey.com

DANGER OF MUCK

Phil Busey, turf@ufl.edu

“ . . . less fibrous, hemic organic amendments can result in dangerously low air-filled porosity and Ks values when blending errors result in excessive OM contents, making fibricpeats preferable”

McCoy, Edward L. 2013. Commercial amendments for sand-based root zones: Review and interpretation. HortTechnol. 23:803-813.

phil@philbusey.com

A SURPRISING OBSERVATION

Phil Busey, turf@ufl.edu

At Rutgers, 7 years following establishment,

“ . . . turfgrass quality with inorganic amendments equaled or exceeded that of the organic amendments with the exception of biosolids compost”

McCoy, Edward L. 2013. Commercial amendments for sand-based root zones: Review and interpretation. HortTechnol. 23:803-813.

phil@philbusey.com

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EFFECTIVE CORE CULTIVATION

Phil Busey, turf@ufl.eduphil@philbusey.com

• 2 to 6 times per year• Soil exposed should be 3.5 to 10% of area• Prefer 2.5 to 4 inches penetration• Area and depth determine enhancement of diffusion• During times of peak shoot and root growth• Be careful at times of peak goosegrass germination• Prefer cam (vertical tines) over drum• Prefer closed hollow tines over open spoon tines• Not a panacea if soil is not right

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