1/15/2019
1
Basic Soil Physics forSports Turf and Golf Courses
Dr. Phil Busey, CCA, [email protected]
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)
1/15/2019
2
1/15/2019
3
1/15/2019
4
DCBA
SOIL TEXTURE (SIZE DISTRIBUTION OF PARTICLES)
Phil Busey, [email protected]
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
USDA system from: Brady and Weil. 2008. The nature and properties of soil, 14th edition.
} Total fines
1/15/2019
5
SOIL PARTICLE SIZE DISTRIBUTION,SOIL PORE SIZE, AND SOIL WATER
Phil Busey, [email protected]@philbusey.com
1/15/2019
6
SpectrumFieldScoutTRD 300
1/15/2019
7
ULTIMATELY
Phil Busey, [email protected]@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
1/15/2019
8
SOIL TEXTURE (SIZE DISTRIBUTION OF PARTICLES)
Phil Busey, [email protected]
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
USDA system from: Brady and Weil. 2008. The nature and properties of soil, 14th edition.
} Total fines
SOIL PHYSICAL FACTORS – 2 BIGGIES
Phil Busey, [email protected]
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
1/15/2019
9
VARIATION IN ORGANIC MATTER SOURCES
Phil Busey, [email protected]
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
COMPARISON OF 4 SOILS
Phil Busey, [email protected]@philbusey.com
1/15/2019
10
AppearanceSOIL PHYSICS AND HEALTHY TURF
Phil Busey, [email protected]@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
1/15/2019
11
< 1 < 1
5.6 3.0
Saturated hydraulicconductivity (inches/hour) MORE SOIL PHYSICAL ANALYSIS
Phil Busey, [email protected]@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, [email protected]@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
1/15/2019
12
CAN WE SPECIFY THE RIGHT SOIL MIX?
Phil Busey, [email protected]
“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.
DANGER OF MUCK
Phil Busey, [email protected]
“ . . . 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.
A SURPRISING OBSERVATION
Phil Busey, [email protected]
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.
1/15/2019
13
EFFECTIVE CORE CULTIVATION
Phil Busey, [email protected]@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
1/15/2019
14
