on landscaping , soils, soil amendments and proper seed

ON LANDSCAPING, SOILS, SOIL
AMENDMENTS AND PROPER SEED
ESTABLISHMENT (BOTH GRASS
LAWNS AND MEADOWS).
John D. Chibirka
USDA-NRCS Resource Soil Scientist
1238 County Welfare Road, Suite 220
Leesport, PA 19533-0520
(610) 372-4655 x112
(610) 371-8640 fax
[email protected]
Topics
• Topsoil properties & why vegetation needs
topsoil for “permanent” growth
• The importance of Soil Health
• Post-development soil properties
• Soil restoration and the BMP manual
Topsoil properties &
why vegetation needs
topsoil for
“permanent” growth
Topsoil is: The mineral surface
layer of soil that exhibit
obliteration of all or much of
the original rock structure and
must show the following:
(1) an accumulation of
humified organic matter
closely mixed with the
mineral fraction and not
dominated by
properties characteristic
of subsurface horizons;
(2) has reasonable tilth
(biological, chemical and
physical properties) to
support plant growth
Relative Proportion of components
for well-drained soil.
Organic
1-5%
Mineral
45%
Air
20-30%
Water
20-30%
Master Horizons






O horizon
A horizon
E horizon
B horizon
C horizon
R horizon
O
A
E
B
C
R
O horizon
Predominantly organic matter
(litter and humus)
A horizon
Zone of organic matter
accumulation
B horizon
Zone of accumulation (clay, Fe, Al, CaC03, salts…).
Forms below O, A, or E horizon
C horizon
Little or no pedogenic alteration. Unconsolidated
parent material, soft bedrock.
R horizon
hard, continuous bedrock
Back to Topsoil……
and have two or more of the following:
1. A bulk density of less than 1.5g/cc
installed
2. Less than 15 percent by weight coarse
fragments greater than 2mm
3. Identifiable USDA structure, soil clods
called peds, no massive structure
4. No contamination (i.e. Toxic weeds,
chemicals, heavy metals, construction
debris) that inhibit desired plant
growth or human activity.
Requirements
Soil Resource
Min
Max
Oxygen in soil atmosphere (for root survival)
3%
21%
Air pore space (for root growth)
12%
60%
-
93.6 lbs/ft3 (clays)
109.3 lbs/ft3
(sands)
Soil bulk density of the surface 24”
Penetration resistance (moist)‡
Water content
50
lbs/in2
275 lbs/in2 (clays)
300 lbs/in2 (sands)
12%
40%
40°F/4°C
94°F/34°C
5.5
7.5
8 meq/100g
>8 meq/100g
3%
8%
Soil organic matter content of subsoil
-
<1%
Soil coarse fragment content of the surface 6”
(rocks etc. >75mm)
-
<20%
Temperature limits for roots and soil biology
Soil pH
Soil Cation Exchange Capacity (CEC) of the
surface 6”
Soil organic matter content of surface 6” only
Table 2 – Properties for Optimal Plant Growth
Source: developed from Coder, 2000; Craul and Craul, 2006
‡ see Soil texture table from Urban Soil Quality, USDA-NRCS for greater detail
g/cm3
g/cm3
Bulk Densities
that restrict
root
elongation
g/cm3
Sands, loamy sands
<1.60
1.69
1.80
32 – 40%
Sandy loams
<1.40
1.63
1.75
34 – 47%
Sandy clay loams, loams,
clay loams
<1.40
1.60
1.70
36 – 47%
Silt, light silt loams
<1.30
1.60
1.70
36 – 51%
Heavy silt loams, silty clay
loams
<1.10
1.55
1.65
38 – 58%
Sandy clays, sitly clays, clay
loams (35-45% clay)
<1.10
1.49
1.58
40 – 58%
Clays (>45% clay)
<1.10
1.39
1.47
44 – 58%
Soil Texture
Bulk Densities at
Ideal Bulk
which may affect
Densities
root elongation
Table 3 – Typical Soil Density and Porosity Properties for Soil Textures
Source: Modified from “Protecting Urban Soil Quality, USDA-NRCS”
Pore Space
Range
%
THE IMPORTANCE OF
MYCORRHIZAE- GO TO USDA
NRCS SOIL HEALTH PAGE
http://www.nrcs.usda.gov
SOIL HEALTH
INCREASING SOIL ORGANIC MATTER TYPICALLY IMPROVES SOIL HEALTH
SINCE ORGANIC MATTER AFFECTS SEVERAL CRITICAL SOIL FUNCTIONS.
HEALTHY SOILS ARE ALSO POROUS, WHICH ALLOWS AIR AND WATER TO
MOVE FREELY THROUGH THEM. THIS BALANCE ENSURES A SUITABLE
HABITAT FOR THE MYRIAD OF SOIL ORGANISMS THAT SUPPORT GROWING
PLANTS. IT’S NOT DIFFICULT TO IMPROVE SOIL HEALTH. HERE’S HOW: TILL
THE SOIL AS LITTLE AS POSSIBLE; GROW AS MANY DIFFERENT SPECIES OF
PLANTS AS POSSIBLE THROUGH ROTATIONS AND A DIVERSE MIXTURE OF
COVER CROPS; KEEP LIVING PLANTS IN THE SOIL AS LONG AS POSSIBLE
WITH CROPS AND COVER CROPS; AND KEEP THE SOIL SURFACE COVERED
WITH RESIDUE YEAR ROUND.
*this is geared more towards agriculture, not urban soil amendments.
POST-DEVELOPMENT
SOIL PROPERTIES
UNDER POST DEVELOPMENT PROPERTIES, IF A SOIL HAS BEEN SCRAPED,
POUNDED INTO SUBMISSION, THE HSG SHOULD BE A CLASS LESS WHEN MAKING
THE CALCULATIONS.
I HAVE RUN KSAT AT PRINCETON ON SOILS THAT HAVE HAD COMPACTION ISSUES EITHER
THROUGH CONSTRUCTION (MOST COMMON) TO VIBRATION FROM ADJACENT STREETS WHERE
THE KSAT IN THE UPPER 40 INCHES IN VARIOUS LAYERS ARE LESS THAN 0.06 IN/HR. I HAD ONE
THAT WAS 0.001 IN/HR WITH A BD OF 2.11G/CC DRY. MOST OF THE BD WERE AROUND 1.75
TO 1.9 IN MEDIUM TEXTURED SOILS, PLANT ROOTS CANNOT GO THROUGH THAT.
EVEN THOUGH THESE SOILS HAD PORE SPACE, THE PORES WERE NOT
CONNECTED. THE COMPACTION HAD SQUEEZED THE MACROPORES CLOSED AND
THE SMALLER PORES THAT HAD WATER IN THEM DID NOT COMPACT DUE TO THE
INCOMPRESSIBILITY OF WATER.
CRAUL, 2013
SOIL RESTORATION
PENNSYLVANIA STORMWATER BEST MANAGEMENT
PRACTICES MANUAL CHAPTER 6
BMP 6.7.3: SOIL AMENDMENT & RESTORATION
SOIL AMENDMENT AND RESTORATION IS THE PROCESS OF
IMPROVING DISTURBED SOILS AND LOW ORGANIC SOILS BY
RESTORING SOIL POROSITY AND/OR ADDING A SOIL
AMENDMENT, SUCH AS COMPOST, FOR THE PURPOSE OF
REESTABLISHING THE SOIL’S LONG-TERM CAPACITY FOR
INFILTRATION AND POLLUTION REMOVAL.
THE ENTIRE STORMWATER MANUAL IS BEING
REVISED BASED MORE ON SCIENTIFIC REASONING
THAN IN THE PREVIOUS MANUAL. THE COMMITTEE
THAT IS WORKING ON THIS IS ABOUT 140
SCIENTISTS, ENGINEERS, LANDSCAPE ARCHITECTS,
DEP MEMBERS, COUNTY, LOCAL AND CITY
PLANNERS TO MENTION A FEW. THE MANUAL WILL
BE BASED ON PRACTICAL AND PROVEN METHODS TO
REDUCE STORMWATER RUNOFF.
FOR SOIL AMENDMENTS, THERE IS A HOST OF THINGS, THE
MOST IMPORTANT IS THE COMPOST. IT HAS TO BE GOOD
COMPOST, WELL CURED AND BIOLOGICALLY ACTIVE. THE
RATE I USUALLY MIX IN WITH DEGRADED TOPSOIL IS 3.1
CY/1000SQFT (1 INCH OF COMPOST INCORPORATED) OR
FOR SUBSOIL OR SOIL WILL VERY LOW OM CONTENT
(BELOW 1%) I USE 6.3 CY/1000SQFT (OR ABOUT 2
INCHES OF COMPOST INCORPORATED INTO THE UPPER 4-6
INCHES)
[CRAUL AND CRAUL, 2006])
I GUESS THE BOTTOM LINE IS THAT EVERY SITE
IS DIFFERENT AND THE PROCEDURES AND SOIL
AMENDMENTS MUST BE TAILORED TO THE SOIL
PROPERTIES ON SITE AND CANNOT BE GUESSED
AT.
THIS IS WHY SOIL RESTORATION ATTEMPTS ARE
NOT AS SUCCESSFUL WITH A “ONE-SIZE FITS
ALL” SPECIFICATION DOCUMENT
Summary
• Topsoil properties & why vegetation needs
topsoil for “permanent” growth
• The importance of Soil health
• Post-development soil properties
• Soil restoration – BMP Manual
QUESTIONS?