SOIL MANAGEMENT & FERTILIZATION REPORT
Submitted by:
Richell Chiu
John Gimera
Patrick Koebel
Byron Weiker
Josh Williams
CSS 200 - SOILS & PLANT NUTRITION
March 13, 2012 Instructor: Marilyn Alexander
DESCRIPTION OF SITE
The site for the three Soil Management Units included in this report is located at Portland Community
College, Rock Creek Campus in Portland, Oregon. It is in the southwestern area of the campus at the near the
greenhouses, shadehouse and Building 4. On the southeastern side, it is bordered by a gravel road and on the
northeastern side, a paved concrete road. On the northwestern side, it is adjacent to a parking lot. The area is
open and exposed to sun and rainfall.
This whole site receives quite a lot of traffic, creating compaction issues. In most of the turf areas, there
are also drainage issues, with most of the turf in standing water in rainy months.
A variety of evergreen and deciduous trees and shrubs can be found on the site, as well as shrubs and
woody and herbaceous perennial beds. There are also turf areas of perennial ryegrass and a gravel parking lot
within the site. The site has irrigation system in place which is used mostly in the summer months.
SOIL MANAGEMENT UNIT—SHRUB BED I
Rationale for Soil Management Unit
The Shrub Bed I is located on a south facing area, behind Building 4, with a total of 8,560 sq.ft. It is located
adjacent to a gravel road. This site has a relatively flat topography and surrounding trees to give the area some
shade. Plants include deciduous trees, evergreen conifers, shrubs and 1-2” mulch on the topsoil. Based on feel test,
the soil is plastic, mouldable, moist and crumbly with a dark brown color. The soil sample was taken 6-8” depth.
Description of Soil
Consistency (describe) plastic, mouldable, moist, medium, crumbly
Color (Munsell chart) 10 YR, 5/3, Brown
Soil Test Results
Texture Class.
Texture 26.6% sand 60% silt 13.33% clay Silt Loam
Humus (#) 3 (medium in greenhouse/garden soils )
pH (results & average) 6.6pH 5.8pH 5.8pH 6.0pH Average
N-P-K lbs./acre ppm
Nitrogen (N) 20 10
Phosphorus (P) 200 100
Potassium (K) 375 187.5
Ca & Mg ppm meq
Calcium 2000 10
Magnesium 10 .083
Recommendations for Soil Fertilization
LIMING
Based on the soil test pH of 6.0 average, it is not necessary to change the pH of the soil as the areas has mostly
established trees and the ornamental shrubs seems to be doing well. If some acid-loving plants are doing
poorly, fertilize them with ammonium sulfate (21-0-0-24) to lower soil pH. For mature bushes, use 2/3 to ¾ lb
(about 1 1/3 to 1 ½ cups) ammonium sulfate per bush.
N-P-K
This area would benefit from a broadcasted application of 15-15-15 fertilizer at a rate of 15lbs per 1000 sq.ft
based on the soil test results and the recommendations from the OSU table 3 for Western Oregon. In this case,
128.4 lbs of the fertilizer would be required for the whole area. As an alternative, we can also use a 7-3-2
organic fertilizer blend, in which case 256 lbs would be needed at a rate of 30lbs/1000sq.ft.
Application
Fertilize trees and shrubs by spreading the desired amount of fertilizer over the root zone (approximately the
spread of the branches). Incorporate the fertilizer by shallow cultivation or irrigation.
SOIL MANAGEMENT UNIT – SHRUB BED I
Recommendations for Soil Management
In the Fall: Add 2-4 inches of tree chip or mulch to shrub bed. To avoid compaction issues use wheelbarrows
and carts to move mulch around instead of trucks so that soil can maintain its natural structure. Adding mulch
will help improve the soils ability to retain water, prevent evaporation in hot weather and helps in reducing
weeds. Add amendments and fertilizer in accordance with recommendations from above.
In The Winter: Keep equipment and persons from driving or walking in shrub bed area to prevent soil
compaction. Compaction will affect soil porosity and decreases the soils ability to take in water and nutrients,
which are needed for healthy soils and plant growth.
In the Spring: Cultivate shallowly to control weeds and monitor plants for irrigation.
In the Summer: Monitor for weeds and cultivate as needed. Irrigate once a week to maintain non-native plants
and newly established plantings. Drip systems should be set for proper times as specified by the plants needs.
Monitor to prevent over watering.
In Summary: Shrub bed should require little management if done correctly. Limit compaction issues by limiting
equipment use and walking and adding deep mulch will help prevent water evaporation in the summer and
help control weeds.
SOIL MANAGEMENT UNIT – SHRUB BED I
SOIL MANAGEMENT UNIT—TURF VI
Rationale for Soil Management Unit
Turf VI is in a north facing location with a total area of 4770 sq. ft. The turf is a perennial ryegrass with a
mulch path and circular area of mulch. Conifers and deciduous trees, shrubs and rose bushes surround the turf
area. Based on field observations and feel test, the soil is very moist and compact with a medium brown color.
This area also has irrigation in place and there is a slight slope towards the southwest corner. This area receives
foot traffic, and it seems to be compacted. The soil sample taken was 3” deep in different areas within the
zone.
Description of Soil
Consistency (describe) sticky, plastic, mouldable, moist, slightly gritty
Color (Munsell chart) 2.5 YR, 5/4, Light olive brown
Soil Test Results
Texture 36.66% sand 40% silt 23.33% clay Loam
Humus (#) 1 (Very low in garden/greenhouse soils)
pH (results & average) 6.2pH 6.2pH 6.0pH 6.13ph Average
N-P-K lbs./acre ppm
Nitrogen (N) 50 25
Phosphorus (P) 100 50
Potassium (K) 220 110
Ca & Mg ppm meq
Calcium 1,400 7
Magnesium 25 0.206
Recommendations for Soil Fertilization
LIMING
Based on soil pH test results, liming the area is not necessary as the average pH of 6.13 falls within the optimum
range for perennial ryegrass which is between 5.5-6.5pH. Magnesium and calcium levels are also adequate.
N-P-K
To help green up the grass and encourage denser growth, the soil could benefit from an application of a slow
release type of nitrogen fertilizer such as sulfur-coated urea (46-0-0). The recommendation for top quality
ryegrass is 6lbs N/1000sq.ft/year. For the whole lawn, 62.2 lbs of sulfur-coated urea is recommended
(13lbs/fertilizer/1000sq.ft). The fertilizer ratio of 6-1-4 is recommended for turf areas. To enhance the turf’s
hardiness to heat and cold, potassium sulfate fertilizer (0-0-50) is recommended at 8lbs fertilizer/1000 sq.ft or
38.16 lbs for the whole lawn area of 4,770sq.ft. Phosphorus level is at 50ppm which is higher than 20ppm, thus,
phosphorus fertilizer is not needed.
Application Rates
Based on the application rate of 1lb N/1000sqft/application, and the required 6lb N/1000sq. ft/yr for top quality
ryegrass, we would recommend 6 applications once per month during the months of May-October. Be sure to
water thoroughly after fertilizing to avoid foliar burn and bring the fertilizer to the root zone.
SOIL MANAGEMENT UNIT – TURF VI
Recommendations for Soil Management
In The Fall: Add ½ inch of fine finished compost to entire lawn area, making sure to spread evenly and break up any
large clumps. Organic Matter helps soil hold water, keep soil biology in balance and helps retain nutrients that otherwise
may leach out of the soil. Add amendments and fertilizer in accordance with recommendations from above.
In The Winter: Keep equipment and persons from driving or walking on wet soggy lawns to prevent soil compaction.
Compaction will affect soil porosity and decreases the soils ability to take in water and nutrients, which are need for
healthy soils and plant growth.
In the Spring: Monitor grass height for mowing. Mowing can start as soon as grass is actively growing. Avoid mowing
during heavy rains, as it will result in deep soil compaction and rutting of turf grass. A proposed mowing spring schedule
would be mowing every other week and the mower should be set at a height of 3 ½ inches or more. All grass clipping
should be left on the lawn to compost back into the soil. Aeration with a hollow tined aeration machine should be done
in middle spring or when it has not rained for at least a week and soil has dried. Plugs from aeration work should be left on
the lawn and will be incorporated back into the lawn through the subsequent mowing. (*It must be noted that aeration
machines are heavy and can cause extensive damage and this work should only be done when lawn has dried out
thoroughly.) Aeration is done to help break up compactions and helps water and oxygen get down into the root zone.
In the Summer: Monitor grass for signs of drying out and start irrigating in early summer or an soon as grass starts to show
signs of browning. Irrigate once a week in the early morning and water till soil is moist down to 1’’. Watering so first 1’’ of
soil is wet will train plant roots to grow deeper into the soil and prevent a shallow root zone.As soon as turf requires
irrigation reduce mowing to every 2 weeks and keep mowing height at 3 ½ inches or higher to maintain a nice green
color throughout the summer months and grass clippings should be left on the lawn to compost back into soil.
In summary: Lawns and turf typically require the most amount of managing. Incorporating organic matter such as
finished compost will improve soil conditions and help plant growth. Due to the nature of lawn maintenance equipment
being very heavy, compaction of the soil is a big issue. Compaction problems can be very expensive and hard to fix so it
is best to prevent compaction of the soil by limiting when you use lawn maintenance equipment and how often.
SOIL MANAGEMENT UNIT – TURF VI
SOIL MANAGEMENT UNIT—RAISED BED
Rationale for Soil Management Unit
The raised bed is located near Turf VI area in a north facing location. The length of the bed is 23’2” from
end to end and the width is 6’6” deep. The approximate total area is 150.50 sq.ft. It is raised 16” with concrete
blocks. The bed is completely flat and has a drip irrigation system keeping it well watered. Plants in this bed
consist of herbaceous perennials. Based on feel test, the soil has a crumb consistency and is moist and friable. It
is also very dark brown in color. The sample taken is 6” depth.
Description of Soil
Consistency (describe) Crumbly,moist,friable
Color (Munsell chart) 7.5 Yr. 3/1,Very Dark Gray
Soil Test Results
Texture 50% sand 50% silt 0% clay
Sandy Loam / Silt Loam
Humus (#) 5 (very high in garden/greenhouse settings)
pH (results & average) 6.8pH 6.9pH 6.1pH 6.6pH Average
N-P-K lbs./acre ppm
Nitrogen (N) 40 20
Phosphorus (P) 150 75
Potassium (K) 280 140
Ca & Mg ppm meq
Calcium 1,750 8.75 Magnesium 80 0.661
Recommendations for Soil Fertilization
LIMING
Soil texture and consistency as well as humus content for this raised bed is very good, as it is composed mostly
of compost and organic material. For this area in Western Oregon, a pH range of 5.5-6.5 is good. Although, the
6.6pH average for this raised bed is a bit on the higher side, we do not recommend lowering the pH as a 6.0-7.0
pH range is still good for the NPK macronutrients to be available to plants.
NPK
To further improve the perennial plants growth and flowering, the raised bed could benefit from a broadcast
application of a 15-15-15 fertilizer at a rate of 1.5 lbs/100sq.ft. For this area of 150 sq. ft, it only requires 2.25lbs of
the fertilizer. Alternatively, if an organic blend is desired, a 7-3-2 ratio would be best, at a rate of 3 lbs/100 sq. ft.
This area would need 4.5lbs of the organic fertilizer.
Application
Fertilize in the Spring as plants begin their new season of growth. Fertilize perennial plants by spreading the
desired amount of fertilizer over the root zone (approximately the spread of the branches). Incorporate the
fertilizer by shallow cultivation or irrigation.
SOIL MANAGEMENT UNIT – RAISED BED
Recommendations for Soil Management
In the Fall: Add 2-4 inches of finished compost to raised bed. Because raised bed is approx. 2 ft above ground
level compaction issues are limited but take care when adding compost not to walk in raised bed.
Add amendments and fertilizer in accordance with recommendations from above.
In The Winter: Keep equipment or persons from working in or walking on raised bed area to prevent soil
compaction. Compaction will affect soil porosity and decreases the soils ability to take in water and nutrients,
which are needed for healthy soils and plant growth.
In the Spring: Monitor for weeds and hand pull weeds if needed. Monitor plants for irrigation.
In the Summer: Water plants once a week to encourage deep root growth and drip systems should be set for
proper times as specified by the plants’ needs. Monitor to prevent over watering.
In summary: Raised beds need a medium amount of work to be maintained properly. Limit compaction issues
by limiting walking or working in raised bed and adding deep compost will help limit water evaporation during
hot summer months and keep soil nutrients that plants need in the soil.
SOIL MANAGEMENT UNIT – RAISED BED
CONCLUSION
Best Management Practices and Maintenance
The Shrub
Bed I
Use Organic
Mulch
Maintain Proper Irrigation Remove Weeds Plant Appropriate
Shrubs, Trees, and
Bushes.
Low or
No Tilling
The Raised
Bed
Use an
Organic
Mulch
Apply Fertilizers in Spring Remove weeds Water when Dry
“about 2-3 inches”
Low or
No Tilling
Turf VI
”Perennial
Ryegrass”
Aerate in
Spring
Time
Apply Amendments and
Fertilizers In Spring and or
Fall.
Avoid Compaction I.E.
Machinery and Foot
Traffic.
Do Not allow to Dry
Out.
Low or
No Tilling
Lawns and turf typically require the most amount of managing. Incorporating organic matter such as finished
compost will improve soil conditions and help plant growth. Due to the nature of lawn maintenance equipment being
very heavy, compaction of the soil is a big issue. Compaction problems can be very expensive and hard to fix so it is best
to prevent compaction of the soil by limiting when you use lawn maintenance equipment and how often.
The Shrub bed should require little management if done correctly. Limit compaction issues by limiting equipment
use and walking and adding deep mulch will help prevent water evaporation in the summer and help control weeds. It is
the only area in which the soil has had very little fertilization and amendments.
Raised beds need a medium amount of work to be maintained properly. Limit compaction issues by limiting
walking or working in raised bed and adding deep compost will help limit water evaporation during hot summer months
and keep soil nutrients that plants need in the soil.
Overall, we would want to keep amendments and fertilizers to the minimum necessary. Sustainable and best
management practices should be employed to limit negative impact to the environment. Instead of re-working the soil
for plants we want, we should instead use native plants and more appropriate plants that match the inherent soil ph and
soil characteristics.
References:
Soil Science and Management By Edward J. Plaster 5th edtion
OSU Extension Service Fertilizer Guides FG 52- Fertilizer and Lime Materials
OSU Extension Service Fertilizer Guides EC 1503 Fertilizing Your Garden--Vegetables, Fruits and Ornamentals
OSU Extension Service Fertilizer Guides EC 1278 Fertilizing Lawns
www.mawaterquality.org/
http://gardening.wsu.edu/library/lanb003/lanb003.htm