1. Wangari Gardens: Soil Survey
Ann Russell (id# )
EVSP311- Soil Sciences
1002 Sum 14

2. Wangari Gardens
Wangari Gardens is a 2.7 acre garden park in NW Washington, DC near the Washington Hospital Center.
The park was established in 2012 by a non-profit organization.
The park offers educational, recreational, environmental and agricultural programs through:
Public gardens
Personal plots
Tool share
Compost cooperative
Educational events
(Wangari Gardens, n.d.)
(Wangari Gardens, n.d. retrieved from )

3. Understanding Wangari Gardens Soil Survey
In order to properly understand the Wangari Gardens Soil survey, we must first answer a few questions:
How are soils formed?
What are soil horizons?
How are soils named and classified?
What is a soil survey?

4. How is soil formed?
Soil formation and development is a dynamic process. Through weathering; soil, rocks and minerals are changed both physically and chemically into other soil components. This process reflects the dynamic environment where the soil is formed and may proceed rapidly over a decade or slowly over millions of years.
(Soils- Part 1., n.d.)
Schlupp, D., Retrieved from

5. Soil Formation Factors
Parent Material- a combination of underlying rock as well as other materials
Climate- temperature and moisture cause weathering and leaching patterns
Topography- slopes and hills effect temperature (sun exposure) as well as erosion
Biological factors- plants, animals and micro-organisms activities
Time- soil formation is a continuous process, constantly burying underlying horizons
(Oram, B., n.d.)

6. What are soil horizons?
Soil is comprised of distinct layers, or horizons. These layers range from rich organic top layers of humus and topsoil to underlying rocky layers of subsoil and bedrock.

7. How are soils named and classified?
Soil classification, or taxonomy, focuses on soil properties
that can be measured quantitatively such as:
Depth
Moisture
Temperature
Texture
Structure
Cation exchange capacity
Organic matter content
Salt content
(University of Arizona, n.d.)

8. How are soils named and classified?
Soil naming, or nomenclature, is used to establish hierarchies of classes allowing us to understand the relationships among soils, between soils as well as factors that are responsible for certain characteristics.
(Soil Survey Staff, 1999)
(University of Arizona, n.d.)

9. What is a soil survey?
A soil survey is a systematic process where soils of a specific area are analyzed, mapped, described and classified.
(Fairfax Co., n.d. Retrieved from

10. Components of a soil survey:
Mapping of the soils
Characterization of mapping units
Correlation to other soil surveys
Interpretation of soil suitability for land use
(Cornell, n.d.)

11. Wangari Gardens: Soil Types
The north side of the park is composed of U3 soil- Udorthents sandy, while the south side of the park is comprised of CdC soil- Chillum-Urban land complex.
(Natural Resources Conservation Service, n.d.)

12. Wangari Gardens, north
Much of the soil within the District of Columbia is comprised of parent material which has been highly disturbed by man.
The northern section of Wangari Gardens is Udorthents soil, specifically U3 or Udorthents sandy. Udorthents soils are often referred to as ‘fill dirt’.
(Smith, H., 1976)
(What causes foundation settlement, n.d. Retrieved from

13. Wangari Gardens: Udorthents Sandy Soils
Nomenclature
Other properties
Order: Entisols
Suborder: Orthents
Great Group: Udorthents
Subgroup: Typic Udorthents
Family: Sandy loam
Series: Udorthents, sandy
Ap: 0-9 inches- sand
C: 9-72 inches- sand
3-15% slope
Well drained
Very low available water storage in profile

14. Wangari Gardens South, Chillum- Urban land complex
Nomenclature
Ultisol Soils
Order- Ultisols
Suborder- Udults
Great order- Hapludults
Subgroup- Typic Hapludults
Family- fine-silty, mixed, semiactive
Series- Chillum
Ultisol soils cover only 8% of global ice-free land area
(University of Idaho, n.d.)

15. More on Utisoils: cation exchange
Typically low cation exchange capacity
leaching and erosion
Slightly higher cation exchange near surface
nutrient biocycling
(Plant feeding by cation exchange, n.d. Retrieved fromhttp://franklinsoilfertility.com/agriculture/plant-feeding-by-cation-exchange/)

16. More on Utisoils: soil pH
Soil pH is an indication of the acidity or alkalinity of soil measured within a range of 0-14 with 7 acting as neutral. Soil pH has a major impact on the solubility of nutrients and minerals within the soil.
Utisoils have a high soil acidity
Surface pH levels generally between
pH values decrease with depth
(Grunwald, n.d.)
(Corrocount ltd, n.d. Retrieved from

17. Chillum- Urban land complex soil profile
A: 0-2 in., silt loam
E: 2-9 in., gravelly loam
Bt: 9-24 in., gravelly and clay loam
2BC: in., loamy sand
3C: in., gravelly silty clay loam
(University of Minnesota, Retrieved from:

18. More on the Chillum soil series
Chillum series
Use: Cultivated areas produce corn, soybeans, small grains and tobacco. Non- cultivated areas are often used for urban development.
Distribution: New Jersey, Maryland and the District of Columbia
Vegetation: Wooded areas yield mixed hardwood forests comprised of Oaks and Virginia Pines.
(Cooperative Soil Survey, 2001)
Chillum- Urban land complex
8-15% slope
Well drained
Moderate available water storage in profile

19. The future of Wangari Gardens
Those involved with the Wangari Gardens project have utilized knowledge of the soils present. The Udorthents area is used for the learning center, storage and composting area. The southern area is being used as a community garden and orchard. A small area along the street is dedicated to a rain garden to manage the water run-off. The Wangari Gardens are a welcome addition to the community that will have positive impacts for generations to come.