Tree Fruit Soils and Nutrition


Soils and Fertilizers

Outline of a Master Gardener Seminar by Jennifer Moore (formerly WSU-TFREC)

What is soil?

“Soils are complex mixtures of minerals, organic compounds, and living organisms that interact continuously in response to natural and imposed biological, chemical, and physical forces.”
(From Soil Science Society of America News, June 1995)

Soils are formed as a result of 5 factors (ClORPT):

  1. climate
  2. organisms
  3. relief (topography
  4. parent material
  5. time

with four principal components:

  1. minerals
  2. organic matter
  3. water
  4. air

An ideal soil for plant growth will have equal amounts of water and air

Soil Quality

The capacity of a soil to function within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation (NRCS definition).

Functions of Soil within Ecosystems

  • Medium for plant growth and crop production
  • Primary cleansing and recycling medium
  • Source material for construction and medicinal products
  • Sustain biological activity, diversity, and production
  • Store and cycle nutrients and other elements

Indicators of Soil Quality

Physical properties: structure; depth of soil; infiltration and bulk density; water-holding capacity

Chemical: pH; Electrical conductivity; extractable N-P-K

Soil Organic Matter (SOM)

Biological: Microbial biomass; Microbial activity

Next page: Physical Properties of Soil


Updated July 15, 2004


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