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Address: P.O. Box 27552, Richmond, Va. 23261-7552
Phone: 804-290-1141
Agriculture
Lessons:
Plant Science 1
Plant Science 2
Plant Pathology
Weed Science
Horticulture Science
Animal Science
Basic Entomology
Soil Science
Activities
Quiz
Soil SciencePhysical Properties
Soil is considered a critical or limiting factor in the cycles of nature because its properties
determine the availability of the substances necessary for life. Soil for the most part is a
complex mixture of organic material, water, chemical compounds, and mineral particles from
sand, clay or silt. Some of the major properties of soil are particle size, amounts of organic
matter, and its pH.
The particle size determines the texture, mineral holding capacity, and porosity of the soil.
Sand particles are the largest and give the soil a coarse texture and allow water to drain
easily. Because of its high porosity, sandy soil is unsuitable for the growth of many kinds
of plants. In these soils the important elements like calcium, sulfur, and potassium are
leached and not available to plant roots. The particles of silt are intermediate in size
between those of clay and sand. As the percentage of clay particles increases, the water
retention of the soil also increases. Soils in many locations of our state have excessive
amounts of clay particles that cause serious drainage problems and prevent the growth of
many plants.
Please email us with questions or comments.
Soil Science
Physical Properties
Soil is considered a critical or limiting factor in the cycles of nature because its properties
determine the availability of the substances necessary for life. Soil for the most part is a
complex mixture of organic material, water, chemical compounds, and mineral particles from
sand, clay or silt. Some of the major properties of soil are particle size, amounts of organic
matter, and its pH.
The particle size determines the texture, mineral holding capacity, and porosity of the soil.
Sand particles are the largest and give the soil a coarse texture and allow water to drain
easily. Because of its high porosity, sandy soil is unsuitable for the growth of many kinds
of plants. In these soils the important elements like calcium, sulfur, and potassium are
leached and not available to plant roots. The particles of silt are intermediate in size
between those of clay and sand. As the percentage of clay particles increases, the water
retention of the soil also increases. Soils in many locations of our state have excessive
amounts of clay particles that cause serious drainage problems and prevent the growth of
many plants.
