Answer:
The chemical composition of the soil, the topography, and the presence of living organisms determines the quality of soil.
In general, soil contains 40-45% inorganic matter, 5% organic matter, 25% water, and 25% air.
In order to sustain plant life, the proper mix of air, water, minerals, and organic material is required.
Humus, the organic material in soil, is composed of microorganisms (dead and alive) and decaying plants.
The inorganic material of soil is composed of rock, which is broken down into small particles of sand (0.1 to 2 mm), silt (0.002 to 0.1 mm), and clay (less than 0.002 mm).
Loam is a soil that is a mix sand, silt, and humus.
Key Terms
loam: soil with no dominant particle size that contains a mixture of sand, silt, and humus
humus: a large group of natural organic compounds found in the soil composed of decaying plants and dead and living microorganisms
