Page 103 - Calculating Agriculture Cover 20191124 STUDENT - A

CH 9] Calculating Agriculture 9-15

reduction–oxidation
(redox): A type of
chemical reaction in
Figure 9.12 Land judging by high school agriculture students. Slope percentage is which the oxidation
one of the factors which are judged. states of atoms are
changed. Redox reac-
tions are characterized
by the transfer of elec-
trons between chemi-
cal species, most often
with one species (the
reducing agent) under-
Soil, Water, and Texture going oxidation (losing
electrons) while an-
How is soil described physically? Physical properties of soil include color, texture, structure, other species (the
porosity, density, consistence, temperature, and air. Colors of soils vary widely and indicate such oxidizing agent) under-
important properties as organic matter, water, and reduction–oxidation (redox) conditions. Their goes reduction (gains
electrons).
relative proportion in a soil is called soil texture
Texture indicates the relative content of particles of various sizes, such as sand, silt and clay in
the soil. Texture influences the ease with
which soil can be worked, the amount of
water and air it holds, and the rate at
which water can enter and move through
soil.
Soil texture (such as loam, sandy
loam or clay) refers to the proportion of
sand, silt and clay sized particles that
make up the mineral fraction of the soil.
For example, light soil refers to a soil
high in sand relative to clay, while heavy
soils are made up largely of clay.
Think, does a clay soil hold more water
than a sandy soil? These and other soil
questions are important for agriculture.

Soil Textural Triangle
The soil texture triangle indicates
the varying soil types that include parts
of clay, sand and silt. The soil texture
triangle is one of the tools that soil
scientists use to visualize and understand
the meaning of soil texture names. The
textural triangle is a diagram which Figure 9. 13: Soil Textural Triangle. The textural triangle describes the
shows how each of these 12 textures is relative proportions of sand, silt and clay in various types of 9
classified based on the percent of sand, soils. Source: http://soils.usda.gov/technical/manual/
silt, and clay in each. print_version/complete.html

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