SOIL 化学特性,用途語,生産方法
农业用途
Soil is a creation of nature and consists mostly of minerals
(45%) and very little organic matter (about 5%). It
provides a habitat to man and animals, and supports plant
life.
Soil is the unconsolidated mineral material on the
immediate surface of the earth that serves as a medium
for plant growth.
The factors controlling the rate of soil formation and
the final product are (a) parent material, (b) climate, (c)
biota, (d) topography, and (e) time. These five factors
interact to produce all varieties of natural soils. Soil
differs from the material from which it is formed in many
physical, chemical, biological and morphological
properties and characteristics.
Mankind has indirectly or directly created soils.
When natural soils are not suitable, people extensively
modify soils to suit their needs.
Soil usually has two or more horizontal layers, which
can be seen from the soil profile in a vertical crosssection.
The horizontal layers of the soil, with their own
texture and color, are called soil horizons. The thickness
and composition of horizons distinguish one soil from
another; each horizon has a distinct identity. There are
three almost distinct horizons namely, the plow layer, the
leached layer and the accumulation layer.
Mature soil may be described in terms of the
following four soil horizons: (i) A horizon is the uppermost
layer, containing organic matter, though most soluble
chemicals have been leached from it. (ii) B horizon is
strongly leached with little or no organic matter. A and B
together are often called the topsoil. (iii) C horizon is the
subsoil, a layer of the weathered and shattered rock. (iv)
D horizon is the bedrock. The main types of soil are
pedalfers, pedocals and laterites or latosols.
Soils may also be classified in terms of texture.
hams, with roughly equal proportions of sand, silt and
clay, together with humus, are among the richest
agricultural soils. Wearing away of the soil is a primary
cause of concern in agriculture.
SOIL 上流と下流の製品情報
原材料
準備製品