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But soils have different
properties
. They differ in
texture
and
color. Soils also differ in their ability to
retain
water and to support
plant growth. The texture of soil depends on the amount and size of
the rock particles. Soils with a lot of sand and gravel feel gritty. They
fall apart easily when you make a mud ball. Soils with a lot of silt
and clay feel smooth and slippery. They make excellent mud balls.
Soil color depends on the color of the sand, silt, and clay particles,
and the amount of humus. Texture and humus determine the
amount of water that a soil can retain. If the soil has a lot of sand
and gravel particles, water will flow through the spaces between
the particles. Very little water will stay in the soil. Soil with smaller
particles and a lot of humus will retain more water. The water
gets trapped in the smaller spaces between particles. And water is
absorbed by the organic humus particles.
Mud balls made out of sandy soil and clay soil
image to
come
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