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4. Soil Management Considerations
The Life Cycle of Grass
Summer: Plants photosynthesize during the
growing season and build up a reserve of
carbohydrates (often stored below ground
in roots and other storage tissues, such as
rhizomes). As leaf area continues to expand
during the growing season, reserves are
gradually built up until flowering and seed
formation draw them down temporarily.
Fall/Winter: Plants go into the fall with high
levels of stored carbohydrates. Reserves
are gradually used in the winter to maintain
dormant cells and tissues.
Spring: When temperatures warm up, there is
little or no green leaf area to produce energy
directly. More stored carbohydrate is used to
initiate and expand new leaf area. As a result,
reserves drop dramatically in the spring until
the plant has produced enough leaf area to
meet growth demands.
Grazing and root growth
Grazing strategies that provide for intervals
of non-use or rest to allow leaf regrowth and
carbohydrate build-up are more desirable
than continuous grazing. Generally, pastures
are grazed during periods of active growth
(late spring and summer) to optimize livestock
performance. Although grazing may reduce
carbohydrate reserves, the impact is short-
lived if grazing is not severe or continuous.
A grass plant that is severely grazed or
frequently regrazed without adequate rest
periods for energy storage, root growth, and
bud formation, will die.
•
Grazing up to half the blades or leaves
does not affect root growth, but
beyond that the root growth may be
stopped.
•
At 80% leaf removal, root growth stops
completely for as long as two weeks.
•
At 90% leaf removal, root growth stops
completely for more than two weeks
If a plant goes into the winter with a short
supply of stored energy in its roots, it may not
make it through the winter or wake up in the
spring.
Grazing and biodiversity
You can maximize biodiversity by including
warm season grasses as well as cool season
grasses, annual grasses, annual forbs,
perennial forbs, etc., in your pastures and on
your ranges. The more species diversity you
have, the more live roots will thrive in your soil
throughout the year. You will also have green
forage for a longer period of time.
When you lose a species, such as a cool
season grass, it will take longer to get active
roots in the ground when the growing
season starts. It will also take longer to get
green forage above the surface, affecting the
productivity of your land.
Grazing Management