Transcript Grass Growth and Response to Grazing

Grass Growth and Response to
Grazing
Importance of Grasses
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Grasses are the most abundant plant
Most of the energy and nutrients for
livestock
Forage produces approx. 80% of the red
meat consumed in the U.S.
Cheaper gain than concentrates
Utilize land not suited to crop production
Growth and Development
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Tiller = growth unit of the grass plant
producing roots and/or leaves
Vegetative tillers produce leaves
Reproductive tillers produce stem,
seedhead, leaves and roots
Crown = basal area of stem where roots
arise
– produces new tillers
Vegetative Growth
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All leaves arise from the center of the stem
– older leaves wrap around newer leaves
– base of stem is thicker than top
– growing point of all leaves is near the ground
• protected from livestock
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As leaves emerge, stem extends similar to a
telescope
Leaves produce energy for self first, then
other parts of the plant
Reproductive Growth
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When vegetative growth is completed,
reproductive growth begins
Produce, flower stalk (culm), and seedhead
(inflorescence)
Grazing can remove reproductive portion of
plant, thus seed production
Carbohydrate Reserves
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Extra food is stored in the crown and roots
Needed for winter respiration and spring
growth
Season of Growth
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Grasses that grow in cooler time of year are
called Cool Season plants
Early spring as soon as ground is thawed
High quality forage in spring, but poor
growth in hot summer
May begin to grow again in fall
Season of Growth
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Warm Season Plants grow in hot summer
Utilize moisture better, can withstand drought
better
Less digestible than cool season
Cool season plants are in reproductive stage
when warm season plants begin growth
– livestock will prefer new growth to old
– prefer cool season plants if at the same stage of
growth
Which pasture would be
better? Warm Season or Cool
Season
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Actually a mixture of the two would
provide new growth throughout the summer
More nutritious vegetation longer
Only seasonal use if only one type of plant
Factors Affecting Grass
Response to Grazing
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Frequency, Intensity, Season
Frequency is more important than intensity
Allow plants to build reserves and grow
again before grazing (rest)
Continual grazing is more damaging