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How Grass Grows
Developed by:Wendy Williams, NRCS, Bozeman, Montana UNCE, Reno, Nev.
Topics to be covered:
How plants make food Legumes and grasses How pasture plants grow Growth and reproduction Managing growing points Determining forage yield
How plants make food for growth
What plants are growing on my property?
Legumes Grasses Weeds (we’ll talk
about them later) Woody shurbs Trees
UNCE, Reno, Nev.
Legumes
taproot
leaflet
flower
stem
leaf
stolon
Parts of a legume
How legumes grow Vegetative growth Bud stage Flowering
NCSU
Grasses
Parts of a grass plant
Grasses consist of several growth segments
Each segment contains a:
Leaf Node Internode Axillary bud or
potential bud – can produce a new stem or tiller
NRCS, Bozeman, Mont.
OSUPenn State Univ.
2 tillers developing from the crown of
the plant
A joint (node)
NRCS, Bozeman, Mont.
Growing Points Location where
cells divide and produce new growth
Occur close to the ground early in the growing season
Become elevated above ground as the growing season progresses
Stages of grass growth Vegetative
◦ Growth of leaves Elongation
◦ Lengthening of stem internodes, also called jointing
◦ Boot stage is the end of elongation Reproductive
◦ Development of seedhead and seed
Grass plants reproduce by forming seed heads
Some plants also reproduce by sending out spreading roots or shoots
Plant reproduction
USDA NRCS
UNCE, Reno, Nev.
Long-shoot phase of growth (elongated internodes)
Short-shoot phase of growth
Growing points
removed; must regrow from basal
buds
Regrowth
RegrowthGrowing point level
Intact growin
g points
Forage growth and management
USDA NRCS
Forage growth patterns
Growing points at ground level
Growing points on the stem
Growing points at the stem tips
Smooth brome
Carbohydrate reserves (food)
Stored in roots, rhizomes, stolons and base of stem
Used for first spring growth of dormant plants
Allow rapid regrowth from stubble
Kentucky bluegrass rhizome
Penn State Univ.
Adapted from NRCS by A. Miller
Adapted from NRCS by A. Miller
Adapted from NRCS, Bozeman, Mont.
Adapted from NRCS, Bozeman, Mont. by A. Miller
Take-half and Leave-half
UNCE, Reno, Nev.
Nutrient content by plant growth stage
A B Cwww.ag.ndsu.edu by A. Miller
Early to mid-season, maximum forage production can be obtained by keeping the plant in a vegetative state by preventing seed head production
Depending on the species, you may want to let the grass form a seed head at the end of the season
Managing for productivity
Plant life cycles
Annual
Biennial
Perennial
OSU
Identifying grasses
Cool-season plants Optimum temp. range 65 to 75 degrees F Productive in spring and fall Reduced growth in summer Higher in crude protein Respond to nitrogen fertilizer Examples:
◦ orchardgrass, ◦ fescues, ◦ perennial ryegrass, and ◦ bromes
Warm-season plants Better at using atmospheric nitrogen Grow best at high temperatures
(90 to 95 degrees F) Lower in protein but protein is more
efficiently used by animals Triggered by day lengths Examples:
◦ big and little bluestem, ◦ switchgrass, ◦ Indiangrass, and ◦ sudangrass
Cool-season versus warm-season grass productivity
A. Miller
Cool-season bunchgrasses Growth occurs in early spring or late fall Grows in bunches or clumps Grass propagates by seed only More elevated leaves Grazing must be managed to optimize
productivity
Cool-season sod-forming grasses
Growth occurs in early spring or late fall Growth forms a mat of roots or sod Plants propagate from both seed and
rhizomes or stolons More tolerant of grazing
Warm-season sod-forming grasses Growth occurs in late spring to early
summer Growth forms a mat of roots or sod Plants propagate from both seed and
rhizomes or stolons More tolerant of grazing
Legumes Plants that fix nitrogen from the air Can reduce the need for nitrogen
fertilizers More growth in the hot summer
months than grasses Watch out for bloat Need to be inoculated
Determine forage yieldConstruct a
clipping ring: use an eight
foot long piece of cable that
has been bolted
together.
“How much grass do I have?”
NRCS, Bozeman, Mont.
Forage yield examples
If the clipping weight is 200 grams, multiply by 20 for a total available forage yield of
4000 pounds per acre
Usable forage – pasture4000 lbs x 35% (0.35) = 1400 lb/acre
Usable forage – “native” pasture4000 lbs x 25% (0.25) = 1000 lb/acre
Forage availability estimates
Check your pasturelands handout to match hay yield to forage availability.
Clip the grasses for more accurate forage production figures
What are you going to do with your forage?
Graze it! How long can you graze? Just long enough that you preserve
growing points and leaf area Then you must rest your pasture
How long do you have to rest your pastures?
Depends upon:◦ Period in the growing season◦ Availability of irrigation water◦ Amount of active leaf area remaining
following the grazing period◦ Cool-season grasses recover more
quickly in spring and autumn
Approximate grazing length and regrowth periods
Wait a minute! I don’t have grazing animals!
What are you trying to manage?
What are your management goals?◦ Attract and maintain wildlife◦ Discourage wildlife◦ Defensible space◦ Aesthetics◦ Noxious weed management
Methods for removing forage
Mowing◦ Need equipment◦ Need grass species that grow upright◦ Be sure to maintain the growing points◦ Fertilize or add legumes
Leasing to livestock managers for grazing◦ Need to know your forage yield ◦ Don’t assume management will be good
Burning as a management tool?
Removes rank vegetation, duff, litter
Release mineralized nutrients Manage some weeds Regeneration of certain species Control diseases and insects
Problems with burning
Smoke managementUnhappy neighborsRequires a permit
UNCE, Reno, Nev.
Problems with burning
Liability issues – wildfire, etc.
Melts plastic fences
Dust and ash issues
Short-term water quality issues
UNCE, Reno
Remember: love your grass as much as
your animals and you’ll all be happy!
Identify what is growing in your pasture(s)
Determine which plant(s) to use as a “key species” for your pasture(s)
Determine the forage yield of your pasture(s)
Homework Identify three of the most common grass
and legume species in each of your pastures.
Select your key species. Calculate forage yields.