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 plantA 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 examplesIf the clipping weight is 200 grams,

multiply by 20 for a total available forage yield of

4000 pounds per acreUsable forage – pasture

4000 lbs x 35% (0.35) = 1400 lb/acreUsable forage – “native” pasture

4000 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.