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How Grass Grows

How Grass Grows

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How Grass Grows

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  1. How Grass Grows Developed by: Wendy Williams, NRCS, Bozeman, Montana UNCE, Reno, Nev.

  2. Topics to be covered: • How plants make food • Legumes and grasses • How pasture plants grow • Growth and reproduction • Managing growing points • Determining forage yield

  3. How plants make food for growth

  4. What plants are growing on my property? • Legumes • Grasses • Weeds (we’ll talk about them later) • Woody shurbs • Trees UNCE, Reno, Nev.

  5. flower leaf stem leaflet stolon taproot Legumes Parts of a legume

  6. How legumes grow • Vegetative growth • Bud stage • Flowering NCSU

  7. Grasses Parts of a grass plant

  8. 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.

  9. Penn State Univ. OSU 2 tillers developing from the crown of the plant A joint (node)

  10. 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 NRCS, Bozeman, Mont.

  11. 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

  12. Plant reproduction • Grass plants reproduce by forming seed heads • Some plants also reproduce by sending out spreading roots or shoots USDA NRCS UNCE, Reno, Nev.

  13. Regrowth Intact growing points Growing point level Short-shoot phase of growth Regrowth Growing points removed; must regrow from basal buds Long-shoot phase of growth (elongated internodes)

  14. Forage growth and management USDA NRCS

  15. Forage growth patterns • Growing points at ground level • Growing points on the stem • Growing points at the stem tips Smooth brome

  16. 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 Penn State Univ. Kentucky bluegrass rhizome

  17. Adapted from NRCS by A. Miller

  18. Adapted from NRCS by A. Miller

  19. Adapted from NRCS, Bozeman, Mont.

  20. Take-half and Leave-half Adapted from NRCS, Bozeman, Mont. by A. Miller

  21. UNCE, Reno, Nev.

  22. Nutrient content by plant growth stage A B C by A. Miller

  23. Managing for productivity • 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

  24. Identifying grasses Plant life cycles • Annual • Biennial • Perennial OSU

  25. 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

  26. 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

  27. Cool-season versus warm-season grass productivity A. Miller

  28. 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

  29. 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

  30. 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

  31. 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

  32. “How much grass do I have?” Determine forage yield Construct a clipping ring: use an eight foot long piece of cable that has been bolted together.

  33. NRCS, Bozeman, Mont.

  34. 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 – pasture 4000 lbs x 35% (0.35) = 1400 lb/acre Usable forage – “native” pasture 4000 lbs x 25% (0.25) = 1000 lb/acre

  35. Forage availability estimates • Check your pasturelands handout to match hay yield to forage availability. • Clip the grasses for more accurate forage production figures

  36. 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

  37. 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

  38. Approximate grazing length and regrowth periods

  39. 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

  40. 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

  41. Burning as a management tool? • Removes rank vegetation, duff, litter • Release mineralized nutrients • Manage some weeds • Regeneration of certain species • Control diseases and insects

  42. Problems with burning • Smoke management • Unhappy neighbors • Requires a permit UNCE, Reno, Nev.

  43. Problems with burning UNCE, Reno • Liability issues – wildfire, etc. • Melts plastic fences • Dust and ash issues • Short-term water quality issues

  44. 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)

  45. Homework • Identify three of the most common grass and legume species in each of your pastures. • Select your key species. • Calculate forage yields.