6. Jens
Martensson
• Energy runs the show
• “Free” energy in the form of sunlight
• Manage plant to maximize sunlight
• Increase leaves/surface area
• Increase size of leaves
• Increase length of growing season
Energy
8. Jens
Martensson
• Sunlight is single most important influence on plant
• Light collection is influenced by:
• Species
• Leaf angle
• Canopy density
• Leaf aging
• Availability of water and nutrients in soil
Energy Through Sunlight
9. Jens
Martensson
• Rainfall is primary water source for pastures
• Irregular rainfall → deficient or excessive soil water
• Direct effect on plant productivity
and persistence
Water
10. Jens
Martensson
• Too wet → plant growth slows
• Water fills soil pockets, excluding oxygen needed by plant roots
• Fungal root disease organisms will thrive and damage roots
• Longer recovery periods after wet conditions are needed before
grazing
Wet conditions
11. Jens
Martensson
• Second most important influence
• Plants are adapted to certain climatic
conditions
• 10 – 400C
• Plants that can adapt to temperature fluctuations
will do better
Temperature
12. Jens
Martensson
• Crops cannot escape the locations in which they
are growing
• Location influences affect spesies composition
and growth
• Important factors to consider –
• Elevation
• Soil type
• Drainage
• Slope and exposure
Farm Site
13. Jens
Martensson
• Space within plant is limited
• Bare spaces allow growth of unwanted weeds
• As space becomes more limited so does:
• Moisture
• Light
• Nutrients needed for growth
Space Available
15. Jens
Martensson
Producers
A. Sunlight is the main energy source for life on earth
B. Also called autotrophs
C. Use light or chemical
energy to make food
1. Plants
2. plant-like protists (algae)
3. Bacteria
16. Jens
Martensson
D. Photosynthesis—use light energy to convert carbon dioxide and water into
oxygen and carbohydrates
(Remember: 6CO2 + 6H2O 6O2 + C6H12O6)
E. Chemosynthesis—performed by bacteria, use chemical energy to produce
carbohydrates
Light
Energy
17. Jens
Martensson
• Plant roots have a huge effect on plant productivity
• Water absorption
• Nutrient absorption
• Nutrient storage
• Root temperature = soil temperature
• Rhizomes or stolons?
Plant Anatomy
21. Jens
Martensson
• Found near the roots
• Presence of soil organisms helps reduce nitrogen loss through
leaching
• Root area of soil is different because:
• Release of organic materials from roots
• Uptake of nutrients by roots improved
Microorganisms
22. Jens
Martensson
• “Nodulate” the legume root
• To form a small knoblike outgrowth on the roots of many leguminous plants
• Symbiotic relationship with plant
• Requires certain soil nutrients and pH
Rhizobium Bacteria
24. Jens
Martensson
• Pasture production can be as much as 25% higher on earthworm-
containing fields
• Aerate and loosen soil
• Incorporate dead pasture plants
• Break down manure quickly
• Eat nematodes that could harm clover roots
Earthworms
25. Jens
Martensson
• Move 20-30 tons of soil per acre per year!
• Application of urea (fertilizer) can cut earthworm numbers in half
• Use ammonium nitrate instead
• Soil pH below 5.6 is unfavorable
• Herbicides, insecticides can kill them
• Need plant cover (no bare soil)
Earthworms
26. Jens
Martensson
• Beneficial and important
• Lead to rapid decay and incorporation of organic matter in the soil
• Nutrient cycling
• Feed on bacteria, fungi and soil protozoa
• Pathogenic forms are kept in check by predatory nematodes (in soils
that are in good condition)
Nematodes
27. Jens
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• Weeds
• Forbs (example: pigweed)
• Noxious weeds (causes injury, has a bad taste or is poisonous)
• Insects
• Grasshoppers, locusts, crickets, aphids, etc.
• Control by not overgrazing, provide birdhouses, add poultry to pasture
Pests
28. Jens
Martensson
• Diseases
• About 45 disease affect pasture plants
• Mixed populations is best control
• Avoid overgrazing
• Rabbits, hares and rodents
• Favored by overgrazing
• Encourage abundant diversified wildlife (i.e. foxes, owls, eagles, even snakes)
Pests
29. Jens
Martensson
• Only a slight change in a particular environmental factor may
determine death or survival of an individual plant
• Good management decisions have major impacts on pasture
productivity, persistence, and livestock performance
• Many factors that influence pastures can in some way be affected by
management
Things to Remember…