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1
FERTILIZERS AND GRASS CYCLING
Three Main Points:
1. Know why, how much, and what kind of fertilizer to apply.
2. Fast release, high nitrogen fertilizers have the potential to cause plant problems and water pollution.
3. Grass cycling is an effective lawn fertilizer, and saves money and time.
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Why Do We Fertilize?
Q. Why do we fertilize? Replace nutrients that we’ve removed through harvest,
pruning, mowing, etc.
Aid plants not naturally adapted to some soils
Push plants to meet the function that we desire
Q. What is the function of landscaping? Beauty, visual satisfaction – green leaves, colorful flowers
Planting for function – turf to play on, visual screen with hedge
Consider PLANT FUNCTION before we consider FERTILIZER.
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Best for the Environment
Clean Water
No Greenwaste
No Pesticides
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Fertilizers
Organic:
Synthetic:
Reading A Bag of Fertilizer:
What do the three numbers on a fertilizer bag stand for?
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Example of Synthetic Fertilizer
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Example of Organic Fertilizer
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N – P - K
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N-P-K
Nitrogen – Phosphorus - Potassium
Nitrogen (N)
Stimulates photosynthesis, used for vegetative growth
Sources Grass clippings and green leaves Organic sources
fish emulsion blood, fish, cottonseed, soybean or alfalfa meals, high nitrogen bird or bat guanos
Synthetic fertilizers
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N-P-K
Nitrogen – Phosphorus - Potassium
Phosphorus (P)
Stimulates flower, fruit and root production. Rose fertilizers have higher levels of phosphorus.
Sources Synthetic fertilizers Organic sources
Rock phosphates, bone meal, high P bird and bat guanos.
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N-P-K
Nitrogen – Phosphorus - Potassium
Potassium (K)
Stimulates plant vigor, and disease and pest resistance
Sources Synthetic fertilizers Organic sources
horse manures kelp mineral some soils
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Nutrient Solubility
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How do plants get nutrients in nature?
Slow Release (insoluble) fertilizers closer to natural system
Fast Acting (soluble) fertilizers for emergency use
Describe a situation where a plant might need a fast acting fertilizer?
Soluble (fast acting) and insoluble (slow release)
nutrients.
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1. Wasted resources
Once soluble fertilizers get wet, available all at once.
2. Fast acting fertilizers flood roots with only a few nutrients.
3. High solubility fertilizers = pollution potential
Only 30 - 50% fertilizers may reach plant
4. Fast acting fertilizers cause pest problems
Management Problems with High Solubility Nitrogen
Fertilizers
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Nutrient Source Advantage Disadvantage
Greenwaste - Wide range of nutrients
- Generated on-site: saves transport fees
- No purchase costs
- Compatible with existing soil micro-organism population
- Low N-P-K value
- May require shredding or composting, depending upon use
- Slow release of nutrients
Organic fertilizer - Wide range of nutrients
- Benefits soil micro-organism populations
- Low labor costs with infrequent app needs
- High material costs
Synthetic fertilizer – Slow release
- Low labor costs with infrequent application needs
- Narrow range of nutrients
- High material costs
- Potentially destructive to soil micro-organism populations
Synthetic fertilizer –Fast release
- Inexpensive material costs
- Immediate plant response
- Narrow range of nutrients
- High labor costs w/ frequent apps.
- Potentially destructive to soil micro-organism populations
- Benefit only lasts a month
- Potential to make plants more susceptible to pest problems
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Ways To Prevent Problems From Fertilizers
Avoid fast acting, high nitrogen fertilizers
Add organic matter to soil (compost, mulch).
Add organic supplements for plant strength and pest resistance
Kelp
Worm castings (worm manure)
Compost Tea (a liquid fertilizer made by soaking compost and other materials)
Adequate irrigation
Fertilize only as much as and when necessary
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Grass Cycling
What does grass cycling mean?
Leave Clippings:
More fertile soil
More stable soil life
Less compaction
Healthier roots
Better pest resistant
Haul clippings:
Must add fertilizer
Starve micro-organisms
Worse compaction
Stressed roots
More pest prone
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Grass Cycling Facts
Nitrogen from clipping can be recycled in 2 to 3 days (radio isotope studies)
Average lawn = 300-400 lbs of clipping per 1,000 square feet per year
30 lbs of fertilizer with 8-4-6 analysis
Advantages of Grass Cycling
NO cost to buy: Save 35-75% of fertilizer costs
SAVE time: 50% less time
BETTER soil: Adds organic matter addition to soil
SAVE your back: 300 – 400 lbs clippings per lawn
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Fertilizer Field Exercise
Distance of walking stride
Square footage of two ‘lawns’
Amount of fertilizer for each lawn
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Selecting and
Applying Fertilizers for Water Quality
Protection
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Review
Three Main Points:
1. Fertilize to meet plant FUNCTION
2. Benefits of insoluble and organic fertilizers
3. Grass cycling saves money, time and fertilizes the lawn
What do we mean by PLANT FUNCTION?
What does nitrogen do?
What does phosphorus do?
What does potassium do?
Describe the links between fertilizers and pests:
Ways to prevent problems from fertilizers:
What does GRASS CYCLING mean? Why does it help you?
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Homework:
Check fertilizer bags you use.
Look for total analysis, total N, soluble N.
Use the chart to determine how much of this fertilizer to use and how often.
Write down this information and bring to next class.