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49 Cards in this Set
- Front
- Back
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what are the four reasons we do substrate chemical analysis
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1. predict nutrient availability
2. predicting water availability 3. nutrient presence 4. explain plant health problems |
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which substrate analysis is most important
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explaining plant health problems
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what does pH measure
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nitrogen ion concentration
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what does pH influence
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root growth and availability
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what is the general target of pH in soil
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6.2-6.8
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what is the general target of pH in soilless media
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5.8-6.2
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what two things can be used to raise pH
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limestone
dolomite |
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what two things can be used to lower pH
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sulfur
ion sulfate |
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soluble salts
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excess ions dissolved in the soil water
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what effect do soluble salts have on the soil
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limit plant growth
effect nutrient availability & water relations *not all salt is bad |
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what happens when soluble salts are in excess?
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the soil will take the water instead of making it available to the plant
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what are the two things soluble salts are influenced by
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fertilization
irrigation water |
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soil
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a dynamic natural body composed of mineral & organic solids, gases & liquids, and living organisms
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soilless media
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a growth media that does not contain natural soil
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what is: peat
- 2 advantages |
partially decomposed moss
-water retention -nutrient retention -cation exchange capacity |
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what is: sand
- 2 advantages |
weathered mineral particles
-drainage -adds weight -pH neutral |
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what is: perlite
- 2 advantages |
volcanic rock that is crushed and heat treated
-lightweight, adds airspace -water retention |
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what is: vermiculite
- 2 advantages |
mica that is heat-treated
-lightweight -water retention -nutrient retention |
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what is: composted bark
- 2 advantages |
tree bark that has been shredded and composted
-good drainage -excellent nutrient retention |
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what is: coir
-2 advantages |
fiber extracted from coconut husks
-water retention -expensive to ship -nutrient retention |
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critical aspects of soilless media mixes
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1. provide support
2. provide aeration 3. water holding 4. nutrient holding |
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cation exchange capacity
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the ability of a substrate to hold and exchange mineral cations
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dolomite
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pH adjuster
-raises pH |
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sulfur
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pH adjuster
-lowers pH |
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why is the pH of a soilless substrate so important
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pH influences nutrient availability
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what are the two seed sowing machines we saw in lab
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1. belt-based machine
2. vacuum |
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compaction can be beneficial or detrimental in field planting beds. explain.
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compaction promotes seed to soil contact, plants can't have air space on sides when planted
may cause barrier to root growth if too compacted |
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structures
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used in horticulture to modify the growing environment/climate
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what is a: shade house
-list 2 things about it |
frame with cloth or woven covering
-diffuse rainfall -partially blocks sunlight -reduces wind |
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what is a: lath house
-list 2 things about it |
frame with wooden strips
-partial diffusion of rainfall, sunlight, wind -needs to run north-south |
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what is a: cold frame
-list 2 things about it |
a frame that can be covered with plastic film or glass
-used where harsh winters happen -covered during harsh temps to allow moderation of temperature |
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what is a: green house
-list 2 things about it |
glass or poly covered house, typically with heating, cooling, and ventilation
-biggest temperature modifier -controls light |
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what is the #1 concern with plant structures?
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plant exposure to light
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why is light important to manage?
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the more light(heat), the higher the rate of PS, which increases the need for water
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light quality
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areas of light spectrum that allow plant to absorb most light
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what colors of light are best for the plants?
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red and violet
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what do foot candles measure?
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amount of light projected in a space by a one-candela source one foot away
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three ways to manage light
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plant density
pruning tree canopies structures |
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what is a seed
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fertilized, ripened ovule
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sexual reproduction
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reproducing with genetic variation
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asexual reproduction
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reproduction with exact replica
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seed coat
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outside protective covering that regulates when seed with germinate
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cotyledons
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seed leaf
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what does the endosperm store in the seed
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food reserves
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germination
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the activation of the seed
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two types of regulation of germination
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1. physiological
2. physical |
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how can you physiologically regulate the germination of a seed
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-temperature
-light |
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how can you physically regulate the germination of a seed
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-thickness of seed coat
-permeability of seed coat |
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three treatment to overcome natural regulations
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scarification
acid treatment stratification |
