Some Unit 5 and Unit 6 Flashcards
How much coarse to medium sand needs to be in a greens mix?
60%
How much very fine sand, silt or clay is allowed in the greens mix? why?
10% to prevent the formation of Clay horizons which can lead to a number of problems
How many inches of greens mix is reccomended on USGA spec greens?
18-24”
During infiltration, water moves downward from the saturated zone to the unsaturated zone….The interface between these two zones is called the….
Wetting Front
What is the Wetting Front?
During infiltration, water moves downward from the saturated zone to the unsaturated zone….The interface between these two zones is called the….
What is a Textural Interface?
an abrupt change in actual pore size.
Why is a textural interface an issue?
it creates a boundary that affects the movement of water, air and root growth
define Channeling:
an irregular wetting front
What is another name for textural interface?
layering
What is thatch primarily made up of?
Stolon, Rhizome and Root tissue
What can cause a buildup of thatch?
Not cultivating the soil Excess nitrogen application
What is LDS?
Localized Dry Spots
What is the cause of LDS?
Organic Matter
Hydrophobic and Hydrophillic soils both contain organic compounds that can turn hydrophobic. True or False?
True
What causes the rapid change of a soil from hydrophillic to hydrophobic?
When water content falls below a certain threshold.
Define Critical Moisture Content
The point that the OM changes from hydrophillic to hydrophobic and also the reverse.
Adhesion is stronger that cohesion in a _______ soil.
hydrophillic
Cohesion is stronger than adhesion in a _______ soil.
hydrophobic
What happens to the soil particles when they turn hydrophobic?
A hydrophobic organic coating forms on soil particles.
What type of fungi are partially responsible for LDS?
Basidiomycetes
Water repellency in soils can result in:
- Reduced infiltration
- Incomplete wetting
- Irregular distribution of chemicals
- turf decline
- LDS
- Poor Drainage
- Poor Turf Quality
What are some variables that go into how the Critical Moisture Content responds?
- Soil Texture
- Amount of organic matter
- Severity of hydrophobicity
How can you prevent Hydrophobicity?
- Maintenance Practices
- Aerification
- Thatch Management
- Topdressing
- Irrigation Practices
- Fairy Ring suppression
- Soil Surfactants
What does the word Surfactant mean?
Surface Active Agents
What do surfactants do?
They break suface tension. Making water less cohesive and more adhesive by breaking the hydrogen bond
What are the two physical parts of a surfactant?
A hydrophillic head and a hydrophobic tail
What is the most commmony used group of surfactants?
Non-ionic
What is another good way to say what surfactants do?
They make water wetter
Surfactants cure localized dry spots. True or False?
False. They prevent them
Name some things that Surfactants do:
- Prevent Localized Dry Spots
- create more uniform water distribution
- Improve water filtration and drainage characteristics
- Reduce drought stress
- Increase efficiency of other turf chemicals
When choosing a wetting agent, what things should you be concerned with?
- How effective is it? ASK FOR DATA
- How long does the product last in the soil?
- Is it phytotoxic?
- Granular or Liquid?
- Cost
- How available is it?
