End of unit 4....Start of Unit 5 Flashcards
What soil properties influence water movement in the soil?
- Texture and Pore Size
- Soil Structure
- Compaction
What kind of pores are the majority in a sandy soil have?
Macropores
What soil structures make it easier for water to move?
Granular and Blocky
What soil structures make it harder for the water to move?
Prismatic and Platey
At some point, the root can no longer pull any water into the plant for usage….why does this happen?
The force of the roots pulling the water in is weaker than the force of adhesion and cohesion that are keeping the water attached to the soil particle.
What is Soil Water Tension?
Ease with which water can be extracted from the soil
As soil dries, soil water tension ________.
increases
It’s easier for a plant to extract water held at a _______ tension.
lower
What do Tensiometers do?
Measure soil water potential
When did the USGA start using agronomists to do research? What is this group of agromomists called?
1920’s
The USGA Greens Section
Originally….Why were golf greens built to USGA Specifications?
To solve issues with compaction and drainage
What are some issues with maintaining a sand based green?
- Low water holding capacity
- Low nutrient holding capacity - Low O.M.
Why was the USGA Greens Section introduced?
It was formed to do research to try to understand the problems that superintendants are dealing with in hope of finding solutions. They will do course visits and alanyze the golf course.
When were the USGA Green Specifications originally published?
Early 1960’s
What are the key additions to a green when using a USGA Spec.? Besides native soil….
- Drainage - drain pipe & pea gravel
- Choker Layer
- Greens Mix
What do layers of a soil do to water movement?
- They impede water movement
- (slows it down)
What does the Choker layer do?
- Creates a perched water table by impeding water movement and prevents migration of your sand mix into the drains
what is the problem with the “modified” USGA spec. greens?
- They built them without the choker layer and the greens failed because the sand would migrate to the drains and the drains stopped working. Fail!
USGA has modified their specifications allowing greens to be built without the choker layer….But, What has to happen?
- The greens mix and the gravel have to Bridge.
- They have to be tested in a lab to confirm they will work together (bridge) without having the sand migrate through the gravel.
