Wednesday, April 7, 2010

Greens Core Aeration

Our core aeration program was completed last week.  The program involved using our Verti-drain aerator with a 1/2" hollow tine set to a depth of 6".  The USGA green construction recommendation includes 12" of sand, a gravel layer with drainage.  We have push up greens construction at Glen Echo which has been modified with sand topdressing over the years.  There are no drains in our greens except for #9 which is the only all sand green with drainage on our property.  

The sand that has been used in the topdressing program has accumulated a depth of 3-4" per green over the years that this practice has been utilized at Glen Echo.   The water that enters our green system can only evacuate out of the green profile by moving through the sand and soil layer.  When the soil layer under our greens becomes saturated, the water will drain along the sand/soil line from the highest point of the green to the lowest point and will move out of the green through the soil which is usually the front area of the green.  Water that has to move across the green profile is much slower to leave the green complex than water that will go straight down through the profile of the green.  Our deep coring program is placing  sand channels in our push up soil layer which will allow additional water to go through  the profile of the green.  Entry points can also be made into the soil using channels made with our needle tine venting of our greens each month during the rest of the golf season along with our 1/2" solid deep tined aeration in October.   The slower the water moves out of our greens systems,  the greater the impact on putting green quality.  The wet conditions can lead to the course not being opened or delaying return to the golf course, large ball marks and slower green speeds.  A wet green surface can also lead to the green not being mowed for the day because the surface is too soft and the mower could scalp the turf and create extensive damage.  Saturated root  systems can lead to root decline, disease and or death.  Water is a very good conductor for heat and cold.  In the summer, we are concerned with our root systems becoming too hot which is one of the reasons we attempt to keep our water use to a minimum.  

The picture below shows Russ pulling cores from the practice green with the verti-drain aerator.
The next picture is our core harvester which picks up the sand and dirt plugs.
This is the first season that we used the more modern 4 wheel drive Workman to pick up the cores.  Its has much greater bed capacity and creates less imprinting of the tires into the surface of the green which is softened from the aeration process.  Last season we had some severe rutting from this operation using an older 3 wheeled machine.

Once the cores were picked up, we used our topdressor to apply about 50 tons of sand over the 20 greens. 
We then used our leaf blower which is pulled by a cart to begin blowing sand into the holes of the green.    Also, we did some hand brooming of greens which had a heavier concentration of material.  Once a large amount of sand has been blown into the holes, we use our cart drag brush which filled more holes and smoothed the sand to a consistent covering around and over the crowns of our bentgrass/poa greens. 

Since the greens had their growth reduced from plant growth regulators, there was very little turf to mow so we rolled the greens to help smooth the surface.   The greens were fertilized and a micro-nutrient soil building product was broadcast by walking spreaders.

The view below is the practice green on 3/30 after completion of our work. 
The practice green a week later with some warms days and fertilization.
The heat of the past week has helped push the growth and color of our greens.  We've also been fertilizing and adding micro nutrients to the greens to improve the recovery of our turf and assist in spring root growth.

The poa annua has been coming out of its funk over the last seven days.  We've just applied our second seedhead reduction combination product.  We will also be applying some additional growth regulator product to reduce the poa's growth habit and help improve our ball roll over the next few weeks.

The USGA has a video on greens aeration.

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