Tuesday, April 26, 2011

Site Specific Aerifcation Treatment

This past week we began performing site specific aerification and amendment treatments to historically stressed areas on our putting surfaces. These areas are small in size and are positioned along the edges of some of our greens. The impact on playability from this process is minimal while the prescibed treatment results in improved health and performance of our putting surfaces.  These areas performed poorly in the past due to two different soil related stresses that were caused by our 'sodic' irrigation water source.  The performance of these areas has improved significantly this year since we began treating our water source last June and from the site specific aerification treatment  being performed a couple of times over the past year.  As we continue to manage our course with our improved water source, these aerifcation treatments should be needed less frequently over time.

The first areas requiring treatment are located along the higher edges of some of our greens.  These areas have struggled with drought stress symptoms in the past due to our irrigation water containing an extremely low amount of calcium.  Water must contain 20 parts per million (ppm) of calcium in order to maintain adequate infiltration rates.    The process we are using to treat these areas is to hand aerify these small areas strategically where it is needed and then back filling the hole with Lassenite.  Lassenite is a diatomaceos earth product that increases our soil's infiltration rates,  available water holding capacity and CEC while resisting the build up of Sodium in the soil. 

Diatomaceous earth (Lassenite) amendment.

Team Member Jose' Martinez filling the aerification hole with the diatomaceous earth amendment.
The second areas we are treating is the surface out falls of some of the greens.  These areas are located at the edges of the lowest points of our putting surfaces.  These area are prone to build up higher levels of Sodium that results in a fine layer of clay and organic matter located a few inches below the soil surface.  This layer clogs up the soil profile and prevents water from draining though the soil profile.  Once this happens a soil condition known as black layer can develop.  Black layer is a soil that has gone into an anaerobic state that contains a high amount of sulfur in the form of hydrogen sulfide (H2S).  When you probe these areas you can smell an aroma similar to rotten eggs.  The remedy for this condition is to aerify though the layer to allow for proper drainage and to return oxygen to the soil.  We are then back filling the hole with a 50/50 blend of sand/calcitic lime.  The lime is used in combination with the added oxygen from the aerification to convert the sulfur in the H2S form to a leachable form of CaSO4.  Once this chemical reaction occurs the high levels of sulfur will be reduced with the next rainfall or flushing event.

Area affected by 'black layer' on the front of 12 green.

Sand/calcitic lime mix being added to the aerification holes on the front of 4 green.

The zone for 'black layer' formation is at the darker and lighter colored sand interface.

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