(triplexed greens cut at .095")
Showing posts with label Bentgrass Rooting. Show all posts
Showing posts with label Bentgrass Rooting. Show all posts
July 2011 Roots
Proper management of Bentgrass in Southern California can yield dense, deep roots. These photos were taken today, July 21st, on the thirteenth green. Bring on the heat....
Then and Now (2006 & 2010)
Photos from nearly identical locations on September 27th, 2006 and September 27th, 2010. Amazing how far we have come. Just further proof that the correct implementation of Marc Logan's philosophy on Bentgrass management can provide nearly unparalleled conditions in late September in Southern California.
Notes: 100% A4/T1 Bentgrass, cut with a triplex mower at .090", with 7+ inch roots after a week in the mid-100 F degree temperatures.
Soil Temperatures
As air temperatures reached 111.2 F yesterday at ACC, a soil thermometer shows the temperatures at two different depths within a green's soil profile. At 2 pm the air temperature was 109 F. The soil temperature at 1" down was 96.7 F. Within six inches of the initial probes location, the temperature registered five inches down was 88.7 F.
1" below green surface:
Bentgrass versus poa
The poa versus Bentgrass debate is always a contested one. Most say that you cannot grow Bentgrass in Southern California and that poa will out compete Bentgrass in the long run. "It is only a matter of time...." they say. We disagree.
For those of you that remember the tense summers at ACC in years past when the poa would struggle mightily or perish in the heat, I pose the question to you, "Which would you rather have, Bentgrass or poa?" Bentgrass can establish itself and be dominant in Southern California given that the correct management practices are being implemented.
One of the major benefits of Bentgrass is that it is more tolerant of abiotic (non-living) stresses on the extreme levels. I will focus on temperature for this post. The photos below illustrate the difference in root depth between a poa green and a Bentgrass green here in Southern California this summer. The poa root depth may be an inch. The Bentgrass, seven inches.
Root depth and mass are very critical to surviving the summer heat. When soil temperatures reach 80 degree Fahrenheit, new root growth ceases and the aging process begins. At above the mid 90 degree mark Fahrenheit, root hairs dye back and fail to function properly. When the air temperature exceeds 90 degrees fahrenheit, the soil temperature in the upper 1/2" can reach reach upwards of 100 degrees on a bright sunny day. When looking at the illustration below of the shallow poa roots, that can be deadly.
We have had a very mild summer to date and our soil temperatures remain in the upper 60's F in the early part of the morning. Those temperatures creep into the mid to upper 70's F in the afternoon.
Poa Green roots in July:
Bentgrass green roots in July:
Deep Tine Aerification
A key cultural component to developing deep rooting systems is deep tine aerification. The procedure allows for gaseous exchange to take place within the growing medium. Roots will not grow and cannot survive in anaerobic conditions (lacking oxygen). By opening channels from depths of 8" to 12", the turfgrass is able to produce and maintain deeper roots, which allow for less compromised turf as heat related stresses increase in the summers of Southern California. The monthly aerification, followed by rolling, creates minimal visual surface disturbance and no impact on putting. The split day process also benefits water infiltration into the rootzone and is typically non-detectable visually within four days.
Bentgrass Root Development
Photos displaying extensive Bentgrass root density and depth on greens maintained in Southern California under the Greenway Golf Agronomic Program. The photos taken in August 2009, display the Bentgrass root system from 20-month old, sodded A4 greens.
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