Thursday, October 30, 2014


Nick Christians
October 31, 2014

I often get questions at this time of year about creeping bentgrass turning a purple color.  The symptom of phosphorus deficiency is initially a reddish color, followed by a purple discoloration.  Figure 1 shows a study at Michigan State University a few years ago.  It shows true P deficiency.  Notice how the problem disappears when small amounts of P are added to the area.

Figure 1.


In the fall, however, grasses can take on s similar purple appearance in response to cool temperatures.  What you are seeing is a plant pigment called anthocyanin.  This is quite common in creeping bentgrass, particularly some of the old, stolonized varieties.  Figures 2, 3 and 4 were taken on a golf course in Des Moines, Ia. last week.  This course was established more than 60 years ago to a stolonized variety called “Washington”.  Washington bentgrass was known for turning purple every fall when temperatures dropped.  The purple patches are Washington bent and the surrounding greener bentgrass is Penncross and a few other newer varieties. This shows how persistent some of these old varieties are and how long they can be found in greens.

So, how can you tell the difference between true P deficiency and grass turning purple in the fall?   Soil tests can help.  I generally do not see P deficiency symptoms on bentgrass unless P levels fall below 10 lb/acre (5 ppm).  The greens on the course in Des Moines have levels of 250 to 300 lb/acre.  The other way is to simply apply P to the area in a test strip.  Usually 0.5 to 1 lb P/1000 sq. ft. will be sufficient.  If the grass turns green again, it was P deficiency.  If it stays purple, it was a response to cold temperatures.

Wednesday, October 22, 2014


Nick Christians
October 22, 2014

Isaac Mertz is a MS student at Iowa State specializing in turfgrass science.  An update on his research appeared in Golf Course Management this month under the heading "Cutting Edge Research".  The abstract from his study that he will present at the American Society of Agronomy meetings in Long Beach, Ca. in a couple of weeks appears below.  Congratulations Isaac.

The full text of the GCM article is at


Tryptophan is one of the 22 essential amino acid and acts as a building block in protein synthesis, as well as a biochemical precursor for serotonin, niacin, and auxin in most organisms. Previous research has shown that applying biosolids boosted with auxin coming from tryptophan may enhance plant defense chemical responses during limited soil moisture conditions.  This occurs through increases in root production as well as endogenous hormone levels that can result in plant growth regulating activity. Tryptophan is produced industrially, which results in a significant amount of byproducts. Tryptophan byproduct (TRP-B) is currently considered a waste product, however, its amino acid and nutrient contents make it an intriguing subject for the use as a growth promoter for turfgrasses. The objective of this research was to determine whether applications of TRP-B improve ‘Penn-A4’ creeping bentgrass (Agrostis stolonifera L.) performance more than applications of pure tryptophan and/or urea. Creeping bentgrass plugs taken from sand-based putting greens at both the Virginia Tech Turfgrass Research Center (Blacksburg, VA) and the Iowa State Horticulture Research Station (Ames, IA) were transplanted into pots and allowed to reestablish in a growth chamber at both respective universities before being treated.  Treatments included TRP-B, urea, and pure tryptophan + urea, and were applied every 14 days at three different rates. Application rates were based on the amount of nitrogen being applied and were 2.5, 12.2, and 24.5 kg N ha-1.  At trial end (42 days), plant parts were harvested and used for analysis. At 24.5 kg N ha-1, TRP-B and pure tryptophan + urea increased root mass by 18.2% and 16.3% respectively compared to urea only. Creeping bentgrass treated with TRP-B can result in increased root production, but the response is rate dependent.

Monday, October 20, 2014

 Nick Christians
October 20, 2014
This webinar will be offered next Wednesday the 29th.
The Canadian Golf Superintendents Association presents
The Canadian Webinar Series
So They Tell Me My pH is Out of Whack, How Do I
Get it Back Into Whack?
Nick Christians, Ph.D.
Wednesday,October 29, 2014
12:00 to
1:00pm EST

Tuesday, October 14, 2014


 Nick Christians
October 14, 2014

Two of our turf graduate students are traveling to England this month to work with the NFL to prepare the field for the International Exhibition Games.

ISU turf management students will tend Wembley field for NFL International series


See the full story on the ISU web site at:

AMES, Iowa -- Sometimes, when what-you-know intersects with who-you-know, something extraordinary can occur. At least that's how it happened for two Iowa State University graduate students.
Kevin Hansen and Joshua Lenz study sports turf management in the horticulture department. Turf managers are the folks who keep the putting greens green and the yard lines aligned.
As undergraduates at Iowa State, Hansen and Lenz were chosen to intern on the turf crews at Super Bowl XLVII and XLVIII respectively. Besides preparing the fields and practice fields, painting logos on the fields and (in Lenz's case) removing snow, they networked and generally hung out with the top turf field managers from around the country.
Spending a week at ground zero of, arguably, the biggest sporting event of any given year was the most awesome experience a couple of sports nuts/turf majors could have. And yet, the awesomeness continues.

Turf guys for hire

A couple of months ago, Lenz was talking to one of the aforementioned turf managers who told him about another exceptional opportunity: spend a couple of weeks in London preparing the Wembley Stadium field for NFL exhibition games. All expenses plus pay.

Since 2007, the NFL has hosted regular season games outside of the United States in the International Series at Wembley Stadium in London."Basically, he said, 'We have openings in London.' So we said we'd be interested," Lenz said.
"This is the first year the NFL has done three exhibition games there instead of two, so they needed more help," Hansen said. "We were in line for the job because we have experience working on the crew and know what's going on."

"It was a networking thing that worked out for us. They contacted us and asked," Hansen said. "And who wouldn't want to go to London?"And they've both stayed in contact with the turf management gurus they met during their Super Bowl internships.
Lenz leaves on Oct. 16 and will crew for the second game (Atlanta Falcons and Detroit Lions, Oct. 26). Hansen leaves on Oct. 29 and will crew for the third matchup (Dallas Cowboys and Jacksonville Jaguars, Nov. 9). They will each be in London for 12 days.

Greener grass?

While they are thrilled to go to London, they are, after all, really into turf. And Wembley is, after all, natural grass. That's a whole different ball game.
"It will be exciting for us because both of our Super Bowls were on artificial turf," Lenz said.
Hansen especially looks forward to experiencing the rapid "changeover" between games that requires a quick switching out of the team logos on the field.
"I don't think there's time for maintenance like aerating and top dressing between the games, so painting logos will be a big part of what we do," Hansen said
And watching the sold-out games from the sidelines at the world famous 90,000-seat stadium across the pond might even beat — or at least tie — their Super Bowl experiences.
Lenz and Hansen credit much of their success in garnering world-class turf gigs to Iowa State turf manager Tim Van Loo. They have worked under him on the turf crew at Jack Trice Stadium as undergraduates and now for 30 hours per week as graduate assistants.
"He has prepared us and other ISU students for careers after college," Lenz said.

Thursday, October 2, 2014


Nick Christians
October 2, 2014

On April 2, 2014, I posted some information on the very cold winter that we had just emerged from and its affect on warm- and cool-season grasses. It was the 9th coldest winter in 141 years.   This summer was surprisingly wet and mild and the cool-season grasses recovered fine.  The big question this season was how would the warm-season grasses like bermudagrass (Cynodon spp) and windmill grass (Chloris verticullata) that have moved into our region in recent years.  These species are very susceptible to cold and I had speculated that their populations would be greatly diminished by the cold winter.

I was wrong.  Both bermudagrass and windmill grass survived just fine.  This is a bit confusing.  We have assumed that it was our cold winters that kept these species from being a problem in the past and that the recent warm winters were the cause of their increase in the region.  If that were the case, a very cold winter should have killed them.

In the case of windmill grass, it could be the fact that seed had built up in the soil and that germination during the summer was the cause of its return.  That is not what I have observed, the stolons from last year recovered.  Likewise, bermudagrass came back form plant parts.

I can only speculate that it would take a series of cold winters to eliminate these grasses from the region.  It is something that I will keep track of the next few years. They are likely here to stay.

Windmill grass seedhead.

 Windmillgrass in central Iowa lawn.

Bermudagrass incentral Iowa lawns (nest two pictures.