SURFACTANT APPLICATIONS TO PREVENT LOCALIZED DRY SPOTS ON T-1 SAND-BASED GREEN

Drs. Andrew Hoiberg & Nick Christians

November 2, 2012

We were approached at the Iowa Turfgrass Institute (ITI) field day this summer by Jim Turner of Numerator Technologies of Sarasota, Fl. to perform a surfactant trial evaluating the prevention of Localized Dry Spot (LDS) on a California-style pure sand (no organic matter) T-1 creeping bentgrass putting green. What a perfect year to investigate!

The trial started on August 9, 2012, and continued through mid-October. An experimental surfactant  from Numerator Technologies called NT 6001 L was used at three different rates (6, 12, 18 oz/1000 sq. ft.) and applied every two weeks throughout the study period at a total volume of 2 gal/1000 ft. sq. The first application was allowed to dry on the turf for 24 hrs to evaluate potential phytotoxicity, of which there was none at any of the rates applied. Thereafter, treatments were watered in to facilitate movement into the soil, where the product needs to be to perform correctly.  Two weeks after the initial application on August 23, irrigation was stopped to generate LDS.  We were very effective at developing dry spots.  Once the dry spots were present, we resumed irrigation to prevent stress.

We found that the product performed well throughout the season at preventing formation of LDS, and especially shined at the end of the season after another prolonged period of drought. Plots treated at the rate of 18 oz/1000 ft. sq. had significantly less LDS in them when compared to the other rates and the control. The lesser rates of 6 and 12 oz/1000 ft. sq. also ended the season with less LDS than the control plots.

Figure 1.   

Graphical representation of LDS evolution between 9 August and 16 October 2012. Treatment 1 is control, treatment 2 is 6 oz NT 6001 L/1000 ft² , treatment 3 is 12 oz/1000 ft², and treatment 4 is 18 oz/1000 ft². You can see that treatment 4 had the least amount of LDS throughout the study and had significantly less LDS than any other treatment by the end. Treatments 2 and 3 also had less LDS than the control at the end of the study.

 

 Figure 2. 

8-22-12: You can see relatively little LDS on the plots early in the trial.

 Figure 3.

8-23-12: You can easily see where surfactants have been applied. Treatment S4 (18 oz/1000 ft. sq.), nearest the bottom center of the photo, performed the best of any rate throughout the study.

Figure 4.  

10-16-12: By the end of the study, the control plots are clearly evident. In the left column on the top and on the bottom for the middle and right columns. 

REDDISH DISCOLORATION OF ZOYSIAGRASS LAWN

Nick Christians

November 1, 2011

nchris@iastate.edu.

Here is a post from Omaha concerning a reddish discoloration of Zoysiagrass.  I need some feedback from you Zoysia experts.

It is from:

Rob Elder

Owner, Omaha Organics Lawn Care

www.omahaorganicslawncare.com

www.omahafertilizer.com

 e-mail: 
rob@omahaorganicslawncare.com

Rob has several Zoysia lawns, most of which look fine.  This one has taken on a reddish discoloration late in the season.

He uses a 4 step organic program on it.  He also put down gypsum in August for a sodium problem.  He topdressed it with organic matter.Sodium does not appear to be high on the soil test.

He gave me the soil tests and phosphorus in in an adequate range.

Some varieties of grass will turn red in the fall when temperatures cool, but this is the only Zoysia lawn that it is occurring one.  Does anyone with Zoysia experience out there have any ideas.  Let me know or contact Rob directly.  nchris@iastate.edu

 Here is the reddish color on the Zoysia from a couple of weeks ago, just before dormancy.

Here is the lawn a couple of days ago, after the Zoysia became dormant.

 Heavy clay soil on the lawn.