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Student Spotlight: Steven Shavel

Jan. 18, 2017

Student Spotlight: Steven Shavel 

Major: Sustainable Plant Systems

Specialization: Turfgrass Science

Rank: Senior

On January 15, 2017, Steven Shavel was awarded an ONLA Phil Kozel Memorial Scholarship. Steven received the Ohio Turfgrass Foundation award in December 2016. Steven has also won scholarships from Columbus District of Golf, Northern Ohio Golf Course Superintendents Association, and the Central Ohio Golf Course Superintendents Association.

Background and research interest:

Steven Shavel enjoyed working on golf courses so much that the work “didn’t feel like work.” He enjoyed the problem solving that comes with a golf course superintendent’s job but wanted to learn more beyond the golf course. Steven was introduced to research by an academic advisor while attending Notre Dame College before arriving at Ohio State. He started his research working with turfgrass at the Ohio Turf Foundation Research Center at the Waterman Farm for a semester long project in June. This spring, Steven will be moving his research indoors for another semester long project in the greenhouse.

 

Read more about Steven's research below. 

 

The effects of applying Aqua-Aid, a penetrate wetting agent on a USGA style creeping bentgrass 

This research characterizes the effects of applying Aqua-Aid, a penetrate wetting agent on a USGA style creeping bentgrass (Agrostist stolonifera) putting green mowed at .125 of an inch.  I hypothesize that where the wetting agent is applied, the greens moisture content will have a higher percentage level than where the wetting agent is not applied.  Four applications of the higher suggested labeled rate of the Aqua Aid product would be made during the summer months at properly timed intervals.  After the last application, data 
retrieval and observations of the three putting greens will be monitored.  Moisture will be measured with a FieldScout moisture meter once a day for at least one week.  Each plot will be probed ten times each day to get an average moisture percentage.  Color evaluation of the turf will be measured with a NDVI (Normalized Difference Vegetation Index) Trimble handheld crop sensor tool.  Preliminary data suggests that there is a noticeable amount of disease pressure on the plots, primarily dollar spot.  The weather patterns after the final wetting agent application are ideal for measuring the effectiveness of the Aqua Aid product on the greens.  Results indicate that on two of the three plots the average moisture percentage is higher on the side where the wetting agent was applied.  Also, the NDVI results point toward a difference in greener color of the turf (healthier) where the wetting agent was applied.  Aqua Aid appears to have some sort of effect on the turf.
 

Methods

Three USGA creeping bentgrass greens mowed at .125 of an inch were selected to apply an Aqua Aid wetting agent.  During this study, the green was split on the North and South side.  The South side of the greens was where the Aqua Aid was applied.  This plot size was approximately the width of the John Deere spray boom (18 feet) at the Ohio Turfgrass Research Facility.  Greens number five, ten, and eleven were applied with the Aqua Aid wetting agent for the project.  
 
Data collection for the moisture in the turf canopy was with a FieldScout moisture meter.  The moisture meter had two 4.8 inch rods on it.  Moisture readings were taken on October 3rd, 4th, 5th, 6th, 7th, 10th, 11th and 12th.  Ten random pro
bes of the moisture meter were taken on each side of the three greens (wetting agent application and control where nothing was applied) on all of the provided days.  
 
The average of all the probes were taken and logged for further analysis.  Probes were not taken within one foot of the outside lines of the plot in case of application error or not enough product hitting the target area.  Use of the irrigation heads on the green (six of them located on the outside perimeter) was used to determine this area.  (Shown in figure 1 to the right inside the red square line)  
Data collection for the NDVI analysis was with a GreenSeeker handheld crop sensor.  The sensor emits a burst of red and infrared light, and then measures the amount of each light that is reflected back from the plant.  This meter gives a value in terms of an NDVI reading ranging from 0.00 to 0.99.  When the reading is high, the healthier the plant is.  Measurements were taken on October 3rd, 4th, 5th, 6th and 7th.  Each side of the three greens were broken up into transects.  (Example of this is shown right in figure 1 to the right with the solid blue arrows)  Each plot has three transects facing East and West and three transects facing North and South.  The grid pattern was used in determining the average NDVI for the plots.
 
Figure 1:  A representation of a green in the study. The black dots represent an irrigation head. The solid blue arrows represent the transects taken with the NDVI crop sensor. The red box indicates the area of intensive measurement.  This red square was made for visualizing probing accurate moisture  percentages and decreasing error.  

 

Results 

 

North Side Green #5 Moistue Average South Side Green #5 Moisture Average
14.65 15.00
North Side Green #10 Moisture Average South Side Green #10 Moisture Average
15.93 16.30
North Side Green #11 Moisture Average South Side Green #11 Moisture Average
15.48 13.33
Total North Moisture Average (No Product) Total South Moisture Average (Product Applied)
15.35 14.88

 

 

 

 

 

Numerical Data is shown in percentages

Total North NDVA Average Total South NDVI Average
0.7745 0.7805

NDVI scale ranged from 0.00-0.99. Note higher difference with product application 

 

Figure showing the average moisture percentage on the selected days

 

Figure showing the average moisture percentage on the selected days

 

Date

Average Relative Humidity

Max Temperature

Total Precipitation

3rd

84

74.0 F

0

4th

72

79.6 F

0

5th

68

80.1 F

0

6th

69

81.7 F

0

7th

75

81.0 F

0

8th

67

66.5 F

0

9th

65

65.1 F

0

10th

73

67.0 F

0

11th

68

67.4 F

0

12th

66

79.8 F

0

 

There were perfect conditions for seeing the effects of what the wetting agent would do to the turf.  This is shown by 0 inches of rain during the experiment.   

 

South side of green 11 with Aqua Aid.  Note the decreased presence of dollar spot

 

North side of green 11 without Aqua Aid.  Note the increased dollar spot.

Conclusion 

In conclusion, as far as the moisture percentage readings, the South side facing plots with the wetting agent applications was roughly a half of a percent difference from the North control plots.  This data shows that the rod level (approximately 4 inches) was not detecting the product and was dryer than on the control side.  This was not was I was expecting when I created my hypothesis.  I originally thought that with the wetting agent, the south side facing plots would have a higher moisture percentage than the control.  When actually doing some research on what the product does, it penetrates very deep into the soil.  The Aqua Aid might have been carrying the water down into the soil much deeper than where I was probing with the meter and I was not getting an accurate percentage of moisture content.  But if you think about this data, with the equipment used, this makes sense since I was not using a long enough rod for moisture readings.

As far as the disease pressure observations, this was the most interesting part of the experiment.  Since these plots did not receive any fungicide applications during the year, any disease would have been fair game to see throughout the trail.  The focus of observations and data collecting was in October, dollar spot was the only major concern.  Prior to this research, I did not think to look at or measure the disease pressure with using this wetting agent.  I did not know that a wetting agent could decrease the chances to have dollar spot on turf.  From a visual perspective, each of the three South face plots with the wetting agent had less dollar spot infections than the North control side.  My hypothesis is that since the wetting agent is best for moving water down deep into the soil profile, this created the case for surface water to be decreased or eliminated at times of dry weather.  Dollar spot is caused by prolonged dew and wet conditions on the surface of the turf, if the wetting agent helped decrease this prolonged surface water on the leaf blades, than it could be marketed as a alternative for a suppression of dollar spot.  In other terms, this would be a good tank mix product with a cost effective fungicide for prevention for dollar spot.  These observations were unexpected, but very interesting to learn about after the applications were finished.

The NDVI crop sensor provided some good data to prove that using the Aqua Aid wetting agent on creeping bentgrass greens, can increase your turf health and color.  Statistically, the South facing plots with the wetting agent had a tenth of a percent difference than the North control plots.  This might not seem like a lot, but this is a sizable difference when you could also visually see the difference by using the classic color rating scale (0-9).  When I observed the plots for a week straight, you could tell that the North side of the plots were showing some signs of dry spots, wilting, foot printing, and some purple colors in spots. The majority of the South side plots had some wilting and foot printing, but not as bad as the control.  I am confident that the wetting agent applications helped retain water for some period of time and kept the turf canopy in better health.
      
In summary, this project was very interesting to observe if the Aqua Aid wetting agent claimed what is was supposed to do.  Further research would needed to be done to definitively say that the Aqua Aid wetting agent provides enough control for dollar spot suppression to add it to a tank for a spray program.  Data was not effective enough to show that this product supported my hypothesis, but had some effect on the turf in a positive way. 

Future Work

This project will be continued during the spring semester of 2017.  Testing of wetting agents will occur in a controlled environment.  I will be adding another wetting agent to the experiment to look at the effects of a retention-based product.  I would like to compare a retention-based wetting agent to a penetrating wetting agent to see if movement in the soil profile can be measured.  I will have two plots of field soil and will irrigate them with the exact amount of water and measure the dry weight of the soils to see if water is being held on the top, bottom or no where in the soil profile.  This controlled experiment will help solidify the differences between the two types of wetting agents.  

  
Acknowledgments

Dr. Dave Gardner for the use of his connections with Aqua Aid to donate the product to research.  The OTF research facility for the use of USGA plots.