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K-State Turf and Landscape Blog

Author: Jack Fry

Drive Your Car Without a Fuel Gauge?

Posted on by Jack Fry

By Wes Dyer (Ph.D. student)

The dreaded check engine light popped on this past month. Bound to happen to a 15-year-old vehicle, pushing a quarter of a million miles. I immediately stopped by a local auto parts store and connected a diagnostic scanner to find a faulty fuel level sensor. Not the worst diagnostic error, but I knew I had to be more aware of the miles I drive between refueling. It reminded me of a quote by Dr. Dana Lonn, former managing director for technology at Toro Company, in which he states, “controlling an irrigation system without soil moisture data, is like driving a car without a gas gauge.” I realized more than ever what he meant as I found myself making more frequent stops at the gas station to refuel this past month, just to be sure.

The rootzone profile is much like a fuel tank, where adequate water, or “fuel”, is needed in the profile to maintain a healthy turfgrass stand. How do you know when to refill your soil profile? Setting irrigation clocks to specific days of the week to water is prone to lead to overwatering, like myself now, making more stops than necessary to refuel the vehicle. Even calculating daily evapotranspiration rates (which are estimates of the water used by turfgrass) fail to accurately account for moisture in the soil profile. Utilizing technology and devices to determine soil moisture is much like a fuel level sensor that can aid in determining when the plant needs water. This is where implementing technology in the landscape has advantages. The greater period you can stretch between irrigation applications, the greater chance a rainfall event will occur which will serve as “free water”, though I do not anticipate free gas events.

Soil water sensors are like a fuel gauge – necessary! Both wired and wireless are available.

For the past three years, I have been working to determine how to best employ technology in the turf landscape. Soil moisture sensors are one of many tools we can use to precisely determine when irrigation is needed to maximize water savings, increase turfgrass quality, provide consistent playing conditions, and minimize overwatering. Research results from 2020 indicated soil moisture sensor-based irrigation yielded 84% water savings compared to frequency-based irrigation (2x week-1) and 72% savings compared to deficit evapotranspiration (60% ET) irrigation. These significant water savings were achieved by simply monitoring soil moisture and watering only when necessary to “refuel the tank.” For more information as reference to this project, see this past article (Development of Irrigation Scheduling Techniques that Conserve Water in Turfgrass Landscapes using Soil Moisture Sensors and Weather Data. Kansas Turfgrass Foundation Newsletter, September 2019).

Throughout my turfgrass management career, I have had the opportunity to work with many great golf course and athletic field facilities across the United States. Many of those managers took on the philosophy to be data-driven because it removes the guesswork. The more data available at one’s fingertips the better decisions one can make. The key is not to become overwhelmed with the data, however, but to use the data to aid in improving your decisions or as a “tool in the toolbox”. Regarding irrigation, automated systems may become more widespread in the future and use sophisticated technology to control irrigation. Until then, we can use the current technology to establish our own automated irrigation decisions. I often like to think about two or three simple questions before I choose to irrigate. Specific questions and thresholds center around soil moisture data, turf canopy conditions, and future precipitation forecasts. Certain criteria must be met before the irrigation is turned on which has achieved significant water savings while maintaining turfgrass quality. As my research nears an end, I think it is time to schedule that service on my fuel level sensor.

K-State’s Sodcast: Interview with Ted Wilbur, Co-Owner of Sod Shops

Posted on by Jack Fry

The is the first edition of “K-State’s Sodcast,” which is a short interview with an individual to hear information about their involvement in the turf profession.  Several of these will be put together each year.  In this interview, Ted Wilbur, co-owner of Sod Shops in Wichita, KS, provides an overview of his experience in sod production.  These interviews are done to highlight professionals who have been supportive of K-State, not to advertise their accomplishments or their business.  I’d like to acknowledge the help of Gerry Snyder with K-State’s Division of Information Technology for helping put this together.

CLICK HERE TO WATCH!  (about 7 minutes long)

 

 

 

 

 

 

Seeding after Herbicide Application

Posted on by Jack Fry

By Daniele McFadden (recent M.S. graduate at K-State)

With spring in full swing many of you are taking advantage of the warm soil temperatures and overseeding turf areas. Often times we can mistakenly coincide our spring-time herbicide applications with seeding cool-season turf. So, are your new seedlings going to mature and develop if this happens? Research was done over the last two years to evaluate how several herbicides affect the emergence and growth of tall fescue and Kentucky bluegrass when seeded after application.  Following are some takeaways from these experiments.

The good:

  • When dandelions and other common broadleaves start to appear, a standard three-way postemergence broadleaf product containing 2,4-D + MCPP + dicamba (numerous trade names) is often applied. In both the field and greenhouse, we found that seeding tall fescue into an area treated with this herbicide combination was safe on the seedlings, and was comparable to tall fescue growth in areas where the herbicide wasn’t applied.
  • Other combination products used for control of broadleaf weeds were found safe on tall fescue seedlings when seeding was done 0 to 14 days after herbicide application. These herbicides included:
    • Carfentrazone-ethyl + MCPP + 2,4-D + dicamba (SpeedZone)
    • Fluroxypyr + halauxifen-methyl + 2,4-D (GameOn)
    • Triclopyr + pyraflufen-ethyl + 2,4-D + dicamba (4-Speed XT)

The bad:

  • Playing catch-up with yellow nutsedge control? Applying halosulfuron-methyl (Sedgehammer and other trade names) in late summer or early fall for the control of nutsedge could affect your tall fescue and Kentucky bluegrass seedlings if seeding occurs within two weeks of application. Both cool-season grasses emerged in the field with mild chlorotic symptoms that went away within 8 weeks after seeding. However, a closer look at root development showed that seeding tall fescue into soil treated with halosulfuron-methyl significantly stunted development. The Sedgehammer label guidelines clearly state that a four-week delay after application is needed.  Plan your nutsedge control earlier in the summer so it does not interfere with early fall seeding.

The ugly:

  • Did you accidentally apply a preemergence herbicide for crabgrass control before seeding? You might be wasting your seed. Our studies found that seeding tall fescue or Kentucky bluegrass into an area treated with dithiopyr (Dimension) greatly inhibited growth of the seedlings.

Bottom line – reading the label to learn how soon seeding can be done after herbicide application is critical. Labels on some of these products indicate that seeding should be done after a longer interval has passed after application compared to what was observed as required in this research.  Seeding guidelines on labels must be followed; that said, research results from this project provide useful information to herbicide manufacturers and turf managers who may unknowingly seed into herbicide-treated areas.

Evaluating emergence of tall fescue and Kentucky bluegrass when seeded 0 to 14 days after herbicide application in Manhattan, KS.

These research results will soon appear in greater detail in K-State’s 2021 Turfgrass Research Research Report.

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

 

How Did Warm-Season Grasses Fare This Winter?

Posted on by Jack Fry
Green up of Latitude 36 bermuda in mid-April in the Wichita area.

After severe cold, warm-season grasses have responded well and are generally experiencing good green up this spring.  I have had no information regarding winter injury on bermudagrass or zoysiagrass.  If you noticed any significant injury this spring, please reach out to me – I’d like to know.  Air temperatures were very cold throughout the state between February 6 and 19th, reaching a low of -18 F in the eastern part of the state and in the Wichita area.  There were differences in snow cover, however, and that can impact the level of insulation provided to the grasses.  The lowest soil temperature at a 2-inch depth at the Olathe Horticulture Center was 29 F on February 15th.  Winter injury becomes a greater concern if turfgrass crowns are elevated above the soil in thatch, or if there is no snow cover at all during extreme cold.  The Wichita area had several inches of snow on the ground when the extreme cold occurred.  I recently visited a new sports complex on which Latitude 36 bermudagrass was sodded late last summer, and no play occurred on the fields last year.  Green up of those fields is looking very good (see picture above).  Likewise, Northbridge and Latitude 36 bermudagrass in the Kansas City area have greened up well this spring.  I have noticed some slow green up on an area of Riviera bermuda (seeded type) at our research center.  Good green up of warm-season grasses may be due the fact that grasses were at the peak of acclimation (defined as the plant being physiologically prepared to tolerate extreme cold) when the cold temperatures arrived.  There is greater risk of injury if grasses are not fully acclimated.  This could occur with a late fall freeze, or when a short period of warmth in winter or early spring leads to some deacclimation (loss of tolerance), and then severe cold temperatures return when a front passes through.

 

Don’t Moss with Me

Posted on by Jack Fry

Silvery thread moss has been an increasing problem on golf course putting greens over the past couple of decades.  Moss is a bryophyte, and that makes it different from most plants.  It doesn’t have roots, but rather rhizoids that serve as an anchor, but aren’t as efficient at absorbing water and nutrients compared to roots.  It also grows across a wide range of temperatures.  It can be actively growing when creeping bentgrass or annual bluegrass appears dormant in late fall or early spring.  It can also experience severe drought for months (or years), and regrow once water returns; no other weeds we deal with in turf are that resilient.  Research was done on silvery thread moss over several years at K-State by graduate students Dr. Cole Thompson (now Director of Research for the USGA) and Dr. Zane Raudenbush (Dr. Raudenbush just left The Ohio State University to join Davey Tree Company).  Here are some things to know regarding how management of putting greens will influence moss that came from their research:

Things that make it happier:

  • Mowing lower promotes more moss encroachment. For example, research showed that mowing at 0.125 in vs. 0.157 in resulted in greater moss populations.
  • Areas that are thin are susceptible to moss encroachment, so maintain turf density.
  • Moss loves water. If you’re watering frequently, you’ll favor its growth.
  • Soluble nitrogen applied as a liquid on a frequent interval (spoon feeding) encourages the growth of moss.

Things that help suppress it:

  • Mow higher and maintain turf density.
  • Water less frequently while still meeting the needs of the turf.
  • Fertilize with granular products that allow slower N release.
  • Core aerify, verticut, and topdress. Although some may think they could spread moss with cultivation, research has shown that moss populations can be reduced by these practices, which is due in part because the moss colonies are disturbed and allow creeping bentgrass to occupy those areas.
  • Apply products for moss suppression. The most popular product used for this is Quicksilver, which contains the active ingredient carfentrazone-ethyl and is labeled for use on greens.  Follow the label on Quicksilver for effective moss suppression (don’t expect complete control); using this or other products labeled for moss in combination with aforementioned cultural practices will be the best approach.

Here are some useful resources on moss:

An article on the K-State webpage that give more information on moss biology and control:  https://www.plantpath.k-state.edu/extension/documents/turf/moss_2015.pdf

A video by Dr. Zane Raudebush, former K-State graduate student who conducted research on moss here and as a faculty member at The Ohio State University:  https://www.turfnet.com/turfnet-tv.html/winfieldtv/raudenbush_silvery_thread_moss/

A summary of the research Dr. Raudenbush did at K-State in Golf Course Management magazine:  https://www.turfnet.com/turfnettv.html/winfieldtv/raudenbush_silvery_thread_moss/

Some specifics regarding N fertilization and moss:

https://www.golfdom.com/nitrogen-fertilization-and-silvery-thread-moss/

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow the K-State Turf and Landscape Team on Twitter @KSUTurf

Also, visit our facebook page www.facebook.com/KSUTurf

 

 

Tips for Enhancing Efficacy of Preemergence Herbicides

Posted on by Jack Fry

By Dr. Jack Fry

Preemergence herbicide applications for crabgrass, goosegrass, foxtail, and other annual grasses are underway.  Here are some bullet points to consider to increase the efficacy of the herbicide you use.

Maintain turf density and mow higher.  Good turf density resulting from proper cultural practices for the grass you’re managing reduces encroachment of all weeds, including annual grasses.  Mowing at the higher end of the recommended range has consistently shown significantly lower populations of crabgrass and other annual grasses than mowing at lower mowing heights.

Apply before emergence.  Not all annual grass species emerge at the same time.  For example, goosegrass emerges later than crabgrass.  However, even within a species, emergence of new seedlings occurs throughout spring and summer.  With most preemergence herbicides, when seedlings have emerged, they will not effectively control those plants.  However, the application will control emergence of grasses beyond that date.  Dithiopyr (Dimension) does provide control of crabgrass that has emerged but has not begun to produce tillers.

Use effective strategies to guide application.  Calendar dates, soil temperature, flowering of ornamentals, and other strategies are all used to help guide applications and maximize herbicide residual during the period annual grasses emerge.  Here are a couple of articles related to this subject:

https://blogs.k-state.edu/turf/methods-of-predicting-crabgrass-emergence/

https://blogs.k-state.edu/turf/flowering-ornamentals-and-crabgrass-emergence/

Apply uniformly.  Uniform application is critical – just like distributing paint evenly over your house is aesthetically pleasing.  If you leave a section of the house unpainted, it’s clearly visible.  Good annual grass control requires uniform application; if an area is not treated, it’s likely you’ll seed weed emergence there. Uniform application is achieved by proper spreader or sprayer calibration, colorants that indicate areas that have been treated with liquid products, and applying the product in two directions (half rate in each).

Split applications.  Preemergence herbicides generally provide better suppression of annual grasses when applications are split (1/2 rate each application), usually 6 to 8 weeks apart.  This allows a higher level of herbicide presence on the soil surface, which will minimize weed emergence.  Here’s an article from Purdue on this subject:

https://turf.purdue.edu/wp-content/uploads/2012/06/15_AGRY_Patton_sequential20apps.pdf

Water in after application.  For preemergence herbicides to be activated and ensure uniform distribution on the soil surface, irrigation (or rainfall) after application is needed.

Find more information on weed control by clicking on the tags on the blog (left column), such as “weed control,” “crabgrass,” etc., or search by category on the right side of the page.

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow the K-State Turf and Landscape Team on Twitter @KSUTurf

Also, visit our facebook page www.facebook.com/KSUTurf