Viridescent - the Asian Turfgrass Center blog

Nutrient Supply and Plant Species Diversity

On March 28 (or March 29 in Asia), Episode 23 of the Turf Diseases Turf Chat will be on the subject of Soil Nutrients and Weed Management. This promises to be an interesting discussion, led by Dr. Scott McElroy from Auburn University and hosted by Dr. Larry Stowell of PACE Turf.

It is a well-known phenomenon that application of nitrogen favors grasses and reduces species diversity (i.e. reduces the number of weedy species), while increasing the soil pH through addition of lime, and adding potassium fertilizers, as an example, can increase the prevalence of weeds. In a brief exchange on twitter last week, we discussed this, and decided to make this subject the focus of the upcoming Turf Chat.

@asianturfgrass @campbellturf @pendersuper to me the dandelion paper is typical ecology-speak. Making a big deal of something already known.

— Scott McElroy (@malherbologist) March 23, 2013

Dr. McElroy says that this phenomenon is already known, while I would argue that despite it being noticed more than 150 years ago, and the mechanisms of this worked out more recently, among turfgrass managers, there is not universal knowledge of these principles.

That was the subject of an article I wrote with Dr. Frank Rossi from Cornell University about the Park Grass Experiment and some of the results from this classic experiment, especially the noted absence of dandelions from plots to which potassium fertilizer is withheld.

For more detail about this, please read our article about Park Grass from the Green Section Record, and you can find a list of references at the end of that article for additional reading. Of particular interest may be this one, by Silvertown et al., The Park Grass Experiment 1856-2006: its contribution to ecology.

Climate Chart for Cool Season Areas, With Tutorial

I've made a new moving bubble chart, this one focusing not exclusively on warm-season areas, but also including a wide range of cities where cool-season grasses are grown: Beijing, Berlin, Boston, Budapest, Chicago ... Madison, Minneapolis, Moscow ... Topeka, Vancouver, Washington, D.C.. In total, 52 cities, including a few of my favorite warm-season and transition-zone cities such as Atlanta, Bangkok, Hong Kong, Rio de Janeiro, Shanghai, Singapore, and Tokyo.

I've also written this short document that explains, perhaps in excruciating detail, exactly how I've gathered the data and produced this particular chart. I've included links to the data sources and software I use and provided formatted data files and the few lines of R code necessary to make the chart yourself. You may find it interesting to create charts in this format but with different data that changes with time. Perhaps it would be data from your on-site weather station? Perhaps soil test data that change with time, or labor hours to do different jobs on the course at different times of the year, or budget amounts over time, for different line items? 

Click here to go to the climate.asianturfgrass.com page to see the chart at a large size, or adjust the chart at a small size here. Almost every aspect of the chart can be adjusted to find the view of the data that is most useful for you.

Data: climate.52 • Chart ID: ATC_climate_chart_52
R version 2.14.2 (2012-02-29) • googleVis-0.2.15 • Google Terms of Use • Data Policy

ATC Articles Featured on Pitchcare Oceania

Have you seen the Pitchcare Oceania site? This online magazine has information about turfgrass management for golf and sports turf and this year has begun featuring selected articles from ATC.

With news, information, online message boards, and links to a variety of suppliers, this is a site that may be of interest to turfgrass managers in Asia. Check it out here.

Interactive Chart for Climatological Normals

I've previously made a series of static bubble charts that show the climatological normals for a selection of cities where warm-season grasses are often grown. I've now, thanks to the googleVis package in R, been able to use these same data to create motion charts. I find the motion charts fascinating because the differences (or similarities) between cities in various climatological characteristics are easily ascertained. Clearly, the weather has a huge impact on which grasses should be used, and on what maintenance practices are necessary to create the desired playing surfaces. Just because it is a warm-season area doesn't mean all grasses will perform the same. By looking at climatological data in this way, it is evident just how different the weather is between the cities plotted on this chart.

Today I flew from Gatwick to Bangkok, via Dubai. I snapped the photo above as I was boarding the flight to Bangkok, and you can see that the weather in Dubai today was sunny. Which is what we would expect from the climatological data plotted on the motion chart. As the plane passed over India and the Bay of Bengal, there was turbulence, as we would expect during the monsoon season, where it was raining below. And the plane entered a holding pattern to the west of Bangkok to wait for thunderstorms to pass before making its approach to BKK. The data on the chart are average sunshine hours on a monthly basis, average temperature on a monthly basis, and average monthly precipitation. 

Click the chart image above or click here to go to the interactive bubble chart. You can change the data represented on the x- and y-axes, the speed at which the data move, which cities are highlighted, etc.

Free Online Seminars About Seashore Paspalum at TurfNet

TurfNet.com is an excellent resource for golf course superintendents and it is well worth being a member if you like to stay abreast of the latest developments in golf course maintenance. The online seminars (or webinars) are another valuable resource as they are free to TurfNet members. But even for non-members, there are some new webinars just posted that are free to anyone, and these may be especially interesting for people who manage or are interested in managing seashore paspalum. Want to know which seashore paspalum variety may be best for your conditions? Which paspalum gets the most (or least) dollar spot? How to deal with bermudagrass infestation of a seashore paspalum turf? What strategies to use to deal with poor irrigation water quality? You can watch these on-demand webinars to find out.

To view these recorded programs, go to the webinar archive section of TurfNet.com and you can watch on-demand webinars by scientists and superintendents including Stewart Bennett, CGCS, Dr. Bryan Unruh and Dr. Dennis Shepard. All part of a "Perspectives on Paspalum" seminar held in September at Myrtly Beach, these seminars provide a wealth of information and tips about seashore paspalum management on golf courses.

In Dr. Unruh's talk, he mentioned a research project he did entitled "Seashore Paspalum Performance to Potable Water". This research paper is available for download here and includes useful information about different seashore paspalum varieties (including Sea Isle 2000, SeaDwarf, Seaspray, Sea Isle Supreme, Salam, and others) and their performance when irrigated with potable water. If you are considering a paspalum variety for your course, you will want to watch Dr. Unruh's talk and read the paper -- not all varieties are created equal, especially when it comes to dollar spot susceptibility. And not all varieties are the same when it comes to drought tolerance either. Check out the research results before you choose a grass for your site. At the Asian Turfgrass Center's research facility, we have seen a big difference in the way different seashore paspalum varieties respond to drought stress.