Fairway sandcapping revisited: why I still think sand topdressing is often a better option
What Does Sustainability Really Mean?

GCSAA Webcast on Putting Green Nutrient Use & Requirements

Gcsaa_webcast_nutrient_use
Last week's seminar for GCSAA on putting green nutrient use and requirements is now available to watch as an on-demand webcast. In the seminar, I explained how practical experience and a review of many research projects show that conventional soil testing guidelines are broken. What I mean by that is conventional guidelines tend to recommend fertilizer additions when we do not see any benefit to the turfgrass.

I introduced a solution to this problem. By estimating nutrient use and uptake, combined with the new minimum levels for sustainable nutrition (MLSN) guidelines, a turfgrass manager can be confident that just the necessary amounts of each required element are being applied -- and no more. This is an optimum approach for producing high quality turfgrass.

I prepared this supplementary handout as a webpage with links to articles and guides mentioned in the seminar. Even if you don't watch the seminar video, you are sure to find useful information in this handout.

During the live webcast, there were some questions, which I attempted to answer at the time, and which I add to my answers with additional information here.

  1. Could modifying the nutrient supply help control dollar spot on creeping bentgrass? As far as I know, only nitrogen will have an effect on dollar spot. With a more rapid growth rate due to more N, dollar spot severity should be less. With a slow growth rate at low N, the dollar spot could be more severe. I did a search at the turfgrass information file (TGIF) for "dollar spot" & "phosphorus", "dollar spot" & "potassium" and "dollar spot" & "calcium." I didn't turn up anything showing any relationship with disease, except for this study showing application of high rates of potassium on Cynodon can increase disease.
  2. There was a question about saturated paste extractants. These are useful for research purposes and for assessing soil salinity. For putting green management, however, it is impossible to interpret the results to determine if an element should be added or not. Don't use them to determine what fertilizer to apply. I wrote about this for Turfnet Monthly in 2004. Carrow et al. wrote about this for Golf Course Management in 2003
  3. There were questions about nutrient availability and nutrients possibly being bound in a way in the soil that could cause them to be less available. I wrote about why this is not a problem if we follow the MLSN guidelines, explaining the unambiguity of nutrient availability indices
  4. Another question concerned leaching, and whether we need to account for leaching loss in the calculations. In most cases, we do not need to worry much about leaching. I've described this previously for examples of potassium, calcium, and sodium.

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