In an e-mail conversation with Ryan Galles, we discussed calcium, soil tests, magnesium, and a bit more.
From Ryan, "I had recently listened to your YouTube video on calcium in the soil that you did with Larry at PACE Turf on the MLSN Guidelines. I have had some problems on greens and fairly high pH." He explained that he had added a calcium product into his fertilizer application this year, but was wondering, after watching the video, if he was "getting anything out of that product. I have attached my soil test from there where it seems my calcium levels are pretty high."
At that pH [mid 7's] and at that amount of calcium in the soil [more than 1400 ppm], it seems the roots will have access to plenty of calcium. If there are problems on the greens, I don't think they would be associated with a lack of calcium availability or calcium supply to the roots. In fact the soil looks good as far as nutrient supply goes. So I suspect that any problems would be related to air content in the soil, water content in the soil -- more likely that it is physical conditions of the soil causing problems, rather than chemical.
Ryan wrote back:
I am also applying a carbon product to help with the uptake of those nutrients as we thought that was a major problem ... I'm on the Cascade Duplex 4:1 program and last year, replaced both head and tail irrigation nozzles, did 2 flushes late in the season, deep tine aerified to help break up any layers and get sand down deeper into the profile ... I also needle tined every other week. This problem only existed on 3 of my greens, but since changing the program this year have had no issues. We have had a year with abundant rain which always helps, but have had a lot better turf health and recovery along with color this year. Would that change your recommendation and cutting the Calcium product?
With that additional information, I was pretty sure it wouldn't be a calcium issue, and I wrote the same to Ryan:
It sure sounds to me like the wetting agent program and the deep tine combined with the needle tining (and the weather, of course) would be the cause of the improvement, and it would be unrelated to nutrient availability in general or calcium supply specifically.
He has sent some additional information, and again I question whether it is the nutrient application that is causing the benefit, or other maintenance practices.
I actually had Magnesium in the program this year and saw pretty good results even though there is an abundant amount in the soil. I used Iron last year for some color along with a pigment and would get good color for a few days, but this year I haven't seen greens look better utilizing the pigment and Mg together. The color would last the 2 weeks in between sprays. I'm guessing that a lot of those nutrients that were high in the soil test are being tied up in some way. Is there products out there or ways besides what I've tried to do to help make those nutrients more available for the turf. It would be nice to be able to save some costs and cut Mg out of the program, but with how nice of color it gave me all year, it's tough.
That sure sounds persuasive, but I'm still skeptical. I just haven't seen where adding magnesium makes the grass green. This is where check plots are especially useful. Especially since so many things have changed from last year to this year.
When using a pigment, one must be cautious in saying that magnesium is causing the effect. If you would do a check plot, where only pigment was applied, but not magnesium, or vice versa, then you could confirm that one or the other are causing the effect.
I don't expect that magnesium is "tied up" -- I try to avoid that term because it is vague -- in your soil, so I would not be looking to do anything to make it more available [note that Mg is > 150 ppm, higher than both MLSN and conventional guidelines]. Now if you can apply magnesium only, without N, without Fe, without pigment, and get an effect, that would confirm that magnesium is providing a benefit. If you do that, please send photos. I would like to learn about that effect. I've heard people talk about it but I haven't seen it.
I hope I can learn more about magnesium here, or Ryan can either save some costs, or be more confident the Mg is required, through the use of a knockout trial. For more on how to do this, I like Dave Oatis's article, Sayin' It's So Doesn't Make it So, and the PACE Turf's guide to Testing Products and Practices.