# RichS Lawn Test Results - Waypoint



## RichS (Jan 28, 2019)

It's coming together.









I've never understood Waypoint's Mn range - almost everyone else recommends 30-45 as optimum. Pace, of MLSN, says 29-31 based on pH. So I pretty much ignore their reported Mn "shortage".

Strange that pounding the turf with Potassium SULFate increased K from 134 (Medium) last year to ~200+, but Sulfur dropped from 13 (Medium) down to near/into Low.

Time to find a Sulfur source, but it looks like a comparatively dull year - not much to work on. Sources, other than just elemental Sulfur?


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## Lawn Whisperer (Feb 15, 2021)

RichS said:


> Time to find a Sulfur source, but it looks like a comparatively dull year - not much to work on. Sources, other than just elemental Sulfur?


Gypsum, it has calcium and sulfur and will not affect PH.


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## RichS (Jan 28, 2019)

Thanks. I do have a bit of Gypsum in my plan, given the slightly low Ca reading. But only ~4lbs/1000. Plus ~3.5 lbs elemental Sulfur.

But that raises the same question in my mind - with hundreds of pounds of Potassium Sulfate (SOP) over the last two years, and still low Sulfur, would Calcium Sulfate impact an S reading differently?

With SOP, Ferrous Sulfate, Copper Sulfate, Manganese Sulfate, and Zinc Sulfate over the last few years, I would think I'd be swimming in Sulfur. Yes it's been steady/declining.


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## Ridgerunner (May 16, 2017)

> Strange that pounding the turf with Potassium SULFate increased K from 134 (Medium) last year to ~200+, but Sulfur dropped from 13 (Medium) down to near/into Low.


Not really. For every pound of K2O in 2.4 lbs of SOP added per M, K levels will theoretically rise 18 ppm while S levels will only rise about half of that and keep in mind sulfate is nearly as transient/soluble as N. An anion, it's highly subject to leaching.


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## RichS (Jan 28, 2019)

I put about 22lbs/K SOP over two years, so that should be ~160ppm K20, which is in the ballpark of the +110ppm increase I saw, given annual consumption (~10ppm per year from the Soil Growth Potential spreadsheets)

That means +80 ppm S, not even counting the 15lbs/K of Ferrous Sulfate I applied over the same time. And yet I saw a decrease. The soil is a silt loam, CEC 10-11, so it's not the sandy soil I think of as rapidly leaching.

It just seems odd that adding ~100ppm doesn't yield any soil test change.

I guess the good news is that, according to the Purdue research I read, most of the Sulfur applied to plants comes from organic matter, which seems to be in plentiful supply. I'm going to try the bag of elemental Sulfur I purchased and the small amount of Gypsum I planned and just leave it at that.


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