# 0-0-50+S17% ...... High % of Sulfur in a low pH soil. Problem?



## Dave81NJ (Jun 7, 2018)

I am about to pull the trigger on this fertilizer 0-0-50+S17% to deal with low levels of Potassium. One issue is that SOP type of Potassium sometimes is accompanied by high level of Sulfur. This 0-0-50+S17% that I found is an organic fert and it has that 17% Sulfur in it.

Now ... some people tell me that is a problem for soil like my where my pH is 5.8 and some say that that Sulfur won't have any negative impact on my pH. So which is it? Please help as I need to order today.

Thanks.


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## Virginiagal (Apr 24, 2017)

The sulfur that is in potassium fertilizers has no effect on pH. Elemental sulfur lowers pH. Here is some info:
https://www.cropnutrition.com/resource-library/fertilizers-and-soil-acidity


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## Dave81NJ (Jun 7, 2018)

Virginiagal said:


> The sulfur that is in potassium fertilizers has no effect on pH. Elemental sulfur lowers pH. Here is some info:
> https://www.cropnutrition.com/resource-library/fertilizers-and-soil-acidity


interesting. Then why are they adding 17% of sulfur? to increase Sulfur in soil, yet that would play no effect on pH? For example, my pH is 5.8 right now and Sulfur in soil is at "Medium" a bit under Optimum, 12ppm to be exact.


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## Virginiagal (Apr 24, 2017)

Potassium sulfate is a substance (K2SO4) that has potassium and sulfur and oxygen in it. They aren't adding sulfur just to be adding it. Ridgerunner has a section on sulfur in his soil testing thread. I'll copy it it here:
Sulfur (S)
Sulfur is the overlooked nutrient. It is important to plant health, photosynthesis, other important processes and winter hardiness. Unless elemental sulfur has been applied to the soil within the past two years (Sulfur is often used in an attempt to lower pH, more on this supra), the vast majority of the sulfur reported as ppm on the soil test (and the form in which nearly all S exists in the soil) is in the form of sulfate. Sulfate is the only form of S that the turf plant uses. Sulfate will NOT result in lowering soil pH.
Soil Sulfur (sulfate) should be adjusted to the values given for the particular extraction method used (see guidelines supra.). Adjustment amounts are calculated the same way as amendment amounts for any other nutrient:
The FORMULA:: (Desired ppm level -(subtract) test reported level) X 2 / 43.5= total amount of lbs of S per M needed to reach the desired S ppm soil level to a 6" depth. Divide that amount by the % S listed on the bag of fertilizer amendment to determine the total amount of that amendment needed to reach the desired value. If using elemental sulfur (advised against) do not exceed 2#/M every 6 months.
Although Elemental Sulfur can be used, it is suggested that any S deficiency be made up by applying fertilizer amendments such as sulfur coated urea, or even more preferably, a sulfate containing amendment such as ammonium sulfate or when adjusting other nutrients, by applying gypsum, potassium sulfate, magnesium sulfate or K-mag and retesting for S in a subsequently scheduled nutrient soil test.

For the nerds  : 1. Elemental sulfur will lower soil pH BUT Sulfate does not lower soil pH. 2. In very unusual situations, sulfate buildup can create a black layer. This occurs in humid high temperature climates where anaerobic conditions may arise due to excess water and soil compaction and poor soil drainage. This has been observed on some golf courses where intensive sulfate containing fertilizers are applied and due to excess soil water, microbes use the oxygen in the sulfate and replace it with hydrogen producing hydrogen sulfide (rotten eggs) creating toxic conditions.


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## Dave81NJ (Jun 7, 2018)

Virginiagal said:


> Potassium sulfate is a substance (K2SO4) that has potassium and sulfur and oxygen in it. They aren't adding sulfur just to be adding it. Ridgerunner has a section on sulfur in his soil testing thread. I'll copy it it here:
> Sulfur (S)
> Sulfur is the overlooked nutrient. It is important to plant health, photosynthesis, other important processes and winter hardiness. Unless elemental sulfur has been applied to the soil within the past two years (Sulfur is often used in an attempt to lower pH, more on this supra), the vast majority of the sulfur reported as ppm on the soil test (and the form in which nearly all S exists in the soil) is in the form of sulfate. Sulfate is the only form of S that the turf plant uses. Sulfate will NOT result in lowering soil pH.
> Soil Sulfur (sulfate) should be adjusted to the values given for the particular extraction method used (see guidelines supra.). Adjustment amounts are calculated the same way as amendment amounts for any other nutrient:
> ...


appreciate you sharing all this info.
From the previous link you sent, this part stood out to me where they are saying that it DOES effect .... maybe I am reading it wrong?

"The form of S fertilizer added to soil can affect soil acidity, principally through the release of H⁺ ions by the addition of elemental S (S⁰) or thiosulfate (S₂O3²⁻, in ammonium thiosulfate - ATS) (Figure 3). However, the amounts of S added to soil and taken up by plants are generally small in comparison to N."


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## g-man (Jun 15, 2017)

@Dave81NJ Sulfur does not change pH. pH is a measurement of Hydrogren in a log scale.

Multiple products will release hydrogen into the soils and they can change the pH. These include some nitrogen sources and elemental sulfur (via the sulfuric acid reaction, again hydrogen and not sulfur).

Apply the SOP from any brand and it will not change your soil pH.


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## Dave81NJ (Jun 7, 2018)

g-man said:


> @Dave81NJ Sulfur does not change pH. pH is a measurement of Hydrogren in a log scale.
> 
> Multiple products will release hydrogen into the soils and they can change the pH. These include some nitrogen sources and elemental sulfur (via the sulfuric acid reaction, again hydrogen and not sulfur).
> 
> Apply the SOP from any brand and it will not change your soil pH.


Thanks ... it's just that another guy on facebook group is dead set that it does change, and he says

"I have a degree in Soils. I can assure you that sulfur has an acidic effect and can change the pH. I have been doing it for several decades on dozens of properties"

go figure.


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## Virginiagal (Apr 24, 2017)

You were reading under sulphuric fertilizers, in particular referring to elemental sulfur, ammonium thiosulfate, and sulfate of ammonium. Go down to the section on potassium fertilizers. It says:
"The form in which K is added to soil - either muriate of potash (KCl) or sulfate of potash (K₂SO₄) - has no effect on soil acidification. "

Sulfur does affect pH. Potassium sulfate does not,


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## Dave81NJ (Jun 7, 2018)

Virginiagal said:


> You were reading under sulphuric fertilizers, in particular referring to elemental sulfur, ammonium thiosulfate, and sulfate of ammonium. Go down to the section on potassium fertilizers. It says:
> "The form in which K is added to soil - either muriate of potash (KCl) or sulfate of potash (K₂SO₄) - has no effect on soil acidification. "
> 
> Sulfur does affect pH. Potassium sulfate does not,


ok, so that fert that I mentioned that says +17% Sulfur .... that will effect pH?
Could it be that all SOP (Sulfate of potash) has Sulfur and one must then use MOP (Murate of Potash)??


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## Virginiagal (Apr 24, 2017)

Good grief. It's fine to use SOP. I looked at two products with 0-0-50-17 (the fourth element being sulfur). They both said the sulfur % came from potassium sulfate. Don't fear the sulfate form. They are not putting elemental sulfur in the bag. Sulphur is a necessary nutrient for grass.


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## Dave81NJ (Jun 7, 2018)

Virginiagal said:


> Good grief. It's fine to use SOP. I looked at two products with 0-0-50-17 (the fourth element being sulfur). They both said the sulfur % came from potassium sulfate. Don't fear the sulfate form. They are not putting elemental sulfur in the bag. Sulphur is a necessary nutrient for grass.


haha, Virginiagal ... done, understood. Thanks for sharing your knowledge. The other person who was advising me ultimately said that the article is probably a misprint and bailed on me. I will go ahead and get one of those 2 ferts. Thanks again.


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## Lawn Whisperer (Feb 15, 2021)

I think you're getting confused with the word sulfur itself. It depends on the form of sulfur. Sulfur in elemental form (S0[/sup]) will lower soil ph, while sulfur in the form of sulfate (ex. SO[sup]4) will not. The sulfur in SOP is in the form of sulfate, therefore SOP will not affect ph in soil.

SOP may be applied without affecting soil ph.


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## Dave81NJ (Jun 7, 2018)

Lawn Whisperer said:


> I think you're getting confused with the word sulfur itself. It depends on the form of sulfur. Sulfur in elemental form (S0[/sup]) will lower soil ph, while sulfur in the form of sulfate (ex. SO[sup]4) will not. The sulfur in SOP is in the form of sulfate, therefore SOP will not affect ph in soil.
> 
> SOP may be applied without affecting soil ph.


thank you for the clarification. Appreciate it.

will create a new post about my pH and dolomitic lime, hope you can address it as well.


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## Dave81NJ (Jun 7, 2018)

Lawn Whisperer said:


> I think you're getting confused with the word sulfur itself. It depends on the form of sulfur. Sulfur in elemental form (S0[/sup]) will lower soil ph, while sulfur in the form of sulfate (ex. SO[sup]4) will not. The sulfur in SOP is in the form of sulfate, therefore SOP will not affect ph in soil.
> 
> SOP may be applied without affecting soil ph.


hang on ... so I am looking at a lable and it says, K2O is 50 SOP and as you said, no need to worry, but it has an added S17% and that's Sulfur. Here is the label https://www.7springsfarm.com/content/SOP_Label.pdf bad for low pH?


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## Lawn Whisperer (Feb 15, 2021)

Product Label
AG GRANULAR SOP
0-0-50
SULFATE OF POTASH
GUARANTEED ANALYSIS
Soluble Potash (K2O)............................50% 
Sulfur (S)................................................17% 
17% Combined Sulfur
Derived From: Potassium Sulfate

They didn't add elemental sulfur, they are just listing the active ingredient of sulfur which is in in the form sulfate (SO4).

potassium sulfate (K2SO4)

Read the label this way:
Product Label
AG GRANULAR SOP
0-0-50
SULFATE OF POTASH
GUARANTEED ANALYSIS
Soluble Potash (K2O)............................50% 
Sulfate (SO4)................................................17% 
17% Combined Sulfate
Derived From: Potassium Sulfate


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## Lawn Whisperer (Feb 15, 2021)

Dave81NJ said:


> ... will create a new post about my pH and dolomitic lime, hope you can address it as well.


In calcium, there is a difference between calcium (Ca) and calcium carbonate (CaCO3).


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## Ridgerunner (May 16, 2017)

> Good grief.


K2SO4 is 17% sulfur by molecular weight. (look up the molecular weight of potassium, sulfur and oxygen and do the math) It's actually closer to 18%, but not quite; however, labeling laws preclude rounding up. It must be rounded down. The sulfur is in the form of sulfate (not elemental sulfur) and sulfate will not affect pH anymore than water will explode even though water is 11% hydrogen. Go ahead, try to set water on fire.


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