# Is this a good fertilizer?



## hammerhead (May 14, 2019)

Picked up this fertilizer . Was quite cheap, around 30$ for 100 lbs.
I plan to use it for the cool season grass fall nitrogen blitz. It seems there is 2/5 urea and 3/5 ammonium sulphate of the 21% nitrogen in total. As you can see in the pic there are also other micros included. 
Q1: Do you think those micros are contained in reasonable amounts in order to benefit cool season turf grass?
Q2: Do you think that 18% sulphur was added on top or is it contained in the ammonium sulphate? According to my calculation there should be be a total of 14.4% of S in if all of it comes from AS (AS seems to contain 24% of S => 24/5*3=14.4). Does it mean they added another 3.6% of S to the bag?
Thanks!


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## hammerhead (May 14, 2019)

Regarding my first question: Maybe I should ask it differently. Do you think the high Mg content could harm cool-season turf grass? Do you think any of of the other micros are dosed too high for cool season turf grass? Thanks.


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## g-man (Jun 15, 2017)

I dont like adding Mg to a soil unless the soil test indicates it.


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## Ridgerunner (May 16, 2017)

> Q1: Do you think those micros are contained in reasonable amounts in order to benefit cool season turf grass?


 It would depend on current levels. I agree with @g-man regarding using a soils test to make amendment decisions, especially for micros. For instance, each time you apply the equivalent of 1#/M of N via that product, you'll be increasing ppm of B by about 0.1 ppm. Unless your B levels are already excessive, adding that amount would unlikely create issues. However, B at excessive levels (>5 ppm)can be toxic to most plants. Recommended levels are 0.5-1.5 ppm -ish.



> Q2: Do you think that 18% sulphur was added on top or is it contained in the ammonium sulphate? According to my calculation there should be be a total of 14.4% of S in if all of it comes from AS (AS seems to contain 24% of S => 24/5*3=14.4). Does it mean they added another 3.6% of S to the bag?


 There is also some contribution S from the Mg source, magnesium sulfate (MgSo4) and slight (negligible) amount of S from the micros as they are likely sulfate forms. Not likely, but the urease inhibitor might be thiosulfate. It's very possible that they have enhanced the sulfur levels with an addition of elemental sulfur. Most states require a guaranteed analysis label and that will often list the sources of the nutrients, check the bag for that.


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## hammerhead (May 14, 2019)

Thanks @g-man for your input . Indeed the Mg content is quite high. I now did some quick research on magnesium. Mg toxity for plants in general seems to be rare (https://ask.extension.org/questions/401721), so i think I will stick with this fert for this fall, but will exchange it for a better one (pure urea or AS) the next season.


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## hammerhead (May 14, 2019)

Thanks @Ridgerunner for teaching me about B. That means I'd have to throw down about 10#/M of N coming from that fert in order to raise B levels 1 ppm. That would take more than 2 years, so I think I'll be safe using this fert during this fall season.

Also did some research on the magnesium sulphate based on the hints you gave me and i think I got the S numbers right now.

21% N
|__ 3/5 AS (AS contains 24% S)
|__ 2/5 urea
3% Mg

*S from AS: 24/5*3=14.4*

Mg Sulphate contains 9.8% Mg and 13 % S
Mg Sulphate: 3/0.098= 30.6
*S from Mg Sulphate: 30.6 * 0.13= 3.98*

*S total: 14.4 +3.98=~ 18*

So I think there was no elementary S added to the bag. As far as I know that S from those 2 sources (AS and Mg Sulphate) do not have an effect on soil PH since the sulphur is not elementar. Only the ammonium from AS has therefore a direct effect on soil PH(lowers PH). Can somebody confirm?

PS: No further sources for the elements in the fert are mentioned.


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## adgattoni (Oct 3, 2017)

I doubt you will experience any significant shift in PH from using that bag over the fall. You might be able to find a 21-0-0 equally cheap or even cheaper in your area. Rural King for example sells AMS for $10/bag before tax.


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## hammerhead (May 14, 2019)

adgattoni said:


> Rural King for example sells AMS for $10/bag before tax.


I'm in Switzerland, which in general is one of the most expensive countries. 30$ for 100 lbs is dirt cheap for us here. The particular shop did not carry pure AS, so i took Mg-Ammonsulphate. They also had urea for 15$/100lbs, however i prefered something that contains AS.


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