I have not done AMS but I have done Urea and I like it.

My best example is when spraying MSM. .5g per 1000 without urea its not bad, but with urea its a killer for spurge.

 

I have a completely unsubstantiated theory that Urea acts as a mild surfactant as well. These days if I am spraying anything it has .2lb of N by way of urea.

 

Is it possible to over do it at those levels?
For example, what if I sprayed .2 lb of Urea per thousand every 3-4 days...

 

I know use of soluble nitrogen is recommended when using quinclorac (for Drive XLR8, at least), but apparently that's only to reduce turf yellowing, and the label says nothing of improving efficacy that way.

I have a small field of crabgrass that will have a date with some quinclorac soon. Maybe I'll add some of the AMS I got on clearance to it and report back.

 

Also, if you (OP) have access to it, this paper may be of interest to you. It deals with quinclorac specifically.

Quinclorac Efficacy as Affected by Adjuvants and Spray Carrier Water

Laboratory and greenhouse experiments were conducted to determine quinclorac efficacy as influenced by surfactants, methylated seed oil (MSO), basic pH compounds, and salts in the spray carrier water.

[...]

Sodium and calcium ions strongly antagonized quinclorac efficacy when applied with a block copolymer surfactant or MSO. Ammonium sulfate or ammonium nitrate adjuvants were more effective than urea-ammonium nitrate liquid fertilizer in overcoming antagonism from salts in spray carrier waters.

[...]

 

The recommended rates that I have seen for the added AMS are quite low, as little as 1/10 lb per gallon. That's the approximate rate I will try first since my water hardness is pretty low. The last article I read on the subject involved its use with glyphosate apps.

 

Any chance you could share the article?

I have very hard water, I suppose I could try at the same rate.

 

Adding AMS or Urea to any herbicide is going to increase the efficacy as you are feeding the weed and it will take up the "poison" more readily with it in the mix.

 

I will look for it in my browser history. Other than just the N aiding in uptake, there was something about the chemistry of the AMS that mitigates the calcium and magnesium in the water being used. My bag of solutions grade ammonium sulfate is even labeled spray adjuvant, I think.

 

Below is the link from Michigan State. It does say you should use solutions grade ammonium sulfate.

Do I really need to add ammonium sulfate to my glyphosate spray mix?