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EC Nebraska | High pH is difficult to manage. From my limited experience you can't really lower the pH much, at least not in a cost effective way. I've got soils with numbers similar to yours that have had 400-600 lbs/acre AMS applied multiple years with very little change in pH. You simply try to manage the chemistry, not change it much. Sulfates (in excess of plant uptake) can help free up some of the bound nutrients and make them available to the crop. That's your goal with the AMS. But they can get you in trouble too. They'll leach through a well-drained soil (if you have water moving through it) and take whatever cations (K, Ca, Mg, Na) they can along for the ride. That's good if you've got something you're trying to get rid of. But you don't want to run out of anything either. So you've got to keep adding the things you're short of while your excesses drain away. Or at least, that's my understanding of it. Others may view things differently.
So, with what you've told us so far, I'd go with 200 lbs of AMS and 100lbs of K-Mag. You've got plenty of Calcium but lowish on the available K and Mg. Gypsum will just add more Ca, no need for that.
I don't think higher rates of sulfur would be beneficial. By the time you leach out enough Ca to significantly lower the pH you'll have leached out too much of every other cation, which you just have to replace. 300 lbs total AMS and K-Mag should be enough sulfur, IMO. Mix and match those two as you wish.
Edited: Tissue testing for micros should be on the plan for this year. Soil tests probably aren't going to be accurate.
Edited by NE Ridger 1/8/2014 12:37
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ammonium sulfate for high ph soils
