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bit north of London, UK | hmm...i catching up here after a busy winter and months away...
No idea how 10lbs of sodium could start that revolution, but my soil mentor has seen the same.
This is what i thought u were gunning for, or something like it,
1. clay and humus hold ammonium ion indefinitely (unless soil waterlogged and warm...ie rice paddy)
2. Even big prills of AMS applied early spring can supply ammoniium N direct to plant for many weeks, maybe best part of 2 months, before soil temps rise and soil bugs convert ammonium to nitrite to nitrate.
3) Meanwhile plant has fed on ammonium N, grown "slower" and stronger than if nitrate N was involved.
4) Above is because plants have evolved to seek ammonium sources, send roots towards it, and ammonium ion needs a plant controlled active transport mechanism to cross into root hair - plant therefore controls pace of ammonium uptake.
Nitrate meanwhile, crosses into root almost unrestricted and can overload plant...plants solution to get away from potentially toxic nitrate load is to grow like hell to get the stuff processed to something stable.
5) Also, while ammonium not converting to nitrate and leaching....soils natural N fixers (nitrate mostly) are not subject to overload of their end product, and can run harder for longer.
6) A big prill of AMS sitting on, or recently dissolved into, soil surface has a fierce salt load on adjacent soil...enough to inhibit N converter bugs until it has been at least partially diluted by plant uptake
So one question might be...How to keeep ammonium ion in soil as ammonium??
1) Concentration...the higher the better...the principal of knifing in anhydrous and then NOT working the soil i assume (in UK we dont have anhydrous)
2) Be lucky enough not to farm sand and or load humus ( i farm clay similar to Texas Hay's - in Uk we also use it to make bricks)
On my clay soils / 22-24 inch annual rainfall heavily winter skewed at moment i use a spoke wheel injector to pile 180-220 lbs N as AMS 2 inches into the soil...start of spring ..1 hit
If it does not rain May/June (v possibe) wheat yields circa 3.5t/ac and spare N is left such that following winter canola might only get 100 lbs N april the following year on the last date the tractor and spreader can get thru the crop broadcasting 80 feet (ie yellow bud, getting on for waist high). Winter canola would normally be grown with same N load as wheat. ie circa 200 lbs / acre.
NB 208 lbs N acre is our mandated annual farm average N allowance, and then only if crop yield can justify it.
In a soil that is naturally mid 7 pH range, there are other side benefits to the AMS depot idea.
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100 lb nitrogen minimum
