Right on point.But, keep in mind that the soil pH is nothing more than a "quick-reference" for the soil condition...a view from 10,000 feet, if you will.What soil pH really tells you is the presence or absence of hydrogen...nothing more. The base saturation cations, potassium, calcium, magnesium and sodium are the major players in affecting soil pH. When they are out of proportion, you can chase pH for years without success.Rather, if you adjust the calcium:magnesium ratio appropriate to the soil CEC (ie 68%:12%) that will get the right air:water ratio into your rootzone first and create an environment conducive to microbial activity and the soil pH will adjust itself toward neutral. Also, nitrogen applications rates must also be made according to the soil CEC to maximize NUE and lessen leaching risk.
@Marc Suderman You often hear that sulfur helps break cation bonds and helps knock hydrogen loose so that it can be replaced by other cations that the plant needs. But wouldn't the sulfur affect all cations the same? ie, it's not selective in terms of what bonds it breaks? I just wonder the effect of gypsum or ammonium sulfate on base saturation numbers. Does using gypsum increase the ca base sat % at the expense of other cations or just H? Thanks
All great questions, but lets start slowly.Here is a link that shows the basic reaction for a starting point. It focuses mainly on how pH is lowered in the soil with sulfur applications. After that we can address the other questions you posted.http://ohioline.osu.edu/agf-fact/0507.html
So the presence of Ca in gypsum or K and Mg in KMag should bind when the S breaks the H bonds thus creating a neutralizing effect?
S is the "catalyst" and starts the reaction which reacts with water and releases H for the cation exchange (nutrient release) which stimulates root and plant growth response.
I hope I am going in the right direction for you!
I found more info. I will post it soon.
"Nutrients adsorbed on the clay are taken by the plant root mainly as it exchanges hydrogen or acidity for them." - W.A. Albrecht, Ph.D. "Albrecht's Foundation Concepts" - Chap. 26, pg. 322
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