Ammonium sulfate is a very important fertilizer for any kind of soil that's high in pH and needs a little bit of sulfates to work against the high calcium or the high pH. The nice thing about the ammonium sulfate is that the nitrogen in it is a little bit slower releasing so it lasts throughout the growing season better than the nitrate forms of nitrogen.
We also find that ammonium sulfate is very helpful for plants that are producing any kind of oil, like soybeans that produce soybean oil. Those kind of things will take a little extra sulfates. Alfalfa crops will take a little bit of sulfates to make the sulfur-bearing amino acids. Alfalfa and legumes such as soybeans will benefit from some ammonium sulfate.
We never use over 200 lbs. an acre. We would keep it to 100-200 lbs. as typical application rates. We find that the amount of sulfur in the air has been reduced due to the pollution and the environmental controls so that less sufur is given up by industry into the air. And while that can be helpful for the environment where there was a problem with acid rain and the pH is going very low in the soil, for farmers that means there is probably a deficiency of sulfur in the soil. And one of the best ways to provide it very quickly is with ammonium sulfate.
A lot of recommendations that we give at International Ag Labs have ammonium sulfate. We find it to be a very important nitrogen and sulfur source that is very helpful for stimulating bacteria from the sulfates.
The reaction against calcium is also very powerful, so a lot of times we can use ammonium sulfate to help make calcium available. It's a very important tool in the farmer's arsenal of products.
Ammonium sulfate is not usable in organic production.