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Sponsored: 2016: The Year of Mineralization
In all likelihood this winter as you down a short stack of pancakes and cup of coffee at an industry meeting, you’re going to hear talk about “mineralization”. Undoubtedly the 2016 growing season will be remembered as a year where we received a tremendous free gift of nitrogen mineralized from the organic matter in our soils. But what is mineralization and how do we measure it?
Your soils contain a lot of organic nitrogen, among many other nutrients, as a component of the organic matter. As this organic matter is mineralized or “burned” it releases that nitrogen into the soil. The process of mineralization is highly dependent on factors such as pH, oxygen, temperature and proper moisture. When these factors are in the right measure, the organic matter is oxidized and releases the nutrients. If not, mineralization occurs much more slowly.
Take for instance a peat bog. Because of the lack of drainage and often times lower temperatures, the excess moisture and lack of oxygen in combination with the cool temperatures dramatically slow the mineralization of the organic matter and as such it accumulates to high levels.
Here is how we calculate mineralization. An acre furrow slice (~6” depth) of soil contains 2,000,000 pounds of soil. Soil organic matter contains about 5% nitrogen. Therefore 2,000,000 times 1% organic matter = 20,000 lbs of organic matter in an acre furrow slice. 40,000 pounds for 2% organic matter, 60,000 pounds for 3% etc.
If 1% of organic matter weighs 20,000 pounds and that 20,000 pounds contains 5% nitrogen then that equals about 1,000 total pounds of nitrogen per percent organic matter per acre furrow slice. In a year in which all the above mentioned factors are in good balance we can mineralize up to 2 or 3% of that 1,000 pounds. So 1,000 x 2% = 20 pounds of nitrogen. If you have 2% organic matter soil it contains around 2,000 pounds of nitrogen x 2% mineralized = 40 pounds and so on. Keep in mind that these numbers are for every 6” depth.
As you can see, the numbers add up fast and many growers experienced a huge free gift of mineralized N this year. For those growers who waited to apply their N and measured in season they were able to utilize this free mineralized nitrogen this year and produce large yields with much less applied inorganic nitrogen allowing them to save on inputs and increase their return.