The Nitrogen Tightrope

Now that I’ve read the compost study, Albrecht’s article on soil restoration, and the nitrogen myth article, I’m still left wondering how nitrogen directly impacts the formation of organic matter. Albrecht insists that there must be adequate nitrogen present in the soil or else carbon is lost (presumably as carbon dioxide). The compost study results back this up – more nitrogen resulted in more soil carbon. But then the nitrogen myth article implies that excess nitrogen (and I mean extreme, as in 60-190% net addition of N) also results in the loss of carbon from the soil. How does this work?

C + Excess N = CO2

C + Too little N = CO2

C + Just the right amount of N = Soil carbon

I think I need to get my hands on a soil science/microbiology textbook. Maybe I’ll peruse eBay and find a cheap copy that some college student spilled their beer on.

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4 Comments »

  1. David said

    There’s a difference chemically and biologically in N forms. Highly soluable N (ionic; think ammonia) vs N in protein (chelated), for example, will make a considerable difference in effect.

    d.

  2. Agreed – I noticed that the compost study used chicken manure as a nitrogen source, while most commercial farmers (those referred to in the nitrogen myth article) use chemical fertilizers. I can definitely accept that the degree of effect lies in the type as well as the quantity of N, but I’m just curious as to *how* different forms have different interactions with the soil. It’s a very open question with probably a very complicated answer that I might only find by poring over soil science textbooks. That being said, I think my bigger issue is that I don’t have a good foundation in soil science, which is something I hope to remedy soon. Thanks for the feedback!

  3. David said

    I am engaged in the same process as you, albeit with perhaps a different starting place, and the advantage of a bit of land with which to actually work: 11 farmable acres here in Oregon.

    Soil science is in its infancy, frankly, because what one really needs to understand is a wonderfully, densely complex ecosystem. It is a bit easier to understand soil chemistry, which is complex enough, but if you want to gain some idea of how little is actually known, try to find out good actionable information on trace elements. Or look at a soil test, and you will see that most of what is being reported is based entirely on a view of the soil system that is NPK and soluable nutrient based.

    In my view, one must first insure that the soil has what it needs in terms of minerals– rock fertilizers aplenty, although scientific information sufficient to distinguish among commercial products is lacking– and then work on the life of the soil.

  4. beecharmers said

    I may have that book, without the beer stains. Let me look into it.

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