News Feed Forums Soil Health respiration, ammonification, nitrification, denitrification, DNRA! Reply To: respiration, ammonification, nitrification, denitrification, DNRA!

  • Benny Thompson

    May 13, 2023 at 1:22 pm

    I was hoping someone would want to talk about this topic…I guess I’ll just talk to myself, LOL


    I just found out that: Yes, what John Kempf and Olivier Husson said about Nitrate (NO3) being converted back to Ammonium (NH4) under saturated conditions is true-ish. Rather, it does happen, but it’s usually not the dominant pathway for nitrate reduction. It’s called DNRA, Dissimilatory nitrate reduction to ammonium(NO3–>NH4). Which is different from denitrification. (NO3–>N2). More info here:

    from the link above, an important quote!
    Within an ecosystem, denitrification and DNRA can occur simultaneously. Usually DNRA is about 15% of the total nitrate reduction rate, which includes both DNRA and denitrification. However, the relative importance of each process is influenced by environmental variables. For example, DNRA is found to be three to seven times higher in sediments under fish cages than nearby sediments due to the accumulation of organic carbon”

    Effectively, the more organic carbon you have in your soil, the more DNRA will occur under saturated(anaerobic) conditions. That’s a good thing! Because you want to conserve your nitrogen in the soil, in this case, conserve N in the form of NH4. In contrast, denitrification will release nitrogen to the atmosphere in the form of N2 gas.

    Funny how everything seems to point toward –> more organic carbon makes everything better.