posted 6 years ago
A lot of nitrogen fixing bacteria, both the free living kind and legume host needing kind, fix atmospheric nitrogen with an enzyme called nitrogenase. Nitrogenase needs molybdenum in the soil to function. Low levels of molybdenum can result on low nitrogen fixing with really no fault to the bacterium itself, even when in abundance. Often the bacteria are already there in the soil, and giving a little molybdenum boost to a depleted soil can really kick off some abundant nitrogen fixing.
"Study books and observe nature; if they do not agree, throw away the books." ~ William A. Albrecht