"Cobalt is essential for growth of the rhizobium, the specific bacteria involved in legume nodulation and fixation of atmospheric nitrogen into amino acids and proteins in legumes. Vitamin B₁₂, which contains Cobalt, is synthesized by the Rhizobium and circulated in haemoglobin. The haemoglobin content in the nodules is directly related to nitrogen fixation. Thus a deficiency in Cobalt is shown in reduced Vitamin B₁₂ production and lower nitrogen fixation." http://www.fao.org/ag/agp/AGPC/doc/publicat/FAOBUL4/FAOBUL4/B402.htm

Adequate cobalt prevents pernicious anemia (B12 deficiency) in animals. Anyone eating from their garden needs to soil test for cobalt to prevent this problem. Southern soils in the US, particularly, can be very low in cobalt.

Friends, the fact of the matter is that many soils tested for cobalt are largely deficient. Castle Valley Farms has a soil that tests low in cobalt. Our goal is to create healthy soil and gut critters and so we will be adding it each year to achieve optimal levels.

"Molybdenum is required for growth of legumes and by rhizobia in root nodules. It is often deficient in acid soils and legume growth responses to small applications of Mo are well documented. Molybdenum deficiency in legumes is usually denoted by inward cupping of leaflets of young fully expanded leaves. If a legume is totally dependent on its Rhizobium symbiosis for nitrogen, the symptoms of molybdenum deficiency and nitrogen deficiency are similar." http://www.fao.org/ag/agp/AGPC/doc/publicat/FAOBUL4/FAOBUL4/B402.htm 

Folks, nitrates do accumulate in plants when molybdenum is low. The enzyme, nitrate reductase requires molybdenum to begin the protein making process. When nitrates accumulate, aphids, mites, and other issues follow. Grape growers notice nematode issues go away. Consider soil testing for molybdenum so your nitrogen goes to make protein, not toxic nitrates.