Q & A

Q:  Real questions from real farmers

A:  Real answers from NRCS Soil Health Specialist Barry Fisher

Q:   I have been broadcasting cereal rye and disking it in.  I use a conventional disk set at 2 in. followed by a single round bar crumbler.  I wonder if I am defeating expectations of improving organic matter by disturbing the soil? I do not have a drill. Should I consider renting one or is my present practice ok?   --Neil, Indiana farmer

A:  The problem with a tandem disk is that it not only cuts residue, it inverts the soil burying residue and breaks apart soil aggregates with the side to side movement, allowing much more CO2 escape. It will take a lot of cereal rye growth to rebound from that much carbon loss. Additionally, the 2″ depth is deeper than I’d recommend. Loosening the soil deeper than your planting depth promotes shallow rooting of the cereal rye. As roots emerge in the loose soil, they will be slower to penetrate the denser soil beneath. This is a long answer to explain why a straight disk of a no-till planter is superior when planting cover crops and building organic matter. If soybean stubble is the residue being planted through, many conventional drills alone can achieve an adequate CC stand while preserving that precious carbon. –Barry Fisher

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Q:   I was reading over some cover crop power point presentation notes and ran across one that states “Does form Arbuscular Mycorrhizal associations”.  Ok  can you please tell me what exactly they are talking about?  -Doris, Conservationist

A:    Cover Crops that form Arbuscular Mycorrhizal associations are beneficial to row crops like corn and soybeans that also benefit from this mutualistic association.  CCs like cereal rye, oats, annual ryegrass, and most legumes form these associations.  Most brassicas like mustards, canola, rape seed, and oilseed radish do not.  This is why we should usually plan for a cover crop with Mycorrhizal associations be planted in a mix with Oilseed radish or other brassicas when corn or Soybeans are to follow.  –Barry Fisher