How and When to Plant No-till Soybeans

By James Hoorman, Hoorman Soil Services

Planting no-till can be tricky and scary! Successful no-till depends on having fully functioning healthy soils and efficient nitrogen (N) recycling.  Fully functioning soils have higher soil organic matter (SOM) especially the active carbon, sugars, and root exudates  from live roots that allows the soil to crumble.  This leads to good soil structure, improved  drainage, increases water infiltration, and higher soil gas exchange. This aerobic (more oxygen) environment plus the food source (live cover crop (CC) roots) changes the microbial community from one dominated by bacteria (conventional soils, often anaerobic (no oxygen)) to a balanced system with beneficial fungi (mycorrhizal), good nematodes, healthy aerobic bacteria, and protozoa.  The “no-till time line” or transition period is often 3-7 years depending upon how fast and aggressive cover crops, continuous no-till, and manure have been used to promote a fully functioning healthy soil.

Soybeans are hardy, easy, and most simple crop to no-till.  Since they are legumes and make their own N, nitrogen is not a problem. Planting green into a CC (most likely cereal rye or radish) may increase yields 5-7 bushel.  Cereal rye and radish have an allelopathic (weed killing) effect.  Radishes die in the winter and improve soil structure.   Cereal rye has fast spring growth, dries out the soil (.25 to .33 inches/day), reduces Phytophthora  and Rhizoctonia, and reduces soybean cyst nematodes. Planting green into cereal rye (boot stage) has been very effective.

Let the soybeans grow several inches and then terminate (crimping or spray). If the soil starts to dry out and get hard, terminate CC immediately.

Some farmers like to kill the CC first.  Kill the CC at least 2-3 weeks early, because cereal rye that is half dead will hair pin, bind, and wrap; causing planter problems.  The worst-case scenario is killing the cereal rye first when it is tall, then getting a rainy spell that forms a mat which reduces soil drying.  Plant green and then terminate CC later OR kill CC really early for successful no-till soybean planting.