By Andy Westhoven, AgriGold agronomist
Doesn’t that title sound a lot better than prevent plant ground syndrome? The words prevent plant (PP) send shivers down many growers’ backs. For those with PP acres, the season just keeps on offering new challenges. Many growers have worked the ground, sprayed the weeds, chopped the weeds, worked them again… you get the point. Let’s face it, the PP acres are more work to keep clean than the planted acres. In addition to those challenges, the title implies that idle farmland has some more work to do and there is more to watch for with PP acres leading up to next spring.
Fallow syndrome can occur when a corn (or wheat) crop is planted the year after no crop was planted in a field. These grass crops might exhibit a phosphorus (P) or zinc (Zn) deficiency early in the growing season. Plants will appear to be stunted, pale, and purple in color. This can also happen in cool, wet springs. Typically, plants will grow out of these symptoms as they continue to build up their root system and continue growing. P or Zn deficiency might occur after laying fallow due to a decrease in beneficial soil mycorrhiza fungi. Grass crops are hosts of these soil fungi. They provide the fungi sugars (from their root exudates) and in return, the fungi help the crop roots absorb P and Zn. If these crops/roots are not growing in an idle field, the population might decrease during the fallow time period and take some time in the spring to rebuild.
Many growers took advantage of a cover crop program and might have seeded a grass species. The good news is this will most likely prevent the fallow ground syndrome from happening! If you planted only brassicas (i.e. radish and turnips), then the syndrome might still appear. If soybeans were chosen as the cover crop, it definitely helps keep the fungi alive and thriving.
For future recommendations, never have a spring like 2019 — ok that was the obvious one. Plant cover crops (that include a grass species) on fallow acres. Otherwise, consider including starter/popup fertilizer during corn planting. Specifically, add P and Zn to the mix. These nutrients move very little in the soil and banding them early on near the seed will vastly help stave off this syndrome. Unfortunately, broadcasting phosphorus types of fertilizer will not help in this case.
It is also known that soils low in P levels, might have greater injury symptoms too. So be sure to check recent soil samples and identify key fields or areas within a field that might be more susceptible. One might also consider planting soybeans on some of the fallow farmland as an alternative to corn. (Soybeans exhibit less of the symptoms from the fallow syndrome.) Just as a side note, this fallow ground syndrome can also happen within planted fields. Areas of concern would be in drowned-out spots where no crop ever got established. These would also be areas to subsample or micromanage the following season.
This season will certainly go down in the record books for many of the wrong reasons along with some painful memories. However, we’re almost to the finish line and plenty can still be learned. A little prep work this off season will help prevent fallow ground syndrome. Please be safe and productive this harvest season!