“TO PLANT GREEN OR NOT TO PLANT GREEN”
Nathan Hicklin
USDA/NRCS District Conservationist – Springfield, TN
I will preface this article, by saying that after you read this, you will not have the “one size fits all” answer! With more growers planting cover crops as part of a soil health management system, I get this question a lot. “Should I plant green or wait for the cover crop to completely terminate?” My answer most of the time, like many things in production agriculture is, “it depends”. Cover crop management strategies will be different for every grower depending on equipment capabilities, field conditions, inherent soil properties, weather conditions, and the list goes on.
Generally, I tend to lean toward my answer being, plant green, especially with corn. In late March and April weather conditions are usually wet and soils tend to be “heavier”. Planting green takes advantage of the cover crop still being able to pull moisture out of the soil as it slowly dies. This has proven to be very beneficial, especially on river/creek bottoms and poorly drained soils. When cover crops are terminated early, they will continue to hold moisture, which in turn can greatly increase the amount of days it takes before field conditions are right to plant the cash crop. I have noted while working with experience growers that planting green provides better closing of the furrow and less hair pinning.
If you are going to plant green, my guidance is usually to apply herbicides 1-2 days before or after planting. Depending on weather forecast and inherent nature of soils, we have some growers delaying termination up to a week to allow the cover crop to pull out excess moisture. I usually discourage growers from planting into cover crops when they are “yellow”, I have seen this method cause planting issues in the past, like not being able to properly cut through the residue and causing some hair pinning issues.
As far as soybean planting goes, I feel like there are usually less complications with terminating cover crops 2+ weeks prior to planting. From mid-May through June we usually have less rain and warmer temperatures as compared to late March through first of May. Depending on planter set up and whether you have access to an implement to roll down the cover crop, covers can get so big that I have seen issues planting through cover crops that are chest to head high. I always promote as much biomass as practical for successful planting to provide lasting residue throughout the growing season to conserve soil moisture, reduce soil crusting and keeping the surface aggregated to facilitate infiltration for those much-needed summer showers. Like green planting corn, this is usually a case by case basis; based on field conditions, what was in the cover crop mix and how thick the stand is.
As I mentioned in the beginning of this article, I would not be giving you a “one size fits all” answer and if someone tells you they do have that “one size fits all” answer, I would be very leery! Whether we are growers, private agricultural consultants, agronomists or soil conservationists our job should be to give others information and tools to help them make informed economical decisions to rejuvenate degraded soils and have a healthy productive crop.