Cover Crops Part 2:

Prepare now to Plant Green next spring

by Margit Kaltenekker

Agriculture Agent

 

It seems odd to think about next spring just ahead of harvest season? But it is a given. We always need to be a few steps ahead and consider crop rotations this fall that will impact our spring planting decisions next spring. The decision to plant cover crops now, in September, will have the potential to benefit winter grazing options, as well as positively impact spring planting next year. Improvements to soil aggregate structure take a few years after a transition to No-Till, based on keeping the soil covered with living roots and green cover (photosynthesizing even mid-winter). Improved water infiltration can make the difference of getting into fields earlier in the spring, especially if you are ‘planting green’.

‘Planting Green’ is the expression coined by Dr. Erin Silva’s research at UW-Madison, where their trials proved no negative effect of planting corn or soy into a ‘green’, standing cover crop, followed by terminating the cover crop soon after (or at time of planting), using a roller crimper. This research showed that the thick mat laid down by roller crimping also had no negative impact on emergence of the newly sown crops.

The idea is to allow the winter cover crop to remain in the soil through mid-late spring, before planting a cash crop. This extended period of early spring growth photosynthesizes through that ‘dormant’ window of early spring - stimulating soil microbes by dumping carbon into the soil, while drawing up other soil nutrients to the surface, especially nitrogen, phosphorous, and zinc. Deeply rooted winter rye will increase soil organic matter, making soils drought resistant and less prone to wind and water erosion.

Once the cover crop is terminated those nutrients are released slowly to the cash crop as they decompose. The mulch layer created at termination with a roller crimper, moderates soil temperatures between the row crop at the ideal temperature range for soil life (70-90F). Using a roller crimper after planting eliminates weed pressure and reduces the rate of herbicides required. ( Van Mansheim, a farmer in South Dakota, was able to save $30/ac as a result of following these practices).

Timing is still a major concern, depending on the moisture, and rate of warmth in the spring. You must watch soil moisture since rye can use up too much if it grows too tall. For detailed tips on timing the planting, there is a great planting guide at the end of this article. Practical Farmers of Iowa have been conducting various field trials and learning that allowing a winter rye cover crop to grow too tall can produce a yield drag on corn if you are not careful.

As with everything in agriculture, there are going to be variations year to year based on weather and moisture. Keep ahead of the options as you make plans for planting cover crops this fall.

Here are a few other resources from Extension and others:

Roller Crimping Cereal Rye Cover Crop ahead of No Till Beans

Planting Green 101: Penn State

Considerations When Planting Green, UNL

Planting Soybeans Green into Cereal Rye . Practical Farmers of Iowa.