By Don Donovan
Each winter brings new challenges to cover crops. What kinds of issues did we see from the winter of 2017-18 that we might want to think about for next season? Much of Indiana received a late, intense rainfall event — and it seemed like February was warmer than March. How does that impact cover crops?
We saw erosion of all types, including some serious gully erosion. The result of that erosion was streams and rivers full of sediment-laden runoff. The sediment contained nutrients — possibly herbicides — and most importantly, the most productive layer of topsoil. What may take years to produce was lost in a matter of hours. We also saw large areas of cornstalk accumulation, especially where stalks chopped up by vertical tillage were easily moved.
What did we learn? Fields that are conventionally tilled can’t stand up to large rains, but that is not a big surprise. We also learned cornstalks that were chopped with a vertical tillage tool are susceptible to being swept away by runoff. In long-term continuous no-tilled fields — and especially those that also had cover crops — we didn’t see stalks moving off-site because they were still anchored into the soil and caught loose residue.
On steeper slopes, even no-tilled fields — especially fields that are not continuously no-tilled or had been no-tilled for a short time — we still saw erosion. On the other hand, we saw very little erosion in steep fields that had a fall cover crop planted, especially if that cover crop didn’t winter-kill and grew into the spring.
Several farmers said cereal rye was late in breaking dormancy and starting its spring growth due to the cool March weather. If you wanted to terminate your rye while it was relatively immature, this probably was not an issue, or maybe even helped your termination. However, if you were wanting to terminate your rye with a roller crimper, you probably had to delay planting until the rye matured to the boot stage or terminate with herbicide.
This was also an issue for those wanting to establish a mat of cereal rye on the soil surface for season-long weed, moisture and soil temperature control. For 2019, you may want to research cereal rye varieties that break dormancy earlier instead of a “variety not stated” choice, so that the maturity of the rye lines up better with your anticipated planting window.
What can we do different to keep this situation from repeating itself in the future? Get out of your truck and look at your fields. Do some digging. What does your soil look like after heavy spring rains? Is there a compaction layer? What are your organic matter levels? Is your soil crusted? Consider making a change to a system that will build a soil that can stand up to rain events like we had this spring by changing to a complete never-till system, or introducing cover crops.
If you choose cover crops, consider cover crops that overwinter and provide an armor to protect your soil all winter. Seek assistance from someone around you who is experienced in a no-till and cover crop system. Take that step to prevent the damage of winter 2018 from occurring on your farm in the future.
Donovan is a district conservationist with the Natural Resources Conservation Service in Parke County, Ind. He writes on behalf of the Indiana Conservation Partnership.