Cover Crop Establishment

This dry fall weather may be great for harvesting, but it’s not ideal for establishing cover crops. Just like any other crop, cover crop seed needs moisture to establish and that is certainly in short supply this fall. There is some rain in the forecast over the next couple of weeks, and that will hopefully be enough to get cover crops (and our wheat) established. Even a moderate cover crop stand will protect soil from erosion, and bring additional benefits, over the winter and spring period. With limited moisture, and with seed costs being higher this year, how can you increase the odds of a successful establishment?

First, when it’s dry, cover crop establishment will be better if you can drill the seed. Planting the seed into the soil puts it in closer contact with moisture, which will aid in germination and emergence. Broadcasting seed onto dry soil is very risky, especially if there is no regular rain in the forecast. If you have to broadcast, try some vertical tillage or packing to improve seed-to-soil contact. (Remember, however, that tillage can dry out the soil and increase erosion.) Smaller seeds such as clovers need to be planted shallower for successful emergence, while seeds such as wheat and cereal rye can be planted deeper where there may be more moisture. These small grains may be better options in dry conditions. (Plus, see the next point – it’s getting late for species other than wheat, cereal rye, or triticale).

Second, make sure you’re watching planting dates and optimal planting windows. Don’t push them by planting species too late. Some species, like crimson clover, needs to reach a certain size to successfully over-winter. If planted late and it stays dry, plants are unlikely to reach that size. University of Kentucky Cooperative Extension publication AGR-18 gives planting date windows for many common cover crop species. The Southern Cover Crops Council (www.southerncovercrops.org) also has multiple cover crop fact sheets, and information on planting, managing, and terminating cover crops.

Third, make sure your residual herbicide program won’t interfere with the cover crop germination and establishment. The University of Wisconsin has a guide for this (https://ipcm.wisc.edu/download/ pubsPM/2019_RotationalRestrictions_final.pdf); it outlines numerous pre-plant herbicides in corn and soybean, and whether damage might occur for different types of cover crops planted that same fall. Also, see this newsletter article from Ohio State for a simpler table. (It gives names of herbicide active ingredients rather than products, but you can match your herbicide name to its active ingredient online.) If you will graze these cover crops or harvest them for forage, you MUST adhere to the rotational restrictions on the herbicide label.

As always, when choosing cover crops, consider your goals, as well as your location (soil and climate), your cropping system (when can you plant and when do you want to terminate), and available equipment. Goals for cover cropping may include reducing soil erosion or suppressing winter weeds (including marestail). In dry years, cash crops may not take up all the nutrients applied in the spring, so capturing these before they are lost may be an important goal for cover crop plantings this fall. When seed costs are high, consider the most economical species to accomplish your goals. If you’re interested in learning more about cover crops, the Southern Cover Crops Council is hosting a conference in February 2023, in Baton Rouge! See the flier in this newsletter for more information, or contact me at erin.haramoto@uky.edu.