Grazing Cover Crops Prior to Planting Corn

Cover crops utilized as alternative forages can provide benefits to an integrated livestock-cropping system in several ways if managed correctly.

Cool-season annuals – such wheat and rye – can provide early grazing in the spring prior to turnout on permanent cool-season perennial pastures.  These small grains should be managed differently than if they were planted for grain, and it is important to remember that the earlier in the fall they are planted, the greater the potential for yield. Small grains work well when following corn silage harvest and if they will be utilized as forage, they should be planted at a greater seeding rate than if planted for grain production.

Along with extending the grazing season, these forages are often very palatable and high quality, meeting and surpassing the nutritional needs of most classes of ruminant grazing livestock.

A challenge with grazing these forages in the spring can be the rainy weather and wet soil conditions.  Grazing animals typically only cause surface compaction – no deeper than 4-6 inches. Nonetheless, they can cause very significant damage to soil structure that reduces water infiltration and can compromise forage regrowth and the establishment and growth of the crop to be planted after the cover crop. When the soil is at the 'plastic limit' or wetter, there is great potential for causing soil compaction. You can determine whether your soil is at the plastic limit by grabbing a handful of soil and molding it in your hand – if you can make a ball the soil is in the plastic state. If the soil squeezes out between your fingers, it is in the liquid state. You should not be on the field if the soil is in the liquid state, and you should take special precautions if it is in the plastic state. Reducing the stocking rate of these paddocks can help to avoid soil compaction during wetter-than-ideal grazing conditions. Implementing a strip-grazing system to manage grazing livestock can also help reduce soil damage. Make sure you rotate the animals out more quickly if the soil is wet to reduce the time of exposure. Use a long-term program of soil health improving practices to stimulate soil biological activity to restore the soil functions after grazing. Practices like no-till and cover cropping can help the soil to maintain its structure and remain more resistant to compaction over the long term.

When following these alternative forages immediately with corn, doing a complete "graze-out" – or grazing the small grains nearly to the soil surface – can be done to utilize all the available forage and increase overall forage intake prior to burning down the fields to prepare for corn planting.

 
"Graze out" of cover crops can be conducted to eliminate biomass and completely utilize forage availability. Image Credit: J. Williamson

Burndown after grazing and prior to planting can simply consist of applying 1 quart/acre of glyphosate.  However, depending on the cover crop species mixture other burndown herbicides such as 2,4-D or dicamba might be needed for improved control if clovers or hairy vetch are being terminated. Gramoxone (paraquat) can provide some activity on cover crop termination but it is best to tank mix with atrazine and/or 2,4-D for more consistent control. Residual corn herbicides can also be included as needed for additional weed control.