From wet, to dry, to just right … we’ve all seen various weather conditions this spring. With row crop planting finished, producers are thinking of cutting hay, scouting/managing pests, rotational grazing, and the list goes on. Every year I speak with producers who are interested in trying sometime new due to their interest in improving soil health, extending the grazing season, or dealing with prevent plant acres.

If you are seeking alternative forage or cover crop options for any reason, consider the following:

1) Herbicide history. Before planting an alternative to your intended crop, consider your crop rotation as well as haying/chopping and grazing restrictions of herbicides previously applied; this includes herbicides applied in the previous growing season.

2) Insurance and Farm Service Agency guidelines. Be sure to check with your insurance agent and FSA representative on all details regarding the seeding of your cover crop or forage crop. The prevent plant date for “haying, grazing, or chopping cover crops” has been changed to “any time” as of 2021 to “support the use of cover crops” according to USDA RMA.

3) Purpose. Always begin with the end in mind. Livestock feed, soil health, weed suppression, nutrient capture, and soil moisture management may all be common reasons to plant a cover crop. Try focusing on 1-3 objectives when creating a planting plan.

4) Seed availability and price. Each year, demand for annual forage/cover crop seed varies and some species may have risen in price due to demand. Although most producers want to keep costs low, remember that forage crops and/or improved soil health comes at a price, and some investment will be necessary. Try to be flexible, as seed shortages/costs often cause adjustment to plans.

5) Crop rotation. Keep your previous crop and intended crop for 2025 in mind; it is generally recommended to plant cover crops of diverse growth habits that are complementary to the subsequent cash crops, i.e., primarily broadleaves prior to grass cash crops, and vice versa.

6) Termination. Many cover crops will winter kill or die after a late chopping (post heading). However, some species may survive the winter, such as cereal rye or winter wheat. Species such as vetch and Italian ryegrass can stay dormant for a prolonged period (hard seed) and germinate the following spring. This does not eliminate these crops as an option; it simply requires prompt spring management as these crops may be of great value to utilize excess moisture in a wet spring.

7) Weed control. When planting a diverse cover crop/forage mix, it can be nearly impossible to chemically control weeds during the growth of the cover crop. If a mix is well planned and raised under ideal growing conditions, it can usually out-compete weeds. However, if particular weeds are a concern, control issues should be considered before selecting cover crops. A thorough burndown before planting also helps with weed suppression.

8) Soil fertility. If a producer is intending to use cover crops as forage, applying lower rates of nitrogen at planting can be cost-effective in the end. Consider previous crop credits if legumes were planted, and current soil test levels. In many situations, low nitrogen application rates (30-60lbs/a or less) will provide considerable growth for cover crops (especially grasses); it is also important to apply the appropriate rate of nitrogen when planting for forage purposes to limit the level of possible plant tissue nitrate-N accumulation, should plants experience drought or other stresses.

9) Planting time. As most cover crops are grown in blends, it is difficult to establish an exact seeding date based on individual crop species. However, there are suggested planting windows for crop types based on the proportion of different cover crops species in the blend. Warm season species (such as forage sorghums, sorghum-sudangrass, teff grass, etc.) should ideally be planted from late spring into early summer. After the third week of July, as average daily temperatures tend to decrease, certain cool-season species (such as some small grains, peas, clovers, vetch, and radish) are recommended. When planted within these suggested guidelines, cover crops should have ample growth time for fall forage harvest.

10) Silage/forage considerations. If corn silage is not an option, consider a couple close alternatives such as forage sorghum, or sorghum-sudangrass. In some studies, forage sorghum was ~85% the feed value of corn silage. Additional grain could be included in the diet to meet performance objectives compared to feeding corn silage. Although forage sorghum can be an excellent feed alternative to corn, it generally has a short cutting window at mid to hard dough, and can be difficult to harvest at the proper moisture (62-72%), especially if the crop is direct cut (not wilted prior to chopping). In some cases, non-heading types will require a killing frost in order to get plants dry enough for ensiling, which causes quality losses. If forage sorghum is too wet at harvest, corn grain or other forage dry matter can be added to the pile or bunker.

Sorghum-sudangrass can be a bit lower in energy content than forage sorghum, but does not necessarily have to be direct cut, and can be wilted in the field before chopping if needed. In this case, as long as ideal moisture content is reached (~62-72%), no extra dry matter would be needed for ensiling. Sudangrass species are often suited as a rescue forage because their thinner stems allow for faster dry down. Sudangrass and sorghum-sudangrass hybrids have the added advantage of post-harvest regrowth, providing the potential for an additional harvest or extended grazing.

Keep in mind that prussic acid poisoning can be a problem with either of these grasses. It’s found in highest concentrations in the leaves and new shoots typically following a freeze, making cattle susceptible to poisoning. Frost and drought increase prussic acid content and grazing should be delayed for about 10 days to allow the toxin to dissipate. Prussic acid is less of a concern in harvested feeds.

Annual forages and cover crops can be an excellent tool to extend grazing or mitigate delayed planting issues. For more information, please do not hesitate to contact your nearest SDSU Regional Extension Center or local NRCS office for cover crop or forage crop recommendations.

This information is an excerpt from an article written by David Karki, Anthony Bly, Warren Rusche, and myself, find the full article with resources here.