By Jason Hartschuh
Many producers use summer annual forages for grazing and stored forage to either fill the summer slump or keep livestock feed through the winter. With wheat harvest finalized across most of the state and straw baling completed for many now our attention turns to creating a second or third profit center off those wheat acres.
Wheat acres provide an excellent opportunity for double cropping with forages that when harvested at the proper growth stage can either make high quality late gestation early lactation forage, grazing opportunities, or gut fill to mix lower the quality of other forages or concentrates.
Many species of summer annuals can be utilized for forage. Some of them such as radish and turnip can be easily grazed but do not make good stored forage as Baleage or dry hay. For dry hay we have found the best two species to be teff and oats. Most other species can be harvested as silage or Baleage. Be cautious making dry hay that for plant stem is truly dry.
The nutritional value of summer annual forages we sampled ranged from $200-$260 per ton. While it may not be possible to sell these forages for their nutritional value, this is what it would cost to replace these forages in the ration with other forms of protein, energy, and fiber. Figure 1 shows the tons harvested per acre of forages planted on July 2nd and harvested either 63 or 91 days after planting versus a July 29th planting date with a harvest 63 to 84 days after planting. While nutrition content of the crop is important to filling the needs of livestock, the driving factor behind return per acre is the tons produced. While some of these summer annuals can be harvested multiple times over the summer, we compared a single cutting at about 60 or 90 days after planting. Not surprisingly across most species the early July planting had increased yields but the ability to utilize these crops into a late summer planting was surprising. All crops in Figure 1 were managed the same being planted in with a drill in 7.5 inch rows with 50 pounds of nitrogen applied. Early July planted corn yielded almost 7 tons of dry matter compared to late July planted corn only yielding about 2.5 tons. The reduction in yield was also found in sorghum more than other crops. Sorghum 90-day yield dropped from 4 tons per acre to about 2 tons with the later planting date. Both crops could have been grown until just before the first frost increasing tonnage. The balancing act between quality and tonnage is found just before these crops switch from vegetative growth to reproductive.
When these crops are planted late in the growing season, end of July, they will not complete grain fill making it better to harvest them just before seed heads or tassels emerge. While the trial in Figure 1 shows an advantage to corn just a year later under much drier growing conditions Figure 2 show corn as the second to lowest yield species with a mid-July planting date. When double cropping is delayed until early August we have found that Oats has the greatest yield potential with planting dates as late as September 15 yielding over 2 tons of dry matter.
Teff provides advantages that it could be made as dry hay much easier than other forages. It proved to have some challenges though needing tedded twice to dry completely in humid Ohio conditions. It also declined in quality rapidly with crude protein falling from 12% to 6.5% within a week as the plant flowered. Soybeans provided higher levels of crude protein than grass at 90 days after harvest having about 17% crude protein. Forage type soybeans are available which provide higher tonnage than conventional soybeans. Soybean silage/baleage should be made when the beans reach late R6 growth stage. At this point, lower leaves are just starting to turn yellow and seed pods are fully developed. Harvesting later leads to higher oil content which often causes fermentation issues. Oats is the most common double crop forage in our area. Usually we do not recommend planting oats until late July, but some year the early planted oats yields as well as the late planted oat. Oats is a daylength sensitive crop. When planted in early August it is triggered to grow larger leaves instead of working hard to produce seed. Earlier planted oats had lower energy and protein content. Oat Crown Rust was also a critical challenge with oats planted in July and occasionally into early August. By 90 days after planting, rust covered over 50% of Oats leaves. Utilizing a fungicide labeled for Oat Crown Rust did not increase tonnage but did improve digestible NDF, increasing energy values, and dollar value of the forage. Studies using corn silage have also found that rust causes fermentation issues with a higher final silage pH when rust is present versus not present. In 2021 we will continue to double crop with trials in 2 location across the state and a double cropping with summer annuals field day on August 28th in Licking county. Detailed trial reports with for quality analysis are available as part of eFields at: https://digitalag.osu.edu/efields.Source : osu.edu