Winter grazing – Research focuses on inter-seeding forage into corn

Torrington – Keeping winter costs down has always been a challenge for livestock producers. While more and more producers are seeking out cornfield residue to winter their animals, researchers are looking for ways to add nutritional value to the residue. 

Jenna Meeks, a graduate student at the University of Wyoming, spoke to producers about a study she conducted looking at inter-seeding annual forage crops into crop residue during the 2014 Southeast Wyoming Beef Production Convention on Nov. 18. 

“Winter feed costs are very expensive for the cattle producer, so corn stalk grazing has become a common practice,” she said. “The problem is that during the last trimester of pregnancy, the cows need eight percent crude protein in their diet.” 

“Cornstalk residue only provides about five to seven percent crude protein, and that is at the beginning of the season when they can graze the leaves and ears. The cob and stalk grazing at the end of the season is only about five percent crude protein. That makes cornstalk grazing a quantity versus quality issue,” Meeks explained. 

Inter-seeding crops

As part of her graduate research, Meeks has attempted to inter-seed forage crops into growing corn during the summer and fall. Her hope is that the forage will germinate and produce an adequate stand that livestock can graze along with the corn residue. 

By grazing both forages and corn residue, cattle should be able to meet the amount of crude protein they need in their diet. 

As part of her study, Meeks said an irrigated center pivot in Lingle was inter-seeded with five species, including annual ryegrass, crimson clover, rapeseed, turnips and radishes. The species were seeded at a rate of 12 pounds per acre by aerial application. 

In 2013, these varieties were planted every two weeks starting Sept. 2, with the final plantings taking place Oct. 30.

Meeks thought this may be a good starting point because the leaves on the corn were starting to dry up, and the canopy was not covering up the ground. However, these dates proved too late, she noted. 

“We just didn’t feel like the yield was good enough, so in 2014, we tried planting starting July 14,” Meeks said. 

The plots were planted in a randomized complete block design in four replicates. 

To determine how the plot performed, she collected two frames in each plot to determine how much above-ground biomass was being produced. The plants collected were separated by family and species. They were sorted by grasses, legumes and brassicas. 

Results

Although Meeks doesn’t have data completely analyzed from the 2014 study, she has found out that delayed planting dates have decreased forage cover, and the cover produced by each plant species changes as winter progresses. 

“We found some production differences between species,” she said. “Also, the later the planting date, the less biomass these plants produced. I think our next step is to determine what planting date is best. We also want to do more work determining how much seed is lost.”

Meeks said her research so far has shown that some grasses will sustain themselves longer throughout the winter, whereas the brassicas, like turnips and radishes, disappear. 

“We found the total cover decreased during the winter due to corn residue coverage, snow and cold temperatures,” she noted. “We also found differences in species composition due to seed size. Radishes have much larger seeds than ryegrass.”

In fact, Meeks said while ryegrass made up 42 percent of the mixture, her samples showed it only produced six percent of the total biomass. Crimson clover was 25 percent of the mix and produced only 0.3 percent of the total biomass. 

Rapeseed performed better, with 17 percent of the mixture and 16 percent of the biomass, while turnips were only eight percent of the mixture but produced 72 percent of the biomass. Radishes rounded out the mixture at eight percent of the mix and five percent of the biomass.

Planning ahead

Future research will focus on determining the correct planting date and seeding rate range to acquire optimal forage establishment and production, she continued. 

They are also studying seven different herbicides to determine if potential herbicide damage is likely to occur in these forage crops following application of pre-plant herbicides.

This study also helped Meeks determine which forage crops are best suited to broadcast seeding. 

“We found crimson clover hasn’t produced that well in our study,” she explained. “It isn’t as hardy and seems susceptible to frost.”

Meeks also wonders if producers could plant these varieties in early July, when the corn isn’t very tall, they may be able to get some type of tillage implement through the field to get better germination. 

However, obtaining the optimal planting date and seeding rate is most important. 

“Planting more increases seed costs, but planting earlier may reduce corn yields,” Meeks said. 

Gayle Smith is a correspondent for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.