Cover crops offer alternatives
In many areas, dryland wheat farming is undergoing a shift toward no-till and some type of short season forage crop. With this potential additional forage crop, University of Nebraska researchers looked into whether it could generate additional income for farmers by feeding it to cattle.
According to University of Nebraska Beef Extension Specialist Karla Jenkins, if short-season forage crops can be utilized by cattle in wheat fallow rotations, they could potentially provide an alternative to over-grazing native range.
For some producers, it may also provide an alternative to selling the cows when feed supplies run out.
Typically, multiple species of crops are planted in this short season forage rotation, Jenkins said. They may include legumes, annual grasses and deep-rooted species like brassicas.
“Multi-species forage crops are becoming popular in no-till farming operations as an alternative to fallow,” Jenkins said. “Additional benefit from these crops could be realized if some of the biomass produced from these cover crops could be used as a source of forage for cattle.”
The Beef Extension Specialist said each crop can also benefit the soil.
Legumes add nitrogen, while annual grasses add biomass. Brassicas, like radishes and turnips, are deep-rooted and can help break up soil compaction.
“Some farmers plant these mixtures and then just tear them up, but these crops could be of some value to cattle whether they are grazed or put up as hay,” she explained.
Producing these crops in this area comes with challenges, she continued.
“We’re so high up in altitude, and in a semi-arid climate it is a challenge to get our soil temperature to warm up in the spring,” she noted. “Then, we have another challenge as to how late it will get in the fall before we get a killing frost. On top of all that, we need rainfall to get these crops to grow.”
Studying cover crops
Jenkins has performed three years of studies at the High Plains Ag Lab near Sidney, Neb., looking at which varieties grow best and produce the most forage for cattle.
After her 2010 study, she concluded that producers need to determine if quality or quantity is more important when deciding what to plant and if it will be grazed or hayed.
During this study, a combination of grasses, legumes and brassicas were planted.
During the second week of May, the nighttime low temperatures were in the low 20s, and since these plants were planted deeper than one inch, Jenkins thinks these two factors may have contributed to reduced forage production of the brassicas, clovers, vetch and sunflowers.
However, rainfall was above average that year, and the legumes and grasses had good yields once the soil temperature warmed up, she noted.
In a two-year study in 2011 and 2012, Jenkins looked at how the forage quality of cover crops in a no-till farming system compared to crested wheatgrass pastures grazed by yearling cattle.
The cover crop consisted of oats, forage peas and turnips planted in March with a no-till drill. In 2011, no fertilizer was applied prior to planting, and in 2012, 30 pounds per acre of nitrogen was applied according to soil test results.
Jenkins analyzed what was consumed using esophageally-fistulated cattle.
Nutritionally, Jenkins determined that the quality of the cover crop was greater than the crested wheatgrass both years. She also found in both years that oats contributed the most to the dry matter yield.
In 2011, the percentage of oats and peas remained similar over the grazing period, but in 2012, oats increased, and peas decreased. Jenkins said this could indicate more selectivity for the forage peas by the grazing cattle.
“In both years, turnips contributed less than four percent of the dry matter,” she noted.
“Greater cattle performance is expected when grazing cover crops based on NEg (net energy required for growth) adjustments and diet quality data,” she explained. “The predicted average daily gain of cover crops may be supportive of stocker cattle or early weaned calves due to the quality of this forage source.”
The cover crops had greater forage quality and greater digestibility, improving predicted performance at similar intakes compared to crested wheatgrass, she said.
“Depending on the year and environmental factors, cover crops may be able to produce a similar amount of forage as native pastures,” she said.
They can offer a source of high quality forage in addition to the possibility to graze or hay these acres, she added.