Editor’s note: This article is the third part of a four-part series regarding manure-spreading research. The second part was published in the June 27 edition of Agri-View.
Corn silage and alfalfa dominate dairy forages. Excellent-yielding and predictable in a ration, they are the workhorses of a dairy-feed ration. But corn’s small manure spreading windows often lead to challenges when trying to apply manure with unpredictable fall weather and soil conditions.
As previous University of Wisconsin-Discovery Farms research has shown, manure applied when soil and weather conditions are optimal significantly reduces nutrient losses. Diversifying some acres into alternate crops can provide benefits to the farm in addition to water quality.
Crop diversification spreads risk. Weather is not always ideal for every crop. Diverse rotations reduce the risk of crop failure caused by adverse weather. Crops have different planting and harvest times, which can help ease the workload in spring and fall. Labor and equipment can be used through the course of four to six weeks instead of two to three weeks. And best of all crop diversity opens new manure-spreading windows at times of the year when soil conditions are good for manure applications.
Consider adding crops to rotation
Winter cereals — planting a winter-cereal cover crop like rye or triticale immediately after corn-silage harvest can improve manure nutrient retention and provide forage. Plant the cereal as soon as possible following harvest. Manure can be surface-applied after the cereal is planted. The moisture from the manure will enhance germination.
Alternatively once the cereal is established after several weeks, manure can be spread on the field with either a surface or a true lesser-disturbance injection system. The manure application will not significantly harm the cover crop. The cereal will take up some of the nutrients in the manure, protecting them from loss during winter.
In spring the rye or triticale can be harvested as forage. Cereals harvested in early boot stage can provide milk-cow quality feed. Delaying harvest until late-milk or early-dough stage yields tremendous amounts of heifer or dry-cow feed. Manure can then be applied to the field before planting the next crop.
Double-cropped wheat or fall forage — winter wheat can have a valuable place in dairy rotations. Straw is a great bedding material. Even if a producer doesn’t have use for it on-farm, there’s a strong market for straw. Like cereal rye planted after silage, winter wheat provides a living cover that can handle a manure application and provides erosion protection. Winter wheat is harvested in late July to early August when soils are usually dry and weather conditions are favorable to manure spreading.
Winter wheat’s early harvest time also provides the opportunity to double-crop a fall forage. Try drilling a mix of peas and barley or oats following the manure application. The fast-growing barley and peas can be harvested in October as forage. And those living plants will take up nitrogen released from the manure application. Dale Wagner, a Discovery Farms participant in Manitowoc County, Wisconsin, has had great success with that system.
Sorghums — forage sorghum is a warm-season grass like corn but grows even more rapidly during the heat of summer. Sorghum requires warm soil temperatures at planting — 60-65 degrees — so planting in Wisconsin often doesn’t occur until June. The late planting date allows time for manure applications prior to sorghum. A combination of corn and sorghum acres can spread planting across a longer time frame, further reducing the strain on farm equipment and labor resources.
Sorghum sudangrass is a hybrid often managed in a multi-cut system. A multi-cut crop, sorghum sudangrass provides summer opportunities to apply on a growing crop in good soil and weather conditions. Daniel Olson, a dairy producer from Lena, Wisconsin, uses sorghum sudangrass in a cocktail mix with clovers and Italian ryegrass. The clovers and ryegrass bump the feed quality and provide insurance against cool-summer weather that would reduce the productivity of the sorghum sudangrass. The hardier ryegrass and clovers also provide living cover deep into fall and early winter.
Pairing sorghums with a winter cereal like triticale can produce tonnage rivaling corn silage. Sorghum and sorghum sudangrass have more digestible fiber than corn, especially brown-midrib varieties. They have more protein and sugar but less starch. The crop may be worth a discussion with a nutritionist to see if it fits a farm’s program.
Cool-season grass — cool-season grasses are a common forage on European dairies and are being looked at closely in the United States. Small amounts of grasses are often included in alfalfa fields, but managing both alfalfa and grasses optimally is a challenge. A field of cool-season grasses provides manure-spreading opportunities after every harvest. The grasses will readily capture the nutrients in the manure, especially nitrogen. Cool-season grasses are digestible excellent-quality forage that allows for manure hauling all summer long.
Diversifying forage crops beyond corn silage and alfalfa can create great opportunities to grow quality feed. It can spread equipment and labor needs as well as open more-favorable manure-spreading opportunities. Converting even 10 percent to 20 percent of corn and alfalfa acres to some of those different crops that allow summer spreading provides much-needed relief come fall manure-application season. If fall manure-spreading conditions are poor, there are options to wait for better conditions. Consider what additional crops can be grown to fill bunks and empty pits.