Fall manure applications can help meet the high nutrient demands of forage crops if some agronomic and environmental considerations are kept in mind, says Paul Craig, Dauphin County, PA, Extension agent.
Fall is a great time to adjust soil phosphorus and potassium levels, says Craig. It also saves time in spring, when soils also tend to be wetter.
“Fall manure applications also help root development before winter dormancy and help spring growth get started,” he says. “Weed scientists report less weed stimulation from fall manure applications compared to spring applications.”
But he warns that wheel traffic can cause compaction when soil conditions aren’t fit. Over the lifespan of the stand, it can lead to reduced water infiltration and root development. Injury to the developing shoots and the crowns can also lead to reduced stands. Even drag-line manure applications can injure shoots and crowns.
“Using flotation tires and smaller loads can reduce these effects, but staying off poor soil conditions is important,” says Craig.
Fall manure applications can also lead to a greater risk of runoff, although the risk is lower in forage stands than in row crops. Another risk more common in wetter areas is infiltration into tile lines.
“Producers should be aware of field conditions when applying manure at any time of the year,” he says.
Liquid manure is preferable to bedded-pack manure on forages. Crop smothering and the potential for picking up manure clumps next spring increase with bedded-pack manure. A typical rate of 3,000 gallons/acre of liquid manure in fall will be adequate. The application priority should be older grass stands first, followed by the oldest alfalfa stands and younger stands last. Be sure to stay out of waterways and 100’ feet away from streams.
“Check your crop records and soil-test reports to closely monitor soil nutrient levels,” says Craig “It is still possible to take advantage of this fall weather to address nutrient needs and distribute manure to targeted areas.”