Cover your ash
As we approach warmer temperatures and alfalfa greens up throughout the countryside, it is good to think about a key factor in alfalfa production: minimizing ash content during harvest.
While we will never get ash to zero due to natural mineral content of the plant, which is about 8% , several main drivers related to the cutting and merging processes can help keep additional ash content to a minimum. Main concerns of high ash content in forage include the fact that it has no energy value and that elevated soil contamination could potentially result in Clostidria being found in the silage.
Perhaps the number one factor contributing to ash content is the cutting height. A cutting height of 2 inches should be a bare minimum and 3 inches should be a goal with alfalfa. In grasses, a cut closer to 4 inches is desired. We need to keep the cutter bar off the ground as much as possible to prevent soil hitching a ride with the plant tissue as it is cut. This helps accomplish that. Another advantage of the higher cut height is that that alfalfa plants rebound a bit quicker as any new shoots growing for the next crop will not get nipped by the knives during the harvesting process.
Another factor that contributes to ash during the cutting process is making sure the head tilt on the disc mowers it not set too aggressive. While this may be necessary to pick up lodged hay following a weather event, most often a less-aggressive tilt is sufficient to get the job done while creating less of a vacuum to pick up loose soil.
On the merging side of the equation, we need to make sure that we are coaching the individuals who are running the merger. The merger can pick up a lot of soil if set too aggressive with the tines eating the ground. Merged hay also should be delivered onto a windrow that is lying on the ground to help reduce soil contamination while also making harvest smooth. Rakes are less advantageous than mergers on an ash-accumulation front as a rake rolls the hay across the ground and picks up soil during the process.
Lastly, once we have good haylage chopped and into the trucks or wagons, we need to make sure to bring the haylage home on the final stretch. An effort should be made to store it on concrete or pavement when possible. Along with that, equipment considerations during packing and feedout should be reviewed. When it is wet, there should be emphasis put on not dragging muddy or dirty wheels into the feedstuffs and contaminating it.
If we place a concerted effort on the harvest, storage, and feedout process, ash can be – and is being – managed well on many farms. Make sure you take the time to look at your own processes going into this harvest season to cover your ash.
Feed quality and nutrition