Manure is an excellent source of nutrients and can enhance biological activity and soil physical properties. But be careful when applying it to alfalfa so you don't do more harm than good, warns Bruce Anderson, University of Nebraska Extension forage specialist.
Liquid manure can burn leaves due to salt injury, while dry manure can smother plants if applied too heavily or in large chunks. Manure also can spread weed seeds, and the nitrogen in manure can stimulate grasses already in the alfalfa to become more competitive. Manure application equipment also can damage alfalfa crowns and compact soil.
If forced to spread manure on alfalfa, follow these suggestions:
- Apply less than 3,000 gals. of liquid manure/acre, or 10 tons of solid manure, to minimize salt burn or smothering. If manure is dry, adjust the spreader to break up large chunks that can smother growth.
- Spread manure immediately after removing a cutting to minimize direct contact with foliage.
- Only spread manure when fields are dry and firm to limit soil compaction and avoid wheel traffic damaging plant crowns.
- Finally, if you wish to stimulate grass yield, apply manure to fields with lots of grass; otherwise, select fields with little grass if you want to minimize grass competition.