August 22, 2008

If you have manure to spread during summer, sometimes the only place available is an alfalfa field. But, manure can cause problems on alfalfa.

Liquid manure can burn leaves due to salt injury, and dry manure can smother plants if it is applied too heavily or in large chunks. Manure can spread weed seeds, and the nitrogen in manure can stimulate grasses already in the alfalfa to become more competitive. Also, manure application equipment can damage alfalfa crowns and compact soil.

Obviously, spread the manure on other land if it is available to avoid any of these problems, but if you have no other choice but to spread manure on alfalfa, follow these suggestions:

• First, apply less than 3,000 gallons of liquid manure or 10 tons of solid manure per acre to minimize salt burn or smothering. If manure is dry, adjust the spreader to break up large chunks that can smother growth.

   

• Second, spread manure immediately after removing a cutting to minimize direct contact with foliage.

   

• Third, only spread manure when fields are dry and firm to limit soil compaction and avoid wheel traffic damaging plant crowns.

   

• And fourth, 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. 

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.

Bruce Anderson
Extension Forage Specialist