Applying manure to alfalfa is becoming an increasingly popular practice for livestock producers to dispose of and utilize nutrients. Increased regulatory pressure to reduce run-off from row crops has made alfalfa acres an appealing option for manure accommodation.
University of Wisconsin agronomist K.A. Kelling and University of Minnesota agronomist M.A. Schmitt point out the following advantages to applying manure to alfalfa:
(1) It allows more scheduling flexibility: a producer who applies manure to alfalfa has substantial cropland available for spreading throughout the summer months;
(2) It’s good for the crop – alfalfa requires relatively high rates of nutrients, and can benefit from the secondary micronutrients, along with the basics of nitrogen, phosphorus and potassium, contained in manure; and
(3) Alfalfa does an excellent job of recycling nitrogen from the soil. It will take most of the nitrogen it needs from the soil, rather than symbiotically fixing it from the atmosphere, and alfalfa’s deep root system can extract mobile nutrients at greater depths than corn.
The researchers note that applying manure to alfalfa can create increased weed pressure, particularly at high rates of application, and in the case of pre-seeding application. This issue could be countered, however, by commensurate increases in alfalfa yield. They added that excessive weed growth often does not persist past the first year of stand, is often rectified after the first cutting, and may be addressed with herbicides and/or timely clipping.
To read an in-depth report of their research and recommendations, follow this link.