CropWatch March 10, 2010: Applying Manure Before Seeding Alfalfa
March 10, 2010
If you’ve got excess manure you need to apply, a good option would be a field about to be seeded to alfalfa.
Applying manure before seeding alfalfa may seem counter productive since alfalfa is not likely to benefit from the nitrogen in the manure, but manure also is rich in phosphorus, potassium, sulfur, and many micronutrients that alfalfa needs in large quantities.
Research studies show that applying as much as 12,000 gallons or 50 tons of dry manure per acre before planting alfalfa can boost alfalfa yield more than commercial fertilizers at the same nutrient levels. With manure, yield increases occur on both low and high fertility soils while with commercial fertilizers, higher fertility soils may not respond. Other factors like improved soil tilth, increased soil microbial activity, micronutrients, and early nitrogen availability may be why manure works so well to increase alfalfa yield.
Do not apply manure heavily prior to alfalfa seeding if you also plant a companion crop like oats that you plan to harvest for grain. It is likely to lodge and smother much alfalfa unless you cut it early for hay.
- Use a soil test and a manure test to determine how much manure to apply.
- Mix manure well into the soil using tillage, making sure to prepare a firm seedbed so new alfalfa seedlings will emerge rapidly and vigorously.
- Plan your weed control program carefully since manure can stimulate weed seedlings. Proper timing of seeding, firm seedbeds, and herbicides or clipping can control weed pressure.
Extension Forage Specialist