You can cut fertilizer costs and get the most out of your dairy manure by following these recommendations, from Karl Czymmek and Quirine Ketterings of Cornell University’s Department of Animal Science:
1. Rotate from sod to corn. Rotation breaks will give first-year corn crop a yield boost without requiring extra inputs.
2. Eliminate sidedress and manure nitrogen (N) on first-year corn after alfalfa or grass sods.
3. Test your soils. Take soil samples before manure application to see where phosphorus (P) and potassium (K) are needed most. Then, prioritize fields that need N and are low to medium in P and K to take advantage of all three macronutrients in manure.
4. Eliminate starter P from corn fields that get manure and are high or very high, manure or not, in soil test P.
5. Know the fertilizer value of your manure. Get it tested.
6. Apply manure based on crop need. Because most sod N is released to the following corn crop in the first two years, third- and fourth-year corn needs the most N from other sources. Make sure you apply enough manure to these fields to satisfy N needs. Only buy fertilizer N if you are sure it is needed.
7. Follow Cornell guidelines for potassium. Cornell guidelines for potash are based on crop response trials and show that most of our soils have tremendous K-supplying capacity. Limited testing of K needs for alfalfa in recent years confirms a lack of a yield response if fields are high or very high in K.
8. Incorporate manure on the day of applying in spring to double the N value.
9. Request an Illinois Soil Nitrogen Test (ISNT) test for your soil samples to prioritize manure and fertilizer use. The ISNT can help identify fields that do not need manure or sidedress N.
10. Reduce or eliminate starter fertilizer on corn fields that receive generous amounts of manure.
For more information, see the Agronomy Factsheet Series on the Nutrient Management Spear Program website: http://nmsp.css.cornell.edu/publications/factsheets.asp.