By Karl Czymmek, senior Extension associate, Cornell Pro-Dairy Program, and Quirine Ketterings, associate professor, Cornell’s Nutrient Management SPEAR Program
Whether you have enough manure to fertilize all fields or not, here are some good ideas to consider this fall:
• Stalk test. Conduct a corn season post-mortem: Take stalk samples for the late season stalk nitrate test from second or higher year corn fields to assess your nitrogen (N) management this season.
• Soil test. Take soil samples this fall (before manure application) to see where P and K are needed most. Then, prioritize fields that need N and are low to medium in P, K to take advantage of all three macronutrients in manure.
• pH. There is still way too much corn grown on low pH soils- don’t use fertilizer to compensate for a poor liming program- lime is cheaper than ever compared to fertilizer!
• ISNT. When you take soil samples for pH, P and K analyses, also run the Illinois Soil Nitrate Test (ISNT), a great investment at only $10 per sample. The ISNT will tell if some of your corn fields do not need ANY additional N. Fields with a long-term manure history are potential candidates.
• Third and fourth year corn. These fields are most likely to need the highest N rates. If a soil test tells you that they need P and K too, then they are excellent targets for manure.
• Plant fall cover crops after corn silage harvest to protect soil and scavenge nutrients.
• Decide which hayfields will be plowed for corn next year. If the stand is healthy and well managed, the first year of corn will not require any N beyond 10 to 30 pounds per acre starter.
•Manure storage. Storage allows farms to take advantage of the ammonia-N in manure if handled properly. Spring incorporating or injecting manure before corn planting essentially doubles the N credit to that crop, halving the rate of manure required and allowing you to cover more acres or sell some to a neighbor. Fall incorporation does not offer this N conservation benefit.
• Manure testing. Are you making major fertility decisions with only one or two manure samples per year from a manure storage? Ever wonder if the thicker manure at the bottom of the storage was any different nutrient-wise than that at the top? Take more samples and build a nutrient analysis database to track what happens from top to bottom and season to season with your manure.
• Not convinced? Try some test strips in your fields to see for yourself!
For more information on these topics, see the Cornell Agronomy Factsheet Series at http://nmsp.css.cornell.edu/factsheets/.