Manure supplies topdress nitrogen to wheat
Manure has been successfully used as a topdressed source of nitrogen on wheat in the spring
Most everyone plans to apply nitrogen on winter wheat, but have livestock farmers ever thought of using liquid manure as their nitrogen source? Five years of studies at Ohio State University (OSU) and one year in Michigan has shown that when the manure is tested and calibrated accurately for nitrogen value, wheat will yield the same as equivalent fertilizer nitrogen applications. Ideally, it is better to apply spring manure injected or incorporated the same day, but if you need to start emptying storages earlier and will be surface applying, wheat may be a new window of opportunity. OSU has found that forms of disk openers did not improve nitrogen retention, due to the applications on wheat being early when it is still cool. Several forms of disc or aeration tillage did not hurt the wheat yields either.
Since wheat needs only 60 to 100 pounds of nitrogen, depending on location and yield potential in Michigan, the manure needs to be dialed down to achieve this amount, accounting for all of the ammonium nitrogen value. As would be expected, if manure nitrogen is over-applied, it can lead to lodging and, if excessively over-applied, can even kill the wheat. Manure samples, accurate calibration and past experience with nitrogen rates of your manure would be invaluable to the success of topdressing wheat. Liquid manures are recommended; solid manures have not been studied and don’t hold the same potential as liquids.
We will also need to think differently about how to calculate the nitrogen rate from a manure sample. Typically, a surface application would assume considerable volatilization losses of nitrogen, but under cool and damp spring conditions most will be retained. This will be highly dependant on the temperatures the day of and the days following application. Also, the organic nitrogen will not break down and release quickly enough for wheat, so nitrogen needs to be thought of and calculated differently than for other crops and timings.
Apply manure as early as you can; the more the wheat begins to grown, the more chance of leaf burn from all nitrogen sources. Again, it would be better to inject or incorporate spring manure, but for livestock producers with wheat, this may provide new options of where to go with the manure and earlier than normal, thereby relieving some of the normal spring manure hauling workload.
Visit “Utilizing Liquid Livestock Manure as a Top-dress to Wheat and Side-dress to Corn” on eXtension for a complete presentation on manure on wheat.