By Glen Arnold, CCAOhio State University Extension
Last fall was not conducive to spreading manure on agricultural fields. For example, many producers are interested in spring spreading to capture nitrogen from manure to reduce the need for purchased nitrogen.
Manure applications to crops make the best use of the nitrogen content of manure for crop uptake. In the early vegetative stages, the time is close to the period of maximum nutrient uptake by the crop. In maize, placing manure below the surface preserves a higher percentage of nitrogen through reduced volatilization losses. When used as a substitute for purchased nitrogen fertilizer, the economic case for manure used in this way is very attractive and provides an incentive to transport manure over greater distances.
Pre-plant manure applications can work almost as well as in-crop manure application. The challenge is to incorporate the manure, to capture the nitrogen, without delaying spring planting due to a field that is too wet or too rough for planting. One acre-inch of water equals 27,154 gallons. Applying 7,000 gallons in the spring is like adding a quarter inch of moisture if evenly distributed. If manure is applied in bands, the field may take longer to dry out.
The Ohio State University conducted five years of research on pre-emergent manure application. The manure spreading was done after the maize had been planted the day before. Yield results were significantly higher than commercial fertilizers applied at the same time. Based on fall stalk and nitrate tests, manure appears to stay with the growing corn crop much longer than commercial fertilizer. This should give farmers confidence that the manure applied in the spring can supply the necessary nitrogen to the corn crop throughout the growing season.
The key is to apply the necessary nitrogen and bring the manure below the soil surface. Most hog finishers contain 30 to 40 pounds of ammonia nitrogen per 1000 gallons. But there are exceptions to this guide, so be sure to rely on previous manure tests. Dairy manure would be much lower at eight to 15 pounds per 1000 gallons. Research also shows that some agitation of the manure source before spreading will produce a higher consistency of nitrogen, phosphorus and potash during emptying of the manure storage.
Another key is to do your best to avoid soil compaction. Manure tankers are heavy and soil compaction can be seen throughout the growing season and on combine monitors during harvest season. This would be a good reason to favor the use of a garden hose when spreading manure in the spring, if possible.
If a grower gets the manure spread, then they can use a side pre-dressing nitrate test (PSNT) to determine if additional nitrogen is needed or use tissue tests and Y-drop nozzles to determine if additional nitrogen is needed. guaranteed.
Applying manure to corn emphasizes the 4 Rs of nutrient stewardship. It’s the right product, the right rate, the right placement and the right time to maximize crop yield and minimize environmental impacts.