The trend to fertilize with hog manure is growing for those farms with the opportunity to do so. When hog manure is applied according to their manure management plan, generally, most if not all of the phosphorus requirements for crop production are generally met. However, if phytate feed supplements are utilized in their modern hog rations, then less bypass P is found in the resultant manure. As increasing amounts of phytate supplements are utilized, the lower the P value for the manure per 1000 gallons. A check of the manure analysis utilized in determining the application rate is warranted.
A second concern with the current P application rates may be that the P application rate is too low for the higher grain yields being produced. When this occurs constantly, the soil test P values will decline over time.
How are the application rates of K stacking up to the soil maintenance K value determined by your crop yields? Frequently, the manure doesn’t have enough K to maintain soil test K values. To correct this problem, add a liquid application of 1-3-30 (manure special) in a fall dribble band to correct the K deficiency. This added nitrogen and phosphorus in the 1-3-30 fertilizer will enhance root growth in the zone of application. This greater root growth, in the application zone, will enhance K uptake in the plant.
In most instances, the hog manure will supply some sulfur, but additional sulfur should be applied to the crop. However, there exists a need for added zinc and boron for the crop. The 1 lb. zinc and .2 lb. boron per acre, and whatever level of sulfur required, could be added to the 1-3-30 dribble band application, to a liquid N (32%) solution as a weed & feed application in the spring or the zinc could be added to the starter fertilizer (note: B should not be applied with the starter fertilizers).
Here are two thoughts dealing with N management and manures. First, Instinct should be added to all liquid manure at the time of application. The use rate for Instinct is 35 oz./A. By adding Instinct to the manure, increased corn yields will be achieved in most instances. Secondly, a weed & feed broadcast application of 30 to 50 lbs. N per acre in the spring is highly recommended. This broadcast application will place N in the rooting zone of the newly developing corn plant and give the new plant improved early N status.