LETHBRIDGE: A University of Saskatchewan professor is sharing his research, which might make you rethink how you apply manure to your fields as a fertilizer.
Doctor Jeff Schoenau is a soil science expert, who stresses the importance of testing both the manure and soil before combining the two, "Manure's not a perfect fertilizer in the sense that it always doesn't have the ratio or relative proportions of nutrients that crops need. So one of the challenges in dealing with manure, particularly cattle manure, is it tends to have a lot more phosphorus relative to nitrogen than what crops need." He continued that by testing the two you can work on balancing out what's going into your soil.
Another important issue that Schoenau addressed when it comes to manure with too much phosphorus, is the potential environmental impact it can have. He explained that the excess will sit on top and washes into nearby rivers and streams when it rains, "The major concern when we have a lot of phosphorus entering into water, is that the phosphorus can stimulate the growth of organisms in the water like algae, and this process is called eutrophication. It can lead to a significant deterioration in water quality."
To bring the phosphorus under control Schoenau does have a few suggestions. He explained that when using swine manure you can give the pigs additives in their feed that will help them utilize phosphorus, reducing the amount they expel. For cattle he noted that you should keep in mind the fact that putting distillers grain in a ration will increase the nutrients, such as phosphorus, which will eventually be added to their manure.
Schoenau also addressed the proper application of the manure, "I think for many manures, getting that manure into the soil is beneficial from the standpoint of reducing losses of nitrogen to the air as ammonia. Also in some instances certainly having that manure into the soil can help reduce the potential for losing nutrients when water runs across that field." He added that you should avoid putting the manure out in the winter if possible, as a limited amount of the nutrients will make their way into the soil during the cold months of the year.