ScienceDaily reports a study by Agri-Food Canada has found a way to improve the nitrogen to phosphorus ratio in manure, making it a more effective crop fertilizer.
Dairy manure is a common fertilizer, but a low nitrogen to phosphorus ratio forces producers to over-apply manure, meeting appropriate nitrogen levels, but also adding high phosphorus levels that are harmful to the environment. A study by Agri-Food Canada shows the nitrogen to phosphorus ratio can be improved by removing solids from dairy manure, reducing the loss of nitrogen by hastening soil infiltration.
The nitrogen levels in manure were increased by removing solids from manure slurry using a passive two stage lagoon system. The system produced a liquid fraction with less dry matter and higher nitrogen to phosphorus levels.
Over the course of the six-year study, scientists found the liquid fraction allowed for a higher crop yield. The liquid fraction also contributed to 63% more nitrogen recovery than using an equal amount of whole manure.