Research conducted at the University of Manitoba has confirmed the availability of phosphorus for loss into the environment varies according the source of that phosphorus.
To learn more about how phosphorus reacts in the soil and assess potential for run-off losses scientists with the University of Manitoba compared the environmental availability of phosphorus from monoammonium phosphate fertilizer, four sources of liquid swine manure and four sources of solid beef cattle manure under simulated extreme run-off conditions on disturbed coarse textured gavelly soil and fine to medium textured soil.
Soil science professor Dr. Don Flaten reports phosphorus applied as commercial fertilizer was most highly available, followed by liquid swine manure followed by solid beef cattle manure.
Commercial or synthetic fertilizer like 11-52-0 is the most soluble and stays the most soluble even after it’s been incubated in the soil for a six week period before run-off.
Next would come the liquid manure from the pigs barns and then would come the solid cattle manure.
That ranking is important in terms of being careful how we manage each of those nutrient sources.
Thank goodness we put our phosphate fertilizer in the commercial form underneath the soil surface next to the seed after snow-melt.
Actually it’s not very much of a threat of running off if it’s put on in that way and that’s a good thing.
A lot of our liquid manure is injected or incorporated under the soil surface so it’s not much of a threat and, in fact, the solid beef cattle manure which was the least prone to run-off, that actually worked out in some ways quite nicely because it’s also the most difficult source of nutrient to incorporate and, in fact, it’s almost impossible to inject.
So the results showed that commercial fertilizer, liquid pig manure, solid beef cattle manure, they sort of follow that sequence in terms of environmental availability.
Dr. Flaten notes no crops were grown in this experiment so follow-up work could involve looking at the availability of phosphorus for uptake by crops.