Farm-Scape, Episode 2079

The University of Manitoba suggests new water quality regulations being proposed by the Manitoba government will create a particular challenge for livestock producers.

To reduce the amount of phosphorus ending up in Manitoba waterways the province has proposed the draft Water Quality Management Zone Regulation for Nutrients under the jurisdiction of Manitoba Water Stewardship and draft regulations for phosphorus under the Manitoba Livestock Manure and Mortalities Management Regulation under the jurisdiction of Manitoba Conservation.

Public consultations looking at the two proposals are scheduled to conclude later this week.

Dr. Don Flaten, a soil scientist with the University of Manitoba, suggests, while the regulations will apply to all nutrient sources, including commercial fertilizers, manure and municipal biosolids, livestock producers probably face the greatest challenge.

"When they are applying manure, they're applying a collection of nutrients. They can't specify a specific blend to come out of the back end of an animal.

It comes out on its own and so sometimes the ratios of the nutrients aren't exactly in line with what crops take up and so some nutrients accumulate in manured fields at higher rates than others.

The nitrogen to phosphorus ratio of manures is often less than three to one but the nitrogen to phosphorus ratio for crop uptake is usually more than four to one so, if you apply manure to meet the crop's nitrogen removal rate, you're often applying more phosphorus than what you require.

This has resulted in manured fields often having quite a bit higher soil test phosphorus concentrations than commercially fertilized fields where they have the option to put the blend in at the balance that's required for the crop."

Dr. Flaten suggests the key for livestock producers is to be aware of the nutrient contents of their manures and to be aware of the management practices that will reduce the levels of phosphorus in that manure and that will maximize the amount of phosphorus removed from the soil by crops.

For Farmscape.Ca, I'm Bruce Cochrane.