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Composting Manure Improves Nutrient Release

14 August 2012, at 7:23am

CANADA - A researcher with the University of Manitoba says by ensuring liquid swine manure has been fully composted, farmers can maximise the fertiliser value of that material.

As part of research being conducted by the University of Manitoba, scientists have been separating the solids from liquid hog manure then adding a carbon source such as straw or sawdust and composting the materials.

Dr Mario Tenuta, Canada Research Chair in Applied Soil Ecology with the University of Manitoba, says composting offers the opportunity to take animal manures and produce a new product that will stimulate crop performance beyond what raw manure may do.

Dr Mario Tenuta-University of Manitoba :

For true composting to occur it has to go through several stages.

We need these stages and the critical stage is a very high temperature phase called thermophilic stage so temperatures about 60 degrees centigrade. It needs to be there for several days and several cycles.

You turn the compost, it needs to heat up, and stay up above 60 for a day or two and you need to go through several cycles of that.

Then there's a phase that is much longer in duration after that where the temperature starts to decline slowly even after turning so that's the maturing phase.

Then there's the phase after that called the curing stage where it seems like it's not doing very much to us but it's actually doing something. It's getting re-colonized by organisms.

They're coming in from the air or from the dust and they're getting established back in there and it's really important because, when that material goes into soil, it basically is soil but a very enriched organic matter soil.

So this whole process, how long does it take? I would recommend about a year so that would give, in our climate, enough time to go through this curing phase in there.

What we don't want is to have immature compost that's not ready going on to soil because then you can't really predict what's going to happen in terms of its nutrient release.


Dr Tenuta says a nice compost that has been stabilized and fully matured has more predictability in terms of its nutrient release and how the crops can respond to it.

For UniversityNews.Org, I'm Bruce Cochrane.