As the new year starts to unfold we usually take a few minutes to look over our successes and failures of the previous year. Our family attempts to learn from mistakes in order to move forward productively. Our attempts at composting had their challenges but with the help of professionals, the problems are resolving. There is always room for improvement.
In the spring of 2017 we had the opportunity to have some training on composting mortalities and manure following the Manitoba guidelines. It is truly amazing how fast dirt can be produced out of a solid with a little encouragement. Composting large livestock has always been a bit of a daunting task but the Conservation and Water Stewardship department was extremely knowledgeable and helpful for us to get our system working successfully.
Since rendering facilities do not accept ruminants anymore and burying and burning isn’t always permitted, learning to compost is practical. This also allows landowners to rebuild their soil. One caution of where to spread compost made from dead ruminants is that since composting has not proven to destroy the presence of prion in Specific Risk Materials (SRM), composted SRM is still considered SRM.
If carcasses or SRM are composted, the compost should not be spread on land grazed by ruminant livestock for the following five years. The department representative recommended spreading it on hay land to circumvent any issues.
Key compost guidelines
One of my questions was how do you get the pile to work? Do we need to add a starter? They said no. Everything that is needed is in the gut of the dead livestock. Our job was to provide the microbes the best environment in which to work. These are the guidelines we were provided:
- Adequate moisture: Micro-organisms need water to move around and transport nutrients. A moisture content of 40 to 70 per cent is reasonable; the preferred range is 50 to 60 per cent.
- Good aeration: Composting is an aerobic process, which means the micro-organisms need air to compost properly. Oxygen levels should be maintained above five per cent.
- Controlled temperatures: The warmer the pile, the faster the micro-organisms work. Temperatures between 43-65 C (110-150 F) are acceptable, but anything above 70 C (158 F) is too hot for the micro-organisms to survive. The preferred range is 54-60 C (130-140 F). For effective pathogen and weed seed kill, all material must be exposed to temperatures greater or equal to 55 C. For in-vessel systems, the pile must reach at least 55 C for three consecutive days; whereas, windrow systems must reach at least 55 C for 15 days and turned a minimum of five times.
- pH levels: Composting is effective at pH levels between 5.5 and nine. The target pH is seven.
Having a teacher was very helpful because they could look at how we had been attempting to compost and tell us why it wasn’t working and how to change our methodology. Our biggest issue was incomplete composting, which is usually either the pile is too large or b it isn’t aerated enough. To aerate the pile a producer is supposed to stir it with their bale forks/grapple bucket. With a grapple bucket it is much easier to just take bites and move them around allowing the air to get in without uncovering things.
The regulations suggest that mortality compost sites should not be within 100 metres of property lines, water run off paths, etc. and have a gentle slope. The representative helped us pick the best location for our personal needs. The base of the pile is to be made approximately one foot thick and the mortalities should be spaced about four feet apart. They are not to touch. The producer then covers this with as much vegetable matter/manure as we could pile over top and add moisture.
On most farms the pile is not right next to the hose so a question arises on how to tell if it is moist enough. The rule of thumb is to use what is called the ‘hand squeeze test.’ This is to pick up a handful of the vegetable matter in your hand and give it a squeeze following these guidelines:
- Pick up a handful of the compost material and squeeze for 10 seconds.
- Too wet — liquid can be squeezed out of material.
- Too dry — material expands (does not hold shape) and no wetness on palm.
- Just right – material leaves wetness on palm and retains shape.
Our pile receives moisture from rain, melting snow and from the mortality itself. It should not smell if all is working properly but we used a portable electric fence to discourage scavengers. The pile is supposed to be finished in a year and at that time the compost can be used only on the farm of origin.
The hope for our farm is to be able to keep learning, keep rebuilding soil and always add fertility and thereby productivity to our land. Working to improve what we already own will greatly help the next generation succeed.