How can storage stop odours, flies or runoff?
There is no guarantee a storage will stop all odours, flies or runoff from manure, but one can help.
Odours are produced from manure when conditions in the pile, such as very wet, tightly packed manure, are allowed to become anaerobic — decomposing in the absence of oxygen. Aerobic conditions (when oxygen is present) produce fewer bad odours.
Conditions in a pile of manure behind your barn might be aerobic near the top of the pile where water drains away from it, but anaerobic at the lower edges of the pile where the runoff water remains.
Ontario research demonstrated that runoff occurs from the sloped sides of a pile of manure . The larger the pile footprint, the more perimeter with sloped sides it has and the more runoff it produces (Figure 3).
Creating a deeper pile using walls to create more vertical sides promotes the soaking-in of rainfall, reducing runoff while making the pile’s moisture content more uniform.
Flies need food, moisture, optimum temperatures and a place to hide in order to breed and proliferate. The conditions are perfect for this inside a damp manure pile. If the pile is dry, flies are kept to a minimum.
Won’t spreading manure on my pasture result in parasites and weeds?
Figure 3. Horse manure placed directly on the soil creates large, shallow piles, which collect rainfall. The contaminated water sits at the pile base, generating odours and establishing a breeding spot for flies.
If your horse manure is encouraged to properly compost, temperatures in the pile will reach levels high enough to kill parasites, weed seeds and even fly larvae. Ideally, maintain a core temperature in the manure pile of 55°C (131°F) for 15 days.
During composting, micro-organisms, such as bacteria and fungi, break down organic material into a stable, dark brown, soil-like material. This process requires a proper balance of carbon, nitrogen, oxygen, moisture and temperature.
Horse manure composts naturally with the mixture of carbon in the bedding, nitrogen in the manure and oxygen, as it is bulky. The ideal carbon to nitrogen (C:N) ratio is from 25:1 to 35:1, and ideal dry matter content is 40% to 60% (much like a damp sponge after the water is wrung out).
The C:N ratio and dry matter content can only be known by lab analysis, however, Table 1 shows that most horse manures are close to the ideal ranges. Heat is produced during composting, but the process slows if the air is too cold.
Manure storage assists composting since the piles are more compact, especially with walls to help retain heat in winter. Walls promote uniform soaking-in of rainfall, which encourages composting.
Periodic turning of the pile, where possible, introduces oxygen. This stimulates biological activity, speeds composting and raises pile temperatures. Turning is easier in a pile with a concrete floor and walls.
Why build a storage if I get a manure broker to take all my manure away?
Figure 4. Horse manure on this farm is removed by a broker using large equipment and a large truck, so it is important to leave lots of room for manoeuvring.
Many horse farmers pay manure brokers to take their manure because they do not have any use for it in crop production (Figure 4). The fee is based on how difficult it is to remove the manure, how many trips are needed, and who is willing to take and use the manure.
Some horse farmers get local cash croppers to remove and use their manure. In either case, storage helps reduce removal costs and make horse manure more attractive for others to use since it:
- densifies the manure — since horse manure is so light and bulky, it isn’t cost-effective to transport.
- helps retain nutrients, making the manure more useful for crop production.
- makes manure removal easier, in any weather, particularly if there is a concrete floor and walls.
- makes it easier to estimate volumes for transport.
How can I make it easier to get manure from the horse barn into the storage?
Figure 5. Backfill against the outside walls extending near the top can double as a wheelbarrow ramp, if the slope is not too great.
Most horse farmers use wheelbarrows to move manure from the stalls to storage. If the path is wet, bumpy or narrow, the resulting pile of manure ends up very large and too shallow (1 m deep, or less) as in Figure 3.
The key is to reduce the distance you have to manoeuvre over the surface of the manure and find ways to elevate the manure more easily. You could install a fixed-in-place stable cleaner to elevate the manure, but this is expensive.
Here are some ideas to consider:
- Construct the storage so there is access from all sides at an elevated level using soil backfilled against the outside of the walls (Figure 5).
- Construct the storage into the side of a hill that is below the level of the barn (Figure 6).
- Purchase a simple portable belt conveyor that moves manure some distance and to higher levels in the storage (Figure 7).
I want to help protect the environment, but aren’t storages expensive?
Figure 6. Storage in the side of a hill makes it easy to dump wheelbarrows. Install safety stops at the top edge.
Storages do cost money, but costs vary depending on how elaborate you want the walls, floor or roof. There are several things to think about as you ponder whether or not to construct walls, floor or a roof.
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