Manure Management
 Manure Spreader at
Tuck Away Farm |
 Farm Equipment at
Double Dream Farm |
Close up of a pasture spread with manure in early Spring at Filitosa Farm. |
Early stage compost pile at Filitosa Farm. |
Compost pile that is ready to spread or be used as fertilizer for another application. |
Manure management is
vitally
important as horse farms are squeezed onto
fewer acres and are surrounded by subdivisions. Without a proper
manure management routine, manure fosters parasites and pathogens,
generates offensive odors, affects the health of the horses, and can
damage the environment. If handled improperly, manure can put
excess nitrogen and nitrates back into the soil and then into surface
or
ground water. Manure is also a source of phosphorus, another
pollutant that is not good for the health of the water or for the
animal consumers of the water, including us. Phosphorus can also
get into surface water as well as ground water if excess manure is
applied to pastures or is washed into the soil through a concentrated
pile (Wegner and Halbach, 2000).
There are several options
for dealing with manure. The first and
the best in many situations, is to compost the manure and put it back
on the pastures to fertilize and rejuvenate them. Another option
is to put it directly back on fields or pastures and keep the horses
off of it until it gets incorporated back into the soil. A
third option is to have someone come and take the manure away to be
composted or spread on other agricultural land. This may be a
good option for farms that have limited acreage or do not have the
means to compost or spread manure themselves. What is not a good
option is to leave manure in the paddocks and pastures or to
leave it in a pile that sits there and increases year by year (Wegner
and Halbach, 2000).
Spreading Manure:
Spreading the manure back on fields or pastures, whether it was composted first or directly spread, is often very beneficial for the fields and pastures. Horse manure contains nitrogen, phosphorus, potassium, sulfur, micronutrients, and is high in organic matter. If not over done, manure nutrients can replace commercial fertilizers and the organic matter enhances soil structure, water, and
nutrient holding abilities which helps with erosion. And soil quality in general can be improved (Wegner and Halbach, 2000).
Minnesota has some rules that should be followed when spreading manure. If a farm has fifty or more horses or has 10 or more horses on a shoreland, a feedlot permit will need to be obtained and the MPCA guidelines for feedlots followed. For the average recreational horse farm, general guidelines from the MPCA say not to spread manure on soils with a high water table, on flood plains, on lakes, intermittent streams, grassed waterways, on frozen soils with slopes great than 15 percent, or near direct groundwater conduits (Wegner and Halbach, 2000).
Spreading the manure back on fields or pastures, whether it was composted first or directly spread, is often very beneficial for the fields and pastures. Horse manure contains nitrogen, phosphorus, potassium, sulfur, micronutrients, and is high in organic matter. If not over done, manure nutrients can replace commercial fertilizers and the organic matter enhances soil structure, water, and
nutrient holding abilities which helps with erosion. And soil quality in general can be improved (Wegner and Halbach, 2000).
Minnesota has some rules that should be followed when spreading manure. If a farm has fifty or more horses or has 10 or more horses on a shoreland, a feedlot permit will need to be obtained and the MPCA guidelines for feedlots followed. For the average recreational horse farm, general guidelines from the MPCA say not to spread manure on soils with a high water table, on flood plains, on lakes, intermittent streams, grassed waterways, on frozen soils with slopes great than 15 percent, or near direct groundwater conduits (Wegner and Halbach, 2000).
For optimal manure
spreading, the individual farm's situation should be
taken into account. If horses are out on a pasture all of the
time, the manure gets clumped in piles and can give an uneven spread of
nutrients to the pasture. The recommendation is to harrow or drag
pastures regularly to spread the manure evenly over the pasture.
If stockpiled manure is to be spread onto a field, you need to know the
nutrient content so the application matches the nutrient needs of the
crop or pasture. Manure can be sampled, packaged, and sent to a
soil testing laboratory for nutrient analysis to get an accurate
estimate of its nutrient content, or there are tables that can give a
rough estimate. It can get complicated to try and figure out how to
match the amount of manure to what a crop or pasture needs.
Contact the U of M Extension service for more aids and personal help
(Wegner and Halbach, 2000).
The timing of when manure is spread is also an issue. The ideal is to spread manure in the spring. This helps the pasture or crop get the nutrients it needs for the growing season and minimizes the nutrients that are lost to plant uptake. Manure can also be spread in the fall, but it is not as ideal as in the spring and summer. Manure should not be spread in the winter because it can easily shift and create run off if it rains and it cannot soak into the frozen soil (Wegner and Halbach, 2000).
There are also guidelines
for how close to spread manure to other
environmental features. It is recommended that there is a separation
distance of 200 feet for water wells, 100 feet for sinkholes and
individual dwellings, 300 feet for residential development, and 25 feet
for public roadways. The separation distances vary for streams,
rivers and lakes depending on how much of a slope there is, what the
soil type is, and what time of year it
is. For example, it is recommended that for a course soil from
may to October the separation distance be 100 feet. For a medium
to fine soil from May to October the recommended distance is 200.
All of these recommendations go up 100 feet if the slope is over 6
degrees and it is recommended that no spreading happen from November to
April if the slope is over 6 degrees (Wegner and Halbach, 2000).
Composting Manure:
Composting manure before it is spread or hauled away is one of the best ways to deal with manure from an environmental perspective. Composting execrates decomposition by stimulating the microorganisms in the manure and bedding to grow faster, which creates heat, water vapor, and carbon dioxide. This kills weeds, reduces pathogens, reduces odors, reduces volume, and if hot enough, kills parasites. Compost can then be spread on pastures, fields, or gardens as a valuable fertilizer (Wegner and Halbach, 2000).
Different kinds of bedding
and manure compost differently. Manure
has different proportions of carbon and nitrogen that will change the
rate of microorganism activity. So, the amount of manure,
bedding, and other organic materials needs to be balanced to create the
best conditions for decomposition. A compost pile needs the right
amount of water, air, carbon, and nitrogen getting piled, turned, and
aged (Wegner and Halbach, 2000).
The essential elements of a compost pile:
The essential elements of a compost pile:
- Air: needed to allow carbon dioxide
and water vapor
to leave the pile. Too much air does not let the temperature get
high enough for maximum decomposition and too little air doesn't allow
the microorganisms to get enough oxygen to grow and work.
- Water: needed for maximum microorganism growth. It is ideal to have about 50 percent moisture. It is also better to add little amounts of water regularly than to let the pile dry out and then wet it back to 50 percent.
- Manure: provides the nitrogen and carbon.
- Bedding and other organic material: helps create air space and adds some nitrogen and carbon.
- Temperature: ideal temperatures range from 131 degrees to 150 degrees. These temperatures need to be maintained for at least 21 days in order to kill weeds, parasites, and reduce pathogens.
- Location: it is better to put compost piles away from sources of water, such as wells, streams, lakes, and ditches.
There are four groups of composting methods that can be used to create a working compost pile. There is passive composting, windrows, aerated piles and a group of methods known as in-vessel composting.
Windrow composting is when
the manure and bedding are placed in long narrow piles or windows which
are turned or agitated on a regular basis. Windrows can be
different sizes depending on the porousness of the materials being
composted. It is recommended that dense materials, like solid
manure, stay at three feet, while more fluffy materials can be 12 feet
high. The width can vary from 10 to 20 feet. The size and
shape of the windrows should be determined by what equipment you have
to turn the piles (Rynk, 1999). Once the pile is started, the
pile needs to be turned to maintain its decomposition rate. How
much turning
the pile needs is dependent on the size and material make up of the
pile. A good indicator of when to turn the pile is its
temperature. If the temperature falls below 120 degrees
F, and has the right amount of moisture and air flow, this
is generally a good time to turn the pile to get it going again (Wegner
and Halbach, 2000). Turning the windrows over mixes the materials,
releases trapped heat, rebuilds the porosity of the pile, releases
water vapor, and releases gasses. The pile is aerated by the
turning, but the new oxygen gets depleted quickly, so the real purpose
of the turning is to rebuild the porosity so that natural
and passive aeration can take place. Mixing also helps to get all
of the material heated evenly and more pathogens, weeds, and fly larvae
get killed (Rynk, 1999).
Windrows can also be managed by separating the larger pile into at least four piles so that there can be three stages of decomposition: the pile where fresh manure and bedding gets put every day, a pile where decomposition is just getting started, the intermediate pile where decomposition is well on its way, and the final pile where decomposition has taken place and is ready to be spread on the pasture or used in the garden.
Aerated piles can encompass the windrow system. In this method instead of turning the pile, pipes with lots of air holes running their length are placed through the windrows to let in air. The pile can be covered with peat moss or another type of cover and this eliminates odors. A more sophisticated approach to the passive aeration system is to provide a blower to blow air into the pipes at the base of a static compost pile (Rynk, 1999).
In-vessel composting consists of compost piles that are confined to a bin, building, or some other container. Bin composting is the simplest in-vessel method. It much like the aerated static pile, air is let in through a pipe in the bottom of the bin and the materials passively decompose in the bin. There are more complicated ways of using very long bins that allow for the turning of materials with in the bin, as well (Rynk, 1999).
The method really depends on the situation. Static and passive piles are the least expensive, in time and money, but decomposition is slow to almost non-existent. The windrow method is very common among farm composting operations and is probably one of the best choices for the farm. Windrow composting produces the most mixed and even compost that is better to put back on crops or pastures. The passive aerated system also works well with horse manure and bedding (Rynk, ?).
There are many ways to deal with manure. The important thing to remember is that it does need to be managed so that it does not damage the environment or create excessive odors or harbor pathogens or parasites.
Windrows can also be managed by separating the larger pile into at least four piles so that there can be three stages of decomposition: the pile where fresh manure and bedding gets put every day, a pile where decomposition is just getting started, the intermediate pile where decomposition is well on its way, and the final pile where decomposition has taken place and is ready to be spread on the pasture or used in the garden.
Aerated piles can encompass the windrow system. In this method instead of turning the pile, pipes with lots of air holes running their length are placed through the windrows to let in air. The pile can be covered with peat moss or another type of cover and this eliminates odors. A more sophisticated approach to the passive aeration system is to provide a blower to blow air into the pipes at the base of a static compost pile (Rynk, 1999).
In-vessel composting consists of compost piles that are confined to a bin, building, or some other container. Bin composting is the simplest in-vessel method. It much like the aerated static pile, air is let in through a pipe in the bottom of the bin and the materials passively decompose in the bin. There are more complicated ways of using very long bins that allow for the turning of materials with in the bin, as well (Rynk, 1999).
The method really depends on the situation. Static and passive piles are the least expensive, in time and money, but decomposition is slow to almost non-existent. The windrow method is very common among farm composting operations and is probably one of the best choices for the farm. Windrow composting produces the most mixed and even compost that is better to put back on crops or pastures. The passive aerated system also works well with horse manure and bedding (Rynk, ?).
There are many ways to deal with manure. The important thing to remember is that it does need to be managed so that it does not damage the environment or create excessive odors or harbor pathogens or parasites.