Manure is comprised of undigested food, digestive juices, and bacteria.  The bacteria make up as much as thirty percent of the mass.  Urine (usually as soaked bedding), because it is already a solution, contains more readily available nutrients than feces.

     Decomposition of manure begins with the formation of ammonia as urinary nitrogen decomposes.  The level of fermentation depends on the degree of compaction and moisture content of the manure pile.  A well-tamped but frequently turned pile makes the best environment for the aerobic bacteria of fermentation.  The pile should be uniformly moist, about 50 percent.  An absolutely dry pile dehydrates the bacteria and a soggy heap smothers the aerobic organisms.

     The next stage of decomposition is the putrefying of the insoluble nitrogen in the feces.  The degree of fermentation here depends on the composition of the manure.  This, in turn, was determined by the quality and amount of feed given to the animals as well as by the age, health, and condition of the animals.  As the manure solids putrefy, they produce ammonia which is food for the bacteria.

     A strong ammonia smell indicates that the ratio of carbon to nitrogen in the pile is too low.  This can be from feeding excess protein or it can be due to the fact that there is too little bedding mixed in with the manure and urine.  A carbon to nitrogen ratio of about 30:1 is optimum.  Manure has a C:N ratio of 14:1; Sawdust 400:1.  A pile of pure manure would decompose in a few weeks and produce great amounts of heat; a pile of sawdust would create negligible heat of fermentation and take two to three years to become humus.  The normal combination of manure and bedding that comes out of well maintained stalls usually results in a good C:N ratio for composting.

     The hydrated lime which is sometimes added directly to the manure pile speeds up the bacterial action of fermentation but the alkalizing action burns up valuable nitrogen which is lost to the air.  The same lime which is used to "sweeten" stall floors lowers the acidity of the urine in the stall.  It also causes the dirt particles to clump which allows air to more easily get at and penetrate the wet soil, thereby drying the floor.  The negligible amount of lime added to stall floors if taken out with the next batch of manure and bedding will not affect a manure pile's pH significantly one way or another.

     The final phases of composting are the death of the bacteria and the breakdown of fibers.  As the bacteria die and decompose, they release their stored nitrogen.  As the fiber breaks down, carbon dioxide and water are released which decreases the bulk of the manure by up to one-half.

     The process of decomposition of a manure pile can take anywhere from two weeks to two years or more, depending on the type and amount of bedding in the pile and the desired quality of the resulting product.  Managing a pile properly will kill the parasite eggs and larvae, prevent flies from breeding, and result in a good quality fertilizer.  To this end, it might be best to have two or three manure piles: one ready to spread, one in the process of decomposing, and one to which fresh manure is being added daily.

     Before locating a pile, it is best to check local zoning ordinances.  Be sure the pile is out of sight and smell of residences and down-wind from the stable and the house.  The pile should also be convenient for daily dumping and periodic hauling.  If possible, the piles should be located on a sloped concrete floor with four foot walls.  The piles can be covered with a roof, plastic sheeting, or earth.  An open pile is subject to drying by the sun and leaching of nutrients by rain and melting snow.  If an open pile must be used, it should be about six feet high and six feet wide and can be added to in length as needed until hauling is convenient.  Because of the leaching of acids through the pile and down into the ground during rainy and snowy weather, the ground below a manure pile will not be suitable for planting unless major soil corrections are made.

COMPOSTED AND SOLD
     "Horse people think they are sitting on a gold mine when they have a manure pile out back on their small acreage", says our local landscape supplier.  He frequently get calls from horse owners trying to sell them horse manure when in reality it is difficult to interest the firms in hauling it away for free.  In many cases, the piles are simply too fresh, not of good enough quality, or too small for the landscapers to bother with.  In other situations, the locations of the pile has not been properly selected so the resulting soggy product is undesirable.

     Of the various livestock manures, dairy manure with sawdust shavings makes the most uniform and highest quality humus for landscaping; horse manure with sawdust, shavings, or chips comes in a respectable second.  Although horse manure has the potential to be transformed into a good commercial product for landscaping and soil improvement, she must start with quality ingredients and then invest a lot of time and equipment expense into developing them.

     Horse owners trying to interest landscape suppliers into hauling their manure away should avoid the following most common management errors.  The first mistake acreage owners make is choosing the wettest, most poorly drained spot for their manure pile - out back, down in the slough.  Extreme wetness smothers the bacteria necessary for proper composting.  The second error is throwing slabs of old straw and hay and other garbage onto the manure pile.  This makes for an uneven mixture and an undesirable material from a landscaper's viewpoint.

     Horse manure that has been kept dry and is not dominated by bedding is the best.  Lanscapers prefer wood shavings and chips over straw as wood products break down well and hold the base to the humus for a longer period of time than straw will.  There must be no foreign materials such as sticks, rocks, or twine in the manure pile as they are damaging to the processing equipment and very time consuming to pick out.

     "If someone calls me about a manure pile they want hauled away and it sounds like it is big enough and of the proper materials, the next thing I ask them is if they have a big enough farm tractor with a loader so they can load my tandem dump truck." says the landscaper.  He says someone must have a minimum of ten yards of manure (the equivalent of 5-8 pickup loads) for it to be worth the time to send a dump truck and/or loader out to pick up the manure.  At $55 per hour for a tandem dump truck and $75 per hour for a loader, it is easy to see why landscapers do not pay for manure and in many instances can not even afford to pick it up.  And transportation is just the beginning of the equation.  Proper curing requires land and time, both precious commodities.

     It takes from three to five years to make a quality humus.  To begin with, after the manure is collected, the material is put through a mechanical shredder to transform the bedding and manure into a more uniformly textured product.  The shredded material is then piled on the curing farm in carefully regulated rows.  The piles are turned between two and four times a year in order to aerate the various portions of the pile and keep it at a uniform moisture level.  The product is ready to sell 3-5 years after pickup from the horse farm.  Making a connection with a landscape supplier might be a good way to dispose of manure if it is of the proper quality but you may find that their need and availability to haul may not be as regular as you require.