will also offer information about the handling, charac-
composting, see chapter 13.
teristics, and uses of some other animal manures.
Some dairy farmers have built what are called
“compost barns.” No, the barns don’t compost, but
MANURE HANDlINg SYSTEMS
they are set up similar to a free-stall barn, where bed-
Solid versus Liquid
ding and manure just build up over the winter and the
The type of barn on the farmstead frequently determines
pack is cleaned out in the fall or spring. However, with
how manure is handled on a dairy farm. Dairy-cow
composting barns, the manure is stirred or turned twice
manure containing a fair amount of bedding, usually
daily with a modified cultivator on a skid steer loader
around 20% dry matter or higher, is spread as a solid.
or small tractor to a depth of 8 to 10 inches; sometimes
This is most common on farms where cows are kept
ceiling fans are used to help aerate and dry the pack dur-
in individual stanchions or tie-stalls. Liquid manure-
ing each milking. Some farmers add a little new bedding
handling systems are common where animals are kept
each day, some do it weekly, and others do it every two
in a “free stall” barn and minimal bedding is added to
to five weeks. In the spring and fall some or all of the
the manure. Liquid manure is usually in the range of
bedding can be removed and spread directly or built into
from 2% to 12% dry matter (88% or more water), with
a traditional compost pile for finishing. Although farm-
the lower dry matter if water is flushed from alleys
ers using this system tend to be satisfied with it, there is
and passed through a liquid-solid separator or large
a concern about the continued availability of wood shav-
amounts of runoff enter the storage lagoon. Manures
ings and sawdust for bedding. More recently, vermicom-
with characteristics between solid and liquid, with dry
posting has been introduced as a way to process dairy
matter between 12% and 20%, are usually referred to as
manure. In this case, worms digest the manure, and the
semisolid.
castings provide a high-quality soil amendment.
Composting manures is becoming an increasingly
Manure from hogs can also be handled in different
popular option for farmers. By composting manure,
ways. Farmers raising hogs on a relatively small scale
you help stabilize nutrients (although considerable
sometimes use hoop houses, frequently placed in fields,
ammonium is usually lost in the process), have a smaller
with bedding on the floor. The manure mixed with bed-
amount of material to spread, and have a more pleas-
ding can be spread as a solid manure or composted first.
ant material to spread—a big plus if neighbors have
The larger, more industrial-scale farmers mainly use
complained about manure odors. Although it’s easier
little to no bedding with slatted floors over the manure
to compost manure that has been handled as a solid,
pit and keep the animals clean by frequently washing the
it does take a lot of bedding to get fresh manure to a
floors. The liquid manure is held in ponds for spreading,
20% solid level. Some farmers are separating the solids
mostly in the spring before crops are planted and in the
from liquid manure and then irrigating with the liquid
fall after crops have been harvested. Poultry manure is
and composting the solids. Some are separating solids
handled with bedding (especially for broiler production)
following digestion for methane production and burning
or little to no bedding (industrial-scale egg production).
the gas to produce electricity or heat. Separating the
liquid allows for direct composting of the solids without
Storage of Manure
any added materials. It also allows for easier transport
Researchers have been investigating how best to handle,
of the solid portion of the manure for sale or to apply
store, and treat manure to reduce the problems that
to remote fields. For a more detailed discussion of
come with year-round manure spreading. Storage
130
Building SoilS for Better CropS: SuStainaBle Soil ManageMent