For inCreasing organiC Matter and suPPlying nutrients
The quickest way to rebuild a poor soil is to practice dairy farming, growing forage crops, buying . . .
grain rich in protein, handling the manure properly, and returning it to the soil promptly.
—J. l. hills, C. h. Jones, and C. Cutler, 1908
Once cheap fertilizers became widely available after
year; manure from a 100-sow farrow-to-finish operation
World War II, many farmers, extension agents, and
is worth about $16,000; and manure from a 20,000-
scientists looked down their noses at manure. People
bird broiler operation is worth about $6,000. The
thought more about how to get rid of manure than how
other benefits to soil organic matter buildup, such as
to put it to good use. In fact, some scientists tried to find
enhanced soil structure and better diversity and activity
out the absolute maximum amount of manure that could
of soil organisms, may double the value of the manure.
be applied to an acre without reducing crop yields. Some
If you’re not getting the full fertility benefit from
farmers who didn’t want to spread manure actually piled
manures on your farm, you may be wasting money.
it next to a stream and hoped that next spring’s flood
Animal manures can have very different proper-
waters would wash it away. We now know that manure,
ties, depending on the animal species, feed, bedding,
like money, is better spread around than concentrated
handling, and manure-storage practices. The amounts of
in a few places. The economic contribution of farm
nutrients in the manure that become available to crops
manures can be considerable. On a national basis, the
also depend on what time of year the manure is applied
manure from 100 million cattle, 60 million hogs, and 9
and how quickly it is worked into the soil. In addition,
billion chickens contains about 23 million tons of nitro-
the influence of manure on soil organic matter and plant
gen. At a value of 50 cents per pound, that works out to
growth is influenced by soil type. In other words, it’s
a value of about $25 billion for just the N contained in
impossible to give blanket manure application recom-
animal manures. The value of the nutrients in manure
mendations. They need to be tailored for every situation.
from a 100-cow dairy farm may exceed $20,000 per
We’ll start the discussion with dairy cow manure but
Photo by Edwin Remsburg
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Building SoilS for Better CropS: SuStainaBle Soil ManageMent