Prototype machine quickly detects nitrogen and water levels in manure
A prototype manure-analysing device that works off a car or truck
battery has been built by an Agricultural Research Service (ARS)
Chemist James B Reeves designed the portable, easy-to-use analyser so farmers
can quickly tell how much nitrogen and water are in a sample of
Many farmers apply manure to their crops as an organic
fertiliser, but it can sometimes be too much of a good thing. They apply too
much because they're not sure how much nitrogen or phosphorus might be in it and
decide to err on the side of excess.
But excess nutrients can run off
in rainwater and eventually pollute streams, lakes and other bodies of
To determine how much nitrogen or phosphorus manure contains,
farmers can send samples to a laboratory for analysis, but that takes time and
money. And they usually send only one sample from the large pit into which they
flush their manure. According to Reeves, a one-sample analysis can't reflect the
nutrient levels that often vary throughout a manure pit.
prototype analyser passes invisible, near-infrared light through filters onto
about two tablespoons of manure placed in a small cup. The amount of light
reflected back allows a filter spectrometer to quantify both the nitrogen and
water content. Manure samples require no preparation or chemicals, and the
analysis takes about a minute.
Having access to an accurate,
inexpensive manure analyser will become even more important to farmers if
nutrient-management regulations tighten further. The prototype analyser is a
15-inch cube that weighs about 20 pounds. Reeves plans to make it even smaller -
about the size of a shoebox and weighing around 5 pounds.
about the research in the July 2006 issue of Agricultural Research magazine.
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