Agriculture Reference
In-Depth Information
provide a fertilizer analysis, making it impossible to determine application
rates. At best, worm castings would be a very expensive fertilizer and source
of organic matter for any but the smallest orchards. A better strategy is to
create a biologically active soil where your own worms produce the castings
in the soil where they are needed by your orchard crops.
Applying Fertilizers
Soil tests, tissue analyses, and rule-of-thumb guides generally include estim-
ates of how much nitrogen, phosphorus, and other nutrients are needed. Re-
commendations are usually given in pounds per acre or pounds per 1,000
square feet in the United States or kilograms per hectare or kilograms per
100 square meters in Canada. The question then becomes how much fer-
tilizer is needed to provide those amounts of nutrients. Commercial fertil-
izers, organic and nonorganic, are analyzed for the concentrations of nutri-
ents in them, and the fertilizer analyses are printed on the containers. At
least three numbers are shown, representing nitrogen, phosphorus, and po-
tassium, in that order. Other macro- and micronutrients, if present, may be
listed in a table.
Ammonium sulfate, a popular conventional fertilizer, has an analysis of
21-0-0, indicating 21 percent N and no P O or K O. A typical conventional
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garden fertilizer might be labeled as 16-16-16, indicating that it has at least
16 percent each of N, P O , and K O. Most fertilizers contain at least trace
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amounts of micronutrients. Manufacturers are not required to list these nu-
trients unless they advertise that fertilizer as a source of those particular
nutrients. If they do list micronutrients, the claim is usually that the fertilizer
contains “at least” the amounts listed on the label.
Unfortunately, some manufacturers of commercial organic fertilizers
choose not to include the analyses and sell the products as “soil amend-
ments” or “soil conditioners” without specifying exactly what is in them.
When buying such products, you have no clear idea of the benefits, if any,
that you are receiving. You are far better off using materials that are clearly
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