Agriculture Reference
In-Depth Information
cellent guide for large farm-scale composting.
When purchasing or making compost, take great care to ensure that none
of the components have pesticide residues that can damage your crops or
cost you certification. Several years ago, farmers and nursery growers in
Washington State obtained compost from a municipal source. This compost
contained high concentrations of the herbicide clopyralid, once used to con-
trol dandelions and other broadleaf weeds in lawns. Clopyralid is not des-
troyed during the composting process, and many crops were damaged or
destroyed by the residues remaining in the compost. Clopyralid is, reportedly,
still registered for use in some forage and grain crops.
When making your own compost (highly recommended), do not include
diseased or pest-infested plant materials or weed seeds. Burn these materials
and add the ashes to your compost, if you wish. Be very careful not to include
materials that may contain pesticide residues. Grass clippings, leaves, wood
chips, and other plant debris from municipal sources should generally not be
used to produce compost for organic orchards unless you are absolutely sure
they are free of pesticides.
Cottonseed meal.
Cottonseed meal is the dry matter left after cotton has
been ginned and the oil extracted from the seeds. This high-protein product
is often used for animal feed in the southern and western United States and
is used as an organic fertilizer. It provides 6 to 9 percent of slow- to moder-
ately rapid-release nitrogen and lesser amounts of phosphorus and potassi-
um. If you have access to a cost-effective source of this product, it can be a
good orchard amendment. Ensure that any product you use has been tested
for pesticide residues and you have documentation that it is free from such
contamination.
Dolomite.
Dolomite (also known as dolomitic limestone) is primarily mined
from sedimentary deposits and consists largely of calcium magnesium car-
bonate (CaMg(CO ) ). Its primary use in horticulture is to raise soil pH levels
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