Agriculture Reference
In-Depth Information
Hoofandhornmeal.
Containing 12 to 14 percent nitrogen and 2 percent K O,
2
hoof and horn meal are suitable sources of slow-release nitrogen for use as
soil builders. Like blood meal, they are by-products of the slaughterhouse in-
dustry.
Humatesandhumicacids.
Humic materials are derived from plant materials,
such as lignin, and have weathered to the point that they are very resistant
to further degradation. They are important components of the soil because
they help bind the soil particles together, creating aggregations and struc-
ture.
The term “humic acid” refers to a large group of related compounds.
Although they can be created synthetically, humic materials are generally
mined from lignite coal or an oxidized clay-like form of lignite called le-
onardite. The latter is particularly rich in humic acids. While humic acids
are certainly critical components in a biologically active soil, the benefits of
adding them to the soil are less clear. You would need to add vast amounts
to increase soil organic matter even slightly. Mined humates are chemically
different from those found in the soil. From a fruit grower's perspective, com-
mercial humate products appear to have little to offer.
K-mag, sul-po-mag, or sulfate of potassium magnesia.
This naturally occur-
ring material is mined for use as a fertilizer. It is moderately to rapidly avail-
able to plants and contains 23 percent sulfur, 22 percent K O, and 11 percent
2
magnesium. This is a valuable product when you are faced with potassium,
magnesium, and sulfur deficiencies. It has no effect on soil pH. Make your
applications based on recommendations from a soil analysis.
Limestone.
Limestone is a naturally occurring material comprising mostly
various concentrations of calcium carbonate. A typical limestone contains
about 40 percent calcium, which is slowly available to plants. Its greatest
