Agriculture Reference
In-Depth Information
Fertilizers Derived from Plants and Animals
Many of the natural products organic gardeners used in the past are now unavailable to
us because of their environmental consequences. For example, here are the meals we prob-
ably shouldn't use anymore: blood meal, bone meal, alfalfa meal, canola meal, corn gluten
meal, cotton meal and soy meal, just to name the main ones. Let's look at them in order.
Blood and bone meal were great. Blood meal had the nitrogen and trace minerals and
bone meal had the phosphorus and some calcium. But now there is the risk of spreading
mad cow disease. Some scientists don't think this is an issue, but some do. There is also
potential for heavy metal contamination in bone meal.
Plant meals are mostly genetically modified now. Corn gluten meal is a good pre-emer-
gent weed killer for certain weeds, but most corn is genetically modified. In the U.S., it
might be possible to find a non-GMO source, but I suspect not for long due to cross-pollin-
ation. Canola, cotton, and soy are all genetically modified. Alfalfa meal is loaded with nu-
trients, although the USDA has recently approved it for genetic modification, too. We def-
initely don't want to introduce genetically modified DNA into our soil.
Kelp, molasses and humic acids are still good organic fertilizers. Sea minerals and fish
fertilizers are others that come from the ocean. We'll look at all of these in the biostimu-
lants chapter.
