Also from same site, but from the consumer's perspective.
"Eating 100% organic food
Organic food is frequently grown using animal waste, but these animals have often been exposed to pesticides, chemicals, antibiotics, and hormones (except for a small number of farmers who source their manure from organically-raised animals or raise animals on their own farm). In veganic agriculture, because the food is grown using organic plant-based techniques, it’s possible for the farmers to keep the cycle of agriculture 100% organic.
There are growing concerns about chemicals used in food production and contaminants found in the food supply. Choosing organic food is a step in the right direction, because the farmer is not intentionally adding substances like pesticides, herbicides, and GMO’s to the farmland. Unfortunately, however, these substances can still make their way to organic fields.
Organic farmers are permitted to use animal-based fertilizers like manure, blood meal, and bone meal, but these are not necessarily sourced from organically-raised animals. Many organic farms, especially large-scale operations, amend their fields with animal by-products from conventional factory farms and slaughterhouses.
The by-products of these animals can be contaminated with substances that are contrary to the aims of organic agriculture. For example, when farm animals are fed pesticide-tainted food, certain pesticides bioaccumulate in the bodies of the animals, resulting in animal-based fertilizers that still contain pesticides. Bone meal has been implicated in the spread of mad cow disease, causing some people to become wary of bone meal used in vegetable agriculture. Antibiotics that are given to farm animals can be found in the animals’ manure, and certain antibiotics are actually absorbed by vegetables, causing concern about antibiotic resistance (see the University of Minnesota studies, published 2005 and 2007).
For consumers who would like to eat cleanly-sourced food, talk to local organic farmers about how they fertilize their fields, or phone the companies whose exports you purchase. Some small farmers do make the effort to get animal products from organically-raised animals, but you’ll find that many farms are fertilizing their fields from contaminated sources.
In veganic agriculture, farmers use plant-based techniques, and are encouraged to produce as much fertility as possible on their own land, which minimizes the chance of contamination. We recommend that concerned consumers get involved and actively engage with local farmers, to promote these techniques for creating a clean food supply."
