Other aspects of conventional agriculture also have adverse
effects on environmental and human health, as well as a high
price tag. Nutrients from fertilizer and animal manure have
been associated with the deterioration of some large fisheries
in North America (Frankenberger and Turco 2003), and
runoff of soil and nitrogen fertilizer from agricultural production
in the Corn Belt has contributed to the “dead zone”
in the Gulf of Mexico. The National Research Council
(BANR/NRC 2003) reports that the cost of excessive fertilizer
use—that is, fertilizer inputs that exceed the amount crops can
use—is $2.5 billion per year. Modern agricultural practices can
also contribute to the erosion of soil. The estimated annual
costs of public and environmental health losses related to soil
erosion exceed $45 billion