Kimberly J. Workinger
Fertilizers
With all of these advances, there are challenges. Fertilizer use, while continually evolving and necessary to some extent in order to keep up with worldwide demand for food, is not very efficient. Some estimates put the actual uptake of this fertilizer at one third to one half of what is applied. (20) The rest is running off the land and into waterways like the Mississippi River. The runoff is making its way to the Gulf Mexico where some estimate the hypoxic "dead zone" due to the nitrogen loading to be the size of the state of New Jersey (21) Nitrous oxide, which comes from agricultural use of fertilizer, is a gas that is 310 times more potent as a greenhouse gas than carbon dioxide (22).
Pesticides
"The standard approach has been to pump up the dosage of chemicals. In 1965, US farmers used 335 million pounds of pesticides. In 1989 they used 806 million pounds. Less than ten years after that, it was 985 million pounds. That's three and half pounds for every person in the country, at a cost of $8 billion. Twenty percent of these approved-for-use pesticides are listed by the EPA as carcinogenic to humans." (23)
Monocropping activities are responsible for this trend as they are more vulnerable to pests. A farmer vested in one crop will tend to do all that is necessary to support the success of that crop. The effectiveness of this strategy is questionable when after applying nearly a billion pounds of pesticides we are still experiencing crop loss percentages are not changed by appreciable amounts (24) and millions of people living in the Midwestern states are drinking water that is contaminated with the pesticide residues. (25) Pesticides are not applied effectively either. Estimates of 0.1% of the pesticides are reaching target pests while the rest affects the environment including bird and bee populations and the reproductive structures and legs of frogs (26).
Production agriculture or factory farming has used economies of scale to provide food in abundant supply. It is an energy intensive industry consuming about 19% of the energy used in the US with 14% being used in production, processing and packaging (27). Unfortunately, the amount of energy we put in is not efficiently converted as for every three calories of energy we put into production there is only one calorie produced on average with some studies showing energy intensive products like grain fed beef requiring thirty-five calories. (28)
"Satisfy human food and fiber needs. Enhance environmental quality and the natural resource base upon which the agriculture economy depends. Make the most efficient use of nonrenewable resources and on-farm resources and integrate, where appropriate, natural biological cycles and controls. Sustain the economic viability of farm operations. Enhance the quality of life for farmers and society as a whole." -The USDA definition of Sustainable Agriculture.
Sustainable agriculture is a concept that has gained more and more momentum as Americans make daily dietary decisions. It is impractical both from a geographic and an economic point of view to expect that even after being armed with the information, the students in the class will be able to make a complete switch to foods obtained in a sustainable way. It is possible, however, that right now in their homes and certainly as they finish high school and move on to whatever future awaits them they can make decisions and choices about the way they purchase food that could make a large difference to their health and the environment.