FERTILIZER CO-PRODUCTS AS AGRICULTURAL EMTERNALITIES Quantifying Environmental Services Used in Production of Food

The environmental consequences of processes necessary for food production are rarely factored into crop evaluations. Byproducts created as part of an agricultural system inputs, prior to use of the main product, and without further concentration or recycle, require additional fundamental environmental services associated with eliminating their environmental impact, and fall within the food production process. Emergy was used in this evaluation to determine a more realistic sustainability picture for the food we eat and to numerically value a new set of services by suggesting the incorporation of these byproducts into emergy ratios presently incorporating only inputs actually used in the process. This study also suggests the use of emternalities both as a terminology and methodology to evaluate sustainability by using emergy to value a new set of non-traditional externalities. Integrating co-product emergy in the Florida tomato evaluation increased total flows by 28%. Florida cabbage showed an 88% increase in total emergy, oranges increased by 75% and watermelon increased by 55%. A comparison of renewable emternalities to non-renewable emternalities illustrated an emergy deficit of 6.3 E22 sej/yr to the state of Florida from gypsum co-products associated with tomato, cabbage, watermelon and orange yields in 1994. The emdollar value of services to the United States for treatment of diammonium phosphate fertilizer produced in 2000 was valued at 564 billion emdollars.