FROM FARM TO PLATE, the modern food system reties heavily on cheap oil. Threats to the oil supply also are threats to the food supply. As food undergoes more processing and travels farther, the system consumes ever more energy each year. The U.S. food system alone eats up as much energy as does all of France. The actual growing of food accounts for only one-fifth of this. The other four-fifths is used to move, process, package, sell, and store goods after they leave the farm. Some 28% of energy employed in agriculture goes to fertilizer manufacturing, seven percent to irrigation, and 34% is consumed as diesel and gasoline by farm vehicles used to plant, till, and harvest crops. The remainder is for pesticide production, grain drying, and facility operations.
The past half-century has witnessed a tripling in world grain production. About 2,029,000 tons were produced in 2004. While 80% of the increase is due to population growth and more demand, the remainder can be attributed to more people eating higher up the food chain, increasing per capita grain consumption by 24%. Higher demand primarily has been met by raising land productivity through higher-yielding crop varieties in conjunction with more oil-intensive mechanization, irrigation, and fertilization--not by expanding cropland.
World fertilizer use has increased dramatically since the 1950s. China now is the top consumer--rising beyond 40,000,000 tons in 2004. Fertilization has leveled off in the U.S., staying near 19,000,000 tons per year since 1984. India's reliance also has stabilized at around 16,000,000 tons per year since 1998. More energy-efficient fertilizer production technology and precision monitoring of soil nutrient needs have cut the amount of energy necessary to fertilize crops, but there remains room for improvement. As oil prices increase and the price of fertilizer rises, there will be a premium on closing the nutrient cycle and replacing synthetic fertilizer with organic waste.
The use of mechanical pumps to irrigate crops has allowed farms to prosper in the middle of the desert. It also has increased farm energy use, allowed larger water withdrawals, and contributed to aquifer depletion worldwide. As water tables drop, ever more powerful pumps must be employed, perpetuating and increasing the oil requirements for irrigation. More-efficient irrigation systems, such as low-pressure and drip irrigation, and precision soil moisture testing could reduce agricultural water...