Sustainable Urban Living: Green Solar Energy for Food and Biofuels Production - Design with the Desert: Conservation and Sustainable Development - page 415

exports occur from Saudi Arabia, fossil fuels will be too expensive for industrial food
production in many areas, especially high energy use sectors like the West and Southwest.
The net zero export problem makes finding a food supply that produces no or minimal
fossil fuels both mission-critical and urgent for the survival of human societies.
Fossil fuel challenges range far beyond concerns about supply and include subsidies,
consumption, pollution, health impacts, prices, and supply chain. Each must be significantly
reduced to avoid catastrophic outcomes. A solution to aim for is the development of a suite
of green energy sources that are sustainable and nonpolluting while designing ways to
significantly reduce energy consumption.
24.4 Soils and Soil Nutrient Losses
Globally, one-third of the prime cropland has been so degraded it had to be abandoned
over the last 30 years. 17 An additional third is so degraded that farmers must use sig-
nificantly more fertilizers to achieve normal yields. Farmers in the United States abandon
cropland due to soil wear out, soil erosion, and salt invasion from irrigation and tidal
surges. The West is especially vulnerable to irrigation salt build up because most crop-
lands are irrigated and the heat evaporates the water, leaving salt.
Soil nutrients create a serious problem because they are ravenously consumed rather
than conserved with industrial agriculture. Growing a food crop for one season removes
about 50% of the applied soil nutrients which are lost to the field when the crop is
harvested. 18 The field loses another 30% of the applied fertilizer to erosion from wind,
rain, and irrigation. Therefore industrial agriculture forces framers to apply about 80% of
the needed crop nutrients fresh to the field each year. Without nutrient replacement with
fertilizer, the next crop lacks critical nutrients and production diminishes or fails. Farmers
found that adding more fertilizer and irrigation, significantly increased production.
However, mined (inorganic) fertilizers are inefficiently absorbed by plants so farmers must
add substantially more fertilizer than the crop actually needs.
The Green Agricultural Revolution allowed short-term food productivity gains by
mining trillions of gallons of fossil water and substituting inorganic fertilizers for organic
nutrients. However, this fossil food strategy is sustainable only until about a decade
before the first of the Magic 21 fossil resources needed for industrial agriculture runs out
(Table 24.1). 19 Unfortunately, several fossil resources will run out or become unaffordable
before our children reach midlife. 20
Phosphorus is often a limiting nutrient in natural ecosystem because the supply of
available phosphorus constrains the ecosystem size. Food and biofuel production depend
on substantial phosphorus fertilizer which must be mined, packaged, transported long
distances, and stored before application on fields. World governments are beginning to
recognize the strategic value of phosphorus which is also used in the food, munitions, and
chemical industries. India is running low on matches and fireworks as factories run short
of phosphorus. The Brazilian government is debating whether to nationalize privately
held mines that supply the fertilizer industry. In 2009, Beijing imposed a 170% tariff on
phosphate rock exports to try to secure enough for its own farmers.* The U.S. phosphorus
* http://www.icis.com/Articles/2009/02/01/9097380/china-delays-phosphate-export-duty-hike.html (accessed
August 10, 2011).