Wednesday, November 17, 2010

Peak Fertilizer

In his new book, The Coming Famine, Julian Cribb details the looming problems we face producing enough fertilizer to meet agricultural needs around the world. Increased fertilizer use was central to the “Green Revolution” of the Twentieth Century which increased food production by two and a half fold. Farmers worldwide now use seven times as much fertilizer as they did fifty years ago.

The need for fertilizer is magnified by modern farming techniques that allow nutrients to bleed from the soil at alarming rates, particularly in rice and wheat producing areas in Asia, Central and South America, and Africa. Poor use of fertilizers has lead to deficiencies of essential micro-nutrients in the soil. Lack of micro-nutrients can result in Vitamin A deficiency, iron deficiency anemia, and zinc deficiency which can result in increased probability of early death for children and women, and impaired IQ development in children. Vitamin A deficiency leads to approximately one million child deaths every year.

Ninety percent of fertilizers used today are derived from nitrogen (N), phosphorous (P), and potassium (K). More and more of these fertilizers are generated from artificial sources.

Ninety-seven percent of the world’s nitrogen fertilizer is made from synthetic ammonia produced by using hydrogen from natural gas. The International Energy Agency has predicted that global gas production will peak sometime in the decade from 2010 to 2020. As natural gas production declines, so will the industrially produced nitrogen fertilizer.

During the global food and energy price spike of 2007-8, some nitrogen fertilizer prices rose by 160 percent while phosphate prices soared 318 percent, a foretaste of things to come. Rising fertilizer prices caused farmers to cut back on their use of fertilizers which in turn led to a reduction in food output.

The world’s main food crops use an estimated 12 million tonnes of phosphorous a year while only 4 million tonnes of phosphorous are generated from natural weathering of rock or atmospheric deposition. The rest is created from phosphate mined from the ground.

Both phosphorous and potassium fertilizers are mined from rock. Although they are both in plentiful supply at the present, the supply is finite and will eventually run out. Estimates are that the world has an eighty year supply of rock phosphates at present level of use. As with all minerals, the highest quality phosphates are being mined first and as they deplete, production will drop and costs will rise.

In 2007, Canadian physicist Patrick Dery attempted to apply M. King Hubbard’s work on peak oil to rock phosphate and came to the conclusion that world production had actually peaked in 1989. Unlike gas and oil there are no readily available substitutes for rock phosphate. Without phosphorus, plants become “phosphorous limited,” constraining production no matter how many other nutrients can be supplied.

Additionally, most of the world’s phosphate production comes from China (37 percent), Morocco and the Western Sahara (32 percent), South Africa (8 percent), and the United States (7 percent). Potash is obtained by mining potassium salts primarily located in 4 countries, Canada (53 percent), Russia (22 percent), Belarus (9 percent) and Germany (9 percent). As demand outstrips supply these countries could form the fertilizer equivalent of OPEC, or even reduce their exports to save supplies for their own crops.

The Food and Agriculture Organization of the United Nations estimates that the share of mineral fertilizers compared to all sources of nutrients will rise from 43% in 1960 to 84% in 2015. Farmers will be dependent on mineral fertilizers for the overwhelming source of mineral fertilizers just as those minerals reach peak production and begin to decline.

While there is presently a surplus supply of nutrients, increasing demand is outrunning the discovery of new resources, eerily similar to the history of oil discovery and production.

The world must start planning for peak fertilizers now. There is an alternative for nitrogen--fixing nitrogen from the atmosphere though the use of legume crops. Adoption of organic and permaculture farming methods would naturally recycle nutrients into the soil, as would greater use of composting and other methods of conserving and recycling nutrients. Sources of nutrients that are presently thrown away, such as urine--which is high in both N and P--could be harvested to return these nutrients to the soil.

Farmers of the future will need to adopt a very different attitude toward the conservation and recycling of the nutrients their crops require to thrive.