As soils lose organic matter, they become more compact, absorb less water and have a diminished capacity to retain nutrients. Roots grow less and have less capacity to absorb nutrients, nutrients are more easily lost from the soil, and less water in the soil is available for growth. The result is that the use of nutrients from fertilizers becomes less and less efficient, and the only way to overcome such inefficiency is to increase fertilizer doses, as world trends show. But increased application only compounds the problem; inefficiency and soil destruction continue apace. It is not uncommon to hear organic farmers say that they converted to organic because their yields collapsed after years of heavy industrial fertilizer use.
Problems with industrial fertilizers do not end there. The forms of nitrogen provided by chemical fertilizers are readily transformed in the soil, so that nitrous oxides are emitted into the air. Nitrous oxides have a greenhouse effect more than two hundred times as strong as that of CO2, and are responsible for more than 40% of the greenhouse effect caused by current agricultural practices. Worse, nitrous oxides also destroy the ozone layer.
Mineralizing the Soil
In 1992, the official report of the Rio Earth Summit concluded "there is deep concern over continuing major declines in the mineral values in farm and range soils throughout the world." The statement was based on data that shows, over the last 100 years, average mineral levels in agricultural soils had fallen worldwide, by 72% in Europe, 76% in Asia and 85% in North America. As a result, most of the food produced is deficient in minerals, as well as contributing to climate change.
The Rodale Institute, based in Pennsylvania, has conducted research on organic farming for almost 30 years. Their soil carbon data show conclusively that improved global terrestrial stewardship - including regenerative organic agricultural practices - is the most effective available strategy for mitigating CO2 emissions.
"During the 1990s, results from the Compost Utilisation Trial (CUT) at Rodale Institute - a 10-year study comparing the use of composts, manures and synthetic chemical fertiliser - show that the use of composted manure with crop rotations in organic systems can result in carbon sequestration of up to 2,000 lb/acre/year. By contrast, fields under standard tillage relying on chemical fertilizers, lost almost 300 lb of carbon per acre per year. "In 2006, US carbon dioxide emissions from fossil fuel combustion were estimated at nearly 6.5 billion tons. If 7,000 lb/CO2/ac/year sequestration rate was achieved on all 434 million acres of cropland in the United States, nearly 1.6 billion tons of carbon dioxide would be sequestered per year, mitigating close to one quarter of the country's total fossil fuel emissions."
One of the ways being explored to regenerate soil structure is to remineralize with finely ground rock dust as a sustainable alternative to chemical fertilizers. Add minerals to the soil quickly leads to phenomenal growth of the microorganisms in the soil. Remineralization of the world's soils and forests will propagate carbon sinks, thereby absorbing carbon dioxide from the atmosphere - and contributing to climatic stability.
Some view mineralization as a more practical alternative to sequestering carbon underground, which requires extensive site-characterization and long-term monitoring. NYSERDA is funding one such project.
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Read GRAIN's Report
http://remineralize.org
