HRH the Prince of Wales delivered the keynote address at The Washington Post‘s “Future of Food” conference yesterday at Georgetown University. Tim Carman, from the Post’s Lifestyle section, offers some brief thoughts on the Post blog here. Carman calls the speech “inspiring”, quotes an organic advocate who was “really impressed” with it, and links to the prepared text, which you can find here. I thought it was a load of organic fertilizer, personally, so I submitted a lengthy comment, which I reproduce in full:
It’s not surprising that Samuel Fromartz, an organic farming advocate, would praise Prince Charles for a speech that advocates organic farming. But, while he’s condemning conventional agriculture for its use of “chemical pesticides” and “artificial fertilizers”, HRH might also want to acknowledge that organic farming has its own limitations.
Organic farmers also use plenty of chemicals — just ones that are lightly processed minerals such as copper sulfate, or ones derived from plants such as pyrethrum from chrysanthemum flowers. But, ounce for ounce, organic pesticides are just as toxic as modern synthetic pesticides. And in some cases, such as the organic fungicide copper sulfate, they are far more harmful to the environment. With only a few exceptions, organic pesticides control insects and plant diseases far less effectively than synthetic chemicals, so they must be used in much larger doses.
Furthermore, while organic farmers eschew synthesized fertilizers in favor of animal manure and so-called “green manures” — nitrogen-fixing legume crops like clover and alfalfa — plowing legume crops and animal wastes into the soil leads to nitrate leaching into groundwater and streams at rates similar to conventional agricultural practices. The chemical properties of soluble mineral fertilizers that are prohibited in organic farming are identical to those of that are released in uncontrolled quantities by the mineralization of organic matter.
It is also ironic that Prince Charles begins his speech noting that we will have to dramatically increase agricultural productivity over the coming decades to keep apace with population growth. Unfortunately, because organic crops generate lower yields, shifting away from conventional production will make it more difficult to reach this goal.
In any given growing season, the best organic fields can generate yields that are nearly on par with those of of average conventional farmers. Generally, though, organic crops yield from 5 to 10 percent lower than conventional ones, and as much as 30 to 40 percent lower for certain plants, such as potatoes, wheat, and rye. Even those yield figures can be misleading because soil nutrient replacement on organic farms requires lands to be fallowed with nitrogen-fixing plants for two or three years in every five or six, whereas conventional farming that incorporates soluble mineral fertilizers does not need to fallow land. Thus, conventional farms can achieve total yields per acre that are as much as 40 to 100 percent greater than organic farms.
Prince Charles would be well served by reading the UK Royal Society’s 2009 report, Reaping the Benefits: Science and the Sustainable Intensification of Global Agriculture. We currently use 1/3 of the world’s land area to grow food. The report explains clearly that we can not increase agricultural productivity AND save the environment without using the best science and innovative technologies in order to grow more food on less land.