ORGANIC FARMING DESTROYING THE ENVIRONMENT
Organic foods sales are soaring not because consumers think they're more nutritious (they're not) but because organic farming methods are thought to be environment friendly. They're not:
Perhaps the most eminent critic of organic farming is Norman Borlaug, the father of the “green revolution”, winner of the Nobel peace prize and an outspoken advocate of the use of synthetic fertilisers to increase crop yields. He claims the idea that organic farming is better for the environment is “ridiculous” because organic farming produces lower yields and therefore requires more land under cultivation to produce the same amount of food. Thanks to synthetic fertilisers, Mr Borlaug points out, global cereal production tripled between 1950 and 2000, but the amount of land used increased by only 10%. Using traditional techniques such as crop rotation, compost and manure to supply the soil with nitrogen and other minerals would have required a tripling of the area under cultivation. The more intensively you farm, Mr Borlaug contends, the more room you have left for rainforest.Funny how consensus doesn't guarantee validity.
posted by J F Beck at 11:27 AM
1 Comments:
Scientific consensus on manure.
Another Inconvenient Truth.
Here is a well constructed experiment looking at long term yields in a farming systems experiment:
CROP ROTATIONS
Organic and Other Management Strategies with Two- and Four-Year Crop Rotations in Minnesota
Paul M. Porter, Dave R. Huggins, Catherine A. Perillo, Steven R. Quiring, and R. Kent Crookston
Agronomy Journal Volume 95 March–April 2003 Number 2 page 233 to 244
http://intl-agron.scijournals.org/cgi/content/abstract/95/2/233
It shows if you compare the best organic set up (2 crops in 4 years) with the best conventional set up (a crop every year) total corn production was about 46% with organic production. The outcome was even worse for soybeans. The reason why the organic system needed a 4 year rotation was to achieve acceptible weed control. These estimates do do include penalties to account fr the extra land need to produce organic manures as compared to minimal land needed to make synthetic nitrogen fertilizer.
The publication (and others , Liebhardt, W.C., R.W. Andrews, M.N. Culik, R.R. Harwood, R.R. Janke, J.K. Radke, and S.L. Rieger-Schwartz. 1989. Crop production during conversion from conventional to low-input methods. Agron. J. 81:150–159; MacRae, R.J., S.B. Hill, G.R. Mehuys, and J. Henning. 1990. Farm-scale agronomic and economic conversion from conventional to sustainable agriculture. Adv. Agron. 43:155–198.) support the scientific consensus that organic systems need 2.5 to 3 times as much land as high input current conventional argiculture.
My agricultural science colleagues say this Porter 2003 paper is now being quoted as "yet more evidence" that organic systems yield as well as, or almost as well as, conventional systems. But should remember that organic systems only get close if you force the conventional system into the same rotation (2 crops every 4 years) which yields less total output of the main crops corn and soybean.
Even then there is still a yield penalty associated with organic production of about 5-9% for corn and 19-22% for soybean (that is, without factoring in losses due to extra-crpping time away from the main crop).
If you compare the best organic set up (2 crops in 4 years) given in Porter 2003 with the best conventional set up (a crop every year) total corn production was about 46% of best yields with organic production. The outcome was even worse for soybeans. The reason why the organic system needed a 4 year rotation was to achieve acceptible weed control. These estimates do do include an accounting for the extra land need to produce organic manures as compared to minimal land needed to make synthetic nitrogen fertilizer, and they support the scientific consensus that organic systems need 2.5 to 3 times as much land as high input current conventional argiculture to produce the same total crop output.
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