Reason asked Norman Borlaug about the claim that organic farming is better for the environment and human health and well-being. His answer:
That's ridiculous. This shouldn't even be a debate. Even if you could use all the organic material that you have--the animal manures, the human waste, the plant residues--and get them back on the soil, you couldn't feed more than 4 billion people. In addition, if all agriculture were organic, you would have to increase cropland area dramatically, spreading out into marginal areas and cutting down millions of acres of forests.
At the present time, approximately 80 million tons of nitrogen nutrients are utilized each year. If you tried to produce this nitrogen organically, you would require an additional 5 or 6 billion head of cattle to supply the manure. How much wild land would you have to sacrifice just to produce the forage for these cows? There's a lot of nonsense going on here.
If people want to believe that the organic food has better nutritive value, it's up to them to make that foolish decision. But there's absolutely no research that shows that organic foods provide better nutrition. As far as plants are concerned, they can't tell whether that nitrate ion comes from artificial chemicals or from decomposed organic matter. If some consumers believe that it's better from the point of view of their health to have organic food, God bless them. Let them buy it. Let them pay a bit more. It's a free society. But don't tell the world that we can feed the present population without chemical fertilizer. That's when this misinformation becomes destructive...
I want to add a big "ditto" to this answer in reference to the whole food miles and locally grown food movement. There is a lot of evidence that trying to get all of our food locally will actually increase energy use. It will certainly harm the environment by increasing land use.
Why? Because currently, economic incentives push farming of a particular food item towards the land that is best-suited and most productive for that item (government subsidies, both direct, e.g. farm programs, and indirect, e.g. subsidized water for agriculture in arid areas like Arizona and SoCal, interfere with this, but that is a different subject). The locally grown food movement seeks to shift crops from large productive farms located in the best soils and climates for that crop to smaller farms located in sub-optimal growing areas. This HAS to increase agricultural land use, prices, and in many case, energy use. More here.