I don't know what analysis to point you at, but narrowing the options to legumes and grains seems, well, narrow. Is he ignoring all other food sources?

There have been numerous studies that show that not only can organic growing feed the world but that it is better for the environment and our health. This is one such study.

http://www.worldwatch.org/node/4060

kimmq is kimmsr

One thing puzzles me concerning this situation. Why is it "pure organics" or nothing? It looks like to me that the best of the 2 ways could be fairly successful.

What are the "best of 2 ways?" Synthetic fertilizers are expensive and numerous studies show that 3rd world growers do much better without them, following organic growing practices.

kimmq is kimmsr

Thank you kimmq for your "Worldwatch" connection, it actually has numbers in it. Let me restate my principal concern, which is nitrogen. Starting from where the world is now, it uses about 100 metric tons a year of ammonia, usually in derivative format, to feed itself. My concern is, if we were to start moving to organic worldwide, where would the additional nitrogen come from? Accepting that half the nitrogenous fertilizer that's applied is wasted, we need to come up with another 50 metric tons. The relevant piece of the "Worldwatch" item is in "Sidebar one" which referenced a U. of Michigan review study that said the world could produced another 58 metric tons of natural nitrogen a year (implicitly, but not stated, "without reducing acreage devoted to crops.") By the way, I found the minute print in the piece hard to read, I'm in my 80s and my eyes are none too good. I need to dig into that 58 metric tons, it seems like a big stretch. For example, the reference to the U. of M. to a winter cover red clover with an oat/wheat/ corn/ soy rotation would fit the bill, but only if equivalent rotations were available worldwide - which they may be. I'm left with a suspicion that we can't get there from here. Of course, animals don't make nitrogen, they just recycle it, and agricultural recycling is much less tight than nature's. Regards, Peter.

kimmq,

You have asked me a question. It seems to me that a half loaf is better than rejecting the loaf because it doesn't fit our stipulations. We are talking about organic on a large scale. It is doable if we rob from other sources around us, but questionable on a world scale with our money economy.

Just today I brought home a pickup load of horse manure with a lot of hay in it...a wonderful source of organic matter...and there is more to come, but not enough for a hundred gardens though. Yes, I utilize leaves and cover crops.

More often than not we are putting too much Nitrogen into the soil which results in the excess being washed out of the soil and into the ground water causing nitrate poisoning. I have never had to add extra Nitrogen to any garden I had that had adequate amounts of organic matter in the soil.

Excess Nitrogen also limits a plants ability to properly utilize some other nutrients, causes lush growth that is more attractive to insect pests and plant disease and creates far more problems than it will solve. Most everything I have read about using more N is based on "conventional" growing where the soil has insufficient amounts of organic matter in the soil.

kimmq is kimmsr

kimmq: thank you again for the "Worldwatch" reference, because it led me to Catherine Badgley et al's U. of M. research paper. It has lots of numbers, which is the only reasonable approach to an ecological or economic problem. It maintains that present global agricultural acreage could produce 140 million metric tons of nitrogen naturally without loss of crop production. This is a huge number: compared with global nitrogen fixation in nature at 100 to 150 metric tons and the present agricultural use of synthetic nitrogen at 100 metric tons. The key is using cover crops between food crops or by inter-cropping. It sounds plausible. And the paper deals with other inputs of course.

Like you, I don't use synthetic nitrogen. I grow peas and beans in a 5 year rotation, which keeps the soil nitrate level around 80 to 100 lbs per acre. While my produce has high BRIX and good taste, it's smaller than Farmer's Market offerings; I don't grow corn and believe that it wouldn't do well without more nitrogen. Regards, Peter.

Actually, I think the key is "closing the loop." In a normal healthy ecosystem, the nutrients cycle among the soil, the plants, decomposers and animals. Essentially all the nutrients we harvest and eat are in our excreta, but currently, we turn them into a pollutant and then need to add fertiliser to the land to replace them. Only nitrogen tends to evaporate and get fixed back into the soil by certain plants; the other nutrients don't move back and forth into the atmosphere like that.

So organic farming can feed the world if we can find a way to keep the nutrients in the production cycle in a way that people would accept. Many people compost their humanure or use diluted urine as fertilizer in their gardens, and there are many ways to do this safely, avoiding pathogen risks.

Permaculture News article "Closing the Loop"