A 22-year study by Cornell that points to various benefits to organic cultivation of corn over the long term, and demonstrates equivalent yields in normal years and superior yields in drought years.
As far as the intensive/extensive farming debate goes, I think the example of Japan is interesting, as it has rather impressive yields despite what would be considered a very inefficient organization of agriculture -- lots of little farms, with lots of people working at them.
There are some interesting numbers on this point at the World Resources Institute on yields per hectare and whatnot. Comparing the US, home of industrial mega-farming, and Japan, where I look out the window and see 90 year old grandmothers tilling the ground by hand, you can get some sense of the efficiencies possible with small-scale agriculture.
Japan, cereals Average crop yield (kg per ha) 6147 US, cereals Average crop yield (kg per ha) 5824
Japan, Ag. Workers as Percent of Pop, %7.3 US, Ag. Workers as Percent of Pop, %2.9
Now, these are average numbers, and I am sure there are more efficient farms elsewhere that balance out the little plots farmed by 90-year old grandmothers where I live.
Admittedly, Japan has a far higher per-hectare fertilizer usage rate. The stats on this page are all fertilizer types combined.
Japan, fertilizer per hectare 295 US, fertilizer per hectare 111
But when I was studying Japanese history, I read that in the pre-industrial Edo period fish-meal fertilizers were a huge business, and used by most every farmer who had the means to do so. So, I started to wonder what proportion of Japan's fertilizers were of the traditional type, but can't find data on that.
This data is sorta tangential to the discussion
It may be that Japanese soil husbandry over centuries has delivered a more fertile soil today. Which would fit the Cornell study's showing that soil fertility increases over years of organic farming.
This article suggests that Japanese farming today uses chemical fertilisers causing environmental damage, which recourse to traditional fish-meal use may help to limit.
I have to admit, I was surprised at the distinctly greater fertilizer usage by the Japanese, as I'd always thought Americans were the worst. But I suppose if you're out there, looking at every crop and spraying by hand, then maybe you'd end up using more than one would with an even spraying via plane.
With land and labour scarcer and more expensive, and more intensely subsidised food prices in Japan, fertiliser use is more profitable - thus Japanese farmers get their optimal return with a higher amount of fertiliser. It's also a product of much more intensive agriculture, too. Un roi sans divertissement est un homme plein de misères
