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87 comments on The Man Who Wrote the Book on Algal Biodiesel

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rohar1 on May 17, 2007 - 1:33pm

That statement isn't exact, because whether it's stubble or summerfallow seeding, a starter blend is usually added with the seed (i.e. 11-55-00 ammonium phosphate) plus traces, but the bulk of additional nitrogen fertilizer can be eliminated on fallow land.

In a dark brown/black soil zone in Canada, like where our farm is and a lot of Canola is grown, generally you can grow an equivalent crop of cereal or oilseed on land that was fallowed the previous year compared to continuous cropping with 60-100+ lbs/acre of urea.

Legumes (i.e. soybeans) also don't require additional nitrogen fertilizer. An option to summerfallow in Canada is to rotate a legume like alfalfa.

Corn and feed wheat in continuous cropping low-till methods would be about the highest nitrogen requirement crops.

My dad would fallow about 1/3, but it is rarely done now for several reasons (diesel price, wind erosion, bank taking the farm if every acres isn't seeded, etc). One of the major issues with Canola is disease and although fallow acres are much less than ever, I would think if there is any fallow, more often than not Canola seeded in the next rotation.

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PeakOil Tarzan on May 17, 2007 - 1:52pm

Interesting. I'm not familiar with farming practices in that part of the world (you guys are up there!) but you figure you get the equivalent of 60-100+ lbs/acre of urea by leaving land fallow for a year? That's a lot of nitrogen.

Also, AFAIK, N fertilization of soybeans is still frequently recommended but, as you point out -- this may be largely dependent upon your particular crop rotation.

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eric blair on May 18, 2007 - 10:10am

In the past (under hand management of crops) one planted corn and soybeans/pole beans together.

Might be something for the gardners to try.

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