[universa1]

But in the end you have to replace at least some of the nitrogen (and other nutrients) you are taking from the field in some way. And without a major shift in consumption patterns (less meat) this will mean fertilizer, as the alternatives usually lead to a much lower yield.

[dmurray]

Meat farming replaces artificial fertilizer, by providing a source of manure, so doesn't that relationship run the other way?

But having 1/4 of the land under soy beans or other locally appropriate nitrogen-fixing plants doesn't seem like it would hurt yields too much.

[lucioperca]

Nitrogen can also be replenished by crop rotation. Legumes will naturally add nitrogen back.

[throwaway2037]

At the same rate as artificial nitrogen fertilizers? I doubt it. And, is the profit per hectare the same when planting legumes? Again, I doubt it.

[jon_richards]

I was very disappointed on my last trip to Iowa to see that most farmers weren't even bothering with cover crops.

[eru]

I wonder whether genetic engineering can give nitrogen fixing abilities to plants that currently lack this ability?