You are right that under todays prices it doesn't look that competitive, although we reckon our cattle pay their way ok with no bought inputs (ie fertiliser or hard food). However the picture changes if you put the 'real' cost of fertilisers and sprays into the equation, which one day circumstances may dictate that we have to do: as others have pointed out, N fertiliser is very energy intensive to make, cheap fossil fuels enable us to buy it at £250/tonne or whatever, but that is only sustainable if @Farmersdaughter gets her Fission powerplant up and running, or something else comes along.That wouldn`t be competitive under todays price-relations !?
When you can grow 10 ton/ha wheat you can turn that into 3 to 4 tons/ha meat, depending on the animal (pig, chicken), but you have to use 100 ltr/ha fuel and another 200 ltr. as fertilizer at least and add some overseas soybeans.....
How much meat from cows or sheep can be produced on grass with how much fertilizer ??
Which is why I think we need to plan ahead a bit and work out a way of farming using solar power as much as possible, via cover crops, soil biology and all the other stuff we'll learn about tomorrow at the CA Conference in Baldock...
There is another point which we haven't really talked about, which is the issue of what foods are actually good for you. We've spent millenia evolving to eat omnivorously and the bacteria in our intestines have worked out how to process this 'natural' food in such a way as to keep us healthy, then suddenly we are eating processed pap and facing an epidemic of degenerative diseases. A properly run Health Service would be concentrating on this, rather than spending billions treating people who get ill eating the wrong food. As Albert Howard et al used to say, put a fence on top of the cliff rather than have an ambulance on stand-by at the bottom...