Well, Iains, your take on agriculture, if implemented, would be devastating. As soon as you see farming the land as a business that must make profits you are arguing for ecological devastation. If it moves, kill it. There will be some chemical whose name ends in -cide that will do the job. Efficiency means ripping out hedges that take up space and force your massive combine to make uneconomical turns. Efficiency means using neonicotinoid insecticides. They will increase your profit but wipe out bees. Don't waste money ploughing in those winter weeds: diquat will do the job. Stop worrying about the impact on bird and insect life of your planting hundreds of acres with winter Barley or elephant grass.