12 7 8 9 10 11 12 13 A recent survey undertaken on behalf of the Ministry indicates that there are at least 7,000,000 acres below the 700 ft. contour line the productivity of which could be greatly increased if they were ploughed up and sown to crops or re-seeded straight away to good grass leys. Any campaign to increase home food production must be directed to ploughing up as much as possible of these second and third rate grasslands. 3. The ploughing-up campaign involves a great deal of re-planning by farmers of their whole farming systems for a period of years ahead.