Joe Crowley is in Aberystwyth to meet scientists behind some of the biggest new developments in farming and food security, from insect brownies to the revival of historic crops and why some South American visitors could be the saviours of upland farming.Charlotte Smith is in the Lea Valley, home to 3,500 acres of glasshouses providing 75 per cent of the UK's home-grown salads, to investigate why what's known as London's salad bowl is on the brink of collapse. Adam Henson finds out why the shift towards sustainable farming could mean boom time for native breeds, while Adrian Chiles discovers what the future of sheep farming could be in his final report from the Welsh mountains.