Isabelle Legeron travels to California, a part of the world whose soil holds a complex history. She meets the indigenous Californians reviving ancestral methods of tending to the land, and the soil scientists exploring the impact of colonisation and agriculture on the soil of the Golden State. With indigenous Californian land steward Redbird (Pomo/Paiute/Wailaki/Wintu), director of the California Indian museum Nicole Lim (Pomo), indigenous ecologist Dr Melissa Nelson (Anishinaabe/Métis/Norwegian), indigenous educator Sara Moncada (Yaqui/Irish), professor Paul Starrs (USA) and soil scientists Suzanne Pierre (India/Haiti/USA), Kenzo Esquivel (Japanese/Mexican/USA) and Yvonne Socolar (USA). Presenter: Isabelle Legeron Producer: Sasha Edye-Lindner/ Kate Bland A Cast Iron production for BBC World Service (Photo: Native crops at Heron Shadow, California. Credit: Sara Moncada)