Soil erosion and degradation will become one of the most threatening issues facing human security in the 21st century. Nuclear accidents severely damage the environment and previously fertile soil for decades, creating a poisonous habitat. Also, intensive farming with the use of pesticides and toxic fertilisers causes slow poisoning of the soil. The cultivation of inappropriate plants and crops ultimately damage the soil ecosystem and reduce biodiversity. This episode of "Fixing Nature", looks at how biologists, botanists and engineers around the world are fighting the decline of biodiversity.