Because mining and refining nickel is costly, researchers have developed an alternative method for extracting nickel using Streptanthus polygaloides, a plant that absorbs and stores nickel from the soil as it grows  The researchers incinerated a crop of Streptanthus they grew in nickel-rich soil
By chemically extracting nickel from the ash, they produced 100 pounds of nickel per acre of land at a total cost per pound slightly above that of current mining
Because lowering the concentration of nickel in the soil can make land much better for agriculture in general, a plot on which Streptanthus has been grown and harvested can be sold for substantially more than it cost.