WordNet
soil bank
n. land retired from crop cultivation and planted with soil-building crops; government subsidies are paid to farmers for their retired land
Usage examples of "soil bank".
The full tank gets traded for an empty one, and the contents go to the organic soil bank.
Also look into the Soil Bank Program of the United States Development Association and various Department of Forestry programs which pay you to plant trees.
And 10-90 million acres of hemp or other woody annual biomass planted on this restricted, unplanted fallow farmland (our Soil Bank) would make energy a whole new ball game and be a real attempt at doing something to save the Earth.