British Sign Language Glossaries of Curriculum Terms

BSL Chemistry Glossary - root nodule - Definition

If you look at this picture you can see nodules on the roots of this plant, which could be a flower, clover or a pea - these roots come down from the stem above.

O₂ (oxygen) and N₂ nitrogen in the air find their way into the soil where the N₂ is absorbed by the plant's roots and combined to create/convert into compounds called nitrates. These nitrates nourish the plant and keep it healthy, allowing it to grow - this is, for example, how flowers grow; this also fertilises the soil.

When crops are harvested the roots are left in the soil - when the field is then ploughed the soil is turned and the roots are brought to the surface - this is done to keep the soil healthy and it acts as a natural fertiliser; as the root nodules decompose/degrade this ensures that the soil remains fertile for the next crop.