Museum case showing illustrations, diagrams and models of the fertilizers in the soil and their effects in vegetation.

Nitrogen-fixing Bacteria

(Top-left rectangle) Enlargement of root nodules

(Top circle) Enlargement of cells in a nodule

(Middle circle) Enlargement of bacteria within the cell

(Bottom circle) Red top

 

Text and back-lit diagrams showing enlargements of root parts.

Main text fertilizers in the soil

In the fall man takes crops away, and unless he makes replacements of some sort, the soil becomes poor and useless.

He adds commercial fertilizers such as phosphate, nitrates, and potash, or he may grow clover and alfalfa which he plows back into the soil.

These plants have root nodules containing nitrogen-fixing bacteria which take nitrogen directly from the air and turn it into usable nitrates.

Nitrogen-fixing Bacteria

Bacteria enter roots from the soil and establish themselves in cells of the root tissues. These cells become enlarged and finally nodules are formed. The enclosed bacteria fix nitrogen into nitrates which are released when the roots decay.

Fertilizers in the Soil

Part of Hall of New York State Environment.

Museum case showing illustrations, diagrams and models of the fertilizers in the soil and their effects in vegetation.
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In the fall man takes crops away, and unless he makes replacements of some sort, the soil becomes poor and useless.

He adds commercial fertilizers such as phosphate, nitrates, and potash, or he may grow clover and alfalfa which he plows back into the soil.

These plants have root nodules containing nitrogen-fixing bacteria which take nitrogen directly from the air and turn it into usable nitrates.