Lead: By 1900 world population was beginning to outstrip agricultural capacity. Farmers could not grow enough to feed the people. Then Fritz Haber solved the nitrogen problem.

Intro.: A Moment in Time with Dan Roberts.

Content: The three main nutrients required for successfully growing plants are potassium, phosphorus, and nitrogen. Good top soil contains them in sufficient amounts to grow crops, but after long use, soil becomes depleted of these ingredients and must be renewed. Potassium and phosphorus are economically available in sufficient quantities to be put back easily, but nitrogen is not. Nitrogen is in the air. It is a gas that is a large part of the atmosphere. Getting it into the soil for plant synthesis is very difficult. Traditional farmers added plant clippings and animal waste, rotated crops or planted legumes such as beans or lintels, so-called green manure, to restore the soil and increase yields. Traditional agriculture could not keep up with an exploding world population. Farmers were losing the battle.