Any material that is added to the soil to give it the elements that will help plants grow is a fertilizer. Why are fertilizers needed? Basically they keep up the fertility of good soils, and correct or cure the lack of fertility of poor soils.
When crops are harvested, all the food elements that have gone into them are taken away from the land. In this way, crops use up the supply of food elements in the soil. The farmer uses fertilizers to put them back, or to build up the supply of elements that are naturally low in soil.
There are natural fertilizers that come from things that were once alive, such as humus, which is made from decaying plants; meal, made from animal bones or seeds; and animal manures. And there are chemical fertilizers that come from many sources.
Man has used fertilizers for a long time. We do not know just how long, but we do know the Chinese used animal and plant wastes as fertilizers thousands of years ago.
The Romans as early as the second century BC rotated their crops, put lime in the soil, and added nitrogen by planting peas and beans. During the seventeenth century, in parts of Europe, manure was used as fertilizer, town wastes were taken to farms, and clover was used in crop rotation.
In 1748, Benjamin Franklin demonstrated in America the value of a lime fertilizer. He laid out lime plaster in the form of huge letters in a field along a highway near Philadelphia. The letters spelled out the message: THIS FIELD HAS BEEN PLASTERED. The white letters soon disappeared, but when the crop came up, the message reappeared, because the fertilizer area was much greener than the rest of the field.
Published in: Gardening