Nancy Palmer, age 13, of New Bedford, Mass., for her question:
WHY IS FERTILIZER IMPORTANT?
In order to grow, plants must have large amounts of nine chemical elements: carbon, hydrogen, oxygen, phosphorus, potassium, nitrogen, sulfur, calcium and magnesium.
Plants receive most of the carbon, hydrogen and oxygen that they need from air and water. But the rest of the elements must come from the soil.
Sometimes the soil doesn't have all of the elements that are necessary for plant growth. When this happens, fertilizer shows its importance by providing the missing elements.
Normally the soil receives all of the necessary elements through animal matter and decaying plants. The harvest of crops, however, involves the removal of plants from the soil before they die and decay. This means that the soil does not receive the mineral elements contained in the crops. Fertilizers help solve the problem.
Man has been using fertilizer for thousands of years. In fact, he started to use them before he understaood why they benefited his crops.
Today two chief kinds of fertilizers are used: mineral and organic. Manufacturers produce mineral fertilizers from certain minerals or synthetic substances. Organic fertilizers come from decayed plants or animal matter.
Billions of dollars worth of fertilizers are used each year by farmers throughout the world. Fertilized crops probably make up about a fourth of the world's total crop production. Crop yields would be much lower without fertilizer and greater amounts of land and manpower would be needed to produce the same quantity of food and fiber.
The United States manufactures more fertilizer than any other country in the world. It produces about $5.5 billion worth of fertilizer annually and exports about $680 million of it.
About 95 percent of the fertilizer produced in the world is used on farm crops.
Most fertilizers release their plant nutrients into the soil as soon as they are used
Each year large amounts of fertilizer must be produced to meet the world's growing demand for food. The fertilizer industry is trying to match its production with this need. Without this effort, severe food shortages could result.
A shortage of raw materials could cause a low supply of fertilizer. Some materials, such as natural gas and phosphorus, have uses other than in making fertilizer. Their use by other industries could cause a shortage for fertilizer manufacturers.
Fertilizer can be made in a home garden with a compost pile. The pile should consist of alternate layers of plant matter and soil. Lime and animal matter can also be added. The pile is allowed to decay for several months before being used as fertilizer.
The largest deposits of potassium chloride, the major source of potassium fertilizer, occur in Canada and Russia. Canada furnishes about 75 percent of the potassium chloride used in the United States. Potassium chloride is mined in several states including California, New Mexico and Utah.