I'm Gwen Outen with the VOA Special English Agriculture Report.
Many farmers improve their soil, and their crops, with compost. Composting is the mixing of plant or animal wastes so they break down and produce simpler substances that make the soil rich.
Compost is an example of a natural fertilizer. Farmers add compost to their soil instead of burning the plant and animal wastes or throwing them away.
During the growing season, plants take gases from the air such as carbon, hydrogen and oxygen. They combine these gases with minerals from the soil.
After the growing season ends, many parts of the plant die. Farmers gather a large amount of dead plant materials into compost piles. They may add animal wastes. They must add water so the materials will break down, or decay.
Soon the plants are attacked by insects and organisms including worms and bacteria. Oxygen helps the organisms change the plant materials more rapidly. The plants decay into a mixture that can be spread on the farmland where the crops are growing. The compost returns nutrients to the soil.
Some rules need to be followed to produce the best quality compost. Good compost piles need water to speed the process of decay. Yet the piles should not be too wet or the plant material will be ruined.
The temperature of the compost pile should not be too high or too low. The best temperature for a compost pile is about thirty to thirty-seven degrees Celsius. You can turn the pile over and over to help cool down the material. Turning the compost pile over adds more oxygen to the mixture which helps it decay.
Sometimes small animals such as rats and mice like to eat the composting materials. This can be prevented if you add a thin amount of soil to the top of the compost pile.
Internet users can find more information about composting from Volunteers in Technical Assistance, or VITA. VITA is an organization based in the United States. It helps people around the world use science and technology to solve problems. The address of its Web site is vita.org.
This VOA Special English Agriculture Report was written by Gary Garriott. Our reports are online at voaspecialenglish.com. I'm Gwen Outen.
Correction: Compost must reach a temperature of fifty to sixty degrees. At these temperatures, harmful organisms are killed and material is correctly broken down. It takes three to seven months to produce ready-to-use compost from raw compost material.