Artificial fertilizers are inorganic, synthetic chemicals added to soils to promote or sustain plant growth. The start of the 20th century saw the first use of chemical fertilizers. Before then, fertilizers were almost entirely of natural and organic origins. Although chemical fertilizers can increase crop yields in the short term, a number of problems are associated with their use.
Artificial chemical fertilizers can collect on the surface of the soil and cause it to crust. This is often due to excessive fertilizer in the top layers of soil and the death of soil organisms, like earthworms and insects, which normally keep the soil loose. When the soil has a crust, water does not penetrate as deep as it does in looser soils. Soil crusts can also prevent directly seeded crops from properly germinating and breaking through to the sunlight.
Applying an artificial fertilizer improperly can result in fertilizer burn to the roots of your plants. Usually, fertilizer burn is caused by either applying too much fertilizer per application or applying the correct amount of fertilizer too frequently. You can also trigger fertilizer burn by apply both too much fertilizer and applying it too often. Fertilizer burn generally affects the roots of your plants. However, if you allow the chemicals to touch the top parts of the plants, you can sometimes burn the plant above ground.
Although yields initially increase, without organic fertilization or crop rotation, artificial fertilizer requirements will increase over a period of years. As more fertilizers that are artificial go into the ground, more leave the ground in the form of runoff. This runoff feeds streams. Streams feed rivers, lakes and oceans. In addition to runoff, chemical fertilizers can contaminate ground and drinking water. Water pollution tends to be either from excessive nitrogen or phosphorous from chemical fertilizer. Artificial fertilizer-based problems include excessive algae blooms in both fresh and salt water. Toxic algae blooms are linked to excessive nitrogen runoff. Toxic algae blooms kill fish and shellfish either directly through the toxicity of the algae or through using up all available oxygen in the water. Shellfish harvested during a toxic algae bloom can also cause paralytic shellfish poisoning in people. In most states, when a toxic algae bloom, often called a "red tide," is detected, the harvesting of shellfish is banned until the algae infestation subsides.