The Effects of Synthetic Fertilizers

Ingredients in Synthetic Fertilizers

• Many synthetic fertilizers are made up of chemical compounds containing nitrogen, potassium and phosphorus. While these nutrients are needed for plants to grow, they often are found in very high concentrations in conventional fertilizers. A common synthetic fertilizer is ammonium nitrate, which is a nitrogen and ammonia compound. Many conventional fertilizers also are produced using petrochemicals and harmful chemicals such as cyanide.

Runoff

• Synthetic fertilizers often are very soluble in water. This means that as crops are watered by rain or irrigation, the fertilizers run off into nearby streams, rivers and lakes. While the chemicals in fertilizers may be good for plants, too much nitrogen or other chemicals can be bad for fish and other animals that live in the affected water. Chemicals such as nitrates and cyanide also can get into ground water and contaminate it for humans.

Short Term Growth

• Because synthetic fertilizers have higher concentrations of plant nutrients, they will result in short-term growth. While organic fertilizers release nitrogen over a long period of time, conventional chemical fertilizers release nitrogen very quickly, resulting in a burst of growth for crops. This quick release also means that more fertilizer will be needed again relatively soon, resulting in over-use of fertilizers.

Effects on Insects

• Studies show that synthetic fertilizers can increase populations of insects that eat plants. Crops treated with ammonium nitrate, a common synthetic fertilizer, have increased numbers of insects laying eggs on plants. Some types of aphid also prefer to eat plants fertilized with conventional fertilizers, and organic fertilizers reduce aphid populations by providing minerals to the plants that the insects don't like to eat.

Long-Term Soil Effects

• Many synthetic fertilizers are salts that contain other chemicals such as nitrogen and phosphorus. Crops use the nitrogen that is released from the fertilizers, and the salts in the fertilizers often are left behind in the soul. This process results in a salt buildup in the soil, which eventually will make the land unable to support plant life.