fertilizer runoff is good for plants but bad for water supplies

Before modern agriculture, farmers relied on natural fertilizers that didn’t harm the land or environment. Some of these practices included fish, manure, and ground bones. Then along came the modern way of doing things, which introduced manufactured chemicals into the mix. Unfortunately, this change began causing land, ecosystem, and environmental degradation, plus introduced agricultural fertilizer runoff into our drinking water supplies. 

Plants should get most of their nutrients from the soil, but unfortunately, not all soil contains the proper nutrients plants need to flourish. To make up for these soil deficiencies, fertilizer includes various minerals that plants need to grow. These typically include phosphorus, potassium, and nitrogen — often in the form of nitrates and phosphates.

Unfortunately, fertilizer doesn’t just stay in the soil where we put it. Instead, it runs off into surrounding spaces, spreading these minerals to different areas of soil and water that don’t need them. This excess of minerals can cause environmental contamination and, sometimes, serious illness. Such contamination can even result from the fertilizer you use in your garden and yard. By misapplying fertilizer around your home, you can cause unwanted runoff, leading to dangerous ecological effects.


Causes of Fertilizer Runoff

A number of things can lead to fertilizer runoff, so it’s crucial to know which mistakes to avoid around your lawn and garden.

  • Overapplication: Using too much fertilizer and over-applying it leads to oversaturation. Once the plants’ roots reach capacity and can no longer hold any more fertilizer, the remainder will run off into less-saturated areas.
  • Excessive Irrigation: Watering your yard more than it needs can also lead to fertilizer runoff. Once your grass or soil becomes saturated with water, that water will run off to drier areas and carry your carefully applied fertilizer with it.
  • Wrong Time of Year: Many states have regulations prohibiting buying or applying fertilizer from November 15 – March 1. When fertilizer is applied to the frozen or partially thawed ground, it cannot penetrate the soil as quickly as in warmer months. When you apply fertilizer at the wrong time of year, it is likely to run over the hard ground until it finds a more hospitable environment — like a lake, stream, or warmer, more porous soil.
  • Improper Yard Waste Disposal: Your lawn clippings often contain fertilizer residue, so always properly bag and dispose of them. If you dump them, they could end up could causing soil and water contamination elsewhere. For example, if they end up in drains, they could leach chemicals into the water supply.


Effects of Fertilizer Runoff

The word ‘nutrients’ sounds like it should be universally beneficial. But in reality, when nutrients in fertilizer come into contact with the natural environment, they can cause adverse ecological effects.

Nitrate Poisoning

Fertilizer commonly contains nitrates that run off and contaminate the local water supply. But this ubiquitous hazard can negatively impact the health of local infants. Under federal law, public water supplies receive treatment to rid the water of chemicals and minerals. Still, some municipal filters may be older and, therefore, insufficient for filtering nonbacterial contaminants such as nitrates. Untreated well water can also put your infant at risk. If you do not use a filtration system, you could unknowingly use contaminated water to mix their formula.

When infants ingest nitrates, it can cause an illness called methemoglobinemia, or blue-baby syndrome. This condition occurs when the bacteria in a baby’s digestive system mix with nitrates and oxidize the iron in their blood. Infants tend to turn blue because of the lack of oxygen in their bodies and can suffer from fatigue, dizziness, headaches, seizures, comas, and even death. Infants are particularly at risk because fully developed digestive systems keep adults and children older than six months from getting nitrate poisoning.


Eutrophication is excessive nutrient richness in a body of water such as a spring, stream, pond, lake, or estuary, and it is one of the primary effects of fertilizer runoff. Eutrophication resulting from fertilizer pollutants disrupts the delicate natural balance of nutrients and plant life in the water. 

The National Oceanic and Atmospheric Administration (NOAA) reports eutrophication has affected 65% of the studied coastal waters and estuaries in the contiguous United States. 

Algae Blooms

One of the consequences of eutrophication is the quick reproduction of algae blooms. Algae thrive on nitrates and phosphate, and when these nutrients are present, they multiply exceptionally fast. The fertilizer runoff contains these exact nutrients, making conditions perfect for algae blooms to take over freshwater sources.

These blooms can turn the water into different colors, give off unpleasant odors, and make people sick. Some symptoms of drinking water or eating food contaminated with algae include skin and respiratory irritation, headaches, diarrhea, vomiting, nausea, dizziness, and impaired kidney or liver function.

Pets can also be affected by swimming in algae-infested waters or drinking water with algae scum. And they are even more likely than humans to experience serious symptoms, get ill, and die.


How to Prevent Fertilizer Runoff

The side-effects of fertilizer runoff can be severe, but there are steps you can take to reduce runoff and your environmental impact.

  1. Set your mower blades to 3 inches or higher. Taller grass absorbs more water and develops a more intricate and robust root system that can hold water in place. This decreases the amount you need to water your lawn and the likelihood of fertilizer-contaminated runoff.
  2. Consider leaving behind your lawn clippings next time you mow. As they decay, the nutrients return to the soil, lowering the need for outside fertilizer. They also help to absorb water.
  3. Adding mulch to your garden helps hold in soil moisture and keep fertilizer in place, even during heavy rain.
  4. Using slow-release fertilizer controls the delivery of nutrients to keep levels low and constant during the growing season.
  5. Always pay close attention and regulate the amount of fertilizer you are using. Specific nutrient amounts and suggestions will be listed on the bag, but a good rule of thumb is to apply between half a pound to a pound of nitrogen for every 1,000 square feet.


How Does Contaminated Water Get into Your Home?

According to the Food and Agriculture Organization of the United Nations (FAO), the top cause of water pollution is agriculture. In fact, agriculture accounts for 70% of water withdrawals worldwide and plays a significant role in water pollution. When it rains, animal waste, fertilizers, and pesticides wash pathogens like bacteria, viruses, and unnecessary nutrients into lakes and rivers that serve many towns as essential water sources. 


Science of Water

Having a whole house filtration system can help eliminate your worries and fears along with any dangerous contaminants — from fertilizer or otherwise. At The Science of Water, we utilize cutting-edge technology with Puronics water treatment and filtration systems to deliver the cleanest, purest water for your family. Set up a free water test, and we will work with you to determine which of our products is best for your home.

Contact us online or call us at (352) 745-7070 or (904) 580-0000 to get started on the journey to clean water today!


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