Scientists Say: Fertilize

This term has two meanings — one relates to sexual reproduction, the other to agriculture

a hand pinches an acorn between thumb and forefinger

Fertilization is when two gametes, or reproductive cells, combine into one cell that grows into a new individual. In oak trees, fertilized flowers produce acorns, which protect the seed that will one day grow into a new oak tree.

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Fertilize (verb, “FUR-till-ize”)

The word fertilize means two very different things in biology and farming. In both cases, the act of fertilizing is known as fertilization.

In biology, fertilization refers to a particular stage of sexual reproduction. This type of reproduction involves two members of the same species combining their genetic material, or DNA, to create offspring.

Fertilization is the step in that process when two cells called gametes — one from each parent — fuse together. Each gamete contains half of the genetic instructions needed to build the cells that make up the offspring. When two gametes join together, they create one new cell containing the genetic material of both. This new cell containing a full set of DNA ultimately grows into the offspring organism.

In humans, those gametes are the egg and sperm. When the sperm fuses with the egg, scientists say the sperm “fertilizes” the egg.  

In agriculture, fertilization refers to the process of adding nutrients to the soil. Plants take up nitrogen, phosphorus and other nutrients from the soil. They use these nutrients to grow and produce flowers, fruit and other structures.

Crops we grow for food, such as corn and wheat, use a lot of these nutrients. And over time, fields can start to run out of them. So farmers fertilize their crops with added nutrients — fertilizers — to grow enough food.

However, fertilizers can cause environmental problems. Excess fertilizers get washed out of the soil by rainwater. Eventually, they wind up in lakes, rivers and oceans. These added nutrients can boost algae growth, causing algal blooms. Sometimes, these algal blooms release toxins that hurt animals and plants that live in the water.

In a sentence

Replacing lawn grass with native plants saves water and reduces the need to fertilize lawns.

Check out the full list of Scientists Say.

Katie Grace Carpenter is a science writer and curriculum developer, with degrees in biology and biogeochemistry. She also writes science fiction and creates science videos. Katie lives in the U.S. but also spends time in Sweden with her husband, who’s a chef.

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