Advanced-Level Science Projects

Can Healthy Plants Be Grown in Soil Containing No Microorganisms?

Soil is home to a great number and wide range of microorganisms, among them algae, fungi, bacteria, and viruses.

Although the number of microorganisms found in soil can sound alarming, it's important to know that these tiny organisms need nutrients in order to grow and be active in the soil. If the soil lacks the necessary nutrients, the majority of microorganisms may be physiologically inactive.

Microorganisms can be both good news and bad news for plants and those who grow them. Some help to decompose roots, stems, and leaves of plants that die, helping to recycle nutrients in the soil. Others increase nutrients in the soil and make it more fertile. Some even act as natural fertilizers.

Scientific Surprise

There normally are between one and 10 million microorganisms present in one gram of soil—which is only 1/28 ounce—a tiny, tiny amount. There are more bacteria and fungi than any other type of microorganisms.


Not all microorganisms are helpful, however. Some can infect plants through their roots and cause considerable damage.

In this suggested science fair project, you would investigate whether plants grow better in soil containing microorganisms than in soil that has none. To do so, you'd take a sample of fertile soil from your garden or a field, and divide it into two parts. Bake one part in the oven at 350 degrees for one hour to destroy all the microorganisms, and leave the other batch alone.

Plant the same number of the same type of seeds in each of the different batches of soil, and provide the same environment and care to each group. Record your results carefully.

book cover

Excerpted from The Complete Idiot's Guide to Science Fair Projects © 2003 by Nancy K. O'Leary and Susan Shelly. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.

To order this book direct from the publisher, visit the Penguin USA website or call 1-800-253-6476. You can also purchase this book at Amazon.com and Barnes & Noble.

stay connected

Sign up for our free email newsletters and receive the latest advice and information on all things parenting.

Enter your email address to sign up or manage your account.

Facebook icon Twitter icon Follow Us on Pinterest

editor’s picks

highlights

Healthy Smile Checklist for Kids
Have better dental check-ups with this free printable checklist that helps keep your child flossing, brushing, and smiling! Brought to you by Philips Sonicare.

Kindergarten Readiness App
It's kindergarten registration time! Use this interactive kindergarten readiness checklist, complete with fun games and activities, to practice the essential skills your child needs for this next big step. Download the Kindergarten Readiness app today!

8 Easter Egg Decorating Ideas
Need some fun ideas for decorating Easter eggs with the kids? Look no further for colorful and cool designs!

7 Ways to Curb Kids' Exposure to Violence
American children are exposed to violence more often than you might think. Learn how to limit your child's exposure to violence and manage the mental health and behavioral effects it can cause.