Related Links

  • Science Fair Project Guide

Project Summary

Difficulty  2 
Time required Long (a couple of weeks)
Prerequisites None
Material Availability Readily available
Cost Very Low (under $20)
Safety Adult supervision recommended during preparation of nitrogen fertilizer solution

Donate to Science Buddies

Sponsor

Sponsored by a generous grant from Monsanto Fund

Abstract

Plants need nitrogen to build proteins and nucleic acids to grow healthy stems and leaves. Though the Earth's atmosphere is made up of 79% nitrogen, the form of nitrogen found in the atmosphere cannot be used by plants. In this experiment, you will compare plants grown without nitrogen fertilizer to plants grown with nitrogen fertilizer.

Objective

The goal of this experiment is to compare the growth of plants with and without added nitrogen fertilizer.

Introduction

Plants require more than just water and sunlight to grow. They also require many nutrients found in the soil. One of the most important nutrients required for plant growth is nitrogen. Nitrogen is used to build plant proteins and nucleic acids, including DNA.

Nitrogen is found naturally in the atmosphere and in the soil. Even though there is an abundance of nitrogen available, the most common form of nitrogen (N2) cannot be used by plants. Nitrogen can be combined chemically with oxygen or hydrogen to form types of nitrogen compounds that plants can use. These nitrogen compounds can be added to the soil in the form of ammonium (NH2+) and nitrate (NO3+) fertilizers. Plants grow well when fertilizer containing nitrogen is added to the soil, but this method can be expensive and has to be repeated each time the nitrogen in the soil is used up.

In this experiment, you will compare plants grown without nitrogen fertilizer to plants grown with nitrogen fertilizer. You will observe the effects of nitrogen on the health of the plants by measuring the increase in biomass of each plant during the experiment.

Terms, Concepts and Questions to Start Background Research

Questions

  • What nutrients do plants need to survive?
  • How do plants use nitrogen and what do they use nitrogen for?

    Bibliography

    Materials and Equipment

    Note: Adult supervision recommended during preparation of nitrogen fertilizer solution.

    • at least eight small pots
    • potting soil
    • one packet of seeds
    • commercial nitrogen fertilizer mix for house plants (e.g., Miracle Gro, Peter's or equivalent)
    • empty glass or plastic bottle for mixing nitrogen fertilizer

    Experimental Procedure

    Note: Adult supervision required during use of nitrogen fertilizer.

    1. Make sure pots have holes in the bottom to allow the roots to "breathe" and excess water to drain out.
    2. Measure equal amounts of soil into each of the pots.
    3. Moisten the soil in each pot with the equal amounts of water.
    4. Label four pots with "nitrogen fertilizer" and four pots with "no nitrogen added."
    5. Plant seeds in each pot according to seed packet instructions.
    6. Place plants near a sunny window or under a grow light.
    7. Check your plants regularly and water when needed.
      1. Soil should be kept moist.
      2. Water the "no nitrogen added" pots with regular water.
      3. Water the "nitrogen fertilizer" pots with water mixed with nitrogen fertilizer. Follow the fertilizer manufacturer's recommendations for preparing this solution.
      4. All plants should receive the same amount of liquid at each watering.
      5. Keep track of your watering schedule in your lab notebook.
    8. At regular intervals, record observations on the growth of the plants (e.g., height, number of leaves on each plant, etc.) in your lab notebook. For information on scientifically measuring plant growth see the Science Buddies How-to page, "Measuring Plant Growth".
    9. Here is a sample data table for organizing your data:

      No Fertilizer With Fertilizer
      #1 #2 #3 #4 #5 #6 #7 #8
      Date:
      • Height
      • # of Leaves
      • Observations
                                                                                                                                     
      Date:
      • Height
      • # of Leaves
      • Observations
                                                                                                                                     
      Date:
      • Height
      • # of Leaves
      • Observations
                                                                                                                                     
      Etc.




                                                                                                                                     

    10. Allow plants to grow to maturity, then make final measurements of the growth of each plant. Here are some suggested methods for accurately quantifying plant growth: http://sciencebuddies.org/mentoring/project_ideas/PlantBio_measuring_growth.shtml.
    11. Summarize your results by averaging over the No Fertilizer and + Fertilizer Conditions, and prepare one or more bar graphs to compare your measurements.

    Variations

    • Compare different amounts of nitrogen fertilizer to see what the ideal concentration is for growing plants
    • Experiment with other types of nutrient fertilizers to test their effects on plants.

    Credits

    La Né Powers
    Edited by Andrew Olson, Science Buddies


    Last edit date: 2007-03-22 22:00:00


    Career Focus

    If you like this project, you might enjoy exploring careers in Plant Biology.

    Soil and Plant Scientist
    With a growing world population, making sure that there is enough food for everyone is critical. Plant scientists work to ensure that agricultural practices result in an abundance of nutritious food in a sustainable and environmentally friendly manner.
     



    Join Science Buddies

    Become a Science Buddies member! It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives.


    Support Science Buddies

    If this website has helped you, won't you consider a small gift so we may continue developing resources to help teachers and students?

     



  •  

    Science Buddies gratefully acknowledges its Presenting Sponsor
     
    It's free! As a member you will be the first to receive our new and innovative project ideas, news about upcoming science competitions, science fair tips, and information on other science related initiatives.


    Science Fair Project Home      Our Sponsors      Partners      About Us      Volunteer      Donate      Contact Us      Research Grants & Outreach      Site Map

    Science Fair Project Ideas      Science Fair Project Guide      Ask an Expert      Blog      Teacher Resources      Parent Resources      Student Resources      Science Careers      Join Science Buddies     


    Privacy Policy Science Buddies

    Copyright © 2002-2010 Kenneth Lafferty Hess Family Charitable Foundation. All rights reserved.
    Reproduction of material from this website without written permission is strictly prohibited.
    Use of this site constitutes acceptance of our Terms and Conditions of Fair Use.