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• Measuring Plant Growth

Project Summary

Difficulty	6
Time required	Very Long (several weeks to months)
Material Availability	Readily available
Cost	Low ($20 - $50)

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Sponsor

Sponsored by a generous grant from Monsanto Fund

Abstract

Objective

The purpose of this project is to determine which soils will yield the greatest plant growth, root length, and root weight: soil without additives, soil with dry humic acid, soil with liquid humic acid, or soil with a combination of dry and liquid humic acid.

Introduction

Organic matter is an important component of fertile soil. Many different types of organic matter can be used as fertilizers to enhance plant growth, such as manure, compost, etc... Humic acid is believed to be a good organic fertilizer for certain plants. Does humic acid really work to improve plant growth?

Terms, Concepts and Questions to Start Background Research

You should have an understanding of humic acid and humate, how they are produced and what their impact is on soil.

Cation exchange capacity is an important term to understand how humic acid impacts soil.

Bibliography

Basic explanation of Humic Acid:

• http://en.wikipedia.org/wiki/Humic_acid
• http://aggie-horticulture.tamu.edu/extension/newsletters/hortupdate/jun02/art4jun.html

Similar studies looking at benefits of humic acid on growth of different varieties of plants:

• Wheat Plant:
  http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11885604&dopt=Abstract
• Potato:
  http://www.ag.uidaho.edu/potato/research/files/Volume%2035/Vol%2035_87%20Humic%20Acid.pdf

Simple explanation of cation exchange capacity
http://www.extension.umn.edu/distribution/horticulture/components/1731-06.html

Impact of organic matter on soil productivity (includes brief discussion of humic acid)
http://www.agronomy.lsu.edu/courses/agro2051/Chapter%2012.pdf

Materials and Equipment

• Pots
• Potting soil
• Dry humic acid
• Liquid humic acid
• Plants

Experimental Procedure

• Fill pots with potting soil.
• Add dry humic acid to half of the pots.
  *See note below.
• Make sure you have a good location for the plants so that they will all be exposed to the same conditions and they will not be disturbed during the course of the experiment.
• Over the next two months water half of the pots that contain humic acid with plain water and the other half with liquid humic acid. Water half of the plain pots with plain water and the other half with liquid humic acid. This process will ensure that you have the following groups of experiments:
  
  • plain potting soil treated with plain water
  • plain potting soil treated with liquid humic acid
  • humic acid added to potting soil and treated with plain water
  • humic acid added to potting soild and treated with liquid humic acid
  *See note below.
• Two months later pull the plants and begin gathering data. Some things to measure are: root and plant growth, weight of the roots, weight of the plants.

*Experimental Note
Commercial humic acid products are too concentrated to apply to plants straight from the bottle.
Recommended amounts of dry humic acid powder in the ranges of:

• 1/4 teaspoon per pot
• 1/2 teaspoon per pot
• 1 teaspoon per pot

• 2 tablespoons liquid humic acid per gallon of water
• 5 tablespoons liquid humic acid per gallon of water
• 10 tablespoons liquid humic acid per gallon of water

Variations

Try different types of plants, vegetables, fruits, houseplants....

Try humic acid vs. fertilizer

• For more science project ideas in this area of science, see Plant Biology Project Ideas.

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.

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