Do plants grow faster or slower without microorganisms

Question

I am doing a science fair project on that topic and do they grow faster or slower and is this a good topic for a seventh grader and could you please explain the procedure of how to do this?

thanks!

Answer 1

thats a tough question to give a simple answer to. it all depends on the plants you use, the soil content, and the fact that there is always microorganisms. They come from almost any contact with the plant from any living thing. The soil is full of them, and they are after all "micro" so the will be very hard if not impossible to see without magnification. I think it would be a great project, but it may be difficult to maintain a plant that is free of them without tenting it off and only handling with gloves and a mask on. You should also know there are good and bad microorganisms also. obviously good will help the plant, bad will slowly kill it. Good luck, i hope you win.

Answer 2

The easiest experiment to run is to obtain bacterial inoculum such as Rhizobium species.  Have two sets of bean, pea, soybean or peanut seeds, one set treated with the inoculum and the other treated with plain potting soil.  Make sure the plants getting equal exposure to light, water, nutrients.  After the plants have grown for a long as you have time to allow for growth, carefully remove the soil from the roots, dry the plants gently in a hot environment (air dry in a hot garage).  Weigh the plants with a scale that can measure in at least tenth of a gram (preferably thousands).  Average the weights of each set of plants.

Or you could grow sets of plants.  One set in a sterile potting soil (heated in an oven for 1.5 hours at 300 degrees F. compared to a set of seed grown in a garden soil to another set grown in a rich compost (lots of microbes).  Clean, dry, and weigh the plants as described in the first experiment.

A better more difficult project is to try to isolate bacteria or fungi from the roots of plants that you collect in nature.  You'd need to have access to microbiology supplies and would require a microbiologist to help identify the microbes isolated.  You could then experiment with garden plants with inoculation with the microbes compared to non-inoculated plants.