Since nothing has been added to the soil samples, they may be returned to the site where they were collected, and deposited there. Determine percent germination rate and its dependence on soil sterilization. Determine the biomass and its dependence on soil sterilization. Determine whether sterilization of the soil was beneficial or detrimental to plant germination and total growth based on data collected. Many of these organisms that inhabit the soil affect the germination of seedlings and the rate at which the seedlings grow.
Some organisms enhance the growth of plants while others inhibit the growth of plants.
In this investigation students determine whether organisms that live in the soil have a positive effect on the germination and growth of rye grass seedlings. Seeds in the soil that was not sterilized may get damaged by fungi before they germinate, therefore the germination rate and the biomass may be higher in the sterilized soil. This amount of soil will fit in a five-gallon bucket. Students may bring this in as a homework assignment, or the teacher may provide the soil samples. Put half of the soil in a 10 X 20 X 2.5-inch growing tray.