Effect of Nitrogen on Plant Growth

• Determine the effect of nitrogen on bean growth using different concentrations of a nitrogen solution. Plant bean seeds in soil. Use at least eight plants as you will need one control plant (without any nitrogen solution) and at least three plants with varying nitrogen solutions (from low concentration to high concentration). The remaining four plants can serve as a back up in case some plants do not germinate. It will take at about 14 days for the bean seeds to germinate. After germination mix your nitrogen solutions with water and differing grams of nitrogen mix. For instance, one gram, five grams, ten grams. Pour the solutions into the respective plants and be sure to label your plants properly with the amount of nitrogen in which you added. Place the plants in sunlight and allow them to grow for two weeks. Remember to water daily. Measure the bean height with a ruler and weigh the green matter using a balance. Record results. Photos also make a great contribution to a science fair project. The plant that grew the highest and contained the most green matter, grew the most successful.
  
  

Nitrogen-Fixing Bacteria

• Plants require nitrogen to grow, and the form of nitrogen found in the atmosphere is not utilized by plants. Plants need nitrogen rich soil in order to grow. Construct an experiment to compare the amount of plant growth in soil with no nitrogen and soil with nitrogen-fixing bacteria added. Nitrogen-fixing bacteria, such as Rhizobium leguminosarum, can transform the nitrogen in the soil into plant usable nitrogen compounds such as ammonium and nitrate. For this experiment, grow nine clover plants. Three plants will serve as your control (no nitrogen added), three plants will have fertilizer added, and three plants will have nitrogen-fixing bacteria. Allow the plants to grow over a two week period. Measure the increase in plant growth using a ruler and test the nitrogen levels of each plant using a nitrogen testing kit. Record your results. Remember to take pictures for your project.
  
  

Root Nodules

• Explore how bacteria help plants survive using an already grown clover plant. Find a clover and dig it up. Make sure the roots of the clover have no dirt on them by dipping them in the water. Allow the clover to dry on a paper towel. Examine the roots with a magnifying lens and find the nodules on the roots. These will look like small bumps. Cut a section from one of the smaller roots containing some nodules and place the root on a microscope slide. The nodules form on the clover from multiplying bacteria that have entered the root hairs. Take pictures and prepare a poster board explaining the role of bacteria, what the nodules look like and their purpose.
  
  

Effects of Nitrogen on Aquatic Plants

• Examine the effects of nitrogen on aquatic plants. For this experiment you need to go to a park or area containing ponds or creeks. Examine at least four ponds or four different areas along a creek (perhaps choose ponds or creeks with varying levels of shade and sunlight). In addition, make sure the ponds in which you sample contain the same species of aquatic plants. Take soil samples at each location and at differing depths and measure the dissolved oxygen, nitrogen, pH, and aquatic primary productivity. These measurements can be obtained using a La Motte test kit (www.lamotte.com/pages/soil/index.html). Record all results and enter the results into a graph. Remember to take pictures of your location. Determine if there is a correlation between the amount of nitrogen, depth and the amount of primary productivity present in the ponds.