Conclusions 
We observed nodules on the group of plants that had been inoculated. The presence of these nodules represents a successful inoculation. The non-inoculated group did not have nodules, indicating that no Rhizobium Leguminosarum bacteria were present. In our hypothesis, we predicted that the plants with bacteria would grow taller, faster, and healthier than those plants without bacteria. Our experimental data supports this hypothesis. With one exception, the inoculated plants were consistently taller than the non-inoculated plants throughout the entire project. The plants with bacteria grew faster/taller/healthier because they were receiving more nitrogen than the plants without bacteria. The Rhizobium Leguminosarum provided the plants with this abundant source of nitrogen through the process of biological nitrogen fixation. In this process, the Rhizobium converts the nitrogen gas (N2) that lies between the soil particles to ammonia (NH4+). The pea plants use the ammonia to construct amino acids, which are later used in protein synthesis. To grow, plants need to synthesize proteins. Therefore, the plants with bacteria would always have enough ammonia to create the proteins that they required for growth. The non-inoculated plants, however, would rapidly consume the nitrogen in the soil and would then be unable to synthesize amino acids. Since no bacteria were present and no fertilizer was added, once the plants used their nitrogen, there was little left. With no nitrogen available to synthesize amino acids, a slowing of protein synthesis resulted, and, as a result, growth slowed as well. This is the reason why the inoculated plants grew taller than the non-inoculated plants. Nitrogen also contributes to vibrant, green plants. If one looks at the pictures, on will see that the inoculated plants were much healthier than the non-inoculated plants.
We had many difficulties with our project. Our first few attempts to plant seeds failed. We tried different soils, different sowing techniques, and watered different amounts, but the results was always the same: rotten seeds. We then changed the seed we were using from bean to pea. The peas were sown with the inoculum in Frank's seed starting mixture. This time we were very successful. We concluded that there must have been a problem with the bean seeds.
We made one mistake that must be mentioned. The plants with bacteria were labeled "No Bacteria" and the plants without bacteria were labeled "W/ Bacteria". It was not until the end of the project that we realized this error. When we noticed that the roots of the "No Bacteria" were covered with nodules and the roots of the "W/ Bacteria" had no nodules, we realized what our mistake must have been. The data has been rectified and all interpretation has been done as if the mistake did not occur.
There are many different experiments that could branch from this one. We could expand the experiment to include different legumes (i.e. fababean, clover, etc.). We could try several different methods of inoculation to find the most effective method. We could experiment with different types of nitrogen fixing bacteria to find out if the pea plants were only compatible with certain strains of the Rhizobia classification (or which legume was compatible with which bacteria). We could vary soil conditions to see if that affected successful inoculation and nodulation. We could inoculate plants that were diseased or had insects to see if that had any affect on inoculation and nodulation. We could design an experiment to test whether the soil's nitrogen content had any affect on successful inoculation and nodulation. We could fertilize one set of plants and inoculate another set of plants, and see which one grew better. Many different projects could be inspired by our project.
We made many mistakes that would be avoided if we did this project a second time. First, the project took too long. We wasted much time on failed experimentation. For example, in our first attempt we grew our own bacteria and sterilized our own soil. Before planting, we soaked the seeds in a nutrient broth that had been inoculated with the bacteria. We over-watered and allowed the soil to soak in stagnant water. In addition we did not put in enough soil. The result was rotten seeds. This first attempt took about a month, since we had to order the bacteria, wait for it to arrive, grow our own culture, then inoculate and plant the seeds. For our next attempt we bought some Frank's potting soil to plant the seeds in. We planned to inoculate the seedlings once they had sprouted by pouring the nutrient broth with the bacteria over the soil. Again we over-watered and allowed the soil to soak in stagnant water. Again the seeds rotted. For the third attempt we reused the soil from attempt number two, but this time mixed it with peat. We inoculated the seeds before they were sown using an inoculum provided by Mr. Waltman. This time three seeds sprouted. The rest rotted. For the fourth and final attempt, we used Frank's seed starting soil, inoculated the seeds with the inoculum before sowing, and used pea seeds instead of the bean seeds we had used previously. This time we had success. Almost all of the seeds sprouted, and there were no rotten seeds. But we made mistakes this time too. We positioned the trays next to each other, so it was possible for the bacteria to move to the other tray. Two different people measured, and their different techniques yielded different results. At times watering was erratic, and by the end, most of the plants were beginning to die. If we did this project again, we would do the following things differently:
- Do not be lazy about caring for plants
- Purchase seed starting soil - it's sterile
- Fill containers with soil - the soil should be no more than ½ inch from the top edge of the container
- Use inoculum on the seeds before sowing (Do not start your own culture)
- Water if the soil is becoming dry, and not at any other time (Bottom watering is best, but one must empty the bottom pan after the plants have had a chance to absorb the water - usu. about 5 minutes)
- Use the same type of large container for both groups (If you do not, another variable is created)
- Keep a large distance between the plants from the two groups (So it is not possible for the bacteria to get into the non bacteria group)
- Don't waste time (set up the experiment and finish it)
- Before planting, test the seeds capacity to germinate by placing them on a wet paper towel
- Make sure the labels on the containers are correct
10 Things That Were Learned 
- Excessive watering is harmful to plants and will rot the root systems.
- Bottom watering is best, but the bottom tray must be emptied after the plants have absorbed the water.
- If soil is baked for long periods of time, it loses many nutrients and its consistency (Baked soils are poor for plants).
- The best type of soil for starting seeds is seed starting soil.
- The best way to inoculate plants with Rhizobium Leguminosarum is to purchase an inoculum and coat the seeds with it.
- Rhizobium Leguminosarum is a nitrogen-fixing bacterium that converts atmospheric nitrogen to ammonia. The plant uses the ammonia to make amino acids. In return, the plant supplies the bacteria with carbohydrates (which the bacteria use for energy.)
- The techniques for growing bacteria in a petri dish
- If left in a petri dish for too long, bacteria will draw all food from the agar and die, leaving a thin disc that once was the nutrient-filled agar.
- Peas are monocots. As they grow, they produce tendrils that hook on to support. Peas eventually produce flowers, which self fertilize and begin to form pea pods (peas are fruits).
- If you fail, change something and try again. (You're bound to get it right sooner or later)
References Cited 
- Dazzo, Frank B. MSU Microbiology Facility. October 28, 1995. Available http://www.msu.edu/user/wingerdb/webpage/cmb/dazzo.htm (Dec. 17, 1997)
- Killpack, Scott C. and Daryl Buckholz. "Nitrogen in the Environment: Nitrogen Fixation." Department of Agronomy, University of Missouri- Columbia: WQ0261. October 1, 1993. Available http://muextension.missouri.edu/xplor/waterq/wq0261.htm
- "Nitrogen Fixation. "Microsoft Encarta 97 Encyclopedia". 1997 ed.
- NRI. "Nitrogen fixation: Nitrogen fixing plants?" May 12, 1995. Available http://lupin.csv.warwick.ac.uk/gene/pages/nitfix2.html (December 15, 1997)
- NRI. "Nitrogen fixation: Why is nitrogen important?" May 12, 1995. Available http://lupin.csv.warwick.ac.uk/gene/pages/nitfix1.html (December 15, 1997)
- "Soil Improvement with Legumes." Available http://www.gov.sk.ca/agfood/farmfact/scs03-2.htm (Dec. 17, 1997)