All plants require nitrogen in forms they can absorb through their roots, and that accessible nitrogen is provided by certain soil bacteria. while many plants rely on the activity of free-living soil bacteria for ammonium ions (nh4+) and nitrate ions (no3−), some plants form extremely close symbiotic relationships with nitrogen-fixing bacteria. for example, rhizobium bacteria (one type of nitrogen-fixing bacteria) take up residence inside the root cells of legume plants, which include peas, soybeans, and clover. in this activity, you will indicate how the legumes and the rhizobium bacteria are affected by this symbiosis.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.