1. Nitrogen Cycle This topic just keeps coming up, over and over again

2. The Nitrogen Cycle 78% of air is nitrogen gas. Nitrogen gas is USELESS.

3. The Nitrogen Cycle Small amount is turned into ammonia (useful) by lightning. Bacteria in the soil and on the roots of some plants turn it into biologically available nitrogen.

4. The Nitrogen Cycle Legumes are high in nitrogen (which is what makes up protein). Alfalfa is one of the best animal feeds. Leave usable nitrogen in the soil when they die. Many people improve their soil by planting legumes.

5. The Nitrogen Cycle Legumes form nodules on roots to hold bacteria. Beans, peas, clover, vetch and alfalfa (a kind of clover). “Fix” nitrogen for plants, plants provide the bacteria with food.

6. Nitrogen Limits Plant Growth Deprived plants grow slower and look yellow/light green. Notice dog urine (high in nitrogen) helps grass grow dark green. Unless way too much raises pH beyond tolerance = dead spots.

7. Nitrogen Limits Algal Growth The ocean is a nutrient desert.

8. The Nitrogen Cycle Nitrogen in the atmosphere Nitrogen-fixing bacteria in the nodules on roots of leguminous plants fix atmospheric nitrogen. Nitrogen-fixing soil bacteria Some excess nitrogen evaporates from soil. Nitrogen compounds released into soils and acted upon by soil bacteria Released to the atmosphere Assimilate d by plants Urine from animals Dead plant matter Decomposing organisms Decomposers—bacteria and fungi— break down tissues and wastes and nitrogen-containing compounds are released. Converted to other nitrogen compounds by soil bacteria

9. Haber Bosch Process Turns hydrogen made from natural gas and pure nitrogen coiled from atmospheric air into ammonia (NH 3 ) a biologically available nitrogen source. Uses a LOT of natural gas.

10. Ammonia Injection Farming is “subsidized” by natural gas derived ammonia fertilizer.

11. Too much nitrogen Runoff from over fertilized lawns and crop fields. Animal waste. Sewage (even properly treated)

12. Too much nitrogen Algae grow, die, sink to the bottom and rot. Use up oxygen. Fish and other animals die from suffocation. Gulf of Mexico “dead zone”