Nitrates, Phosphates and Sulfates

Questions

1. What are the cycles and chemistry associated with Nitrogen, Phosphorus and Sulfur?
2. What role do these chemicals play in the chemistry of our planet?
3. What is fertilizer and why is it used?
4. How are nitrates, phosphates and sulfates measured?

News Articles

• Beijing Sends Nitrogen Downstream
• Nitrate Levels Rising in Northwestern Pacific Ocean
• Minnesota's sulfate standard to protect wild rice
• Army Corps Tries to Assess Impacts of Sprawling Phosphate Operations in Fla.
• Phosphate fertilizer warning for China
• Feeding the World's Hunger for Phosphorus
• Nixing Nitrate Flow from the Farm

Background Information

There are many, many websites that explain the cycles of nitrogen, phosphorus and sulfur. I suggest you search the Internet and look for interesting links.

• Summary of Cycles
• The Sulfur Cycle
• The Phosphorus Cycle
• The Nitrogen Cycle
• Phosphorus Cycle (video)
• The Nitrogen Cycle
• Example of a Nitrogen Cycle (video)
• A Homeowners Guide to Fertilizer

Take Away (Main) Points

1. NKP labels on fertilizers stand for three macro (main) plant nutrients: nitrogen, potassium and phosphorus.
2. The chemical symbol for Nitrogen is N, for Potassium is K, for Phosphorus is P and for sulfur is S.
3. Nitrogen exists as N₂, a very stable, triple-bonded molecule that makes up 78% of our air and doesn't react with easily.
4. Plants require nitrogen in the form of nitrates or ammonia to grow. They cannot use nitrogen gas.
5. Before Fritz Haber demonstrated a chemical process to make ammonia farmers had to rely on natural processes to return nitrogen to the soil such as bacteria in the roots of legumes (beans and peas).
6. Plants also require phosphorus but it exists primarily as a very, very insoluble mineral in the Earth's crust.
7. Sulfuric acid is manufactured from sulfur so that it can be used primarily to dissolve phosphate minerals to make fertilizer.
8. Too much fertilizers can run off into our waters causing algae blooms (over growth of algae).
9. We need to know a little bit about sulfur, nitrogen and phosphorus to understand discussions about soil fertility.