Soil and Plant Nutrition

1. What are the main chemical components of plant tissue?

2. What is an essential nutrient, a macronutrient, a micronutrient?

3. Why are the following (carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, potassium, calcium and magnesium) considered macronutrients (i.e. why do plants need them in such large quantities)?  In what molecular form are carbon, oxygen, hydrogen and nitrogen acquired by plants?

4. What is the main function of most micronutrients?

5. What is topsoil?  How do soil characteristic influence plant growth?

6.  Why is fertilization, thoughtful irrigation, and erosion control necessary for sustainable agriculture?

7.  The atmosphere is nearly 80% nitrogen gas, why then is nitrogen so often a limiting nutrient for plants in terrestrial environments?  What are the roles of bacteria in nitrogen fixation, and in supplying nitrogen to plants?

8. What are mycorrhizae, and what is their role in plant nutrition?

9. What are some of the alternate forms of nutrition that have evolved in plants and why have they evolved?