Welcome to Part 1 of two weeks of nutrient management glory.  We talk about the importance of nutrients and the visual cues to determine if you have a problem.  First we get into Nitrogen, Phosphorus and Potassium, your Big 3, along with some of the secondary nutrients.  Week 2 will be dedicated to the micronutrients, equally important but more nuanced in the soil.
Buckle in and be prepared for your spellchecker to blow up.