Soils

The composition of soil
The difference between soil texture and soil structure (effects of excessive tillage), the advantages and disadvantages of each soil texture (clay, silt, sand), the importance of organic matter in the soil.
Soil fertility and pH
The role and importance of soil pH
The pH scale (acidic to basic, logarithmic)
How pH adjustments are made in the soil
Cation Exchange Capacity (CEC) and its relation to fertility
Essential macronutrients and micronutrients needed for plant growth
Soil testing and interpretation
Don’t Guess, Soil Test! – The importance of soil testing.
How to sample soil and complete the soil testing form properly
How to interpret a soil test and its recommendations
How to compare fertilizers
Types of fertilizers and their relative attributes (synthetic & organic)
How to interpret a fertilizer label
How to select the appropriate fertilizer for a specific use
How to select a substitute fertilizer, when the fertilizer recommended in your soil test results is not available at the store
How and when to apply fertilizers to minimize environmental impact
Cover cropping and organic soil amendments
Reasons to use cover crops
Appropriate cover crop for each reason
Cover crops and when they are planted in Maine
Organic amendments and how they affect soil

Soil and Plant Nutrition: A Gardener’s Perspective, by Lois Berg Stack, Ornamental Horticulture Specialist, University of Maine Cooperative Extension

UMaine Extension Bulletins

UMaine Extension Videos

Additional UMaine Resources

MOFGA fact sheets — Look for:

Using Green Manures
Natural Sources of Plant Nutrients
An Organic Farmer’s Guide to the Interpretation of a Standard Soil Test from the University of Maine

Additional Resources

Building Soils for Better Crops, SARE: A one-of-a-kind, practical guide to ecological soil management, now expanded and in full color. It provides step-by-step information on soil-improving practices as well as in-depth background — from what soil is to the importance of organic matter. Case studies of farmers from across the country provide inspiring examples of how soil – and whole farms — have been renewed through these techniques. A must-read for farmers, educators, and students alike. Free download available.
Interactive soil map, UCDavis
Measurement Conversion Chart and pH Preference Table (PDF), University of Maryland
Organic Matter Management, University of Minnesota Extension
Soil Biology Primer, Natural Resources Conservation Service
Soil Health/Soil Quality, Explained
Web Soil Survey, Natural Resources Conservation Service
Soil Society of America