Description:
Published by Ohio State University Extension this fact sheet provides growers with an overview on the subject of micronutrient management for good plant growth in soilless mixes.

Accessible from:
http://ohioline.osu.edu/hyg-fact/1000/1252.html

Description:
This site contains three computer models to help growers decide what if any nitrogen (N), phosphorus (P), or potassium (K) fertilizer is needed for their crops. The N and P models can be specialized for different areas of the world, and instructions are available for combining the models to run a N, P, and K simulation.

Accessible from:
http://www.qpais.co.uk/npk/

Description:
An article in an on-line journal, "Troubles in the rhizosphere" describes the relationship of tree roots to rhizosphere microbes, especially in relation to tree declines and root diseases. The site links to a version with photos.

Accessible from:
http://www.agroforester.com/overstory/overstory70.html