Module 6 focuses on the barriers to root growth. Unit 6.1 provides an overview of these barriers which include physical barriers (including the strength of the soil), chemical barriers (such as salinity and sodicity) and biological barriers (such as insect attacks).

Unit 6.2 delves into the mysteries of soil structure and unit 6.3 has practical ideas on measuring your soil's strength. 

Units 6.4 and 6.5 introduce two new methods for reducing soil compaction, namely controlled traffic and Tramlining.

The last three units (6.6, 6.7 and 6.8) deal with various aspects of soil acidity and liming.