Agriculture Reference
In-Depth Information
4
Where the Vine Roots Live
Soil Structure
Chapter 3 gives examples of how grapevines, being woody perennials, have the
potential to develop extensive, deep root systems when soil conditions are favor-
able. One of the most important factors governing root growth is a soil's structure,
the essential attributes of which are
• Spaces(collectivelycalledtheporespaceorporosity)throughwhichroots
grow, gases diffuse, and water flows
• Storageofwaterandnaturaldrainagefollowingrainorirrigation
• Stableaggregation
• Strengththatnotonlyenablesmoistsoiltobeartheweightofmachinery
and resist compaction but also influences the ease with which roots can
push through the soil
The key attributes of porosity, aeration and drainage, water storage, aggregation,
and soil strength are discussed in turn.
Porosity
Various forces exerted by growing roots, burrowing animals and insects, the move-
mentofwateranditschangeofstate(e.g.,fromliquidtoice)togetherorganize
the primary soil particles—clay, silt, and sand—into larger units called aggregates.
117
