Water Availability
What it is: The amount of water in soil is based on rainfall amount, what proportion of rain infiltrates into the soil, and the soil's storage capacity.
Why it is important: Water availability is an important indicator because plant growth and soil biological activity depend on water for hydration and delivery of nutrients in solution. Runoff and leaching volumes are also determined by storage capacity and pore size distribution.
Specific problems that might be caused by (too little, too much etc.) are:
Too little: crop moisture stress under dry conditions, increased runoff or leaching volumes under wet conditions
Too much: soggy fields under wet conditions
What you can do: You can improve your soil water availability by increasing organic matter levels or incorporating storage capability in tile drainage systems (to increase water availability) or decreasing organic matter or installing tile drains (to decrease water availability).
For more information go to Soil Management Practices.
Ways that you can measure water availability include:
| Method | How Performed | Comments |
|---|---|---|
| Available water capacity (AWC) | ||
| Water holding capacity (WHC) | ||
| Water filled pore space (WFPS) | ||
| Infiltration | ||
| Ponding |
The different methods have different levels of accuracy and precision.