Skip to content

Back to Reading the soil test

Available P

Available P is what the root meets, not the purity on a bag.

Speed
  1. Available P。
  2. Available P is what the root meets, not the purity on a bag.。
  3. The P column the root can actually use. High total, low available: acid or lime soils.。
  4. The P column the root can actually use. High total, low available: acid or lime soils.。

How it appears on the sheet

The P column the root can actually use. High total, low available: acid or lime soils.

A sketch. Do not fertilise from the picture alone.

Common units

Often mg/kg. The method (Olsen etc.) is on the sheet.

How to read the number

The P column the root can actually use. High total, low available: acid or lime soils. Fix pH and band it. Don’t only dump more powder Easy to mix up: Available P is not total P. Read both to see lack versus lock Available P is what the root meets, not the purity on a bag.。

Thresholds only, not a prescription. Rates live in the field guide. This page does not hand you a bag count.

What it looks like in the field

The P column the root can actually use. High total, low available: acid or lime soils.

Don’t do this

  • High total P, so you never ask available P.
  • Adding powder without opening the pH lock.
  • Available P is not total P. Read both to see lack versus lock.

Lesson video