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Bulk density

Bulk density is how tight the soil is. A hoe that will not enter asks this before hunger.

Speed
  1. Bulk density is how tight the soil is.
  2. A hoe that will not enter asks this before hunger.
  3. High bulk density in the tilled layer means compaction.
  4. Organic matter lowers it slowly.

How it appears on the sheet

How heavy a given volume of soil is. High in the tilled layer means compaction.

A sketch. Do not fertilise from the picture alone.

Common units

Often g/cm³. High in the tilled layer means tight.

How to read the number

How heavy a given volume of soil is. High in the tilled layer means compaction. Wheelings, tilling wet, and yearly rotavating lift it. Organic matter lowers it slowly.

Porosity is the other face: high bulk density, few pores. Bulk density is how tight the soil is. A hoe that will not enter asks this before hunger.

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

How heavy a given volume of soil is. High in the tilled layer means compaction.

Don’t do this

  • Driving on wet soil until the road dies.
  • Sideways roots chased with fertiliser.
  • Porosity is the other face: high bulk density, few pores. Not two unrelated words.

Lesson video