HomeGlossary of termsModule Map


1.1 Properties of a ‘Healthy’ Soil

Friability (tilth)

A ‘perfect’ agricultural soil will form small (2-3mm) aggregates that do not disintegrate under heavy rain or tillage, but have sufficient pore spaces to hold water. Ideally, the aggregates should bond together slightly to prevent them from moving down the slope with water flows, but break apart easily when cultivated.

Friable soils:

  • Allow water and air to move more freely in the soil. As water infiltration improves, waterlogging problems decrease and better use is made of soil water.

  • Are easily worked improving seed and soil contact and allow uniform germination and emergence of seedlings.

  • Allow roots to penetrate and better exploit water and nutrients in the soil.

Freedom from Barriers

Barriers to roots, that limit their growth and ability to exploit the soil, prevent crops achieving potential yields. Barriers to root growth, such as a compacted layer, can be reduced or eliminated. Those from boron, shale and stone or high lime layers are difficult or expensive to change. The productive potential of a paddock with such barriers will be much less than the rainfall potential.

Provides Storage for Water and Nutrients

The capacity of the soil to hold water and its availability to plants directly affects productive potential. The ability of a soil to store water and nutrients depends on the number and size of pores, ‘storage sites’ in the soil and the amount of clay and organic matter in a soil. Measuring the ‘cation exchange capacity’ of the soil can assess the storage capacity for a range of nutrients. The availability of nutrients from this store can be assessed by standard soil and tissue tests.

Resistance to Erosion by Water and Wind

Exposed soils with poor structure and lack of organic matter or vegetative cover are prone to erosion.

Biologically Active

 Soil organisms carry out a wide range of processes that are important for soil health and fertility. There is a two-way relationship between soil organisms and agricultural production. The retention of plant residues provides an important source of energy and nutrients for soil organisms. In turn, they improve organic matter breakdown, nutrient availability, soil structure, disease suppression and the degradation of pollutants such as herbicide residues.

Freedom from Pests and Diseases

 Root, stem and leaf pests and diseases can be carried in the soil. Root disease control, combined with improved soil structure that has allowed better root exploitation of the soil, has been one of the main reasons for yield increases in many areas during the last decade.

  • How ‘healthy’ is your soil?

  • What is limiting the productive potential of your soil?

  • Are there opportunities to improve your soil ‘health’?



1.1 Properties of a ‘Healthy’ Soil

Next ]


Top of page
Any recommendation contained on this website does not necessarily represent the policy of the Agricultural Bureau of South Australia Incorporated, or any of the contributors of material held here in. No person should act on the basis of the contents of this website, whether as a matter of fact or opinion or other content, without first obtaining specific, independent professional advice which confirms the information contained in this publication.