Humic Products

Potential or presumption for agriculture

Publisher Description

A range of products, often referred to as alternative fertilisers, are marketed with numerous claims relating to soil health and improved plant growth. However, there is often an absence of evidence about the veracity of the claims and the effectiveness of these products. Producers and consumers alike are left to rely on the advertised promises which come with little proof.

One common group of alternative fertilisers are the humic products that are often sold as soil amendments with or without accompanying plant nutrients. More than 200 humic products are currently manufactured and sold in Australia. Thousands more are available for purchase via overseas websites. Is there a place for humic products in Australian agriculture? Do they have the potential to realise at least some of the advertised claims or are these benefits merely presumption on the part of manufacturers?

This technical bulletin ‘Humic products – Potential or presumption for agriculture’ is the first in a series that will cover a range of alternative fertiliser products. Written and produced by NSW Department of Primary Industries, these reports ask two basic questions:

1. Can the product work? Given our current understanding of the physical, chemical and biological mechanisms that interact in soil-plant ecosystems, can we explain how the product functions?

2. Does the product work? Is there sufficient evidence from independent trials that the product will work under field conditions?

This publication is written primarily for agronomists, soil scientists, consultants and other farm advisors. However, the readable style, explanations and diagrams provided by the author, Kim Billingham, make it accessible for others with a more rudimentary understanding of the soil and plant sciences. ‘A brief history of humus’ will engage readers from both conventional and more alternative philosophies as we all work towards farming in a more sustainable manner.


Abbreviations, Symbols and Units

List of Tables

List of Figures

Executive Summary

A brief history of humus

Humic substances

Humic products

Claims of humic products

Conclusion and recommendations


1. A brief history of humus

The Humic Period [before 1840]

The Mineralist Period [1840 – 1940]

The Ecological Period [1940 – 2000]

2. Humic substances

What are humic substances?


Humus and soil organic matter

Characteristics of humic substances

Formation and structure of humic substances

3. Humic products

What are humic products?

Survey of Australian companies selling humic products

4. The claims of humic products

Research into humic products

Plant growth and yield

Claims of physical properties

Claims of chemical properties

Claims of biological properties

Conclusion and recommendations


Appendix 1 – Definitions of humic substances

Appendix 2 – References used for Tables 2 – 4

Appendix 3 – Companies and websites used in the survey of humic products


    February 25
    NSW Agriculture
    Regional NSW

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