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.
TABLE OF CONTENTS
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
Introduction
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?
Terminology
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
Appendices
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
Glossary
