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Biochar and Avocados

Biochar and Avocados

  • Author: SWCC
  • Date Posted: Aug 27, 2014
  • Category:
  • Address: Middlesex, Western Australia

Project Details

Project Delivery: Warren Catchments Council

Contact: Wendy Wilkins (SWCC – Bridgetown).  Ph: 9761 4184


Website: SWCC Sustainable Agriculture

Start Date:  May 2014                     End Date: Dec 2017

Site ID:  IN2.1.005

Size Are Ha: 0.4


Project Aim

This project seeks to assess the effects of a range of soil amendments extended over 4 years on:
• Plant growth and vigour
• Plant uptake of nutrients
• Fruit nutrients and quality (testing not currently available commercially)
• Soil health (physical, chemical, biological including mycorrhizal fungi)
• Moisture retention
• Nutrient retention within 0-30cm layer
• Sub-soil acidity
• Disease and pest protection (especially Phytophthora cinnamomi)
• Soil oxygen levels (if additional funding/expertise can be obtained



This project will establish three replicates of application of biochar, biochar-activated compost, compost and control to avocado orchard. Benchmark testing and treatment testing will occur prior to application of the compost and biochar-activated compost. Subsequently annual testing will occur during 2015, 2016 and 2017. Monitoring will occur throughout the trial to record pest/disease/moisture/anecdotal observations (on-going). A field day will be held in spring 2016.



The trial has been established and pre-trial soil sampling has been undertaken.  Soil amendments have been applied and tested, the treatment and control ripped and rotary hoed.  Trees have been planted and individually identified (GPS and log for each tree).  Photo monitoring points have been established.  Irrigation has been installed and watering occurring.

Following a leaf analyst it was discovered that non-charcoal amended avocado trees had 23 per cent more salt or chlorine in the leaf tissue than the charcoal-amended avocado trees.   Is the charcoal absorbing the chlorine which is present in the irrigation water?

This project is progressing very well.  It is receiving considerable interest by avocado producers and other horticulturists, some of whom have already adopted this practice.   This is largely due to the fact that the biomass of the trees in the trial are double the size of the ones in the control.  When the farmer was asked whether he has any regrets about the trial, he said, “Only that I should have put the whole orchard to biochar.”  He anticipates that the trees with biochar will fruit one year earlier than those in the control.  “This could be a game changer,” he concluded.

A trial update for this project, dated July 2016, that explains how this practice was implemented, and some of the early results, can be found at

An interview with the landholder and others by ABC Rural can be found at

SWCC has produced a video on the landholder and his trial which can be found at

*Join the growing number of farmers and industry advisers receiving trial updates by subscribing to SWCC’s Sustainable Agriculture E-newsletter.  Simply email with “Subscribe to SWAG” as the subject.


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