RESEARCH & EVENTS
Spotlight on whole orchard recycling
Whole orchard recycling has the potential to improve yields , soil health and moisture retention in the orchard . The practice is currently being trialled in Victoria .
WHILE the Californians have been trialling whole orchard recycling ( WOR ) for over 20 years and have been able to demonstrate improved yield , soil health and moisture retention benefits , the practice of recycling orchards has only taken off in recent years as a result of recent regulations and reforms regarding air pollution ( all burnings are prohibited as of January 1 , 2025 in the San Joaquin Valley due to concerns about air quality ) and groundwater use ( increased water scarcity in groundwater reliant areas as a result of Sustainable Groundwater Management Act ). Earlier this year when ABA Industry Development Manager Deidre Jaensch and Almond Centre of Excellence Farm Manager Anthony Wachtel travelled to California to attend the International Society for Horticulture Science Symposium on Almonds and Pistachios , they noticed a lot of orchards had been grubbed out and were waiting to be chipped , or stockpiles of wood chips waiting to be spread out and incorporated into the soil . The symposium coincided with two grower field days on ‘ soil health and sustainability ’ and ‘ almond replant ’ and WOR was a common topic at all three events which meant Deidre and Anthony were able to spend more time with leading expert Brent Holtz ( University of California Cooperative Extension in San Joaquin County ). Brent indicated that ~ 200,000 acres ( 80,937 ha ) of orchards have been recycled across California . Brent has spent a lifetime researching WOR and after 23 years the results are clear . However , Brent indicated that it can take 7-8 years before these benefits are seen by the grower and cost of WOR starts to pay for itself with improved yields and reduced inputs . The Whole Orchard Recycling best management practice guideline for Californian almond growers released by Almond Board of California clearly shows the benefits are much more than avoiding burning with improve yields by 19 % when compared to conventional orchards , can increase soil structure and water retention by more than 32 % and has a range of soil health benefits :
• Increased soil organic matter by 58 %
• Increased soil carbon by 58 %
• Increased microbial biomass
• Increased soil nitrogen levels by 17 %.
In Australia , WOR is being trialled under the Hort Innovation project AL21000 to see if the same benefits are able to be achieved in north-west Victoria . The SARDI research team undertaking the trial are gathering valuable soil data information throughout the season and comparing tree growth for when almond compost has been incorporated into the soil against conventional replanting . The trial also compares a commercial compost blend against WOR .
Continued page 28
industry . australianalmonds . com . au
27