Almond orchard recycling a climate-smart strategy

Almond orchard recycling a climate-smart strategy
Wood chips from recycled almond trees are spread across an orchard in California's Stanislaus County. Credit: Brent Holtz, UCANR

Recycling trees onsite can sequester carbon, save water and increase crop yields, making it a climate-smart practice for California's irrigated almond orchards, finds a study from the University of California, Davis.

Whole orchard recycling is when old orchard are ground, chipped and turned back into the soil before new almond trees are planted.

The study, published in the journal PLOS ONE, suggests that whole orchard recycling can help almond orchards be more sustainable and resilient to drought while also increasing carbon storage in the soil.

"To me what was really impressive was the water piece," said corresponding author Amélie Gaudin, an associate professor of agroecology in the UC Davis Department of Plant Sciences. "Water is central to how we think about agriculture in California. This is a clear example of capitalizing on soil health. Here we see some real benefits for and for growers."

Burn vs. turn

Drought and high almond prices have encouraged higher rates of orchard turnover in recent years. The previous practice of burning trees that are no longer productive is now restricted under air quality regulations, so whole orchard recycling presents an alternative. But how sustainable and effective is it for the environment and for farmers?

Almond orchard recycling a climate-smart strategy
Almond blossoms bloom in Yolo County. Credit: Kat Kerlin, UC Davis

For the study, scientists measured soil health and tree productivity of an almond orchard that turned previous Prunus woody biomass back into the soil through whole orchard recycling and compared it with an orchard that burned its old trees nine years prior.

They also experimentally reduced an orchard's irrigation by 20 percent to quantify its water resilience.

Their results found that, compared with burn treatments, whole can:

  • Sequester 5 tons of carbon per hectare
  • Increase water-use efficiency by 20 percent
  • Increase crop yields by 19 percent

"This seems to be a practice that can mitigate by building the soil's potential to be a carbon sink, while also building nutrients and water retention," said Gaudin. "That can be especially important as becomes more limited."


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More information: Emad Jahanzad et al, Orchard recycling improves climate change adaptation and mitigation potential of almond production systems, PLOS ONE (2020). DOI: 10.1371/journal.pone.0229588
Journal information: PLoS ONE

Provided by UC Davis
Citation: Almond orchard recycling a climate-smart strategy (2020, April 1) retrieved 26 May 2020 from https://phys.org/news/2020-04-almond-orchard-recycling-climate-smart-strategy.html
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