Recycling almond trees onsite can sequester carbon, save water and increase crop yields, making it a climate-smart practice for California’s irrigated almond orchards. These are the findings of a study from the University of California.
Whole orchard recycling is when old orchard trees are ground, chipped and turned back into the soil before new almond trees are planted.
A new study conducted by the University of California 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 in a statement. “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 water conservation and for growers.”
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.
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 orchard recycling can sequester five tons of carbon per hectare, increase water-use efficiency by 20 per cent and boost crop yields by 19 per cent.
“This seems to be a practice that can mitigate climate change 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 water becomes more limited.”
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