Almond farmers will remember a UCCE demonstration last February when the 50,000-pound Iron Wolf rolled like a tank through an almond orchard in Chowchilla, ripping whole trees into shreds and incorporating the wood into the soil.
Researchers are now considering a less dramatic approach to removing an old orchard and incorporating the wood chips into the soil onsite. Combining a traditional horizontal chipper with a wood chip spreader modified for this purpose can be a viable alternative to the now-mostly banned burning of old orchards or transport of almond tree residue to co-generation facilities that convert biomass to energy.
“It's still cheaper for the farmer if he or she can sell the wood chips for co-generation,” said Brent Holtz, UC Cooperative Extension advisor in San Joaquin County and the research leader. “But co-generation plants are closing and our research is showing that incorporating the biomass into the soil has many benefits.”
When the wood breaks down, it returns nutrients to the soil. Organic matter increases, resulting in carbon sequestration, important for moderating the release of greenhouse gases into the atmosphere that may contribute to climate change.
The chipper and spreader combination pencils out at about $1,000 per acre, while the Iron Wolf costs about $1,500 per acre.
“The Iron Wolf turned out much more expensive and slower than we anticipated,” Holtz said. “It could only grind up and incorporate about two acres of trees per day, while the horizontal chipper can chip 15 acres per day. With the chipper and spreader combination, the chips do have to be disked in, which most growers can easily do.”
The whole orchard recycling project was funded by the Accelerated Innovation Management program of the Almond Board of California.
Whole Orchard Recycling Demonstration
11630 S. Airport Way (near Roth Road), Manteca, Calif.
Thursday, Oct. 13, 2016
10 a.m.
Whole almond orchard recycling and the effect on second generation tree growth, organic matter and soil fertility presentation
Brent Holtz, Ph.D., UC Cooperative Extension advisor
10:30 a.m.
Kuhn & Knight Wood Chip Spreading Demonstration
Randy Fondse, G & F Ag Services, Ripon, Calif.
11 a.m.
Morbark Horizontal Chipper Demonstration
Randy Fondse, G & F Ag Services, Ripon, Calif.