As you may know, the almond is made up of three parts; the hull, the shell, and the kernel. Californian almond growers use all three parts of the almond as a part of their ongoing commitment to sustainability. In addition to the kernel we eat, hulls are sold as livestock feed, which reduces the amount of water used to grow other feed crops, and shells are used for livestock bedding. The use of these additional products, along with the actual almond tree (biomass) at the end of its lifespan is key to reducing the industry’s environmental impact. In fact, the almond industry in California is currently offsetting about 50% of its carbon emissions.1
With the industry anticipating an increase in orchard removals over the next several years based on historic planting rates and the natural life cycle of the trees, the Almond Board of California (ABC) is stepping up research on several fronts into alternative uses for almond tree removal biomass. In addition to investing in research, ABC is working closely with the Almond Alliance of California (AAC), formerly the Almond Hullers and Processors Association, to provide relevant data to assist AAC in its efforts as part of a broad coalition seeking state legislative and regulatory solutions to the state’s management of wood materials.
Last year, Almond Board launched Accelerated Innovation Management, a major new strategic effort designed to make the almond industry even more efficient and sustainable, and an area of focus is exploring alternative uses of almond byproducts
One alternative for dealing with tree biomass upon orchard removal is the process of grinding up entire almond trees and incorporating the tree biomass into the soil. This leads to the question of how this additional organic matter affects the soil, and more importantly, how it might impact the health of a subsequent almond orchard planted in these soils.
An orchard recycling trial project conducted over six years at UC Kearney Ag Center has shown some promising results, according to Dr. Gabriele Ludwig, the Almond Board’s Director of Sustainability and Environmental Affairs. “The results look promising in that the young trees could handle it and after three years we saw benefits to the soil.” San Joaquin County UC Cooperative Extension farm advisor Dr. Brent Holtz has led this research.
The Board is now funding additional trials with Holtz to see if the results can be replicated in different types of soils, to learn how best to grind up the trees and incorporate the material, and to ensure that the practice doesn’t spread diseases.
Bioenergy and Value-added Alternatives
Almond Board-funded research is delving into the area of bioenergy, also known as bio-economy, to maximize potential value of almond biomass as bioenergy feedstock. This approach utilizes newer, more efficient thermal, biochemical or biological conversion and/or extraction technologies to produce biogas, liquid fuels, biochar, bioethanol, liquid fertilizers, value-added materials and chemicals from almond biomass. Biogas and biofuels are clean energy feedstock and biochar can be used as a soil amendment. The modified materials can be used as additives to improve properties of plastic containers such as garbage cans, flower pots and rubber tires. The chemicals may also be used to make fiberic materials and food/pharmaceutical additives.
Air Quality Implications
While the bio-economy processes look promising as another sustainable method for maximizing almond biomass, a lot of questions need to be answered before they can be widely adopted. “We don’t know whether they can meet certain parameters of the ‘new source review’ requirements under the Clean Air Act in California,” noted Ludwig. “With all of these possible approaches we need to figure out how to make them usable under a wide range of circumstances and sort out any possible regulatory issues,” Ludwig said, "and this will take time."
The Almond Board of California is committed to ensuring the almond community becomes even more efficient and sustainable. Stay tuned to this blog for progress along our sustainability journey.
1Kendall, A., Marvinney, E., Brodt, S. and Zhu, W. (2015), Life Cycle–based Assessment of Energy Use and Greenhouse Gas Emissions in Almond Production, Part I: Analytical Framework and Baseline Results. Journal of Industrial Ecology, 19: 1008–1018. doi: 10.1111/jiec.12332