Green and purple grapes next to glasses of red and white wine.

The benefits of biochar have been known to indigenous Brazilian farmers for centuries. However, this age-old technique is just recently being adopted by winegrape growers in California. Discover how growers are using biochar to increase their yields and profits while improving the soil.

What is Biochar?

Biochar is a form of charcoal that is made by burning organic material at temperatures above 500°C. The controlled approach to burning that is used is referred to as “pyrolysis.” While biochar can be made from any material, the most common source of biomass for burning is wood from agricultural and forestry waste.

What Are the Benefits of Biochar?

When produced correctly, biochar remains stable in the soil for 1000 years or more. When mixed with the soil, it makes the soil more porous and helps to hold the nutrients in place. Two soil types that benefit from biochar are sandy loam and clay. In sandy solid, the biochar increases the soil’s ability to hold water and keeps the nutrients closer to the plants. In heavy clay soils, biochar improves water filtration and makes the moisture more available to plants.

Biochar’s Benefits for Soil Life

Soil that’s “alive” is healthy soil, and that’s what is ultimately best for your vines. When mixed with the existing earth, biochar provides a habitat for arthropods, fungi, and soil microbes, improving the diversity and abundance of soil life. The porous surface of the charcoal retains water, nutrients, and air, encouraging the proliferation of beneficial organisms. It can also soak up heavy metals like cadmium and lead.

Biochar’s Benefits for Grapes

We’ve explored the benefits of biochar for the soil. However, biochar appears to improve the quality and yield of grapes, as well. Between 2019 and 2021, the Oasis Vineyard in the Salinas Valley conducted a trial with support from the California Department of Water Resources and researcher Doug Beck. In this trial, different rows of the plot had the following treatments applied:

  1. Biochar (10 tons per acre)
  2. Compost (15 tons per acre)
  3. Compost plus biochar (15 tons per acre compost and 10 tons per acre biochar)
  4. Control (no treatments applied)

As water efficiency was the primary topic of interest to the sponsor, all of the rows were watered via drip irrigation with no differences in the amount of water applied. The soil treatments were replicated four times to ensure a clear, unambiguous result.

The Results

In the first year of the experiment (2019), the rows with an application of biochar had the highest number of grape clusters. In 2020, the compost-biochar rows showed the highest number of clusters. These are the results on the fourth leaf in 2020:

  • The biochar treatment produced 1 additional ton per acre
  • The compost treatment had an increased yield of 1.8 tons per acre
  • The compost-plus-biochar treatment led to the highest increase at 2 additional tons per acre

Wanting to be certain that the benefits of biochar didn’t compromise the quality of the grapes, the group analyzed 300 samples from across the 16 sub-blocks. What they found is that the grapes that grew in the biochar rows were of equal quality — or even superior — to the grapes that were grown conventionally. In addition, the time to harvest was exactly the same for each row of grapes.

Are Biochar’s Benefits Economically Viable?

Three stacks of coins with small seedlings on top.

The benefits of biochar are clear, but it has to make economic sense for growers to apply this treatment on a larger scale. 

Cost

According to the primary researcher, biochar costs $200 per ton, which comes out to $2,000 per acre. The cost of compost in the study was undisclosed, but typically costs around $50 per ton, for a total of $750 per acre. The total for the compost-plus-biochar treatment at the rates of application in the study would cost around $2,750 per acre.

Revenue

In 2019, at the third leaf stage, the biochar-treated acres produced 1.3 additional tons per acre. With a grape price of $2,000 per ton, that represents a $2,600 increase in revenue over and above the revenue that was expected for the control and a $600 profit per acre overall — in the first year. In the second year, the biochar-treated plots again produced an additional ton per acre, for an additional $2,000 of revenue — with no additional biochar.

If we consider the compost-plus-biochar combination, we are talking about 2 tons x $2,000 additional grapes per acre for $4,000 additional revenue with an upfront cost of $2,750. You can begin to see how lucrative the benefits of biochar are, considering that a single application could generate years of additional revenue!

Which Source of Biochar is Best?

If you would like to incorporate biochar in your vineyard, researcher Doug Beck recommends finding a source of biochar that is local to your area. Perfect sources of biochar and biomass for making your own include:

  • Agricultural waste, including pulled vines that have been thoroughly dried
  • Biomass harvested from local forests in preparation for wildfire season

Once you obtain the material, the key is to burn the pile from top to bottom and put the fire out immediately once the material turns into charcoal. Letting the pile turn completely to ash removes all of the potential benefits of biochar.

Maximize Biochar’s Benefits with Fruit Growers Supply

At Fruit Growers Supply, sustainability is a top priority. We manage several timberlands under the Sustainable Forestry Initiative and offer wooden pallets from responsible sources. We also design solar-powered irrigation systems to help growers water their crops without waste.

If you’d like to make your operation more sustainable, get in touch with our experienced team. We can help you source local biochar, compost, and amendments to improve your soil and increase your yields. 

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