Why Grape Growers Are Turning to Biochar for Vine Growth

Biochar in flames

Growers can produce their own biochar by burning pulled vines from their fields.

Centuries of precedent, dating back to human prehistory, support the soil benefits of biochar. But it is the last two years that have really sold Doug Beck on the agricultural perks of terra preta, or the “dark earth.”

Beck, a Ph.D. soil scientist with experience across four continents, has spent the last four growing seasons in California monitoring a Salinas Valley-based trial to evaluate the impact of biochar and compost as soil amendments for wine grapes. Several factors are being assessed in an 8-acre block of newly planted ‘Pinot Noir’ vines, including vine growth, water use, yield, and fruit quality.

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With two harvests (2019 and 2020) documented, the Oasis Vineyard trial is showing significant increases in yield with each of three treatments — biochar alone, compost alone, and a combination of them. Of importance, all three treatments have attained this success while receiving the same irrigation regime throughout the trial. This demonstrates improved water-use efficiency where the soil has been amended.

“It had become clear in recent literature that composting the biochar together with the compost substrates gives a mix that’s much like a super-charged compost,” Beck says. With this trial, “I have definitely been converted into a biochar proponent.”

Worldly View

Beck is the Science Advisor for Monterey Pacific Inc. (MPI), a vineyard management firm that operates vineyards throughout the California Central Coast. MPI manages the Oasis Vineyard, formerly San Bernabe Vineyards, for Westchester From Nuveen, a farmland asset management business.

After spending about 15 years working as a soil scientist in various cropping systems in Asia, Africa, and South America, Beck arrived on the California vineyard scene in the late 1990s. The overriding theme of those years abroad, he says, was that successful cropping systems have a critical level of soil organic matter, and building soil organic matter leads to healthier, more productive crops.

Upon reaching Monterey County he was “really surprised,” he says, by the low levels of organic matter in the vineyards where he was working. Soil organic matter levels below 1% were common; levels as low as 0.5% weren’t unusual.

“To bring vineyards into health and productivity, I thought that 1.2% organic matter would be a minimum and 1.5% would ensure the best profitability in the vineyard,” Beck says. “So, my task first was to figure out how to improve organic matter levels in existing vineyards.”

Doug Beck and Milt McGiffen on grape harvest

Monterey Pacific’s Doug Beck (left) and Milt McGiffen of UC Riverside walk the Oasis Vineyard in Salinas Valley.
Photo by Raymond Baltar

Cover crops that were being disked in and replanted annually were modified to no-till permanent cover to build organic matter in the middles. In turn, soil organic matter rapidly increased, soil pH came into balance, calcium availability and cation exchange capacity (CEC) went up, and salts went down.

“That took care of the middles, but how do you get high organic matter near vine roots, where they could possibly impact vine growth?” Beck says.

For starters, compost was applied at 3 tons/acre every other row on a yearly basis, side-dressed along the vine row, and disked in 12 to 14 inches deep. Three tons per acre applied to about one quarter of the vineyard surface area comes out to roughly 12 tons/acre, Beck says. “That’s enough to positively impact vine growth and productivity, especially when added over many seasons.”

The best time to improve vineyard soils with organic matter additions is at planting, Beck adds. A first pass of a GPS-controlled winged ripper shatters the compacted soil to over 3 feet deep and leaves a groove where the compost is applied down the vineyard row. The final ripping pass, to a maximum depth of 3 1/2 to 4 feet, is then made to mix the amendment deeply.

At this point, Beck had yet to begin incorporating biochar, which had grabbed his interest in the early 1990s while he was stationed in South America.

“This dark soil, rich in organic matter, is attributed to the prehistoric civilizations that once thrived in the Amazon,” he says. “It might be that the terra preta soils are in part what sustained their productivity over time, but we have yet to figure out how ancient civilizations made these dark soil mixtures. What we do know is that the soils contained high amounts of char wood, also referred to as biochar.”

Biochar, Naturally

Biochar is a charcoal-like substance that is made by burning organic material from biomass — agricultural and forestry wastes — in a controlled process called pyrolysis. Different feedstocks, including grape vines, produce different biochar with varying properties.

“This is very important,” Beck says. “Biochar produced from wood is going to be different from biochar produced from nut shells or straw or manure. You really can make it from any biomass.”

Biochar is a naturally occurring component of soil organic matter and can induce positive changes in soil carbon. When produced from woody biomass, above 500°C, it is stable for 1,000 years or more in the soil, Beck says. “You have to think long term when using it as an amendment,” he adds. “I mean, loooong term.”

Biochar has a positive effect for water-use efficiency in sandy and heavy clay soils. In clays, it improves water infiltration, percolation, and availability to plants by improving soil structure and increasing hydraulic conductivity. In sand, it provides additional water-holding capacity and prevents leaching of nutrients by reducing water loss from the soil system.

Biochar creates an ideal habitat for soil microbes, fungi, and arthropods. Studies consistently demonstrate enhanced biological activity and diversity in soils using biochar. Air, water, and nutrients are retained in the pores and on surfaces, providing perfect habitat for all kinds of beneficial organisms. In addition, because of their charge, biochar surfaces can absorb heavy metals, such as lead and cadmium.

“So, the big question for us was how do applications of biochar to the soil impact wine grape productivity and quality?” Beck says. “In theory, it should provide considerable benefits, and indications have been positive. But you sure wouldn’t want to put biochar on the ground under your vine, lasting the life of a vineyard, if yields or grape quality were decreased. There are studies in publications that show benefits. That’s what kind of prompted us to go forward.”

Trial Specifics

After the Oasis Vineyard ground was prepped in late 2016, the ‘Pinot Noir’ vines, on 1103P rootstock, were planted 9 feet by 5 feet apart in March 2017, resulting in 968 vines per acre. Vine rows were drip-irrigated, with mechanically box-pruned sprawl on a high-cordon trellis system. Soil, while variable throughout the plot, was primarily Oceano Sand with an organic matter content of 0.7%.

The four treatments, applied at depth down each planting row, were: biochar 10 (10 tons per acre biochar); compost 15 (15 tons per acre compost); compost plus biochar (15 tons per acre compost, 10 tons per acre biochar), and a control. Each was replicated four times.

The biochar-only treatment increased fruit yield on the fourth leaf in 2020, as it had in 2019, by a little over 1 ton per acre, while the compost-only treatment increased yields by 1.8 tons per acre. The compost-plus-biochar treatment increased yields even more, by 2 tons per acre.

“There were no differences in cluster size or cluster weight in either harvest,” Beck says, “but cluster numbers did differ and basically accounted for the yield differences. The biochar treatment had the highest number of clusters in 2019, and the compost-biochar mix had the most clusters in 2020. More clusters looked to be the result of larger, more vigorous vines, especially in the 2020 harvest.”

With regard to water use, the California Department of Water Resources, which funded the trials, was looking for decreased water use in the trial. What actually occur-red was greater water-use efficiency in some of the treatments. “By that, I mean that, for the same amount of applied water, more fruit was produced,” Beck says.

Wanting to be sure there were no negative impacts from biochar on fruit quality, the trial analyzed 300 berry samples from each of the 16 sub-blocks to determine statistical differences. “We confirmed that biochar did not negatively affect grape quality or time to harvest,” Beck says. “There were, in fact, some hints that grape quality may have been improved, and we’re anxious to look at this in the future.”

Biochar Bottom Lines

The total biochar cost was $200 per ton or $2,000 per acre, Beck says. The yield increase in the third leaf, the first year of production, was 1.3 tons per acre. At a grape price of $2,000 per ton, that’s additional revenue of $2,600 per acre.

“That’s a $600 profit above the biochar costs, so you paid for the biochar with year-one yield,” Beck says. “At harvest in 2020, biochar again yielded about a ton more per acre than the control, giving an additional income for the two years of about $2,600 per acre. If you assume only 0.5 tons per acre increase per season from a single biochar application over future years, then the extra income becomes quite attractive.”

The Oasis Vineyard trial used biochar produced from woody forest waste at a commercial plant in the Sierra Foothills. Santa Rosa-based Pacific Biochar provided the product in bulk and delivered it to the compost yard.


BIOCHAR: THE NEXT REVOLUTION IN FARMING?

Doug Beck believes agriculture could benefit from an increased use of biochar.

To accomplish that, he recommends:

  • Utilizing abundant local sources of carbon for pyrolysis, specifically agricultural and woody waste. “If you can bring biochar to the local level, people will begin to use it. In trying to control wildfires, we’re going to be taking out a lot of biomass to create burn-resistant areas. Take that biochar and put it back into the ground rather than just burn it.”
  • Focusing on high-value permanent crops with a long-term payback.
  • Developing biochar standards and testing, something the International Biochar Initiative has begun to address.
  • Developing standardized trials to test the different feedstocks and types of pyrolysis so the benefits can be defined and confirmed.
  • Applying credits of some kind for biochar use. “If farmers are able to get some extra cash for putting biochar in the ground, I think we would see a real revolution in farming.”

According to Beck, there is an opportunity for permanent crops, such as vineyards, to sequester biochar underground and provide high-value carbon credits to offset industrial carbon dioxide emissions. Currently, the certified carbon credit market is voluntary, he says, “but with some certainty the process will become mandatory for many industries, as governments develop ‘cap and trade’ measures for climate change.”

While the carbon offsets will not pay for the entire cost of a biochar application, the revenue-stream credits provided will offer a healthy monetary offset, Beck says, especially as the burgeoning market develops.

Even without the carbon credit revenue stream, biochar is a solid investment in the long-term health of the soil and its biological capacity, Beck says. “This benefit alone is worth the price of application, and we anticipate the application cost will come down as the product is more widely available,” he says. “Furthermore, in the future we anticipate making our own biochar on site from the vines we remove during redevelopment. We are also working on a program to combine carbon credits with our grape contracts to help a winery offset CO2 emissions as Cap and Trade becomes mandatory. We anticipate this would enhance our ability to sell grapes in an over-supply market situation.”

Growers who want to produce biochar with pulled vines from their fields must light piles to burn from the top down so the heated gas goes up without taking the wood all the way to ash, Beck says. “You’ll need a water truck to quench the fire when you get to the charcoal stage. If you let it continue to burn, you end up with ash only, which is of no value in the ground,” he says. “You also might need a big magnet to remove all of the metal mixed with the vine trunks. We usually just rip out everything, including trellis, put it in piles, burn it, and then take away the metal. But in this case, you want what’s underneath the metal, so you have to take the metal away to get at the biochar. It’s a little bit complicated.”

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Avatar for Joseph R Heckman Joseph R Heckman says:

Interesting. Extension is getting questions about biochar.

Avatar for Sig Villa Sig Villa says:

I find it interesting that the most educated people are reverting back to primitive practices. Just goes to show you how backwards our pig headed thinking of manifest destiny really was. We have been and continue to destroy our planet and are just starting to revert back to our native ancestral ways that respect and use our natural resources. Centuries of precedent, dating back to human prehistory can teach us a lot. Too bad the Spanish burned the majority of the aztec and mayan literature.

Avatar for Joseph R Heckman Joseph R Heckman says:

Read book: Nutrition and Physical Degeneration by Weston A Price as another such example primitive knowledge.

Avatar for Greg Shipley Greg Shipley says:

This article does the agricultural and forest industries a huge disservice. Both Dr. Lehmann (Cornell University and founder of the International Biochar Initiative) and Dr. Novak (Lead scientist for the USDA-ARS Federal Labs in Biochar) … are the top two Biochar Experts in the World. Both of these experts define “Biochar” as ONLY produced by a high-heat, in the absence of oxygen process. That is, to say, real Biochar can only be produced using a Pyrolysis Process … anything else is either burned wood or ash.

This is the statement that is wrong: “Biochar, Naturally Biochar is a charcoal-like substance that is made by burning organic material from biomass.” Burning requires oxygen and a flame. The correct terminology is: “deconstruction of biomass into a synthetic natural gas (as one by-product) and a highly structured carbon material that have large voids and dramatically increase the surface space of the carbon.”

It is the excessive surface space within the voids that create the magic in “Biochar”! These voids attract microbes and are hydroscopic in nature. That means, that the Biochar attracts moisture and holds the moisture until the plant roots need it. This mechanism is call a Cation Exchange Capacity. Between these two phenomenal and natural characteristics … resulting from the controlled processing conditions found only with Pyrolysis … make Biochar a valuable agricultural and forest tool to dramatically increase conditions to enhance “healthy soils”!

Healthy Soils create increased yield in crops, maintain soil conditions that are advantageous for fighting draughts, reducing irrigation demand, and sequestering carbon to boot!

Pyrolysis also dramatically decrease air emissions (CO2 emissions represent 50% of decaying biomass materials) and eliminates Particulates from burning biomass waste in the field. These controlled conditions within the Pyrolysis Process greatly decrease air pollution in agricultural and forest areas of the World.

Once you put any fine particles into the soil … you cannot go around with tweezers and take it out. Therefore, any application of char must meet strict International Biochar Initiative Standards. Each batch of “Biochar” should have corresponding test results demonstrating that this product actually is “Biochar”. It should also have a “Chain of Custody” protocol that identifies where the biomass feedstock came from, what the elemental and chemical makeup of the substrate consists of and how it was processed!

Only by dealing with a reputable “Biochar” processor, using real Pyrolysis Equipment, can the agricultural and forest managers be assured of positive results from its use! Never buy Biochar based on price. You apply Biochar according to three things: 1) what is the soil you are applying it to, 2) what is the crop and what specifically does that crop require from the soil, and 3) what is the feedstock used in the Pyrolysis Process.

That combination of problem-solving will result in good, healthy soils that are “designed and engineered” to compliment the farming or forest management for the desired results!

Biochar can also be engineered with additives that can manipulate the pH of the soil, add microbes, add fertilizers or other organic nutrient packs that can be pelletized for accurate measurement of application and reduce floating carbon particles.

Biochar will also act as an adsorption mechanism in later years. Like rocks that work their way up and down the soil, so does Biochar. It can last 100 years or more. So, as the Biochar works its way beyond the root of the plant, those wonderful “VOIDS” now attract pesticides and other chemicals sequestering those materials before they reach the water table. In fact, some CA Water Board experts consider Biochar to be a “water play”!

Avatar for croploss croploss says:

What do the air regulatory agencies think about making biochar, when burning of ag waste is prohibited in CA? What happens when someone sees and reports to the Air Resources Board?. There is a net release of carbon dioxide when making biochar, which tends to get regulator’s panties in a wad. Do growers get a pass if they only half burn ag waste? It would be good to know the answers to these questions before you light that pile.

Avatar for Greg Shipley Greg Shipley says:

You are correct. Air Regulators have a ban on burning ag waste in fields. Any ag operation must get a special permit with good explanations and then, it is only a fraction of the waste in any one burn. Particulate matter is a big problem in ag burns, along with Greenhouse Gas emissions.

In the San Joaquin Valley (SJV), it is a “Crisis” with so much Ag waste generated per year. The issue arises from the State of California discontinuing their tax credits and incentives for incineration plants burning in incinerators to produce power. They can’t compete with the Solar and Wind generated electrical production … that now has their old tax credits and incentives. The Government Giveth and the Government Taketh-away. At least 19 Incineration Plants are now or will shortly be out of business, for lack of Power Purchase Agreements (PPAs). Each one of those facilities was processing between 300-500 Tons/Day of mostly ag waste woodchips – that is almost 2.8 million tons of woodchips that no longer have a home and rotting in the fields – emitting approximately 1.4 million tons of CO2 per year in the SJV.

Pyrolysis Process with the TRU Model 4000 has passed CA-SJV Air Pollution Control Air Emissions, while making Biochar and Activated Carbon and Low-Sulfur Marine Fuels … with 99% of air emissions eliminated. The Biochar is USDA-Certified, designed and engineered, with corresponding test data that meet or exceed International Biochar Initiative Standards.

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