The results of The Prevention of Pesticide Infiltration Or Translocation (PPINOT) Project.
By: Manuel Garcia-Jaramillo, Alexander Levin, and Kristin Trippe
Summary
Oregon wines are celebrated around the world for their unique qualities, especially Pinot Noirs. In Oregon, many winegrowers are committed to producing grapes with sustainable management practices that preserve our natural resources; however, balancing production needs, maintaining grape quality, and achieving sustainability goals is challenging. Adding biochar to the soil may help vineyard managers and grape growers meet this challenge by increasing soil carbon, moisture retention, and plant productivity. Furthermore, biochar could prevent the accumulation of pesticides in wine. To explore the potential of biochar-based amendments in sustainable grapevine production, Manuel Garcia-Jaramillo and Kristin Trippe from the USDA teamed up with Alec Levin from Oregon State University to establish vineyard trials in the Fall of 2018.
How biochar was produced
Kylie Meyer produces biochar in the Oregon Kiln.
The biochar used in this experiment was produced by gasification and provided by Oregon Biochar Solutions (OBS). Most of the feedstock used to produce the biochar is sourced from logging residues. Excess energy from the production process is used to power a 25 MW energy plant, which produces renewable electricity for Southern Oregon.
We also used an Oregon Kiln (designed by Kelpie Wilson) to produce a small batch of biochar from grapevines. Although we did not produce enough of the biochar to use in our field trial, our laboratory analyses indicated that the physicochemical properties of the two biochars were similar.
Application…..Oregon Field Studies
We chose two sites (Willamette Valley and Rogue Valley) with distinct soil types and climates but planted with the same grapevine scion/rootstock combination that is very common in Oregon (Pinot noir/101-14). Four treatments were applied under existing vines at each location: (T1) no biochar/no tillage; (T2) no biochar + tillage; (T3) 8 tons/acre biochar + tillage; (T4) 16 tons/acre ; biochar + tillage (see photo below).
Representative grapevine plots at the Rogue Valley field expeririment. Treatments: (T1) no biochar/no tillage; (T2) no biochar + tillage; (T3) 8 tons/acre biochar + tillage; (T4) 16 tons/acre biochar + tillage.
In 2019, a suite of soil health, plant, and crop variables were measured, and wines were produced after harvest. While biochar amendments did not affect vine physiology or crop yield, the addition of biochar decreased microbial activity in the soil. Furthermore, biochar amendments did not influence the amount of residual glyphosate (Roundup®) in the wine. The concentration of glyphosate in wine produced from Rogue Valley grapes (3.8 parts per billion; ppb) was four times higher compared to that produced from Willamette Valley grapes (1 ppb). Although any amount of pesticide in wine can worry consumers, the concentration of glyphosate we detected was 13 to 50 times lower than the limits established by the EPA for glyphosate in food (50 ppb). For perspective, the average wine has 11.6% alcohol by volume or 116,000,000 ppb! Results from our first-year field studies suggest that inherent soil properties, and not biochar, may ultimately determine the concentration of glyphosate in wine.
Lessons Learned and Future Efforts
The incorporation of biochar modified the chemical and physical composition of soils at the two studied locations, increasing the bioavailability of carbon and nitrogen, their gravimetric water content capacity and the concentration of plant-available micro- and macro-nutrients.
Pinot Noir grapevines.
However, the addition of biochar had a negative effect on the soil enzymatic activity with reductions of up to 63% in sites amended with the highest application rate. This is in line with many studies that observed decreased microbial activity after biochar amendments.
No responses of plant physiology parameters or productivity at either site were found after biochar incorporation when compared with controls. Conversely, a significant and gradual decrease in the amount of wine tannins was found as a result of biochar application at both application rates in wines produced from grapes from the Woodhall location and decreased the amount of iron-reactive phenolics at the higher rate.
Finally, our results didn’t show a significant reduction of residual amounts of glyphosate in wine produced from the biochar treatments.
Long-term field experiments are required to assess the effects of biochar on soil properties, vine physiology, productivity, and grape and wine quality several years after incorporation.
The fact that the incorporation of this particular biochar did not has a significant effect on the reduction of glyphosate translocation into grapes and wine doesn’t mean that biochar can’t prevent the translocation of other pesticides. As an example, we observed nearly 100% of retention of the herbicide diuron, when it was tested under controlled laboratory conditions. Future research should explore the possibility that biochar decreases the concentration of herbicides in food and beverages.