Good Science Makes Good Neighbors

Impacts of cannabis volatiles on vineyards

Hi, I am Dr. Alex Guenther, Chief Research Officer at Pacific Environmental Analytics. In this month’s Better Business Column, we are taking a closer look at the tension facing rural communities trying to reconcile traditional agriculture with newly legalized cannabis cultivation.

Many modern communities have a diverse mix of residents with a range of livelihoods and motivations for where they work and reside. One outcome of this for rural communities is a struggle to develop strategies that allow inhabitants seeking clean country solitude to coexist with their neighbors living off their land in working farms that generate odors, dust, noise, pesticide use, road congestion and other issues. Even among neighboring farmers there are activities that require some compromises. For example, “pesticide drift” from vintners applying chemicals to protect their valuable grape crops can decimate the value of adjacent cannabis fields if the deposited pesticides exceed allowable limits. Conversely, there is concern that natural emissions of cannabis plant volatiles, such as terpenes, could taint grapes in nearby vineyards. While pesticide drift has been relatively well studied, and impacts are unambiguously determined by mandatory pesticide testing, characterizing the impact of cannabis volatiles on grapes is considerably more difficult and substantially less understood and yet there has been almost no research focused on this timely and important topic.

Scientific understanding is the key to resolving disputes in an equitable manner and enabling all members of a community to live together. In the case of potential impacts of cannabis volatiles on vineyards, it is essential to fully understand and quantify each of the core controlling processes including cannabis emission rates for individual strains as well as the transport and dispersion factors, deposition rates and chemical transformations that determine the amounts that can be taken up by grapes. In addition, it is necessary to ascertain the ultimate impact of each cannabis volatile by determining an objective odor/flavor detection threshold in wine along with the perception levels since many volatiles can have a negative (taint), neutral (no impact) or even positive (improvement) effect on the wine aroma profile depending on the amount present.

A comprehensive analysis of the interaction between cannabis cultivation and vineyards requires considering not only site-specific data and analysis of the cannabis operation (e.g., direct quantification of complex emission profiles of individual cannabis strains using leaf and bud enclosure measurement systems and atmospheric modeling to estimate deposition to grapes) but also input from the neighboring vineyard (e.g., measuring miniscule quantities of a wide range of odor molecules (hundreds of compounds including terpenes, thiols, amines, and oxygenated compounds) using headspace analysis of grapes and wine). Together these analyses deliver a complete picture of the collision of these two agricultural industries and provide critical data and insights needed to objectively detect problems and identify solutions. The ultimate outcome of collaboration is a fair and effective approach for alleviating community concerns and moving forward with mutual benefit.

As you can see, there are a variety of factors that must be considered and evaluated in order to ascertain the impact, if any, of cannabis cultivation operations on nearby vineyards. In order to have full and complete answers to the most difficult questions, further research is necessary and that will clearly require collaboration between cannabis cultivators and vintners. Only once both sides have put down their swords and put their heads together can science step in to help both be good neighbors.

April 2020
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