The Effects of Biochar on Vine Growth and Grape Quality: A Possible Treatment for Increased Water Stress Due to Climate Change?

With global climate change, it is predicted that some parts of the world will experience longer and more severe droughts, as well as more intense weather events.  This is disconcerting for those in agriculture, including viticulture, as it will force the industry to develop and adapt new ways to keep crops fed with water and nutrients in an efficient and sustainable manner.  As plants become weaker due to extreme drought and lack of nutrients, susceptibility to disease as well as potential increased damage due to more severe weather events, new methods and technologies will need to be employed.

One method that has been shown to increase soil water holding capacity, soil water availability, nutrient retention, hydraulic connectivity, and soil aeration is the addition of biochar to the soil.  In other words, studies have shown that adding biochar to soils not only improves the ability of the soil to hold on to water and nutrients, giving the plant access to water and nutrients for a longer period of time, it also allows the plant to more easily utilize the nutrients that are present in the soil.

What is biochar?

Biochar is basically just a fancy name for charcoal.  Biochar is basically created by burning

Photo By K.salo.85 (Own work) [CC-BY-SA-3.0 (], via Wikimedia Commons

Photo By K.salo.85 (Own work) [CC-BY-SA-3.0 (], via Wikimedia Commons

stuff (biomass).  It is currently under investigation for being a possible “carbon sink” and a possible solution to the negative effects of carbon dioxide emissions.  When stable (i.e. no longer burning), biochar has the ability to store excess carbon and other greenhouse gases.  This keeps excess gases in the ground and out of our atmosphere, potentially slowing down the runaway freight train that is the greenhouse gas levels currently present.

Some studies have shown that biochar may also be useful in terms of agricultural productivity.  In tropical and subtropical climates, the addition of biochar has been shown to improve soil fertility, plant growth, and yield.  The effect of biochar on soils in more temperate climates, however, is not well known.

Other studies have shown that when freshly produced biochar is used, there are actually some negative effects including reduced plant growth due to the absorption of nitrogen and dissolved organic carbon from the soil into the biochar while it stabilizes.

To combat the negative effects seen with “fresh” biochar, several studies have shown that adding the biochar to compost or composting the biochar with other organic matter prior to using it for agricultural purposes is beneficial.  Perhaps adding compost or composting with organic matter would add nutrients to the biochar matrix, thus providing greater nutrient availability those plants treated with the concoction.  Some studies suggest that the addition of compost to the biochar might also degrade any potential toxic compounds produced from the burned material.

What about using biochar in vineyards?

Most of the research into agricultural applications of biochar have only focused on yield and other quantitative measures, though as you might know, grape quality is more important than quantity when it comes to viticulture and grape growing.

A recent study compared biochar, biochar with compost, and a no treatment control to Pinot Noir vines in Switzerland (southern face of the Rhone Valley), and found mixed results.

This study examined the effect of biochar and biochar with compost on various plant and fruit quantity and quality parameters (including pH, total phenols, etc) using Pinot Noir vines as the “study subject”.  After three seasons, they found no significant effects either positive or negative.  The first season did show some negative effects of biochar alone on plant development and growth, as somewhat expected based on previous studies that have found negative effects on growth using “fresh” biochar, though these negative effects otherwise “disappeared” after subsequent seasons (3 seasons).

So, what does this mean for using biochar in vineyards?

Well, it was just one study, so really, it doesn’t mean much.  It means that we need to keep looking at it using different grape varieties; different parts of the world; different concentrations, etc.  This is just one

Photo By Bert Kaufmann from Roermond, Netherlands (Drought  Uploaded by russavia) [CC-BY-2.0 (], via Wikimedia Commons

Photo By Bert Kaufmann from Roermond, Netherlands (Drought Uploaded by russavia) [CC-BY-2.0 (], via Wikimedia Commons

of hopefully many studies examining the use of biochar in vineyards to see if it could be a possible “band-aid” to the increased drought problem many places are going to see due to global climate change (if they aren’t seeing the effects already).

In this particular case, the study used 30 year old vines that had recently undergone a switch from conventional viticulture to organic viticulture practices (including the use of cover crops in between rows).  I am not convinced that these were the best vines to use for this experiment, since the switch in farming method in and of itself may have added a level of variation that could potentially dwarf any of the possible effects associated with using biochar and biochar with compost.  I think it’s fantastic that the vineyard made these changes, though I think as a result of these recent changes (within one year of the start of study procedures), it was a very bad decision on the part of the researchers to use it for this experiment.  There’s no way to know for sure if the biochar or biochar with compost had a significant effect on grape quality, since the changes due to switching from conventional to organic viticulture method occurred almost concurrent to the aforementioned experiment.  Too much variation.

It is also possible that no significant effects of the biochar or biochar with compost could be seen due to the relatively short period of time of focus for this study in conjunction with the age of the vines.  These were 30 year old vines that were used, meaning that they likely had a very established and deep root system.  Placing the biochar and biochar plus compost on the surface of the soil and then only looking at them for 3 seasons may not have allowed enough time to see any effects.  In other words, perhaps it takes longer than 3 seasons for the concoctions to travel deep down into the soil in concentrations high enough to have a significant effect on grape quality?  I would be willing to bet that younger vines that are

Photo By Erik Zachte (Own work) [CC-BY-SA-3.0 (], via Wikimedia Commons

Photo By Erik Zachte (Own work) [CC-BY-SA-3.0 (], via Wikimedia Commons

not yet established would be more sensitive to the effects of biochar and biochar plus compost addition, since these plants are in a more active growing stage than older, mature, “set in their ways” vines.

Concluding Thoughts

Well, this recent study showed no significant effects of biochar or biochar with compost on grape quality in Pinot Noir vines, however, I would definitely take these results with a grain of salt.  I think we need to see a lot more work done in this area before we can jump to any conclusions.

How about you all?  Do any of you have any experience using biochar or biochar with compost in the vineyard?  We’d love to hear your stories!  Please share them with us!


Schmidt, H.P., Kammann, C., Niggli, C., Evangelou, M.W.H., Mackie, K.A., and Abiven, S. 2014. Biochar and biochar-compost as soil amendments to vineyard soil: Influences on plant growth, nutrient uptake, plant health and grape quality. Agriculture, Ecosystems and Environment 191: 117-123.


1 comment for “The Effects of Biochar on Vine Growth and Grape Quality: A Possible Treatment for Increased Water Stress Due to Climate Change?

  1. February 3, 2015 at 1:34 pm

    Biochar is actually a very interesting issue. There are italian research experience where both water stress reduction and yealds and quality on grape have been evaluated and results are more significative than in the suisse experience, probably due to the more deficiency soil and climate of center Italy. You can find these paper at this link

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