As you know at Tahbilk we are keen to do our best to keep our environment clean and healthy. This is an ethos we are doing our best to instil across the whole organisation from the vineyards, the winery and the finished product which falls into your hands.
Composting and/or mulching is one of those things we are doing in the vineyards which is a simple and essential way for us to improve our soil health (promoting earthworm activity) and also retaining moisture; making for happy vines.
We do two things here on the Estate. The first is straw under vine and the second is the spreading of grape marc compost throughout the vineyards. The only challenge we have is getting it all out quick enough and producing enough to spread across the place.
We would estimate the application of straw under vine improves soil moisture retention by 25% which is huge. So we roll out our straw program across the vineyard over a rolling three year period.
In 2011 we also embarked on a grape marc composting program which was motivated by our first carbon audit in 2008. At the time of this audit scope 1 emission’s, under the International Wine Carbon Calculator Protocol version 1.2, included carbon dioxide produced from the breakdown of cuttings from the primary fruit cycle. In other words the anaerobic breakdown of vine pruning waste. This is no longer the case vine pruning’s are now excluded from the calculation as part of the short term carbon cycle.
BUT for us at that time the audit told us a staggering 150tCO2 annually was attributable to the anaerobic decomposition of the vine marc, skins and stalks. This information, coupled with Tahbilk’s location in a Phylloxera Infestation Zone, meaning waste cannot be taken outside the area and must be managed onsite, prompted us in 2010 to pursue the making of compost from the winery grape marc (grape skins and stalks) onsite.
In 2011 Tahbilk purchased an Aeromaster PT120 to commence processing the organic waste in to compost. The compost is now spread under the vines each year, clearing the compost pad in preparation for the next harvest.
Whilst the composting currently has no impact on reducing our carbon profile, the result has created valuable compost through a low tech and low input approach which will be utilised on the vineyard to improve soil health. So it has been a pretty special decision.
There is some really interesting research and evidence out there to suggest composting is hugely beneficial for your vineyard site. A great piece of research comes from the CSIRO (Commonwealth Scientific and Industrial Research Organisation), Australia’s peak research body.
In a paper developed by John Buckerfield and Katie Webster it was established that mulch was highly effective in controlling weeds, conserving water and in establishing and maintaining vineyards; overall reducing stress on the vines.
It is an exciting prospect to look at the benefits of composting on the vineyards.
We’re always looking for more ways to enhance our compost and its application to generate high quality yields of fruit to go into Tahbilk Wines. So if you know of someone who is keen to explore new composting methodologies send them our way.