Worm Activity

Monitoring Worm Activity in the soil 

We dig sample holes, between the vine and the wheel track in the rows, and look at all macro-organisms in the soil including worms, grubs, millipedes, centipedes etc. These holes are 30cm x 30cm wide by 15cm deep.
 
Two years ago our best results were for one of our Shiraz blocks, which had 47 worms per hole (up from 13 worms the previous year). When this is multiplied out per hectare the worms had increased from 1.4 million per hectare to 5.2 million per hectare (for this block). Just in the last 12 months our count is higher again as we have recorded worm averages from 2 million per hectare to 8.5 million worms per hectare across the vineyard. Very pleasing numbers indeed.

We use information about the production of worm castings that have been obtained from Charles Darwin's 1881 book on Earthworms called "The formation of vegetable mould through the action of worms with observations of their habits" In this book he states that worms are generally active for approximately 6 months of the year and they produce between 0 and 5 grams of castings per day.
 
So by multiplying 8.5 million worms with an average of 2.5 grams of worm cast per day for 6 months means we are producing over 3,500 tonnes of worm casts per year. Of course, the other great benefit of worm action is to aerate the soil, allowing water and air to flow freely through the soil for other organisms.
 
Whilst doing the quarterly soil macro hole counts in February 2011, our vineyard staff counted 134 worms in one hole in a particular block of Shiraz (which would equate to 14.9 million worms per hectare).

To put this all into perspective, from research into earthworms, any result over 2 million worms is considered very good for general farming.

These last 12 months have been characterised by milder conditions with generally warmer evenings, cooler days and double the rainfall from previous drier years. This has meant our soils are wetter, softer and therefore more biologically active.