TVNZ 1 recently aired a segment on our use of biochar and vermicast to reduce waste and enhance our soils. It's a great little piece with James Dicey, our Viticulturalist.
Further detail from James can be found below:
"We process well over 200t of marc on our compost pad, adding in other raw materials (such as hay, straw, cow and horse manure), and turn this marc into compost by windrowing and regularly turning the materials post-harvest. The process of composting turns the raw materials into about 120t of organic matter that is decomposed and recycled, ready for distribution back onto the company vineyards.
Recently we have taken the next step by using the compost as a feed source for tiger worms to turn the already valuable compost into vermicast (or worm castings). Vermicast contains water-soluble nutrients and is an excellent, nutrient-rich organic fertilizer and soil conditioner. We have further tapped into other local waste streams such as reject apples and cow manure to add to the compost as a further feed source for the worms. This significantly reduces waste going landfill and adds to the volume of vermicast created by the earthworms.
The next step is to add biochar to the vermicast. Biochar is the creation of charcoal from biological materials – effectively creating a carbon-based “sponge” which is mixed in with the vermicast to hold the water-soluble nutrients in suspension ready for the grape vines to use as they need them. Waste, untreated, wooden pallets which would be sent to landfill are used as the feed source for the creation of the biochar in a pyrolysis oven we have built for this purpose. This will enable us to add considerably to the soil our vines are growing in. The resultant bio-char enhanced vermicast will be added to the Single Vineyard sites initially and then to the rest of our vineyards as material becomes available".