Organic advisor’s report

By Bart Arnst, Viticultural Consultant


Bart Arnst walks growers through the vines at the first Organic Focus Vineyard field day at Mission Estate


This was the first visit to Mission Estate as part of the focus vineyard comparison between an “in organic conversion” vineyard and a “conventional or agrichemically run vineyard.”

We initially had an in-office discussion. This entailed checking over a potential spray program, discussing nutrient requirements, weed control, and the possibility of taking comparative soil tests including MRT (multi residue tests).

After our initial discussions we followed with a vineyard walk, looking at the various blocks and getting an understanding of the property.

Between 3.00pm and 5.00pm Caine hosted an interested parties vineyard walk and discussion; approximately 30 growers attended.

Weed control options, pest and disease control strategies and soil health were all discussed.

The biggest issue I see at this stage is the enlivenment of the soil. It appears very tight, compact and tired. Imagine your root system attempting to penetrate through concrete: difficult of course, and likely to be restricting nutrient uptake, moisture penetration and reduced soil aeration, which in turn affects root metabolism. The property is after all one of the oldest (if not the oldest) vineyard sites in New Zealand, so in all likelihood has had all sorts thrown at it and on it over the previous decades.

Soil drenches and appropriate covercrop options were discussed and considered. Unfortunately we have missed the window on spring sowing and with the typically hot dry weather ahead we will wait to post-harvest for an autumn sowing.

The weeder used is unknown to me (developed locally) and has left a ready lawn turned over appearance. The owner/operator (local contractor) of the machine has indicated that the turf will be broken apart with the next pass.

Soils such as these can easily create pans, so varying depth of cultivation will be necessary. But most importantly feeding the soil and encouragement of soil microbial diversity should be the priority.

Caine is comfortable with the choices available for canopy spraying and will operate a conservative spray program this vintage. By this I mean it will be based around looking to substitute organically certified products for those previously applied. If previously product X was applied, then we will replace it with organic product Y. This is likely to evolve over time as all parties become more comfortable with the change in management systems.

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