Wickham Estate Replanting Programme

Wickham Estate Replanting 2015
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Ormond Nurseries Ltd. Replanting 2015

This year we will be beginning a multiple year replanting project with one of our own commercial blocks planted in 1997.   This project has been instigated as a method of recovering information to pass on to our growers as Marlborough begins to explore the concept of vineyard replanting.  Being a service provider as well as commercial growers, we acknowledge the fact that no two vineyards are identical.  Every grower needs to address his/her own individual constraints before laying the groundwork for their own personal replanting programme.  We can only offer our own personal experience as a vehicle for sharing information. 

Overview to date
  • Wickham Estate is still functioning well, but there is some vine decline which means the block has the potential to lose yield in the future. We do not have a resident Mealy Bug population yet, but there is some evidence of virus within the block.
  • This year, we are only replanting two rows due to vine availability (some of our vines have been on-sold.). We have cut off the canes of the vines we are replacing, and we are waiting to pull them out. Being an unirrigated block, the root system is massive. We are using Simcox to remove our vines with a digger due to the size of the area we are replanting.
  • For our rows to be replanted this year, ONL has missed the boat on the first Confidor application as outlined in the Winegrowers Fact Sheet NZVE 108. Considering that we don’t have a big mealy bug problem, and that the evidence of virus is less than 20%, our viticulturist has suggested that we use Confidor as an autumn application as a precautionary measure.
  • Because in our case the incidence of mealy bug (and we suspect Leaf Roll Virus 3) is so low and the carryover of root and soil Cylindrocarpon pathogens unlikely, we are not leaving the area to be replanted fallow for a year. Mark Allen has suggested that as a precaution for the new vines, we follow the Confidor programme (3 applications) outlined in the fact sheet mentioned above.
  • We are replacing our wooden posts with steel posts and tie back end assemblies, which we feel are structurally the most efficient, use the best technology, and are the most sustainable.

The clear take home message from our replant conversation was:

‘Replanting is an opportune time to replan your soils, improve your drainage, and change your row spacing.’

Row Spacing

The block has been surveyed and we are thinking of changing the row spacing. If we ever have the chance to change our block, replanting is a perfect opportunity. It is important to carefully review this option. Another point to consider is that our block to be replanted is dry farmed. There is no irrigation, which could make a possible block change easier.

  • We currently have 3 meter rows. If we change 3 meter to 2.7 we gain an extra 3.8 km over the entire 10 hectare block. At 4.5 kilos per meter (typical cropping) level, we could gain another 17 tonne over the entire block, or 1.7 tonne per hectare. This could be the uptick as long as winery is prepared to take kilograms per meter and not tonne per hectare.
  • Kilograms per meter versus tonnes per hectare... Obviously, if there are more meters per row, then there is a higher yield per hectare. But what if your wine company has no intention of changing to kilos per meter, and they prefer to stick with a clear cap on their tonnes per hectare? If the latter case exists, than we should probably stay where we are at 3 meters, but if they are prepared to go to kilos per meter than we should change. The return will outweigh the extra work.
  • It is important to note that in the past tractor size dictated row spacing. With new technology this obstacle no longer exists. As a general rule of thumb for row spacing, as long as the row width is not narrower than the canopy height (Ratio of 1 to 1) than there is no detrimental effect (vine to wine).
  • If you do change your row spacing, it is important to consider the effects on your chemical application rates per hectare. All spray rates are traditionally based around 3 meter row spacing. If you go to 2.4 meters, you will need to add another 25% to chemical rates and requirements. Concentration is the same but you will do more meters.
  • If you have an irrigated vineyard that you are replanting at closer row spacings, it might be easier to lay a new submain. Irrigation can be done in stages as well.
Replanting and Soil Conditioning

Vineyard replanting is the perfect chance to replace your irrigation and trellis systems, change your vineyard density, and replace your blocks with high health vines. Before you start, you need to look at what is happening underground, especially if you have soil issues (cylindrocarpons, etc.). A replant will not fix any underlying issues in the soil. If a problem is evident, you need to start from the ground up.

  • Replanting will give you the opportunity to assess and address both your drainage, and any issues with virus and mealy bug.
  • It is also an opportunity to address your soil situation to your best advantage. With a good understanding of what is happening in your subsoils, you can consider deep ripping your vineyard to really condition your entire paddock.
  • It is recommended to get a soil test done so you can accurately see what is happening and plan accordingly. Soil pits a meter deep will also give you an understanding of what is happening in the sub soils e.g. is it stony and free draining or do you have an impervious layer and water logging.
  • Although reworking your block is not as effective with silty sandy soils, it would not hurt just to use a tractor with a ripper and just line rip it. If you have stony rocky soil perhaps it is best to totally rework your site.
  • In regards to removing old root systems, old debris will only need to be pulled out in areas of wet feet because of leftover pathogens. This kind of ground needs to be left fallow and planted with a bio-fumigant like mustard seed.
  • Removal of roots would also apply in vineyards that have high level of mealy bug infestation such as in Hawke’s Bay and Gisborne. In Marlborough the Mealy Bug population is considerably lower, therefore any consideration of leaving the ground fallow and attempting to remove as many roots as possible, would have to be a case by case decision. The same can be said for Confidor drenching pre vine removal and post planting in the spring and the following autumn. If the area you are replanting has a number of mealy bug ‘hot spots’, then Confidor drenching would be a good safeguard.
New Vine Planting

Mark Allen is confident with his recipe for planting new vines in a replant situation:

  1. Premeasure before you plant.
  2. Plant before the 15 October.
  3. 50 grams of Agroblen (slow release fertiliser) per vine slotted in with a spade (25 grams each side, about 200 mm down and 200 mm away from the vine.) Yates slow release tablets are also good, but Agroblen easier to apply. At 35-40 cents a vine, it is worth it.
  4. No fertigation.
  5. Use either a short 1.1 m bamboo secured to the 900 cm cropping wire and a length of string tied to a foliage wire at 1.7 m, or a long 1.8 m bamboo attached to the 1.7 m wire and no string. (The 1.8 m bamboo is more cost effective as it is quicker to install and requires less training). Spend a dollar a vine on training.

We are using HI-STEMTM tall vines with our replant. Mark suggests using tall 1.8 m bamboo canes with the young vines and tying them straight up to the foliage wire at 1.7 m. By growing straight up rather than along the fruiting wire, the tendrils attach to the bamboo. They are also more resilient to high equinox winds that occur around the same time as you are trying to train young vines along a 900 cm cropping wire. Trim young vines when they get to the forehead height 1.7 m wire, or, if growing strongly, roll along the 1.7 m wire. This leaves 800 mm of straight cane (10 – 12 buds) to wrap down in the first winter and 3 – 4 tonnes/ha at 18 months.