Replanting a grubbed parcel: rootstock, density and training choices
A 1.1 ha parcel at 480 m in the Paphos district is being replanted. The old own-rooted Xynisteri vines were grubbed in autumn after declining yields. The soil is a clay loam with pH 8.1, 25% active lime, and a previous soil sample found root-knot nematode (Meloidogyne spp.) plus a patch of phylloxera-infested roots near the gate. The site is on a 6% south-facing slope. Irrigation water comes from a borehole with EC 1.4 dS/m, and the water allocation is 1,200 m3/ha per year. The grower plans to plant own-rooted Xynisteri at 1.5 x 1.0 m, train the vines as a single Guyot, and start cropping in year 2 to recover the investment. He has budgeted for certified vines but asks whether a rootstock is really needed, since the old vines grew fine for 40 years.
1. Advise on whether grafting is necessary and shortlist rootstocks with justification, comparing the trade-offs for this site.
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Grafting is not optional here. Phylloxera was found on old roots in the parcel and root-knot nematode is present. Own-rooted Vitis vinifera on infested soil will decline; the fact that the old vines survived 40 years shows the infestation arrived late, not that it is absent.
Selection criteria, in order of weight: (1) phylloxera resistance, which all commercial rootstocks provide; (2) root-knot nematode resistance; (3) tolerance of 25% active lime; (4) drought tolerance given only 1,200 m3/ha.
- 140 Ruggeri (140Ru): V. berlandieri x V. rupestris; very good lime tolerance, strong drought tolerance and good nematode resistance. Vigorous, which suits a dry calcareous site if the scion is not already too vigorous.
- 1103 Paulsen: similar parentage; very drought tolerant with good nematode resistance, though lime tolerance is slightly below 140Ru. A safe first choice where water is the main limit.
- 41B: the most lime-tolerant option and useful above 25-30% active lime, but weaker against nematodes and less drought tolerant. Choose it only where chlorosis risk outweighs the water and nematode risk.
- SO4 and 161-49C: good nematode resistance and lower vigour, but lime tolerance is marginal at 25% active lime, so they are not the best fit.
Shortlist: 1103 Paulsen and 140 Ruggeri, with 41B as a fallback for the most chlorotic patch. Buy certified, virus-tested grafted vines and confirm rootstock identity with the nursery.
2. Critique the proposed spacing, training system and year-2 cropping plan in the light of the water allocation and site vigour, and outline better establishment choices.
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Density. 1.5 x 1.0 m is about 6,670 vines/ha. With 1,200 m3/ha, each vine would receive only about 180 L/year, far too little for a mature vine on a dry calcareous site. Even 3,000 vines/ha gives only 400 L/vine. The plan creates a vineyard that cannot be irrigated adequately, raises establishment cost and forces excessive competition. Widen to at least 2.5 x 1.2 m (about 3,300 vines/ha) or 2.5 x 1.5 m (about 2,670 vines/ha), which fits the water allocation and local machinery.
Training. Single Guyot on a vigorous rootstock and soil concentrates growth in one cane and can produce a dense, shaded canopy. A vertically shoot-positioned system with a wider or divided canopy, or a cordon with spurs, gives better light distribution and more balanced yield. On a 6% south-facing slope, orient rows near the contour where possible to limit erosion and improve light interception.
Year-2 cropping. This is a false economy. The vines are building roots and reserves on a site with nematode and lime stress. Remove flowers in year 1, allow 1-2 kg/vine in year 2 and reach full cropping in year 3-4. The income lost is smaller than the cost of a permanently stunted vineyard.
Establishment: deep rip along the rows, remove old roots, add organic matter, correct iron chlorosis with chelate where needed, and install the drip system before planting.