Establishing vineyards: Decide on planting widths, system of irrigation and trellising in consultation with your viticultural advisor and order the necessary material. See Wynboer Tegnies, No 21, July 1987 for schematic illustrations of various trellising systems, material required and the performance of the different systems.
Soil preparation: If the soil is to be trenched after winter, a cover crop must be sown in autumn. The cover crop removes water so that an optimum soil water content for soil preparation is reached earlier. If the contractor cannot turn up in time the cover crop must be sprayed with a herbicide to conserve soil water. If the cover crop is cut with a shrub beater it should not block implements.
Pest control: Inspect all vineyards and clearly mark vines infested with mealybug for effective control in winter.
2. VINEYARD PROGRAMME
Post harvest programme: Complete the post harvest programme according to the hints for March.
Nematode control: Can be implemented during March/April or after bud burst in August/September. Pesticides are taken up by the roots during the periods of active root growth. It is important to control all weeds before the treatment and to apply a thorough irrigation afterwards.
Weed control: Spray quick grass with gliphosphate. Take care not to apply the herbicide directly onto vines as there are indications that this herbicide is translocated from the vines to the roots during autumn with harmful results.
Pest control: The control of snails should be commenced immediately after the first autumn rains, as snails lay eggs during the rainy months.
Fertilising: Nitrogen. Post harvest fertilising is carried out according to the growth and crop of individual vineyard blocks. (Where the soil differs within a block the fertilising applications should be adapted). When vines grow luxuriantly the total nitrogen fertilising requirement can be applied after harvesting or be left completely. In all cases apply the mineral which is lacking as fertiliser mixtures are not justified in many cases.
Phosphate and Potash. Can be applied based on soil analyses.
Lime must be applied before winter where soil with a pH lower than 5,5 is prevalent. In established vineyards applications must occur according to analyses and it is advisable to spread the applications over a few seasons if the deficiency is pronounced. The type of lime used will depend on soil composition and the quantity of lime per seaon on the clay content of the soil. Maintenance liming is very important to keep the soil pH at the required level. In the winter rainfall areas where limited irrigation water is available, gypsum must be applied to the surface of alkaline soil.
Soil cultivation for cover crop: After the application of fertilisers the soil is cultivated shallowly before sowing. The seed can be harrowed in. (See video “Soil tillage in vineyards”, obtainable from Nietvoorbij, Stellenbosch).
Sowing of cover crop: Cover crops prevent the leaching of nutrients and stimulate microbial life in the soil. Suitable crops are rye, barley, oats, wimmera, triticale “korog” or Saia oats. Saia oats and rye are well adapted to sandy and acid soil while barley is more suited to heavier soil and to a certain extent even alkaline soil. Oats can be used under a wider range of conditions, but produces less fibre than rye. A mixture of oats and rye produces a high yield of green material. Triticale has a wide soil adaptability and a good yield of green material.
Where a deficiency occurs, single phosphatic fertilisers can be applied and worked lightly into the soil when the cover crop is sown. Band placing at about 300-450 mm depth is recommended where a serious deficiency occurs. When feeding conditions are optimum, cover crops can be sown with an ordinary grain fertiliser mixture or only LAN. To get the maximum results from the cover crop it should be sown as soon after harvest as practically possible.
The following may be used as a guide to decide whether a cover crop should be sown or not:
- sloping soil where erosion may occur
- sandy soil where a soil cover is advantageous during summer
- compacted subsoil where a cover crop is sown after ripping.
The relative advantage of a cover crop must be determined in terms of the above factors and its economic implications.
Taking out old vineyards: Old vineyards which are no longer financially viable can be taken out after harvesting. Try to grub up as many of the old vine roots as possible to prevent the survival of harmful nematodes.
Young vineyards: Anchors and poles should be planted at this time.
Soil conservation: Make provision for the oncoming winter rains by cleaning, and if necessary, repairing water diversions and other furrows.
Virgin soil: Soil which has already been deep ploughed in preparation for planting can be fumigated. Especially sandy soils or soils where nematodes occur will benefit from fumigation. Due to the high cost of fumigation the prerequisite for fumigation should be adhered to.
Loose, wet soil compacts easily. Deeply ploughed soil can therefore easily compact because of tractor movement over the soil. Tractor movement over newly prepared soil should be kept to a minimum or concentrated in certain zones.
3. VITICULTURE CONSULTANTS IN THE VARIOUS KWV DISTRICTS
For viticulture enquiries consult your nearest KWV Viticulture Consultant.
Paarl/Wellington/Tulbagh: Bennie Liebenberg (021) 8873018 , 083 455 5197
Malmesbury: Johan Pienaar (021) 8870014 , 083 309 7637 , Nelius van Huyssteen 083 455 5198 or Bennie Liebenberg (021) 8073018 , 083 455 5197 .
Robertson/Klein Karoo: Francois Viljoen 083 309 7626 , Briaan Stipp (02351 3017) 083 455 5196 , Leon Dippenaar 083 455 5194 or Stephan Joubert (02351) 3017.
Bonnievale: Hendrik Myburgh (02351) 3017 or 083 455 5195 .
Orange River: Dirk Malan (054) 4612299 , 082 495 7999 or Dricusvan der Westhuizen ( 083 309 7625 ).
Stellenbosch: Johan Pienaar, 083 309 7637 or Cobus van Graan (021- 8870014) (021) 8870014.
Worcester:Schalk du Toit 083 303 0530 , Pierre Snyman (0231 72795) 083 455 5191, Anton Roos 083 629 1735 or Hanno van Schalkwyk 083 455 5192 (0231) 72795.
Olifants River:Dricus van der Westhuizen ( 083 309 7625 ) or Nelius van Huyssteen ( 083 455 5198 ).
4. OENOLOGY CONSULTANT
1.Planning and design of new cellars (50 to 5 000 tons). A total package in this regard is now supplied by the service from cultivar recommendations, costings, cellar design incorporating the latest cellar technology through to the design and management of waste systems.
2.Upgrading of existing cellars to enable them to become internationally competitive.
3.Latest production methods regarding different cultivars and wine styles.
4.Recommendations regarding problem wines, adjustments and blends.
Eugene van Zyl can be contacted at 082 577 2758 .
5. WINE GRAPE PLANTING MATERIAL
Enquiries regarding planting material can be obtained from KWV’s Plant Improvement Division:
- Clone information – Charles Visser (021) 8073036
- Planting material purchase/availability – Andre le Roux (021) 8073019 .
- Grafting and Nursery activities – Dirk Visser (021) 8073206 .