A Technical Guide
for Wine Producers

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WYNBOER GUIDELINES FOR AUGUST 2000

1 PLANNING

Short term

  • Calibrate fertiliser spreader and spraying pump to ensure that the dosage is correct.
  • Identify problem weeds and draw up weed control programme in conjunction with expert and/or viticultural consultant.
  • Order pest and disease control products for the spring protection programme according to IPW guidelines and check expiry dates.
  • Flush micro and drip irrigation systems thoroughly and chlorinate the lines before the start of the growing season.

Long term

Consult your viticultural consultant and/or expert about the correct choice of irrigation system since this requires thorough advance planning so that factors such as water distribution and water retention of the soil may be taken into account. Computer programmes are available to facilitate scheduling guidelines.

Financial
  • Contact VinPro (SA) agricultural economists for information about:
    • Purchase of additional land or farm evaluation
    • Feasibility studies and breakeven analyses
    • Establishment planning and cost
    • Budgets and cash flow statements
  • Compare the actual expenditure with the budgeted expenditure on a monthly basis and make adjustments where necessary.
  • If you are interested in or are already participating in Production Plan (an economic study group), make sure that your questionnaire is completed and returned for analysis to VinPro (SA) Consultation Service.

2 VINEYARD PROGRAMME

Pest control

  • Good snail control is obtained by baiting in humid conditions just before budding. Where infestations are heavy, bait may also be placed in the forks of vines.
  • Where chemical treatment of nematodes is economically justifiable in bearing vineyards, spring treatments may be applied during the active root growth period following IPW guidelines. Vines infested with mealybug should be sprayed twice before budding, at intervals of 14 days, and at high pressure. Thorough soaking of infested as well as adjacent vines is essential. Also control ants, especially around vines infested with mealybug.

Pruning

  • Vines subject to frost, delayed budding or poor set should preferably be clean and spur pruned at the same time and as close as possible to budding.
  • If climatic conditions were problematic and delayed budding may be expected in sensitive cultivars, basal buds may be treated with a budding stimulant approximately three weeks before normal budding. Budding stimulants may also be used when shaping the young vines to improve budding of eyes. Consult your viticultural consultant about the use of budding stimulants.

Planting of vines
See "Wynboer Guidelines for July". Keep replacement vines in plastic bags on hand, to be used where vines did not take this year.

Training of vines
Trellis systems may be erected now. See the video entitled "Wingerdoplei" by VinPro (SA) Consultation Service.

Preparation of the soil
To prevent drying out of uncultivated soil that will only be trenched in November/December, the soil must be cultivated with a 3 point disc after the winter. This will prevent large clods from forming during preparation.

Cultivation
Cover crops should preferably be sprayed with a systemic herbicide. If an early soil cover is required, flatten by dragging rather than using a bush beater.

Fertilisation

  • Fertilisers are usually applied in an organic (e.g. chicken manure) or anorganic form (e.g. LAN). Organic fertilisers are less subject to nitrogen leaching and are more beneficial on poor sandy/stony soil.
  • Seeing that vines generally have a low fertilisation requirement, the macro elements such as nitrogen (N), phosphorus (P) and potassium (K) are the main replacements. Micro elements such as zinc (Zn), manganese (Mn) and boron (B) are required in very small quantities. About one half to one third of the NPK is returned to the soil by means of leaves and shoots.
  • A fertilisation programme should be drawn up for each block on the farm in conjunction with a fertilisation expert and/or viticultural consultant.
  • N-fertilisation is determined mainly by the vineyard's vigour and soil potential, while P- and K-deficiencies are controlled by soil analyses every 3 - 5 years.
  • N, which is rather subject to leaching, is usually given in three equal applications (post-harvest, four weeks after budding and after set). If growing conditions are very vigorous, N-fertilisation should be reduced and a post-harvest application only may be considered.
  • Since P is relatively static in soil, deficiencies are usually corrected during soil preparation. K, which is subject to leaching, may also be given in installments.
  • Single fertilisers are preferable to combinations, since nutrient requirements differ from block to block.
  • Trace element deficiencies/toxicities occurring especially on poor sandy/stony soils in high rainfall areas, must usually be determined by leaf analyses.
  • Maintenance liming is recommended on low pH soils, while problems with salinity may be adjusted by the application of gypsum, good quality irrigation water and drainage.
  • General:
    Apply fertiliser only if there are deficiencies. Soil/leaf analyses should be done every 3 - 5 years to monitor the fertilisation programme.
    Apply N- and K-fertilisation judiciously, since this influences grape quality.
    The post-harvest period is the most important time for the application of fertilisers.

A more detailed version may be ordered from Gerda Kriel at (021) 807 3027.
Compiled by: VinPro (SA) Consultation Service

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