WINETECH Technical Yearbook 2020

In 2019, the third year of the Gen-Z cov- er crop project, 12 different treatments (single species or mixtures) were sown at 13 demo sites near Robertson, Worcester, Rawsonville, Paarl, Franschhoek, Stellen- bosch, Constantia and Swartland. A unique set of recommendations were developed for each site and soil type. Six demo sessions were held in September and October at a selection of the demo sites. Producers and viticulturists were invited to view, assess and discuss the performance of the differ - ent treatments and share their experiences and knowledge. The information below is a summary of the collective observations made by the Gen-Z team, Vinpro consul- tants, producers and technicians from Agricol and Barenbrug. MAJOR OUTCOMES/HIGHLIGHTS PER AREA

Performance* (Biomass production, even development of the stand and weed suppression)

Recommended sowing rate kg/ha

Approximate seed cost R/ha

Treatment

Forage rye

45 55

Excellent

695 695 590

Rye

Good

the bitter lupines to a degree. An increase in the sowing rate of the bitter lupines sow- ing rate would overcome this. The forage radish also developed well on this soil and produced good above- and below-ground growth.

Saia oats + bitter lupines

25 + 30

Very good

Forage radish + vetch 600 * Performance is an overall indication of the quantity of biomass produced, the development of the stand in terms of even or patchy growth and the degree to which the cover crop suppressed weeds. 2 + 10 Good/very good

Breedekloof Site: Klipdrift Soil description: Sandy Sowing date: Mid-April 2019

At this demo site, forage rye produced considerable biomass and provided good weed suppression. The standard rye was less impressive in terms of biomass and had begun to dry out in late September, which is perhaps an advantage if water resources are limited and a chemical spray is to be avoided. The black (Saia) oats pro- duced excellent biomass, but suppressed

Forage rye (left) and Saia oats with bitter lupines (right) at Klipdrift, Rawsonville.

WINETECH TECHNICAL YEARBOOK 2020 130