WINETECH Technical Yearbook 2021

TABLE 1. The 17 cultivars and their respective clones.

trained on a lengthened Perold trellis system (figure 1). During planting a plastic mulch was laid on the vine rows. The vineyard is dryland cultivated. SOIL-SCIENTIFIC ASPECTS The soil is loamy up to 90 cm with heavy clay in the deeper layers. Thorough soil preparation is critical for establishing v ineyards , espec i a l l y for dry l and cultivation. The soil was mixed ripped in two directions to 90 cm in May 2018. After soil preparation the penetrometer

resistance was lower than 2 000 kPa, i.e. the resistance at which root penetration is restricted (figure 2). The method of soil preparation was thus effective. The soil water content was measured every 14 days throughout the year with a neutron moisture probe over 30 cm increments to a depth of 1.5 m on the vine row. Since 2019, the gravimetric soil water content has also been measured more of less monthly in the middle of the work row during the growing season. This is done until the soil is too dry to take samples. As expected, the water

Penetration resistance (kPa x 100)

0

10 20 30 40 50 60

0

Cultivar

Clone

10

Red Arinarnoa

1B 1A

20

Durif

Undisturbed After first rip After cross rip After 32 mm rain

Grenache noir

513 71B 980 45K

30

Malbec

Figure 3

40

Marselan

Pinotage (reference) Shiraz (reference)

50

1C

Depth (cm)

60

Tempranillo

776

Touriga naçional

1A

70

White Assyrtico

12566 2K

80

Chardonnay (reference) Chenin blanc (reference)

277E 220B 1025

350

“Field capacity” (≈ Ψ S ca. -0.2 MPa)

90

Macabeo Marsanne

300

COVID lockdown

GWI (≈ Ψ S ca. -1.6 MPa)

100

574 463

Piquepoul blanc

FIGURE 2. Penetrometer resistance before and after soil preparation.

250

Verdelho

1B

Vermintino

856

200 Soil water content (mm/1.5 m) 2018/19 2019/20 2020/21

cultivated along the Mediterranean Sea and in France. Pinotage, Shiraz, Chardonnay and Chenin blanc were included as reference cultivars. All the cultivars were grafted onto 99 Richter and planted in July 2018. Three replications of each cultivar were planted in a randomised block design. The planting width was 3 m x 1.25 m and the vines were

EXPERIMENTAL BACKGROUND The trial vineyard is located on the western side of Malmesbury (-33.46110; 18.66872). Nine red and eight white cultivars were selected based on recommendation of experts in the wine industry (table 1). The lesser-known cultivars are all commercially

150

Sep

Oct

Nov

Dec

Jan Feb Mar

Apr

May

Jun

Jul

Aug

FIGURE 3. Progression of soil water content on the vine row from September 2018 to March 2021. The values in brackets indicate the expected stem water potential at the specific soil water content as indicated by the broken lines.

WINETECH TECHNICAL YEARBOOK 2021 | 29