SATI Beyond The Bunch 1st Quarter 2026

DEWALD KIRSTEN | LUCENTLANDS

Ridging can increase the effective rooting depth in shallow soils.

Spatial variability

Prepare the ground Establishing vines in a uniform planting medium lays the foundation for uniformity in the vineyard. The first step is mapping the soil by sampling a 50 x 50-metre grid. Soil samples are discussed in detail in the 2025 Q2 issue of Beyond the Bunch. Soil maps and GPS-enabled variable spreaders allow precision chemical soil preparation. Keep in mind that many chemical corrections (such as addressing acidification and phosphorus levels) can only be made before planting. Once vines are established, deeper soil layers (below 20 cm) are no longer accessible. Soil maps also reveal physical problems such as waterlogging and abrupt textural transitions that repel roots. Impeding layers due to the natural soil structure or compaction likewise block root growth and hinder water infiltration. When properly executed, physical soil preparation provides favourable conditions for deep (at least

60 cm) root development. It includes loosening and mixing soils, breaking up compaction, and incor porating ameliorants. However, injudicious mixing of shallow soils, for example, using a delve plough, can permanently damage the topsoil by bringing subsoil to the surface. Depending on the soil type, ripping too-dry soils could result in coarse clods, and ripping too-wet soils can cause smearing. In waterlogged soils, installing drains can alleviate wetness and salinisation. Shallow soils can be ridged, with the added benefit that ridged soil warms faster in spring, promoting an earlier root flush, which may be helpful in early cultivars. If a block contains radically different soil types, and drainage and ridging are insufficient to bridge the gap, then drier patches could be variably mulched. Larger areas (more than 0.5 hectares) with contrasting soils could also have their own irrigation taps.

BEYOND THE BUNCH • 6 • QUARTER 1 • 2026