WINETECH Technical Yearbook 2019

SAMPLING PROCEDURE: HOW AND WHERE TO TAKE THE SOIL SAMPLES • For stock sampling: New recommended programmes or adjustments The samples should be taken up to a maximum depth of 90 cm (Photo 2) or at the point where a root restricting layer occurs that cannot be lifted during soil preparation. Sample the different soil layers separately, for example 0-30 cm, 30-60 cm and 60-90 cm (Photo 3). • For maintenance fertilisation: New r e c omme n d e d p r o g r amme s o r adjustments Soil samples can be taken at a depth of 0-30 cm (Photos 14 and 15). • For problem spots: New recommended programmes or adjustments The samples can be taken at a depth of 0-30 cm. In such instances it is also recommended to sample at 30-60 cm depths. GENERAL GUIDELINES • Take the sample within the active root zone (Photo 7). • The sample should be taken within the fertilisation zone (Photo 8). This is especially important where grapevines receive drip irrigation. Do not take samples directly below a dripper in the wet zone.

PHOTO 3. Example of the samples taken at the various layers.

hot. In difficult conditions sampling is neglected, making the analyses useless. The ideal time is March/April after the harvest – the results will be available in April/May and may be used to draw up new fertilisation programmes or adjust existing programmes for the spring season. Post-harvest fertilisation can be adjusted according to the previous season’s vigour. • Samp l es o f nematodes i n young vineyards: Because most nematodes

hatch in the presence of root excretions, it may take up to eight months before the nematode populations are significant enough to be observed. • Samples of nematodes in established v ineyards : Sampl es may be taken throughout the year. Populations are highest during the summer months and decrease when the soil temperature drops. Soils that are either too wet or too dry should preferably not be sampled.

PHOTO 2. Example of the different layers to be sampled before soil preparation.