WINETECH Technical Yearbook 2019

PHOTO 1. Johan de Jager engaged in soil analysis with a view to vineyard establishment.

A

B

• To evaluate biological activity in the soil in order to monitor nematode populations and soil-borne diseases inter alia. These samples should be handled according to specific prescriptions. To obtain the best results, sampling should be done at specific times only. • Note that the concentrations of the plant nutrients as reported in an analysis represent plant accessible values, in other words the nutrients that are available for uptake by the grapevine. The objectives of leaf analyses are: • To aid evaluation of the plant’s nutrient uptake ability.

PHOTO 2. Soil samples taken at various depths.

• To serve as a basis for balanced fertilisation programmes and to monitor fertilisation practices. • To quantify problem situations in order to enable adjustments.

C

D

PHOTO 3. Deficiency symptoms in grapevine leaves (A-D).