WINETECH Technical Yearbook 2019

PHOTOS 12 and 13. Mix the samples taken on either side of the grapevines and place in plastic bag.

Intensive study of the sample will identify problem spots within blocks. Maintenance fertilisation can be sown varyingly by using precision applicators, if nutrient imbalances are the cause of the problem. Producers should consider whether this provides sensible information, however, in view of the fact that soil nutritional differences are not always the reason for weak growth. Sensible processing of data to information per management unit may be tricky. • Smart sampling per management unit is probably more effective. A composite

sample per management unit (block/ i r r i gat i on b l ock ) i s ana l ysed and fertilisation programmes may be based thereupon. Please note that problem areas should still be sampled separately. INTERPRETATION The data obtained using these soil samples must be interpreted by various experts – including soil scientists and viticulturists – so that they may make reliable and accurate recommendations. Soil analyses are an instrument in the hand of the fertilisation consultant. These should combine the vineyard’s nutritional requirements and the

production objectives, based on scientific and economic principles, in a programme that can be managed practically. It is very important to know the physical nature of the soil, in addition to its chemical composition, in order to give optimal advice about fertilisation. Before the producer commits to a specific sampling method, it is necessary to consider the level of management that can possibly be applied on the farm and how the data will be translated into practical management information. For example, if it is not possible to sow variably, grid sampling will not be worthwhile and composite samples at block management level are recommended. A soil

scientist will be able to help recommend the most appropriate sampling method. Make an effort to take the samples correctly and in the right spot; any analysis and recommendation are directly dependent on the quality of the sample received by the laboratory. Fertilisation programmes, lime applications, leaf nutrition, problem solving and nematode treatments are all based on the analysis of the samples submitted. In order to make the best technical recommendations and obtain optimal economic value, the best possible sample should be analysed.