FERTILISER GUIDELINES FOR THE WINE INDUSTRY

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FIGURE 1: Leaf sampling.

SAMPLING PROTOCOL: The way in which vines are sampled for analysis has a major effect on the re sults obtained. As shown in Figure 1, leaves opposite the bunch, or if removed, the leaf on a bearing shoot between nodes 3 and 5 are sampled. Thirty leaf blades or petioles, immediately separated at sampling, are sufficient. Either one can be analysed although, as already discussed, petiole analyses are generally regarded as more accurate. Sampling time should be at fruit set or veraison. The phenological stage (e.g. set or veraison) of sampling must be indicated. Leaves should not be sampled during the hottest part of the day since it can influence leaf composition. It is preferable to collect samples in the morning. Samples are placed in a clean plastic or paper bag and should be kept cool until delivered to the laboratory. The samples must not be frozen under any circumstances.

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