Sampling of crops

Guidelines for the methods of sample collection of crop samples are detailed in the Codex Alimentarius, but generally in most instances crop samples should be representative of the crop being grown. As a general rule, the quantity of sample required is a minimum of 12 units or 1 kg of field sample, e.g., potato mbers, cabbages, etc. Samples selected should not be damaged or suffer from severe defects, disease symptoms, or other abnormalities. 

The best way to collect accurate information on the fate of test items, and hence their residues, would be to analyze the total yield of a plot. This is, of course, not feasible. Therefore, the only manageable solution is to collect representative samples from within the treated and untreated plots. 

When choosing sampling locations and methods, take into account the factors which influence the crop, e.g., the plant morphology, differences in plant growth, the way the plot was treated, etc., all of which have an influence on the distribution of residues both on individual plants and in the trial plot as a whole. The actual material required to produce a field sample can be selected, as a rule, by one of the following methods  

Samples are collected with a free choice of the sampling places within the respective plot. Care must be taken to avoid the plot boundaries and margins. 

Samples are collected along a defined paffern such as an X or an S or in fhe case of narrow plofs sfarfing from fhe edge of the plot and working across the plot  

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Rogge WF, Medeiros PM, Simoneit BRT, Organic tracers in soil samples of crop fields from the Fugitive Dust Characterization Study, Atmospheric Environment, 2007. 

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