To ensure that the sample is representative of the field, use a sampling pattern similar to that recommended for the standard soil test under Soil Sampling in the Soils section. Handling the Sample Cores should be placed in a clean plastic pail, crushed by hand and well mixed. Microbial action in the sample can change its nitrate content quite quickly if it is not handled properly. Samples should be chilled or frozen as soon as possible. For shipping, samples should be packed with insulating material to keep them cool and sent by courier to ensure quick delivery to the lab.
Samples can also be air-dryed.
Spread the sample in a thin layer on a clean plastic sheet, breaking up any large lumps in the process. It should be dry in 1 to 2 days, and can be shipped to the labs without any extra precautions. Do not dry the samples in a warm oven, as it can affect the nitrate content. There are situations where the fertilizer recommendations based on the nitrate-nitrogen soil test should be modified. The nitrogen in manure or legumes applied or plowed down just before sampling will not have converted into nitrates and will not be detected by the soil test.