SUGGESTED COLLECTION AND PREPARATION TECHNIQUES:
One of the most important aspects of analytical work is the proper collection and preparation of representative samples. Below are some guidelines on sampling techniques for soils and water. However, these guidelines are very general and information concerning your specific project should be obtained prior to sampling for submission to the WETICO analytical lab.

SOILS:
Soil sampling is a particularly difficult task when attempting to get a representative sample. Normally a 500-gram sample is submitted to the laboratory for analysis. If the area covered by the sample is not uniform, the chemical analysis may not accurately reflect the nutrient/toxic status of specific sites. Factors that need to be considered when sampling soil include the depth and time of sampling.
When sampling soils, the area should be subdivided into as homogeneous sections as possible. Between 10 and 20 subsamples should be composited from each area. Sub-samples should be small enough that the composite sample will be of a size that can be completely processed for analysis.
Once samples have been collected, they must be processed promptly to prevent any changes that might affect the analysis. Soils should be air dried and crushed in a soil pulverizer to pass through a 2-mm sieve. Freezing the samples will prevent changes in the nitrate levels.

WATER:
Samples must be representative. Samples should be collected in clean, plastic bottles that have been rinsed three times prior to use. Well-water samples should be collected after pumping for at least 30 minutes. Sampling from distribution systems should be done after the lines have been flushed sufficiently to ensure that the sample is representative of the supply. If NO 3-N is an element of interest and the analysis cannot be completed within three hours of collection, the samples should be frozen or kept below 40°F. Samples collected for alkalinity, conductivity, phosphate and sulfate should also be refrigerated until analysis can be completed. Due to the problems of absorption or precipitation, if micronutrients are of interest, the sample, or a subsample, should be acidified to pH <2 as soon as possible after collection.