Soil Sample Collection Method

Soil Sample Collection Method
by Hans Walter-Peterson

Timing. Soil samples may be taken at any time during the year, however avoid extremely wet soil conditions unless absolutely necessary. I suggest that sampling occur at the same time each year in each area where samples are collected. Unless you're working to correct a particular problem, soil sampling should only be necessary in any given field every 3-5 years.

Where to sample. In general, composite soil samples should represent no more than approximately 10-15 acres, assuming uniform conditions in that area. Separate samples should be taken where:

• Soil texture changes (clay, silt, gravel)
• Substantial changes in slope, or where a restrictive layer is present
• Irrigated vs. non-irrigated blocks

Surface and subsurface samples. Ideally, two samples should be sent to the laboratory: (a) a surface soil sample from the 0- to 8-inch depth, and (b) a subsoil sample from the 8- to 24-inch depth. The subsurface soil sample is useful as vine roots function and obtain nutrients from this level in the soil profile also. If tests indicate that the soil is relatively uniform at both depths, a surface soil sample alone should be adequate.

Proper sampling tools. There are two important requirements. First, that a uniform slice be taken to the desired depth, and second, the same depth and volume of soil be taken from each spot sampled. A soil probe or augur is the best tool for taking samples, but a regular garden spade or shovel will work well also. The technique for using a spade is to dig a hole to the sampling depth, cut a 1/2 inch thick slice of soil from the face of the hole, and trim both vertical sides of the slice so as to obtain a strip of soil about 1 inch wide from top to bottom. Do not use galvanized tools or containers because of probable zinc contamination.

Obtain a representative sample. Each soil sample should be a composite consisting of the soil from cores taken randomly at several places across the vineyard. The purpose of this sampling procedure is to minimize the effects of any local non-uniformity in the soil. Cores or slices of soil, from about 10-20 locations over the area, should be taken for each soil sample. The soil cores should be mixed well in a paper or plastic bag or plastic bucket. Metal containers, i.e. galvanized metal will contaminate the sample. Small, unusual areas should be avoided when the intent is to estimate the fertility level of the field. Areas that should be avoided include near windbreaks, trees, fence lines, old manure and lime pits, wet spots, areas near lime rock roads, or boundaries between slopes and bottomland. To troubleshoot a small area with poor crop growth, a separate sample of the unusual area should be taken.

Sample preparation.
DO NOT SEND WET SAMPLES TO THE LABORATORY.
They may leak in the mail, provide inappropriate results, and delay analysis. If it is necessary to sample wet soil, spread the sample in a thin layer on an aluminum pie pan or on a clean sheet of wrapping paper or waxed paper, and allow to dry out at room temperature. Do not use heat to hasten drying. A fan blowing across the sample usually speeds drying. In a wet sample, rapid biological transformations of the amounts and forms of soil nutrients (particularly forms of inorganic nitrogen) can occur. Drying is an effective means of preserving the field chemical characteristics of the soil sample. Place about two-thirds to one pint of the composite sample in the plastic bag and close, then enclose in the cloth bag supplied with the kit. The plastic bag should contain sufficient soil to fill the cloth bag to the line. Tie the cloth bag securely with the drawstring. Include only one sample in each bag.

Fill out the information sheet. Complete the blue information sheet for each sample being submitted for analysis. Please be as accurate and complete as possible on this sheet. The recommendations may not be accurate if the information sheet is not filled out properly. Seal the completed information sheet into the envelope. Do not detach the envelope from the bag.

Return samples to the LERGP office in Fredonia (412 E. Main St.) and we will mail them to Cornell. If you prefer, you can submit them yourself to the Nutrient Analysis Laboratory using the envelope attached to the sample bag.

For questions concerning the status of your sample, contact the Cornell Nutrient Analysis Laboratories at (607) 255-4540. Please indicate:
CLIENT'S NAME, COUNTY, DATE SAMPLE SENT TO LABORATORY, FIELD NAME and SAMPLE BAG NUMBER.

The results from your soil test(s) will be sent to the LERGP office for interpretation and recommendations. Results and recommendations will be sent to you together.