SAMPLING SOILS FOR MEANINGFUL RESULTS
Fall is a good time to take soil samples for analysis of fertility status prior to the next cropping season. Applying fertilizer without the benefit of a good soil test can be like throwing money away. It might mean less profit from lower yields or through increased expenditure. A soil testing program can be divided into four phases:
1. Collecting the soil samples
2. Extracting and determining the available nutrients
3. Interpreting the analytical results
4. Making the fertilizer recommendations
The first phase is the responsibility of the farmer, the next three are under the care and control of the soil testing lab. Each phase is important for meaningful results The objectives of soil testing are to accurately determine the available nutrient status of soils, to clearly indicate any deficiency or excess that may exist, and to form the basis on which fertilizer needs are determine
Collection of a soil samples from a field. The whole soil testing program can never be any more accurate than the accuracy of the soil sample or samples taken to represent the field. In all fields considerable variation exists. In fields especially where fertilizers have been hand applied, large differences are often found in the nutrient levels of samples taken from different parts of the same field. These differences usually are not sampling or testing errors but are actual variations in the fertility patterns. To minimize the effect of these inherent fertility differences, an accepted sampling procedure should be followed:
- Each soil type in a field should be sampled separately. Divide each field into uniform soil and past cropping areas (see figure). Assign a permanent identification number for long-term record keeping.
- To sample an area of one soil type take at least 15-20 small samples or cores at random from each area to give a composite sample.
- Take the samples to plow depth or about 6 to 8 inches (3-4" for grasses) using a soil probe, soil auger or spade to collect the samples.
- Avoid unusual areas such as field depressions, eroded areas, dead furrows, fertilizer bands and gate ways.
- The samples should be collected into a clean container and mixed together well. Use a clean plastic bucket, especially for micronutrient tests.
- From this composite sample take out about a cupful of soil and air dried on a non absorbent surface prior to placing it into suitable container (zip-lock bag) for shipping.
- Label outside of bag with your name, address, field sample identifier, and intended crop.
- Send to UMass Soil Testing Lab, West Experiment Station, UMass, Amherst, MA 01003 Packaged samples may be posted directly to the UMass Lab. Be sure to enclose a check payable to UMass for $8 ($12 for standard soil test with organic matter) for each sample.For further information contact the Soil Test Lab (413-545-2311) or Stephen Herbert (545-2250)