More information on soil testing

by Caroline Brown

A previous post that I wrote on soil testing gets a lot of traffic (for some reason). So, I thought that people might like more detail about how to prepare for a soil test. And as it happens, I’m in the middle of process of collecting soil to send to the UMass Soil & Plant Tissue Testing Lab.

I’m sending 4 soil samples to UMass ($9 to test each sample). The band of soil at the top of the photo is from the sort-of raised bed that we’re probably going to put flowers in; the bottom band is from the small back yard lawn that we established last year (without doing soil testing first, which was bad & dumb, duh).

This soil is drying out, it was a little damp when I collected it. Once I get it sorted and put it in bags, I’ll collect two more samples, one from the front yard and one from the side yard. (I only have one flat box like this to let the samples dry out in).

Here’s the process taken directly from the UMass soil test order form. I didn’t do 12 diggings for each sample, only 2. In class, they said that was OK, esp. with the size of the areas I’m testing (very small). If you’re testing bigger areas you may want to follow their instructions to the tee but for me it’s overkill. Before I bag the samples & send them in, I’m also going to pick out all the rocks/non-soil thingys that are hanging about.

Soil Sampling Procedure

1. Soils that are distinctly different as judged by appearance, crop growth or past treatment should be sampled separately.
2. Each sample submitted for testing should be a composite or mixture of approximately 12 separate scattered samplings taken over a well-defined area.
3. Look your field or property over. Define a sample area based on uniformity of texture, slope, drainage, color, and past pest and fertility management.
4. Avoid sampling very wet soils. In soils where fertilizer has been placed in bands (rows), do not sample directly in a band. It is best not to obtain samples very near the edge of the field or plot.
5. Using a clean spade, auger, or sampling tube obtain soil from the surface through the primary rooting zone of the crop. Rooting depth will vary with crop type. For most plants the top 6-8 inches is appropriate. For established grasses sample the top 3-4 inches.
6. Place each of the 12 randomly spaced samplings in a clean container (pail or bag) and mix thoroughly. Spread the mixture out on a clean paper to air-dry (do not place soil in an oven).
7. Mix the soil again. Obtain a one cup measure of the soil mixture and place it in a zip-lock type bag.
8. Label the outside of the bag clearly with your name, address, and your name for the sample (ID).

Happy soil testing!


One Comment to “More information on soil testing”

  1. This is a great little post on soil testing, and or percolation testing. My brother-in-law is a soil scientist, and you nailed some of the things people should know. Thanks for the post and info.

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