skip to content
Sampling Protocol for sampling overwintering legumes and grasses in frozen soil

Sampling Protocol for sampling overwintering legumes and grasses in frozen soil

 

[Follows much of what is in Can. J. Plant Sci. 59:549-550 (1979)].

 

A gas-powered concrete saw is used. One can be rented (saw costs about $900 U.S.). The only saw blade that has held up is a "Carbide-chip" blade, costing about $400 each (U.S.).

 

At a given site, the following will be recorded, if known:

  1. snow depth above ice, snow depth under ice, if applicable.
  2. ice depth
  3. species and varieties present
  4. age of stand
  5. location in field (low spot, high spot, etc.)
  6. soil type
  7. several samples should be collected per field, in different areas of the field, but this may be difficult, as it is probably better to sample more fields. Takes at least a half hour or more to get 1 sample.

 

A rectangle is cut out that fits in metal greenhouse trays (ours are about 1.5 x 2 feet and about 4 inches deep).

 

Two cuts are made about 5-6 inches or more apart as deep as the saw will cut. Width depends on the depth of ice and frost. If thick ice is present, some may need to be cut away to get the saw down into the soil. If the ice is "soft" it can be almost completely chipped away from the soil surface without damage to the plants below. The soil/ice between the 2 cuts can be chipped away with a large pry bar or pickaxe. The sample block is then pryed out with a large crowbar, and transferred to the metal tray. It appears we often need to get below the frost to force out the sample (so far, some areas sampled have no frost, others 10" plus deep). According to researchers at Purdue University, we need to get about 4 inches of an alfalfa taproot to test for plant viability, so we will try to get 4-5 inches of soil depth in all cases.

 

Tray are placed in the greenhouse at standard temperatures and allowed to thaw and greenup. They are watered if necessary (not allowed to dry out). Alfalfa and grass both take about a week to evaluate for live plants (or not). We will sample as many fields across northern New York as we possibly can.

 

We took our first samples approx. Feb. 1 (we have sampled Miner Inst. and several areas in St. Lawrence County, so far). We will likely go back to the same sites and re-sample in 2-3 weeks, and maybe another re-sampling date before winter is over.

 

Jerry H. Cherney

Dept. of SCAS

Cornell University