A NEW SOIL SAMPLER AND ELUTRIATOR FOR COLLECTING AND EXTRACTING WEED SEEDS FROM SOIL

A soil sampler, elutriator, and associated sample flushing device were designed and constructed for an intensive study of weed seedbanks. Th is equipment was used in 1993 to collect and process 4980 soil samples . The sampler was durable, core size was consistent, and sampling was efficient, Cores were approximately 200 cm(3) and two people could tak e 120 cores/h. The elutriator separated weed seeds from 36 of these co res at a time. Washing required 60 to 75 min depending on soil texture . Seeds as small as 0.3 mm in diam were recovered and almost 100% of t he seeds were recovered from samples spiked with barnyardgrass, redroo t pigweed, velvetleaf, and witchgrass. The flushing device was used to transfer sample contents from strainers of the elutriator to propylte x bags for drying and storing. Equipment like this, plus improved tech nology for identifying and counting seeds, is needed to make weed seed bank studies more feasible.