RAPID SEED EXTRACTION FROM SOILS BY A FLOTATION METHOD

In this study a flotation method is described which enables the rapid extraction of seeds from soil. Essentially, soil is mixed with 11.0 M K2CO3 and thoroughly dispersed by mechanical stirring for 3-6 min. The dispersed soil samples were delivered to plastic tubes, then centrifuged at more than 4000 g for about 5 min. Buried seeds and lighter organic materials floated in the supernatant and could be removed by filtration, washed and subsequently identified. This method performed reliably using soil samples artificially loaded with white clover and a range of cultivated grass species. In addition, a wide range of weed seeds which differed in size and density were also effectively recovered from a range of soil types from loam to gravel.