Germination of seed from five broadleaf weeds after burial for up to 28 years in two soils

Abstract

Some herbaceous broadleaf weed species are major weeds of pastures and are difficult to manage with ongoing reinfestation from the persistent soil weed seedbank In this study seeds from five weed species were collected in 2009 from two sites where they had been buried at three depths since 1981 The species were Scotch thistle (Cirsium vulgare) Californian thistle (Cirsium arvense) nodding thistle (Carduus nutans) ragwort (Jacobaea vulgaris) and giant buttercup (Ranunculus acris) Very few of the seeds were viable after being buried for 28 years in a clay soil while in a sandy soil seeds of the three thistle species remained viable when buried at 200 mm depth It is estimated that these seeds may remain viable for up to 66 years