The hish Naturalist. 



April, 



ON THE VITAUTY OF SEEDS BURIED IN THE 



SOIL. 



(SECOND ArTICI^K.) 



BY J. ADAMS, M.A. 



(Read before the Dublin Naturalists' Field Club, 28th February, 1905.) 



In the Irish Naturalist for November, 1904, I gave a list of 

 plants, mostly annuals, which appeared after turning up the 

 soil of fields which had been lying for many years previously 

 under pasture. I have long thought that it should be possible, 

 by making a careful analysis of the soil, to obtain the seeds 

 which are actually buried therein. So during last Christmas 

 holidays an attempt was made on the field previously referred 

 to, which has been tinder pasture for twenty years. 



The turfy sod was removed at intervals over the field to a 

 depth of about 3 inches ; then the underlying soil to the depth 

 of 3 or 4 inches more was collected. About as much soil 

 altogether was collected as would fill a gardener's barrow, and 

 the total area from which the soil was removed was about a 

 square yard. As the soil was taken from different places over 

 the field its contents would therefore be an average sample of 

 the whole. 



This soil was then carefully washed and passed through 

 sieves of various mesh, and the seeds found therein were 

 collected and examined. These reached the number of 829, 

 and this number is very considerably under the correct figure, 

 as the washing turned outfa very tedious operation, and a con- 

 siderable number of the seeds were lost in the process. As 

 these 829 seeds were obtained from about a square yard of 

 soil (and probably more seeds wotild have been obtained on 

 digging deeper) there would therefore be present in this field 

 at least 4,012,360 weed seeds per acre. 



The seeds belonged to the following 22 species : — Wheat or 

 other cereal, Perennial Ryegrass, Sweet Vernal, Birch, 

 Polyg07iu77i Co7ivolvulus, P. aviaila?% Rumex crispus or R, 

 obtusijolius, Chenopodium alb^mi, A triplex patula, E2iphorbia 

 Helioscopia^ Rajiunculus acris, Charlock, White Clover, Rasp- 

 berry or Blackberry, Fool's Parsley, Yellow Rattle, a I^abiate 

 (probably Lamiu7n pmpufeum)^ Pla7itago la7iceolatay Galium 



