VITALITY OF WEED SEEDS 75 



Cow's Dung. Horse's Dung. 



149 Fat hen (Chenopodium album) 1213 Fat hen 



12 Pigweed n Pigweed 



14 Bindweed (Convolvulus arvensis) 12 Bindweed 



4 Foxtail (Alopecurus pratensis) 28 Foxtail 



2 Timothy (Ph leum pratense) 6 Timothy 



3 Clover, Trifolium sp. 

 5 Mustard, Brassica sp. 



(morning glory). 

 2 Convolvulus sp. 



It thus seems that more weed seeds are destroyed by 

 passing through the digestive system of a cow than of a horse. 

 Experiments in India also show that fat hen seeds are not 

 injured by being fed to bullocks, 1 and in this way animals do 

 a good deal towards spreading weeds over considerable areas. 

 Seeds are also able to survive after being eaten by birds, as 

 shown by various authorities. 2 3 



When, however, weed seeds are buried and stored up in 

 manure heaps many of them succumb, as they are unable to 

 withstand the high temperature generated in a well-made 

 heap. The excessive moisture, together with the acrid nature 

 of the liquid, may also have much to do with the destruction 

 of the weeds, experiments having shown that certain seeds, 

 such as dodder, lose much of their germinating capacity when 

 they are immersed in liquid manure or even pure water for 

 any length of time. 4 Even if they are only slightly buried 

 beneath the surface, the majority of dodder seeds perish in 

 well-made manure in about a month, only a small percentage 

 retaining their vitality. On the other hand, it is not safe to 

 assume that all weed seeds are killed by storing in manure. 

 Experimental results are not available, but it is exceedingly 

 probable that many seeds escape, as many of them are pro- 

 tected by stout outer coats which enable them to resist the 

 adverse conditions. The seeds of fat hen (Chenopodium album) 

 not only survive, but germinate and flourish exceedingly on 

 manure heaps. 



To the farmer and gardener the most important aspect of 



1 Milne, D. (1915), " The Vitality of Seeds Passed by Cattle," Agric. Jour. 

 India, X, pp. 353-369. 



2 Collinge, W. E. (1913), "The Destruction and Dispersal of Weed Seeds by 

 Wild Birds," Jour. Bd. Agric., XX, pp. 15-26. 



3 Kerner, A., and Oliver, F. W. (1895), "Natural History of Plants," pp. 

 863-865. 



4 Morettini, A. (1914), Le Stazioni sperimentali agrarie italiane, XLVII, pp. 

 733-751- 



