134 TRACE ELEMENTS IN ANIMALS 



Table XVII. Uptake of molybdenum by pasture 

 grasses and clovers. (Data from Lewis) 



Species 



Holcus lanatus (Yorkshire fog) 

 Agrostis alba (fiorin) 

 Phleum pratense (timothy) 

 Festuca pratensis (meadow fescue) 

 Dactylis glomerata (cocksfoot) 

 Poa trivialis (rough-stalked 



meadow grass) 

 P. pratensis (smooth -stalked 8 6 6 8 



meadow grass) 

 Cynosurus cristatus (crested dogs- 10 8 5 9 



tail) 

 Lolium perenne (indigenous peren- 11 11 11 11 



nial ryegrass) 

 L. italicum (Italian ryegrass) 

 Trifolium repens (wild white clover) 

 T. pratense (wild red clover) 



These results show very clearly that the clovers and Holcus 

 lanatus contain a much higher proportion of molybdenum than 

 the other pasture plants examined. Teart pastures generally 

 contain very little Holcus, but often a good deal of clover. 

 Lewis is of the opinion that it cannot be assumed that the clovers 

 are the only cause of teartness because analyses made of a 

 number of grasses other than Holcus growing on teart land show 

 that these can contain a much higher proportion of molybdenum 

 than was found in the plants grown in pots (cf. Table XVIII). 



Table XVIII. Molybdenum content in p. p.m. of dry matter 

 of pasture plants growing on teart land. (Data from Lewis) 



Soil type 



, *■ 



Ham- I 

 Species 



Dactylis glomerata (cocksfoot) 



Poa pratensis (smooth-stalked meadow grass) 



Lolium perenne (perennial ryegrass) 



Cynosurus cristatus (crested dogstail) 



Bromus mollis (soft brome) 



Agrostis spp. (bent) 



Phleum pratense (timothy) 



Festuca spp. (fescues) 



Arrhenatherum avenaceum (tall oat grass) 



Trifolium spp. (clovers) 



