POOD 199 



is periodically ploughed and placed under cultivation. 

 The nature of the herbage in these two cases is not quite 

 the same. 



Another and important division of grass lands is into 

 those which are grazed and never mown, and those which 

 are mown and not grazed ; the first is known as pasture, 

 the second as meadow land. In these two cases also the 

 grasses found are observed to differ considerably, and in 

 addition the soil of the two lands is not the same, for the 

 one has had the benefit of the excreta of the animals 

 grazing on it, and thus a good deal of its nourishment 

 returned, while the other suffers a direct loss in its hay 

 crop, which can only be returned by manuring. 



Meadow lands will vary greatly from year to year, depend- 

 ing upon the nature of the fertilizer which has been applied. 

 There is a constant struggle for existence among plants, 

 some flourish under one and some under another manure, 

 some withstand drought, others droop and die ; these and 

 other conditions determine whether the plant shall survive 

 or not. This has been clearly demonstrated in the classical 

 experiments carried on at Eothamsted, where twenty 

 different plots laid down to grass have been carefully 

 observed for thirty years, and the influence of the above 

 factors considered. 



These observations show a tendency in the reduction of 

 the number of species as the result of the struggle for 

 existence, though the total amount of grass yielded has 

 been actually higher than when the number of specimens 

 was greatest. 



The following were found to be the principal surviving 

 grasses after many years, on the old meadow land at 

 Eothamsted, the hay on which had been regularly cut :— 



Common bent Cocksfoot 



Meadow foxtail Sheep's fescue 



Sweet vernal Yorkshire fog 



Tall oat grass Perennial rye grass 



Yellow oat grass Smooth stalked meadow grass 



Downy oat grass Eough stalked „ ^ 



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