278 THE EFFECT OF MANURES. 



localities, and not to be generally applicable to meadow land 

 which is mown for hay. The hay crop is a great exhauster of 

 the mineral constituents of the soil ; and these owing to the high 

 price of the salts of potash, cannot, with profit, be fully restored 

 in artificial manures. The return of the mineral constituents is 

 better accomplished by means of farmyard manure, night soil, 

 and the like. 



" The grasses proper appear to be tlie most strikingly inde- 

 pendent of any artificial supply of carbon. The hay crop is 

 more exhaustive of potash than wheat or barley. 



"A predominance of mineral elements in the fertilizers in- 

 creased the proportion of the culms of grasses, while a predom- 

 inance of ammoniacal salts increased the proportion of leaves. 



" Those manures which much increased the produce of hay, 

 at the same time very much increased its proportion of gramina- 

 ceous plants. 



" The total miscellaneous herbage (chiefly weeds) were the 

 most numerous in kind and nearly in the greatest proportion on 

 the unmanured land, viz: 16 per cent., while on the manured 

 plat they decreased to 2 per cent." 



'*An artificial manure containing a sufficiency of mineral and 

 nitrogenous constituents affected some of the grasses as follows: 



LoUum 2>e'>'enne proportionally considerably increased. 



Holcus lanatus proportionally largely increased. 



Arrlicnailicrimi avcnaccum proportionally largely diminished. 



Anthoxanthum odoratum proportionally largely diminished. 



Agrostis vulgaris proportionally very much diminished. 



Briza media proportionally very much diminished. 



Cijnosurus cristatus proportionally very much diminished. 



Dactylis glomcrata proportionally very much increased. 



Poa jJratensis proportionally very much diminished. 



Bronius mollis proportionally reduced. 



Avena pratensis proportionally increased. 



