CH. xi] Ejects of Manures 185 



is almost constantly borne out by a comparison of the turf of 

 inferior pastures with that from better class pastures in a given 

 district. 



While this reduction of species is chiefly due to the disappear- 

 ance of weeds belonging to a number of widely separated Natural 

 Orders, it is also found that the number of grasses frequently 

 becomes reduced. Crested Dog's-tail, Golden Oat-grass, Sweet 

 Vernal-grass, and perhaps to a less extent Hard Fescue and 

 Fiorin are often materially reduced as regards number of indivi- 

 duals, or even die out altogether when land is highly manured. 

 This is not because manures are of no benefit to these plants, 

 for if grown separately they respond readily to them. It is usually 

 because more vigorous species present respond to such an extent 

 that the above named plants are largely elbowed out of existence. 

 It is however necessary to speak more precisely as to the effects 

 of the various kinds of fertilisers. 



The general effect of Nitrogenous manures upon grasses is to 

 favour luxuriant and continuous growth. If applied in excess the 

 vegetative organs are especially developed and the ordinary pro- 

 cesses of maturation are delayed until late in the season. The 

 very dark green colour of the foliage is characteristic of plants 

 receiving excess of nitrogen in proportion to other plant food 

 materials. Leguminous plants are much less favoured than 

 grasses and thus tend to die out. 



The use of Sulphate of Ammonia or of Ammonium Chloride 

 alone usually tends to reduce the number of species composing 

 a turf very considerably, and this reduction appears to be shared 

 by plants belonging to all the Natural Orders commonly repre- 

 sented. Usually two or three kinds of grasses are greatly stimu- 

 lated and caused to predominate. The following grasses appear 

 to be specially favoured by salts of ammonia: Cock's-foot, Timothy, 

 Meadow Foxtail, Tall Oat-grass, Sweet Vernal-grass, Sheep's 

 Fescue and its varieties, Fiorin and Yorkshire Fog. 



Nitrogen in the form of nitrate (Nitrate of Soda, etc.) generally 

 favours a larger number of species than salts of ammonia, and the 

 herbage therefore remains more mixed in character, even when 

 the nitrate is continuously applied. This appears to be at least 

 partly due to its being more readily available to plants whether 



