EFFECT OF CHANGING THE MANURES 169 



of grasses, the nitrogenous manures were discontinued, and in 

 their place a complete mineral manure containing potash was 

 applied. The diagram Fig. 29 shows the effect of this change 

 of treatment on the composition of the herbage ; the columns 

 show the average proportion of grasses, leguminous plants, and 



Before. After. 



Before. After. 



Before. After. 



Plot 6. 

 Change to Minerals 



from 

 Ammonium-salts. 



1862 75. ^ 



I 



Grasses , per cent. 



Plot 15. 

 Change to Minerals 



from 

 Nitrate of Soda. 



Le|uminosae, 

 percent. 



Plot 8. 

 Omission of Potash. 



'.V.'.J Weeds, per cent.. 



FIG. 29. Progressive effect of Changes in the Manuring on the Composition of the 

 Hay Crop. Five-year periods. 



weeds before the change, and for successive five-year periods 

 afterwards. 



On Plot 6 ammonium-salts alone was applied up to 1868, 

 at which time the grasses constituted 63 per cent, of the 

 herbage, and the weeds 37 per cent. the leguminous plants 



