56 



THE MANURING OF GRASS LAND 



[CH. 



The Lancashire experiments also gave similar results. But 

 when the amounts of kainit and of superphosphate were increased 

 there were no such increases in the yield of hay. It makes very 

 little difference to the yield whether sulphate of ammonia or 

 nitrate of soda is used, but such advantage as there is lies in favour 

 of the nitrate of soda. 



Poor hay land. 



In some cases, however, the herbage is so poor that there 

 would be no object in trying to get large crops, and an 

 improvement must first be effected. This can usually be done 

 on boulder clays by a dressing of basic slag. 10 cwts should be 



Unmanured 5 cwts basic slag 10 cwts basic slag 



per acre per acre 



Fig. 10. Effect of slag on grass land laid in for hay at Saxmundham (from the 

 1903 Report by T. H. Middleton). The lower part represents the yield with- 

 out manure, the central portion the amount required to pay for the cost 

 of the manure, and the top portion the profit. 



given in autumn, and nothing else for two or three years: 

 meanwhile careful watch should be kept on the clovers. If 

 after this period the herbage shows improvement, 1 cwt of nitrate 

 of soda may be applied annually for two or three years, to be 

 followed by a dressing of basic slag as before. Fig. 10 shows the 

 effect produced at Saxmundham. 



Where slag alone does not improve the herbage the case is 

 often difficult. No general rules can be given; each case must 

 be decided by itself. 



