PRACTICAL REMARKS 95 



expect that the manure recommended above would yield an 

 increase of 14-15 cwts. of hay in the first or main crop, it 

 would also make an addition of about 2 cwts. of hay to the after- 

 math. Both at Rothamsted, and on the farms in Dumbarton- 

 shire, sulphate of ammonia has given a distinctly heavier 

 after math than nitrate of soda. 



In the case of the rye grass and clover grown in a rota- 

 tion, the use of ammoniacal manure can be still more con- 

 fidently recommended. A mixture of 3 cwts. of kainite, 2 

 cwts. of superphosphate, and i cwt. of sulphate of ammonia, 

 employed as a spring dressing, should give excellent results. 

 The experiments made in Dumbartonshire would lead us to 

 expect a return of at least 14 cwts. of hay from such manuring, 

 but the crops obtained in a single season can not be taken as 

 safely indicating what may be generally expected. 



POTATOES 



i. Experiments at Rothamsted. The field experi- 

 ments with potatoes commenced in 1876, and have been con- 

 tinued down to the present time. The land had previously 

 been cropped for nineteen years with wheat, experimentally 

 manured. The manures applied to the potato plots were 

 generally similar in character to those previously employed 

 when the land was under wheat, the potato experiments thus 

 started with the soil of each plot in a special condition as to 

 the accumulation or exhaustion of particular elements of plant 

 food. The only exception we have to note is plot 3, which 

 had previously been unmanured, but afterwards received farm- 

 yard manure and superphosphate for the potatoes. 



The cinereal manures applied to the potatoes were super- 

 phosphate 3^ cwts, and alkali salts containing 300 Ibs. sulphate 

 of potash, 100 Ibs. sulphate of soda, and 100 Ibs. sulphate of 

 magnesia per acre. The ammonia salts consisted of 400 Ibs. 

 of equal parts sulphate and chloride. 



The whole of the manures are applied to the land in March 

 or April, after the land has been ploughed and harrowed. 

 After broadcasting the manures, the land is again harrowed, 



