BEST TIME FOR APPLYING AMMONIA 123 



by Dr. Somerville, the details will be found in his Reports. 

 The Norfolk experiments were conducted by the Norfolk 

 Chamber of Agriculture, and are described in their Reports. 



The turnips (usually the Scotch Yellow turnip) or swedes, 

 were in all cases grown in their ordinary place in the rotation. 

 The quantity of sulphate of ammonia applied per acre only 

 reached 2 cwts. in the case of a single farm ; in a few cases it 

 was i cwts., 120 Ibs., and i cwt.; in the majority of cases the 

 amount applied was about 90 Ibs. per acre. 



It will be noticed that the number of experiments in which 

 potash salts were added to the phosphates was much smaller 

 than the number in which phosphates were used alone ; the 

 mean results obtained with and without potash do not therefore 

 admit of an exact comparison. The general order of the results 

 is nevertheless exactly what we should expect. One cwt. of 

 sulphate of ammonia gives an average return of 58 cwts. of 

 roots when both phosphates and potash are supplied. The 

 return falls to 47^ cwts. when potash is omitted. It falls 

 still further when a liberal dressing of dung (frequently 20 tons 

 per acre) is employed ; the return amounting to 38 cwts. when 

 phosphates and potash are used with the dung, and to 29 cwts. 

 when potash is omitted. The advantage of employing potash 

 salts when full crops of turnips are to be grown, especially 

 when dung is not used, is thus plainly indicated. Neverthe- 

 less in some of the Scotch experiments the use of potash salts 

 with farmyard manure resulted in the production of a smaller 

 crop, and "potash depression" is frequently spoken of in the 

 Edinburgh Reports. One would like to inquire how the potash 

 salt was applied in these cases. Both potash salts and super- 

 phosphate tend to retard the decomposition of farmyard man- 

 ure, and are frequently used in Germany to check the fermen- 

 tation in a dung heap ; it is obvious therefore that they 

 should not be spread on the dung, but mixed with the soil 

 before the dung is brought on to the land. 



Best Time for Application. The experiments organ- 

 ised by Dr. Aitken furnish also information as to the best time 

 for applying sulphate of ammonia to the crop. In 1891 an ex- 

 periment was made on 26 farms, in which all the plots received 



