47 



with superphosphate only in addition to the nitrogenous 

 manures, the reverse was the case. It must also be noticed 

 that in each year nitrate of soda with superphosphate pro- 

 duced a rather better effect than the same manures with 

 muriate of potash in addition. On the other hand, the 

 addition of muriate of potash to sulphate of ammonia and 

 superphosphate raised the yield of both straw and grain. 

 Thus, again, we see the different effect of potash manures 

 with nitrate or sulphate of ammonia. 



In each year the most productive plot was that manured 

 with sulphate of ammonia, superphosphate, and muriate of 

 potash, not only of those plots included in Table XXIV., 

 but of others also which were in the scheme of the experi- 

 ments. Whether this manuring would prove most econo- 

 mical, would, of course, depend on the market price of the 

 manures and of produce. In any calculation on this subject, 

 it is well to remember that the quality of grain is likely to 

 be distinctly better when sulphate of ammonia is used than 

 with nitrate of soda. 



In view of the common practice of top-dressing corn crops 

 with nitrogenous manures alone, when any top-dressing is 

 given, it is interesting to note the large increase obtained 

 by the use of mineral manures in addition. On the average 

 of the two years, the gain is equal to about 6 bushels of 

 corn and 2| cwt. of straw r per acre. 



In passing, it may be noticed that these experiments seem 

 to explain an apparent discrepancy between the results 

 obtained at Rothamsted and those of Baessler quoted 

 above. It will be remembered that at Rothamsted, 

 ammonia salts and mineral manures gave a larger yield 

 of straw than nitrate and mineral manures ; while Baessler 

 found the opposite to be the case. In the latter experi- 

 ments, however, phosphates only w r ere given in addition to 

 the nitrogenous manures. Turning to the Scotch experi- 

 ments, we find both these results confirmed ; ammonia salts 

 yielding most straw when phosphates and potash were sup- 

 plied, nitrate when phosphates only were added. 



As a general rule, a dressing of f cwt. to i^ cwt. per acre 

 will give the best results in practice, though more than i cwt. 

 will only be required when the land is in poor condition. 

 Even in the case of ordinary farm land, the addition of 

 minerals to the nitrogenous manure will on the average give 

 a largely increased crop ; about 2 cwt. per acre of super- 

 phosphate, and the same quantity of kainite, being suitable 

 amounts to apply ; or basic slag might be used in place of 

 the superphosphate. 



MANGELS. 



In considering the results of experiments on this and other 

 similar crops, we are met with a difficulty in estimating the 

 economical effect of manures, because the composition, and 



