12 Experiments with different Top-dressings upon Wheat. 



wheat-crop. Indeed, I did not expect any increase from the 

 application of this marl, and used it in this experiment chiefly to 

 ascertain the extent of variation in the produce of two separate 

 -acre plots. The result plainly shows that the experimental field 

 was very uniform in its character and productiveness. We may 

 also learn from this result that the efficacy of a manure is greatly 

 affected by the chemical composition of the soil to which it 

 is applied. However beneficial chalk-marl may be in other 

 localities, it cannot possibly do any good on land which contains 

 already an abundance of the same elements which are supplied 

 in the marl. 



2. The application of only If cwt. of nitrate of soda raised 

 the produce in corn to 38 bushels, and that of straw to 1 ton 

 4 cwt. 8 Ibs. We have thus here an increase of 11 bushels of 

 corn, and 6J cwt. of straw, at an expense. of 17. 12s. Qd. 



3. By mixing nitrate of soda with common salt, the produce 

 in corn was raised to 40 bushels, and that of straw to 1 ton 

 4 cwt. 1 qr. 20 Ibs. It appears thus that the admixture of 

 salt to nitrate of soda was beneficial in this experiment. The 

 quantity of salt used amounted to only 1 \ cwt. : notwithstanding, 

 it had a decidedly beneficial effect upon the produce. As salt 

 is cheap, it may be worth while to try in future experiments 

 whether a larger dose of salt mixed with nitrate of soda will be 

 of advantage. 



4. Peruvian guano produced very nearly the same quantity of 

 corn as the mixture of nitrate of soda and salt, but somewhat less 

 straw. 



5. The smaller dose of wheat-manure gave almost \ a bushel 

 less increase in corn, and rather more straw, than guano. The 

 difference in the yield of these two plots, however, is trifling. 



6. The larger dose of Proctor's wheat-manure (6 cwt. per acre), 

 it will be seen, gave an increase of 1 7 bushels of corn, and 9 cwt. 

 1 qr. 12 Ibs. of straw, over the yield of the unmanured plot. 

 4 cwt. of the same wheat-manure gave an increase of 12J bushels 

 of corn, 6 cwt. 12 Ibs. of straw. One-half more of wheat- 

 manure, or 6 cwt., very nearly gave one-half more increase in corn 

 and straw. The chief points of interest which attach to these 

 experiments are : 



1. That nitrate of soda applied by itself materially increased 

 the yield of both straw and corn. 



2. That the admixture of salt to nitrate of soda was found to 

 be beneficial. 



3. That guano produced as good a result as nitrate of soda. 



4. That the increase in corn and straw corresponded with the 

 quantity of the wheat-manure which was used. 



5. That ammonia and nitrogenized organic matters which 



