282 TALKS ON MANURES. 



ammonia alone. This result may be ascribed to the fact previously 

 alluded to the ashes dissipated some of the ammonia. 

 "Plot 11, with 100 Ibs. of plaster, 400 Ibs. ashes, 300 Ibs. of super- 

 phosphate of lime, and 200 Ibs. Peruvian guano (which contains 

 about as much ammonia as 150 Ibs. sulphate of ammonia), pro- 

 duced precisely the same number of total bushels per acre, as plot 

 4, with 150 Ibs. sulphate of ammonia alone, and but 4 bushels more 

 per acre, than plot 13, with 200 Ibs. Peruvian guano alone. It is 

 evident, from these results, that neither ashes nor phosphates had 

 much effect on Indian corn, on this impoverished soil. Plot 14 re- 

 ceived the largest dressing of ammonia (500 Ibs. Peruvian guano), 

 and produced much the largest crop ; though the increase is not so 

 great in proportion to the guano, as where smaller quantities were 

 used. 



" The manure which produced the most profitable result, was 

 the 100 Ibs. of plaster, on plot 2. The 200 Ibs. of Peruvian guano, 

 on plot 13, and which cost about $6, gave an increase of 14 bushels 

 of shelled corn, and 6 bushels of 'nubbins.' This will pay at the 

 present price of corn in Rochester, although the profit is not very 

 great. The superphosphate of lime, although a very superior 

 article, and estimated at cost price, in no case paid for itself. The 

 same is true of the ashes. 



"But the object of the experiment was not so much to ascertain 

 what manures will pay, but to ascertain, if possible, what constitu- 

 ents of manures are required, in greatest quantity, for the maxi- 

 mum growth of corn. * * Hitherto, no experiments have been 

 made in this country, on Indian corn, that afforded any certain in- 

 formation on this point. Indeed, we believe no satisfactory experi- 

 ments have been made on Indian corn, in any country, that throw 

 any definite light on this interesting and important question. A 

 few years ago, Mr. Lawes made similar experiments to those given 

 above, on his farm, at Rothamsted, England ; but owing to the 

 coolness of the English climate, the crop did not arrive at maturity. 



" Numerous experiments have been made in this country, with 

 guano and superphosphate of lime ; but the superphosphates used 

 were commercial articles, containing more or less ammonia, and if 

 they arc of any benefit to those crops to which they are applied, it 

 is a matter of uncertainty whether the beneficial effect of the appli- 

 cation is due to the soluble phosphate of lime, or to the ammonia. 

 On the other hand, guano contains both ammonia and phosphate ; 

 and we are equally at a loss to determine, whether the effect is at- 

 tributable to the ammonia or phosphate, or both. In order, there- 

 fore, to determine satisfactorily, which of the several ingredients 



