MANURES FOIl SPECIAL CROPS. 283 



of plants is required in greatest proportion, for the maximum 

 growth of any particular crop, we must apply thes2 ingredients sep- 

 arately, or in such definite compounds, as will enable us to deter- 

 mine to what particular element or compounds the beneficial effect 

 is to be ascribed. It was for this reason, that sulphate of ammo- 

 nia, and a purely mineral superphosphate of lime, were used in 

 the above experiments. No one would think of using sulphate of 

 ammonia at its price, [sulphate of ammonia is now cheaper, while 

 Peruvian guano is more costly and less rich in ammonia], as an 

 ordinary manure, for the reason, that the same quantity of ammo- 

 nia can be obtained in other substances, such as barnyard-manure, 

 Peruvian guano, etc., at a much cheaper rate. But these manures 

 contain all the elements of plants, and we can not know whether 

 the effect produced by them is due to the ammonia, phosphates, or 

 any other ingredients. For the purpose of experiment, therefore, 

 we must use a manure that furnishes ammonia without any ad- 

 mixture of phosphates, potash, soda, lime, magnesia, etc., even 

 though it cost much more than we could obtain the same amount 

 of ammonia in other manures. I make these remarks in order to 

 correct a very common opinion, that if experiments do not pay, 

 they are useless. The ultimate object, indeed, is to ascertain the 

 most profitable method of manuring ; but the means of obtaining 

 this information, can not in all cases be profitable. 



" Similar experiments to those made on Indian corn, were macle 

 on soil of a similar character, on about an acre of Chinese sugar- 

 cane. I do not propose to give the results in detail, at this time, 

 and allude to them merely to mention one very important fact, the 

 superphosphate of lime had a very marked effect. This manure was 

 applied in the hill on one plot (the twentieth of an acre,) at the 

 rate of 400 Ibs. per acre, and the plants on this plot came up first, 

 and outgrew all the others from the start, and ultimately attained 

 the height of about ten feet ; while on the plot receiving no ma- 

 n ire, the plants were not five feet high. This is a result entirely 

 different from what I should have expected. It has been supposed, 

 from the fact that superphosphate of lime had no effect on wheat, 

 that it would probably have little effect on corn, or on the sugar- 

 cane, or other ceralia ; and that, as ammonia is so beneficial for 

 wheat, it would probably be beneficial for corn and sugar-cane. 

 The above experiments indicate that such is the case, in regard to 

 Indian corn, so far as the production of grain is concerned, though, 

 as we have stated, it is not true in reference to the early growth of 

 the plants. The superphosphate of lime on Indian corn, stimulated 

 the growth of the plants, in a very decided manner at first, so 



