206 



MANURE 



minerals alone, the evidence, though at present sufficiently conclusive, would havo 

 carried \rith it somewhat more of systematic proof. 



' In Table II. we have given a few results selected from those obtained at the harvest 

 of 1 845, the second of the experimental series. By the table it would seem that we have, 

 at the harvest of 1 845, a produce of rather more than 23 bushels without manure of any 

 kind, instead of only 16 as in 1844 ; and in like manner the farmyard manure gives 

 32 bushels in 1845, and only 22 in 1844. 



TABLE II. Harvest 1845. Selected Results. 



' We assume, then, 23 bushels or thereabouts to be the standard produce of the soil 

 and season, without manure, during this second experimental year ; and as part of plot 

 5 (previously manured with superphosphate of lime), and which is now also without 

 manure, gives rather more than 22 J bushels of dressed corn, the correctness of the 

 result of plot 3, the permanently unmanured plot, is thereby fully confirmed. 



' This plot No. 5, previously two thirds of an acre, was, in this second year, divided 

 into two equal portions: one of these ('plot 5a') being, as just said, unmanured, and 

 the other (' plot 5b") having supplied to it in solution, by top-dressings during the 

 spring, the 'medicinal carbonate of ammonia, at the rate of 250 Ibs. per acre ; and it is 

 seen that we have, by this pure but highly volatile ammoniacal salt alone, the produce 

 raised from 22 bushels to very nearly 27 bushels ! 



' In the next section of the Table are given the results of plots 9 and 10, the former 

 of which had in the previous year been manured by superphosphate of lime and a 

 small quantity of sulphate of ammonia, and the latter by superphosphate of lime and 

 silicate of potass. To each of these plots l cwt. of sulphate and 1 cwt. of muriate 

 of ammonia were now supplied. Upon plot 9 the whole of the manure was top-dressed, 

 at once, early in the spring ; but on plot 10 the salts were put on at four successive 

 periods. The produce obtained by these salts of ammonia alone is 33 bushels and three- 

 eighths, when sown all at once, and nearly 32 bushels when sown at four different times 

 quantities which amount to about 10 bushels per acre more than was obtained with- 

 out manure. In the case of No. 9, indeed, the produce exceeds by 1 J bushel that given 

 by farmyard manure, and in that of No. 12 it is all but identical with it. And if we 

 take the weights of total corn, instead of the measure of the dressed corn, to which latter 

 wo chiefly refer, merely as a standard more conventionally understood, No. 10 by 

 ammonia only, has given both more corn and more straw than the farmyard manure, 

 with all its minerals and carbonaceous substance. 



1 Let us see whether this almost specific effect of nitrogen, in restoring, for the 

 reproduction of corn, a corn-exhausted soil, is borne out by the results of succeeding 

 years. 



' We should havo omitted all reference to the results obtained with the wheat manure 

 of Professor Liebig, but that whilst fully admitting the failure of the manure the 

 composition of which, to use his own words when commenting upon it, ' could bo 

 no secret, since every plant showed by its ashes the due proportion of the consti- 

 tuents essential to its growth ' he implied that the failure was due to a yet imperfect 

 knowledge of the mechanical form and chemical qualities required to be given to 

 the necessary constituents in order to fit them for their reception and nutritive 



