205 



on the other hand, being then considered of less importance, was used in a few 

 instances only, and in these in very insignificant quantities. Rape-cake, aa being a, well- 

 recognised manure, and calculated to supply, besides some minerals and nitrogen n 

 certain quantity of carbonaceous substance in which both corn and straw so much 

 abound, was also added to one or two of the plots. 



TABLE I. Harvest 1844. Summary. 



' The indications of the table are seen to be most conclusive, as showing what was the 

 character of the exhaustion which had been induced by the previous heavy cropping, 

 and what therefore, should be the peculiar nature of the supply in a rational system of 

 manuring. If the exhaustion had been connected v.-ith a deficiency of mineral con- 

 stituents, we might reasonably have expected that by some one at least of the nine 

 mineral conditions, supposing in some cases an abundance of every mineral con- 

 stituent which the plant could require, this deficiency would have been made up ; but 

 it was not so. 



' Thus, taking the column of bushels per acre as given in this summary as our guide, 

 it will be seen that whilst we have without manure only 1 6 bushels of dressed corn, we 

 have by farmyard manure 22 bushels. The ashes of farmyard manure give, however, 

 no increase whatever over the unmanured plot. Again, out of the 9 plots supplied with 

 artificial mineral manures, we have in no case an increase of two bushels by this means ; 

 the produce of the average of the 9 being not quite 17 bushels. On the other hand, we 

 see that the addition to some of these purely mineral manures of 65 Ibs. of sulphate of 

 ammonia a very small dressing of that substance, and containing only about 14 Ibs. of 

 ammonia has given us an average produce of 21 bushels. An insignificant addition of 

 rape-cake too, to manures otherwise ineffective, has given us about 18J bushels; and 

 when, as in plot 18, we have added to the inefficient mineral manures 65 Ibs. of am- 

 moniacal salts, and a little rape-cake also, we have a produce greater than by the 14 tons 

 of farmyard manure. 



'The quantities of rape-cake used were small, and the increase attributable to it also 

 small, but it nevertheless was much what wo should expect when compared with that 

 from the ammoniacal salts, if, as we believe is the case, the effect of rape-cake on grain- 

 crops is due to the nitrogen it contains. 



'Indeed, the coincidence in the slight or non-effect throughout the mineral series on 

 the one hand, and of the marked and nearly uniform result of the nitrogenous supply 

 on the other, was most striking in the first year's experimental produce, and such as to 

 lead us to give to nitrogenous manures in the second season even greater prominence 

 than we had done to minerals in the previous one. This is, in some respects, perhaps, 

 to be regretted, as had we kept a series of plots for some years continuously under 



