On Agricultural Chemistry. 



13 



salts alone a produce equal to that of the farm-yard manure, we 

 have again a similar result: for 2 cwts. of sulphate of ammonia 

 has now griven 1850 lbs. of total corn, instead of 1826 lbs., which is 

 the produce on plot 2. The straw of the latter is, however, 

 slightly heavier than that by the ammoniacal salt. 



Again, plot 5«, which was in the previous season unmanured, 

 was now subdivided : on one half of it (namely, 5a') we have the 

 ashes of wheat-straw alone, by which there is an increase of rather 

 more than 1 bushel per acre of dressed corn ; on the other half 

 (or hd^) we have, besides the straw ashes, 2 cwts. of sulphate of 

 ammonia put on as a top-dressing : 2 cwts. of sulphate of am- 

 monia have, in this case, only increased the produce beyond that 

 of ba} by 71 bushels of corn and 768 lbs. of straw, instead of by 

 9|- bushels of corn and 789 lbs. of straw, which was the increase 

 obtained by the same amount of ammoniacal salt on 10 a,' as com- 

 pared with 105. It will be observed, however, that in the former 

 case the ammoniacal salts were top-dressed, but in the latter they 

 were drilled at the time of sowing the seed ; and it will be remem- 

 bered that in 1845 the result was better as to corn on plot 9, 

 where the salts were sown earlier, than on plot 10, where the top- 

 dressing extended far into the spring. We have had several direct 

 instances of this kind in our experience, and we would give it as a 

 suggestion, in most cases applicable, that manures for wheat, and 

 especially ammoniacal ones, should be applied before or at the 

 time the seed is sown; for, although the apparent luxuriance of 

 the crop is greater, and the produce of straw really heavier, 

 by spring rather than autumn sowings of Peruvian guano and 

 other ammoniacal manures, yet we believe that that of the corn 

 will not be increased in an equivalent degree. Indeed, the suc- 

 cess of the crop undoubtedly depends very materially on the pro- 

 gress of the underground growth during the winter months ; and 

 this again, other things being equal, upon the quantity of available 

 nitrogenous constituents within the soil, without a liberal provi- 

 sion of which, the range of the fibrous feeders of the plant will not 

 be such, as to take up the minerals which the soil is competent to 

 supply, and in such quantity as will be required during the after 

 progress of the plant for its healthy and favourable grov/th. 



The next result to be noticed is that obtained on plot 6, now 

 also divided into two equal portions designated respectively 6a 

 and Q)h. Plot No. 6 had for the crop of 1844 superphosphate of lime 

 and the phosphate of magnesia manure, and for that of 1845 

 superphosphate of lime, rape-cake, and ammoniacal salts. For 

 this, the third experimental season, it was devoted to the trial of 

 the wheat manure manufactured under the sanction of Professor 

 Liebig, and patented in this country. 



Upon plot 6a, 4 cwts. per acre of the patent wheat-manure were 



o 



