214 



On Agricultural Chemistry. 



On comparing the produce of No. 1 in this table with that of 

 the superphosphate of lime as given elsewhere, it will be seen that 

 the substitution of 65 lbs. of superphosphate of lime by 65 lbs. of 

 sulphate of ammonia has caused an increase of 4 J bushels of corn, 

 and 248 lbs. of straw. Again, the increase shown in No. 4, 

 where 80 lbs. of sulphate of ammonia were employed, is from 8 

 to 9 bushels of corn, and about 600 lbs. of straw, over the pro- 

 duce of the best mineral conditions as given in a former table. 



The evidence afforded in these experiments regarding the im- 

 portance of ammoniacal manures caused us to discontinue the 

 employment of mineral manures alone in the second year. It 

 was highly desirable to ascertain whether the minerals supplied 

 during the first year, and also those naturally contained in the 

 soil, were capable of being taken up by future crops. For this 

 purpose ammoniacal salts alone were subsequently employed on 

 some of the plots : — 



Season. 



Same Space of Ground each Year. 



Grain. 



Straw. 



1841 

 1845 



isie 



jSaperpliospbate of lime, 560 lbs.; silicate of 1 

 i potass, 220 ll)s. . . . " j 



Sulphate and muriate of ammonia, each \ \ cwt. 



Sulpnate of ammonia, 2 cwt. o = . . . . 



Bush. Pks. Qts. 



16 0 0 



31 3 1 

 27 1 2 



Pounds. 



1112 



426G 

 2244 



From the immense increase, both of corn and straw, obtained in 

 the second and third years, without any fresh addition of minerals, 

 it is evident that the deficient produce in the first year could only 

 result from the want of some power in the plant to assimilate 

 those already at its command, and that such a power was not 

 wanting in the succeeding years. 



I shall only notice one more set of experiments in connecti(m 

 with this point, and which were tried in the season of 1846 with 

 the wheat manure patented by Professor Liebig, and prepared 

 and sold under his name and authorit}'. On referring to the 

 specification of his patent, it will be seen that his object is to re- 

 duce the solubility of the alkalies by fusing them with lime and 

 phosphate of lime, and to employ those substances which will 

 form a compound resembling the ash of wheat : — 



1. tJnm an lived acre 



2. 4 cwt. of Liebig's wheat-manure alone 



3. 4 cwt. of Liebig's wheat-manure, with 4 cwt, rape-cake 



4. 4 cwt. of Liebig's wheat-manure, 1 cwt. each of sulphate" 



and muriate of ammonia 



5. 4 cwt. of Liebig's wheat-manure, 4 cwt. rape-cake, 1 cwt. 



each of sulphate and muriate of ammonia . . 



Grain. 



Straw. 



Busli. Pk. Gal. 

 17 3 3 

 20 1 2 

 22 3 1 



29 0 3 

 313 0 



Pounds, 

 1513 

 1676 

 1968 



2571 

 30G7 



