On the Groicth of Barley Inj different 3Ianurcs, S^-c. 487 



tion of the " mixed alkalies " to the superphosphate of lime and 

 ammoniacal salts of the latter, is only 51 lbs. of com and 93 lbs. 

 of straw ; or little more than that of the "mixed alkalies" over 

 the unmanured produce when they were used alone. Thus the 

 total annual gain (in experiment 11) by the addition of both the 

 " mixed alkalies " and phosphatic manure to the ammoniacal salts 

 (of experiments), is 405 lbs. of corn and 729 lbs. straw; that is, 

 rather more than by the addition to the ammoniacal salts of 

 superphosphate of liine alone. On the other hand, calculating 

 the effect of the addition of the 50 IIds. of ammonia per acre per 

 annum to the mixed mineral manure of No. 6, it is seen to be 

 682 lbs. of corn and 1255 lbs. of straw. And lastly, the average 

 annual increase over the unmanured produce, due to the conjoint 

 effects of the ammoniacal salts, the " mixed alkalies," and the 

 superphosphate of lime, is 1011 lbs. of corn and 1507 lbs. of straw ; 

 which is 189 lbs, corn and 477 lbs. straw, more than by the farm- 

 yard-manure. 



From the results of Series 3, as a whole, we see that the mean 

 annual increase by the supply to the soil of nitror/cu = 50 lbs. of 

 ammonia per acre per annum, in the five different states, or con- 

 ditions of combustion, is 710 lbs. of corn and 1090 lbs. of straw, 

 or 112 lbs. less corn, and 60 lbs. more straw, than by the farm- 

 yard-manure. Or, taking the increase over the unmanured pro- 

 duce, due to the conjoint action of the mineral manures and 

 supplied nitrogen (as in experiments 9, 10, and 11), its mean 

 annual amount, calculating from 18 experiments (that is with three 

 different mineral conditions each over six years), is 64 lbs. more 

 corn and 285 lbs. more straw than by the dung. Or, lastly, if 

 we take the conjoint action of the 50 lbs. of ammonia, and those 

 mineral manures only which contain phosphates, we have from 100 

 to 200 lbs. more corn and from 400 to 500 lbs. more straw, per acre 

 per annum, by such a combination, than by farmyard-manure. 



In the next series (4), as already mentioned, there was about 

 twice as much nitrogen supplied per acre as in experiments 7, 8, 

 9, 10, and 11, in which, as has just been seen, the amount of 

 produce averaged more, and sometimes greatly exceeded, that by 

 a large annual supply of farmyard dung. It should be stated in 

 the outset, that the quantities of nitrogen now under considera- 

 tion were considerably beyond what the barley could turn to good 

 account with such seasons on the soil in question, as was shown 

 by the invariable falling of the crop, and the consequent deficient 

 proportion and quality of the corn. The result of this was, that 

 Ave had in every case very much less increase of produce for a 

 given amount of manure in Series 4 than in Series 3. In fact, 

 there is, on the average, only about once and a half as much 



2 K 2 



