On tJie Groioth of Barley by different Manures, Sfc. 529 



amount represented in the Tables as nnrecovered in the increase 

 of crop, will be under rather than over stated. 



It has been seen that the average annual produce of nitrogen 

 in the barley crop was, without nitrogenous manure, from 17^ to 

 324 lbs. per acre per annum, giving an average of about 28g lbs. 

 The Table further shows that, when at least 41 lbs. of nitrogen 

 were annually added per acre, in the forms respectively of ammo- 

 niacal salts and nitrate of soda, we obtained an average annual 

 increase of nitrogen in the crop of about 16^ lbs. when the ammo- 

 niacal salts were used, and about 15^ lbs. when the nitrate of 

 soda was used. Again, when double the amount, or at least 82 

 lbs. of nitrogen per acre, per annum, were added, we recovered 

 when it Avas given in the form of ammoniacal salts about 34^ lbs., 

 and when as nitrate of soda, about 33^ lbs., in the increase of crop. 

 Lastly, by from 82 to 100 lbs. of nitrogen annually supplied in 

 the form of rape-cake, we got back, taking the average of three 

 years only, not quite 36 lbs. in increase. 



If, instead of stating the actual acreage amounts as above, we 

 represent the j)ro])ortioa of nitrogen recovered or unrecovered in 

 the increase, for 100 parts supplied in manure, the result is as 

 follows. Where about 41 lbs. of nitrogen were added per acre, 

 per annum, in the form of ammoniacal salts, we get back in the 

 increase, on the average of six years, 39-J per cent, of the amount 

 supplied ; there are unrecovered therefore, about 60^ per cent, of 

 the so supplied nitrogen. When about the same amount of 

 nitrogen was supplied in the form of nitrate of soda, the average 

 of five years shows 37i per cent, recovered, and 62f per cent, 

 not recovered, in the increase. It will be remembered, that it 

 Avas in these instances where there is seen to be an average of 60 per 

 cent., or rather more, of the supplied nitrogen unrecovered in the 

 increase, that we had a far better yield of increased produce of 

 corn and straw for a given amount of nitrogen supplied in manure, 

 than where the larger amounts of the latter were employed. It 

 is worthy of remark, that, notwithstanding the far higher propor- 

 tion of increase of corn and straw for a given amount of nitrogen 

 in manure, where the smaller quantity was employed, we have, 

 where the larger amount was used, also the larger proportion of it 

 recovered in the increase. Tlius, instead of 39*8 per cent, re- 

 covered, and 60"2 per cent, unrecovered, as with the smaller 

 amounts of nitrogen in manure, we have with the 82 lbs. of 

 nitrogen per acre in ammoniacal salts, rather more, or 41*6 iier 

 cent, recovered. Again, the larger amount of nitrogen given as 

 nitrate of soda, taking the ayerage of five years, afforded 40*6 per 

 cent, recovered in increase, by the side of only 37*2 per cent, 

 when half the amount of the nitrate was employed. ,,. Lastlv, 

 taking the rape-cake to have supplied its minimum amount of 



