500 On the Growth of Barley hy different 3Ianures, Sfc. 



barley corn, and little more than half a ton of straw — together 

 equal to not a ton of dry substance of produce — must be 

 admitted to be exceedingly small. The condition of the land 

 after ten successive crops of turnips, must have been, for barley 

 growth, at the lowest possible point. 



That a liberal supply of mineral constituents distributed 

 through the soil, cannot restore this exhausted fertility, is seen by 

 the produce of barley after the mineral-manured turnips. After 

 ten years of turnips, the last eight of which were grown by exces- 

 sive supplies of mineral manures, we have an annual average of 

 54 lbs., or 1 bushel of corn more, and 79 lbs. of straw less, 

 = 25 lbs. less total produce, than after the unmanured turnips. 



In what constituent or constituents had these unmanured and 

 mineral-manured turnips exhausted the soil, in so far as the alter 

 ])roduction of barley was concerned, to a point even far below 

 that arrived at in the other field by the previous growth of one 

 crop of wheat, one crop of barley with sulphate of ammonia, and 

 one crop unmanured — that is, three white straw crops in succes- 

 sion without mineral manure? An examination of Table XII. 

 will throw some light on this point. 



It has already been said, that there was an average annual 

 increase of 54 lbs. of corn, but a decrease of 25 lbs. total produce, 

 where the barley succeeded the mineral-manured turnips, com- 

 pared with the produce after the unmanured turnips. Taking 

 now the produce after the mineral-manured turnips as the 

 standard of comparison, there was, where in the six middle years 

 of the ten of turnips ammoniacal salts had also been applied, an 

 annual average increase in the succeeding barley of 102 lbs. corn, 

 and 94 lbs. straw, ==196 lbs. total produce. 



Still comparing with the produce after the mineral-manured 

 tui'nips, we have, where in six years out of the ten rape-cake was 

 employed in addition to the minerals, an average annual increase 

 of succeeding barley, of 333 lbs. corn, and 381 lbs, straw, = 714 lbs. 

 total produce. 



Lastly, where during six years both ammoniacal salts and rape- 

 cake were added to the mineral manures for the turnips, the suc- 

 ceeding barley gave an annual average increase of 315 lbs. corn, 

 and 331 lbs. straw, = 646 lbs. total produce. 



We had then, with a residue in the soil of merely mineral 

 manures, even a loss of produce of barley — due to a greater growth, 

 and consequent greater exhaustion of other matters, by the 

 turnip. We find, on the other hand, a perceptible gain in the 

 barley wherever the turnips had received either ammoniacal salts 

 or rape-cake as well as the mineral manures. Even here, how- 

 ever, the produce, with this nitrogenous and full mineral residue 



