MANURES FOE SPECIAL CHOPS. 281 



plot without manure, of 38 bushels. Now, the sulphate of ammo- 

 nia contains no phosphate of liine, and the fact that such a manure 

 gives a considerable increase of crop, confirms the conclusion we 

 have arrived at, from a comparison of the results on plots 2 and 5 ; 

 that the increase from the superphosphate of lime, is not due to 

 the phosphate of lime which it contains, unless we are to conclude 

 that the sulphate of ammonia rendered the phosphate of lime in 

 the soil more readily soluble, and thus furnished an increased 

 quantity in an available form for assimilation by the plants 

 a conclusion, which the results with superphosphate alone, on. 

 plot 5, and with superphosphate and sulphate of ammonia, com- 

 bined, on plot 6, do not sustain. 



" On plot 12, half the quantity of sulphate of ammonia, was 

 used as on plot 4, and the increase is a little more than half what it 

 is where double the quantity was used. Again, on plot 13, 200 Ibs. 

 of Peruvian guano per acre, gives nearly as great an increase of 

 sound corn, as the 150 Ibs. of sulphate of ammonia. Now, 200 Ibs. 

 of Peruvian guano contains nearly as much ammonia as 150 Ibs. 

 sulphate of ammonia, and the increase in both cases is evidently 

 due to the ammonia of these manures. The 200 Ibs. of Peruvian 

 guano, contained about 50 Ibs. of phosphate of lime ; but as the sul- 

 phate of ammonia, which contains no phosphate of lime, gives as 

 great an increase as the guano, it follows, that the phosphate of 

 lime in the guano, had little, if any effect ; a result precisely simi- 

 lar to that obtained with superphosphate of lime. 



" We may conclude, therefore, that on this soil, which has never 

 been manured, and which has been cultivated for many years with 

 the Ceralia-or, in other words, with crops which remove a large 

 quantity of phosphate of lirne from the soil the phosphate of 

 lime, relatively to the ammonia, is not deficient. If such was not 

 the case, an application of soluble phosphate of lime would have 

 given an increase of crop, which we have shown was not the case 

 in any one of these experiments. 



" Plot 10, with 400 Ibs. of unleacheil wood-ashes per acre, pro- 

 duces the same quantity of sound corn, with an extra bushel of 

 'nubbins' per acre, as plot 1, without any manure at all; ashes, 

 therefore, applied alone, may be said to have had no effect what- 

 ever. On plot 3, 400 Ibs. of ashes, and 100 Ibs. of plaster, give the 

 same total number of bushels per acre, as plot 2, with 100 Ibs. of 

 plaster alone. Plot 8, with 400 Ibs. ashes, and 150 Ibs. of sulphate 

 of ammonia, yields three bushels of sound corn, and five bushels 

 of 'nubbins' per acre, less than plot 4, with 150 Ibs. sulphate of 



