MAXLRES K<>K SPECIAL C'UOPS. 281 



plot without manure, of ;iS husht'ls. Now, Hk- sulphate of aiutuo* 

 niacoDliiins no pbosplialeof lime, and the fact that sucli a manure 

 gives a c-onsiilcralih' increase of crop, confirms the conclusion we 

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

 that the increase from the supcr[)hosphate of lime, is not due to 

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

 that the sulphate of ammonia rendered tlie phosphate of lime in 

 the soil more ri'adily solui)lc, and tlius furnished an increased 

 quantity in an available furm for assimilation by the plants — 

 a conclusion, which the results with superphosphate alone, on 

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

 biaed, on plot 6, do not susUiin. 



"On plot 12, half the (piantity of sulpJiatc of ammonia, was 

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

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

 of Peruvian guano i)er acre, gives nearly as great an increase of 

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

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

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

 due to the ammonia of these manures. Tiie 200 lbs. of Peruvian 

 guano, contained al>out 50 ll)s. of piiosphate of lime ; but as the sul- 

 phate of ammonia, which contains no phos|>hate of lime, gives as 

 great an incn-ise as the guan(», 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 manuivd, and which has been cultivated for many years with 

 the Cerdlia— or, in other words, with crops which remove a large 

 quantity of phosphate of lime 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 lbs. of unleached wood-ashes per acre, pro- 

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

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

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

 ever. On plot 3, 400 lbs. of ashes, and 100 lbs. of piaster, give the 

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

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

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

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



