80 
Experiments upon Swedes. 
Flat 7. Manured with 2 cwts. of Superphosphate and 1 cwt. of 
Peruvian Guano. 
tons. cwts. qrs. lbs. 
Produce 18 11 1 20 
Increase 3 17 0 16 
The increase produced by a mixture of 2 cwts. of superphos- 
phate and 1 cwt. of Peruvian guano, it will be seen, is greater 
than the increase produced by 3 cwts. of the same super- 
phosphate. 
In many instances I find that a mixture of two parts of good 
superphosphate and one part of Peruvian guano gives a better 
crop than either superphosphate or guano applied alone. 
Plot 8. Manured with 3 cwts. of Peruvian Guano. 
tons. cwts. qrs. lbs. 
Produce 18 17 2 20 
Increase 4 3 1 16 
In this case Peruvian guano produced rather a better result 
than the mixture of superphosphate and guano used in the pre- 
ceding experiment. However, the difference does not amount to 
more than 6 cwts., which is too insignificant to decide the ques- 
tion whether in the case before us Peruvian guano alone had 
really a better effect upon the crop than the mixture of super- 
phosphate and guano. In former years I have found, however, 
that Peruvian guano produced not nearly so great an increase as 
superphosphate alone, or a mixture of superphosphate and 
guano. There are, no doubt, soils for which guano is the most 
profitable manure even for root-crops ; but this is rather the 
exception than the rule. 
If there is a deficiency of available nitrogenized matters in a 
soil, a moderate amount of ammoniacal matters appears decidedly 
to benefit the turnip-crop. 
On the soil of the experimental field nitrogenized matters 
appear to have had a beneficial effect even when applied by 
themselves, which was not the case in the experiments which I 
tried on other soils in past years. 
The composition of the Peruvian guano used in this and the 
preceding experiment shows that it was a genuine sample of 
superior quality, as 100 parts on analysis yielded — 
Moisture 16-12 
*Orgaiiic matter and ammoniacal salts .. .. 52"31 
Phosphates of lime and magnesia 22'55 
Alkaline salts 7-94 
Insoluble siliceous matter 1'08 
100-00 
t * Containing Nitrogen 14-64 
Equal to ammonia 17-77 
