Experiments upon Swedes. 13 



Plot 7. Manured with 2 cwts. of Superphosphate and 1 cwt. of 

 Peruvian Guano. 



tons. cwts. qrs. Ibs. 



Produce .. .. .. .. 18 11 1 20 



Increase 3 17 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. Ibs. 



Produce 18 17 2 20 



Increase .. ' -11. JraiiisfcJo 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 



*0rganic matter and ainmoniacal salts .. .. 52'31 



Phosphates of lime and magnesia 22*55 



Alkaline salts 7'94 



Insoluble siliceous matter 1*08 



100-00 



* Containing Nitrogen 14'64 



Equal to aramouia 17'77 



