Experiments upon Swedes. 175 



A comparison of the analysis of this patent article with that 

 of genuine Peruvian guano will show at once the inferiority of 

 Binn's manure, for it is poor in all the essential and expensive 

 fertilizing matters. It contains no soluble phosphate whatever, 

 and very little insoluble phosphate, nor is it rich in ammonia. 

 On the other hand it abounds in sand and carbonate of lime — 

 constituents which on a calcareous clay soil, like the one on which 

 the experiments were tried, cannot possibly do any good. 



It will be observed that Binn's manure contains likewise a 

 considerable quantity of common salt, and I cannot help think- 

 ing that the salt in this otherwise all but valueless artificial 

 manure has had a beneficial effect upon the crop. It is possible 

 that salt added to superphosphate will prove as valuable to 

 swedes as to mangolds, particularly in dry seasons like the last. 

 I hope to be able at a future period to report the results of field 

 experiments with salt as a manure for swedes. In the mean 

 time I would recommend to the notice of agriculturists the 

 following experiments, as likely to throw light on the use of 

 salt as a manure for turnips : — 



1. 3 cwt. of superphosphate per acre. 



2. 3 ,, of same superphosphate and ^ cwt. of salt per acre. 



3. 3 „ of „ „ 1 „ of 



4. 3 „ of „ „ li „ of 



5. Ij „ of salt alone per acre. 



6. 2 „ of „ 



Salt, perhaps, may be found useful in preventing mildew in 

 turnips. 



Whether or not it was the salt in Binn's patent manure that 

 produced almost as good a crop as 3 cwt. of Peruvian guano, 

 we have here presented to us a striking example of an inferior 

 manure giving as good a result as the best artificials. Tliis 

 shows plainly how little dependence can be placed upon a single 

 field experiment, and how fallacious it is as a test, so called prac- 

 tical, for arriving at anything like a fair conclusion as to the 

 value of artificial manures. 



In dry and unfavourable seasons, the very best manures are 

 much more likely to do harm than poor or indifferent fertilizers. 

 The reason of this is obvious. A manure, such as a concen- 

 trated superphosphate, rapidly pushes on the plant, and when 

 there is abundance of moisture the process of assimilation goes 

 on without interruption ; but when dry weather sets in and 

 continues for a long time, the vigorously growing plant receives 

 a sudden check, from which it has difficulty in recovering, whilst 

 plants scantily supplied with the more energetic fertilizing sub- 

 stances are far less liable to suffer under these circumstances. 



