LIMITED VALUE OF CHEMICAL ANALYSIS. 221 



enable them to discover what nutritive substances their 

 land contains in minimum proportion, and what manuring 

 agents ought to be applied to ensure the production of a 

 maximum crop. 



In matters of this kind the farmer must pursue his own 

 course, and the proper course is the one that will most 

 fully secure the object he has in view ; he must not put 

 the least faith in the assertion of any foolish chemist, who 

 wants to prove to him analytically that his field contains 

 an inexhaustible store of this or that nutritive substance. 

 For the fertility of a field is not proportionate to the 

 quantity of one or several food elements analytically 

 shown to exist in it, but to that fraction of the total 

 nutritive substances which the field is able to give up to 

 the plants ; and the only means of determining that 

 fraction is by the plant itself. The most that chemical 

 analysis can do is to supply a few data for comparing the 

 condition of two fields. The experiments made by the 

 beet-root growers on the extensive tract of land in Eussia, 

 known as the Tschernosem or ' Black soil,' whose fertility 

 for corn plants is proverbial, show that this earth, though 

 analytically proved to contain upon the whole, to a depth 

 of twenty inches, 700 to 1000 times the quantity of 

 potash required for a full beet-root crop, is, after three or 

 four years' cultivation, so exhausted, that without manur- 

 ing it will no longer yield a remunerative crop of beetroot.* 



* With regard to the general ojjinion about the abundance and 

 inexhaustibility of potash in land, the ibllowing announcement, in the 

 ' Badische Centralblatt fiir Staats und Gemeinde-Interessen,' May 18G1, 

 is not without interest. ' In the District of Bretten. — The contracts 

 which usually take place in the early part of the year for the cultivation 

 of beetroot, are now fully open for competition in this district, and for 

 good articles 30 francs the cwt. are ofFered this year, whereas last year 

 only 26 francs were paid. Notwithstanding this rise of prices, and the 

 premiums oflered for superior roots, not many transactions have been 

 concluded. The reason of this is quite intelligible, for the very injurious 



