214 THE SYSTEM OF FARM- YARD MANURING. 



ments would readily enable them to discover what 

 nutritive substances their land contains in minimum 

 proportion, and what manuring agents ought to be ap- 

 plied 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 ex- 

 tensive tract of land in Russia, known as the Tscherno- 

 sem or ' Black soil,' whose fertility for corn plants is 

 proverbial, show that this earth, though analytically 

 proved to contain upon the whole, to the depth of 

 twenty inches, TOO 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 manuring 

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



In the produce of cereals there is only one proper 

 proportion between grain and straw ; but the unfavour- 

 



* With regard to the general opinion about the abundance and inex- 

 haustibility of potash in land, the following announcement, in the ' Badische 

 Centralblatt fiir Staats und Gemeinde-Interessen,' May 1861, 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 offered for superior 

 roots, not many transactions have been concluded. The reason of this is 

 quite intelligible, for the very injurious effects resulting to land on which 

 this product has been cultivated, are too well known.' The effects must 

 have reference to fields which had been adequately manured, for otherwise 

 no profitable returns can be expected. 



