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THE FARMER'S MAGAZIiNE. 



concur in the conclusions we iiave thus deduced, it is 

 nevertheless true, that the great majority of English 

 farmers, in the full, but probably very fallacious belief 

 of the invariable efficacy of phosphatic manuring on 

 the turnip field, have given to it a very general use in 

 that periodical division of the farm. It may be added, 

 however, that in Scotland, where a much more complete 

 body of practical evidence has been collected, to deter- 

 mine the comparative merits of extraneous manures, 

 than has yet been acquired in this country, a decided 

 preference has been given to guano over any form of 

 phosphatic fertilizer, in root as well as cereal husbandry. 



Sut be that as it may, the great preponderance of 

 practice anywhere is not on the employment of phos- 

 phates alone, but irasMjUj^/ewent of farm-yard dung. Let 

 us then reason for a moment on the chemical action, 

 and consequent economical results, that necessarily 

 must ensue from that combination. In doing this, we 

 will agree with the Rothamsted experimentalists that the 

 part played by phosphoric acid, adventitiously inter- 

 mingled with the soil in manure, is chiefly or entirely 

 that of a re-agent ; that in the exercise of this property, 

 it reduces substances existing in the staple in a state 

 unabsorbable or unassimilable by the organs of plants, 

 into the condition of available nutriments. With these 

 experimentalists we shall also concur that the phos- 

 phatic re-agent itself contributes little or no alimentary 

 ingredient; and having conceded these postulates 

 in Rothamsted argument, we would next, in the 

 way of preliminary illustration, remark what in- 

 deed is known to every one, that vitriol, spirit of salt, 

 or aquafortis employed to decompose bone or mineral 

 phosphate into superphosphate, adds no substantive 

 fertilizing element to the mass, but only renders more 

 immediate the designed reactionary function of the 

 phosphoric acid when commingled with the crude con- 

 stituency of the ground. So in like manner analogy 

 teaches us that the application of the manure to the 

 soil, how great soever its quantity, adds nothing, or at 

 best but little, to the normal vegetative element, and 

 only converts more or less of what before was present 

 therein, but dormant, into what by the reaction be- 

 comes active, and hence available as plant food. But 

 if these propositions be true, does it not necessarily 

 follow that that which we do, when in tilling roots we 

 use a phosphatic manure in supplement to dung from 

 the court-yard is, to extract from the soil, and possibly 

 in still greater proportion from the more tractible ele- 

 ments of the stercoraceous dressing, and to forestall for 

 the turnips more or less nutriment, which if not fore- 

 stalled would have contributed its fertilizing effect to 

 the subsequent barley and other crops of the rotation ? 

 The farmer, no more than the school-boy, can both eat 

 his cake and keep his cake. Assuming, therefore, that 

 the wide-spread use of phosphatic manure inEnglandhas 

 been greatly to increase the acreable produce of roots, 

 this important circumstance has, nevertheless, been 

 overlooked, alilce in practice and experiment, in com- 

 puting the benefit, that although to Rothamsted ad- 

 vocacy may be due the favour into which superphosphate 

 of lime has risen in the southern* division of the island. 



neither the investigations in fact, nor the reasonings in 

 argument, of this school exclude the intuitive conviction 

 which must arise in every considerate mind, that what 

 the turnips or mangolds may gain through its use, the fol- 

 lowing and more important cereal crops will lose, and that 

 industrially there is and can be no real advantage in the 

 expedient. Looking at the relative interests of land- 

 lord and tenant in the prevailing use of manurial stimu- 

 lants, Liebig has applied the expressive term "spoliation" 

 to the practice, and to this category phosphatic manure 

 belongs. As between a phosphated root crop and the 

 after greatly more valuable straw crop members of the 

 course, the expedient may be characterized as suicidally 

 spoliative. But what gives peculiar force to these con- 

 clusions is the circumstance that in a series of experi- 

 ments forming the text of part of an article by these 

 experimental authors, in vol. xviii. of the English 

 Agricultural Journal (1858), they receive a very strik- 

 ing confirmation. The trials now to be cited were 

 entitled " Experiments with barley in four-course 

 rotations, commencing with roots differently manured, 

 the same manure being employed on the same land for 

 thn roots of the three successive courses of each rotation." 

 The rotations themselves were three in number, and 

 from Nos. 1 and 2 of the series is contracted the fol- 

 lowing table : 



Table V. 



Is it possible for any one, perusing with attention the 

 significant figures of this simple table, to disassociate 

 the less yield and the manure used, from each other as 

 effect and cause, or to withstand the persuasion that the 

 excitement of phosphatic stimulant is surely followed 

 by a stage of collapse exactly proportioned to the degree 

 of induced excitation ? For more than ten years 

 Rothamsted has not ceased to insist on the pretensions of 

 this substance as a manure peculiarly, we might almost 

 use the term physiologically, adapted to the nurture in 



