SUPERrilOSI'IIATE OF LIME. 



277 



From ihe (London) Farmer's Magazine. 



SUPERPHOSPHATE OF LIME. 



USE OF SUPERPHOSPHATE OF LIME, PRODUCED WITH ACU) AND BONES FOR MANURE. 



BY W C SPOONKR. 



[Prize Essay of ihe Royal Agricultural Society. 



The (litriciillifs under which the pursuit of 

 Agriculture has for some years hibored — the 

 iuiportauce, and, indeed, the absohite neces- 

 sity of i~aising the largest crops of roots at the 

 lecist possible expense, afford ample reasons 

 for the Council of the Royal Agricultural So- 

 ciety of Eughuid proposing as a subject suita- 

 ble for a prize essay, " The Use of Bones 

 with Acid," which on high authority' has been 

 designated " the most important saving which 

 wiis ever held out in the use of manure." If 

 any additional reason were recjuired v^hy the 

 utmost attention should be devoted to tliis 

 irapk)rtant matter, and the most extended in- 

 fonnatioii gained respecting it, it may be 

 f(juud in the fact that while the constantly in- 

 creasing population of this country demands 

 a corresponding augmentation of animal and 

 vegetable food, the sources of supply both of 

 bones and guano are likely to become greatly 

 diminished. Thus, not only as it affects the 

 interest of the occupier and owner of the soil, 

 but also on national grounds, is the subject 

 of our essay worthy of the deepest considera- 

 tion. The superior economy of ein|iloying 

 bones mixed with an acid, over that of using 

 bones alone, is no longer a hypothetical or 

 even a probable statement, but an established 

 fact ; and though I shall have to offer somt^ 

 results in corroboration, yet I do not hold 

 tliem as essential to the subject, so fully has 

 the success of the mixture been es1al)lislied 

 from the numerous e.xperiments related in 

 the .louniiil of the Royal Agncultural Society-, 

 and more particularly iu the excellent and 

 elaborate essays of ]Mr. Hamiam. And though 

 I shall liud it necessary to pass i'a]iidly over 

 all the various branches of the subject, yet 

 mv claims for hoiioraiy notice will princi- 

 I»ally rest on affording such practictd intbrma- 

 tiou on points hitherto but briefly attended 

 to, as may, I hope, render this essay of really 

 practical aud pecmiiary value to agriculturists 

 in geuer:J. 



The specific effect of bone as food for the 

 turnip crop has long been known — long, in- 

 deed, before science was in a position to ex- 

 plain the cause of its peculiar effects, or to 

 assign correctly to what portion of its con- 

 stituents the benefits are chiefly due. 



It was found, greatly to the surf)rise of 

 niiiny, that bunit bones, in which of course 

 the organic parts had been desti-oyed, were 

 equal, if not superior, in their eflect to bones 



(565) 



not so treated : and that when l)oiled, in 

 which state the fat had been expelled, they 

 were more productive than bones in a fresh 

 state. It was thence supposed by those who 

 jinn[ied to conclusions too hastily, that the 

 suljstances thus expelled were useless at any 

 rate for the turuij) crop, and they were ap- 

 parently supported by the theoiy of a very 

 ennnent chemist, who, if we mistake not. laid 

 it dov^-n as his opinion that the value of ma- 

 luii-es depended principally, if not entirely, on 

 their inorganic ingredients — a doctrine alto- 

 gether at variance with the previous generidly 

 I'eceived notions, that ammonia was the true 

 fertilizing element, and that its amount af- 

 forded thtj measure of the value of manure. 

 In medio tufissimHs ibis — the truth, we take 

 it, will be foimd to lie between the two ex- 

 tremes. We may justly reg;u'd the inorganic 

 constituents as being the most imiiortant and 

 essential portion of manure, affording to the 

 plant what the skeleton does to the anim;il, 

 the basis of support ; and, as plants can ob- 

 tain no other supply but through the soil, we 

 may justly regard them as Ihe most essential 

 constituents. 



The other elements are, to a great extent, 

 supi)lied through the atmosphere, and even 

 nitrogen and its combinations may thus be 

 furnished. The avenues through which this 

 atmospheric supjily is furnished are the leaves 

 of the pbuit, and their size afl()rds a correct 

 criterion, ccrferis 'paribus, of the amount ot" 

 nutrhnent derived from the aerial source. 

 Thus beans and other pulse obtain more ibod 

 from the atmosphere than cereal plants ; roots 

 more than tiie fonner; and wheat, from the 

 stnall size of the leaves, less than any. Thus 

 only can we accoimt for the striking fact that 

 if we give a good supply of inorganic ele- 

 ments only to the tnnnp crop, we shall very 

 probably have a plentiful crop, while it" these 

 be absent, however rich the mamire may 

 otherwise be, the crop will be a failure. Not 

 that we must therefore draw the conclusion 

 that the organic manures are of little or no 

 imjiortance to root crops : they are of value, 

 aud particularly to the grain crops which 

 succeed. 



The organic matter which composes about 

 one-third the substance of bones is, however, 

 so intimately combined with the earthy por- 

 tion, and their disunion is accomplished with 

 sucli difliculty, that the good effects of either 



