A'OL. I. No. 3. 



THE AGRICULTjURAL NEWS. 



41 



THE PURCHASE OF ARTIFICIAL 

 MANURES. 



Tho t'ollij\vii)g is till' fii-st, jMH-tinn uf a jtujx'i- wliich 

 ,'ipj)oarcd in the Jaanud of tlu- B mrl nf A'/ririit/ n ri' 

 fi.r March 1!)02:— 



Thi'iT are three suUstaiu'es, and nnly three, that are 

 valiieil in artifieial manures, namely, nitrogen, jilujsphates, 

 4iiid [lotiish. Aceoriling, therefore, to ^tlie greater or less 

 <liiantity of one or other of these substances the vahie of 

 tlie manure will rise or fall. Some manures contain only 

 one of these substances — for instance, nitrate of soda and 

 sul])hate of ammonia contain only nitrogen : siijier-jdiosiihate, 

 jirecipitated i>hos])liate, and basic slag contain only iihosjdiate ; 

 iind kainit, sidjihate of [(otash, and muriate of )iotasli contain 

 <iidy ]iotash — while other maniu'cs Imld two substances of 

 value, as in the case c>f bones, which furnish lioth nitrogen 

 iind i)hos))hates, or saUpetre (very seldom used, however, as 

 ;i mainire), which su|i|ilics both nitrogen and [lotash. Only 

 one class of so called artificial manure, namely, Peruvian or 

 other similar guano, contains an imjiortant ainount of all 

 three substances. 



>itroi;i:n. 

 In i)rice lists nitrogen is freiiuently expressed as ammo- 

 nia. The relationshi|) between the two substances is, 

 however, a very simple one, and need occasion no ditKculty 

 or iniueitainty : ITU), of ammonia alwaj'S contain exactly 

 141b. of nitrogen, or, what is the same thing from the farnici's 

 ])()int of view, 141b. of nitrogen are the ecpiivalent of 

 171b. of ammonia, if, therefore, a samj)le of, say •corn 

 manure' is offered as containing 4".5 |ier cent, of ammonia, 

 this is the same as saying that it contains 3'7 per cent, of 

 nitrogen. Sometimes, though not often, the figure is made 

 to look more attractive by being stated as sulidiate of 

 ummonia ; but this also need cause no difficulty, if it be 

 remembered that OGIh. of this substance are eijuivalent to no 

 more than 1411). of nitrogen or 1711). of ammonia. If, therefore, 

 we take the above example, the figures mean one and the 

 .same thing, whether they are stated as .■>-7 ]ier cent, of 

 nitrogen, or 4o ))er cent, of annnonia, or 17 4 percent, of 

 sulphate of ammonia. Hut a nrinure merchant who failed to 

 effect many sales for a fertilizer of e\er .so high-sounding a 

 name on a statement of i pjr cent, of nitrogen or 1 '2 per 

 i-ent. of ammonia might Ije more successful «ith a certain 

 class of buyer if he entered the nitrogen as equal to 4'7 per 

 cent, of sulphate of ammonia, and yet the three figures all 

 represent the same fact. I'nder the Fi.-rtilizers an<l Feeding 

 .Stuff's Act, IS!):!, the invoice must c-oiitain the niiiiimuni 

 guarantee of niU'ogoii, stated as .such. 



I'HOSPHATES. 



Phosphates or phosphate of lime may also be entered 

 in an analysis or i)rice list in several ways, but as a rule this 

 ingredient is either stated as above oi- as [ihosphoric acid. In 

 an invoice, however, the statement must be made as soluble 

 or insoluble ])liosj)hates, as the case may be. 



The relationshii) between phos])liates oi- (iliosphatc of 

 lime, whether soluble or insoluble, and phosphoric acid is 

 (piite as simple as that between nitrogen and ammonia : 

 1421h. of [fhosphoric acid always form ."MOIb. of i(hos[)liate 

 of lime, S3 that to convert the former into the latter one may 

 multijily by 22 which, though giving an answer slightly 



al)o\e the truth, is cpiite accurate enough foi- all ordiii,u-y 

 purj)oses. 



If, therefore, the analysis of a manure is returned as 

 \2 i)er cent, of phosphoric acid, it is eiiuivalent to saying 

 iliat it coutaius fully 2(5 per cent, of phosphates. Similarly 

 .'li.) i)er cent, of phosphites is c pial to nearly 14 ))er cent, of 

 pliosphoi-ic acid. 



rOTASIl. 



Potasli usually exists in manures in the two forms of 

 sulphate of iMjtash and muriate or chloride of potash, lb 

 takes 'J4-L'lb. of pure potash to form 174'2n)of suli)hate of 

 potash, whereas the .s.ime anrjunt of potash will form only 

 149'2 1b. of the muriate or chloride. In the former case, 

 therefore, to convert potash into terms of sul|iliate of potash 

 we multiply by IS.j, whereas in the latter case we multiply 

 by l-jS. If, therefore, an analysis of, say, kainit is stated 

 as ]2.'5 percent, potash, that is e<piivalent to saying that 

 it holds over 23 per cent, of sulphate of iwtash : while 

 muriate of potash guarante3 1 to contain .jSvS per cent, of 

 potash is of about 90 i)er cent, purity. 



Just as a buyer may sometimes be led into purchasing 

 a manure through its nitrogen being expressed as sul])hat(3 

 of auiuionia, so may the contents of ])otash be made to look 

 nnire attractive by being stated as sulphate of |)otasli. In an 

 invoice, howe' r, the potash must be stated as such. 



The ruk-; for approximately converting the various 

 terms int^j their ecjuivalcnts may be thus summari.sed :— - 



To convert Niti-ogcu into tonus of Aininouia i»»ltiply by 1'2 



NitrogL'u Sulpli of Am. '" " i'7 



Plio^plior.Aciil " ■■ " Piiospliiles '■ " 2-i 



Potiish •■ •■ " Siilpli. of Potiisli •' •■ ]-85 



Potnsli " " ■' MiU'i.ate of Potash " ■■ 1-.58 



Nitrogen and phosj)hates, and, to a loss extent, potash, 

 \'ary in ettecti\eness, and therefore, in value, according to 

 their source or origin. Nitrogen is never so etfectivi? its 

 when in the form of )iitrate of soda. [See ' Note added' Ed.] 

 It is not quite so active, and for some jnirposes not 

 so valualjle, when in the form of sulphate of ammonia, 

 though under certain circumstances this somewhat slower- 

 action may be regarded as an advantage. Nitrogen in 

 what is called the organic form is in its least active condi- 

 tion, though here again the rapidity and ett'ectiveiiess of 

 action vary greatly. Nitrogen is in the organic form in 

 blood meal, fish meal, bones, shoddy, etc., and yet, as a, 

 source of plant food, Idood meal is more active tlian thesti 

 other substances. It is claimed as an advantage fin- slow- 

 acting manures that they last longer, which is true ; but one 

 applies manures not to last, but to act. It is only where 

 it is convenient to apply manure at somewhat long intervals, 

 as in the treatment of orchards, that the more inert manures 

 are worthy of much consideration. 



.\s regards |)liosphatic manures, it may be said that 

 while soluble phosphates are all alike active, there is consid- 

 erable difference in the value of insoluble jthosphates. The 

 insoluble phos))liate of bone meal, for instance, is less 

 effective, and for nn)st purposes less valuable, than the 

 insolulile i)hosi)hate of basic slag, precipitated jiliosphate, or 

 (!ven dissolved bones. Some of the insoluble jdiosphate of 

 the last nwnure has once been soluble, and has ' reverted,' 

 and such |>hosphate is not much less effective than soluble 

 phosphate. Hut raw bones as a )n:inure have been longer 

 known to Hritish farmers than other forms of phosphate, 

 and foi- this reason their price has kept relatively high. 



[note added] 



With roo-aril U) the .statt'inrDts above nd.itivu ti> 



