114 



^l)C iarmcr's iHontl)li) Visitor. 



Btihstances, re-obtain the properly of being ali- 

 Borbed by the roots of ibe plants. 



The duration of ibe fertibty of a fiebi depends 

 on the ainount of the mineral alinjentsof plants 

 coiilained in it, and its prodnilive power lor a 

 given lime is in a direct proportion to that part 

 of its composition which possesses the capaciiy 

 of being taken up liy the plant. A nuiiibur of 

 tlie most important agricultinal operations, espe- 

 cially the mechanical, exercise and ijiliuence on 

 the fertilily of the fields only thus far, that ibey 

 remove the impediments ubicli are opposed lo 

 tlie assimilation of tlie mineral food into the 

 vegetable organism. iJy ploii;;hing, e. g., the 

 snrfiice of the fields is renewed and ujade ac- 

 cessible to air and moisture. 'I'he nutritious ele- 

 ments contained in the soil in a latent state, ac- 

 quire by these operations, the properties neces- 

 sary for their transnjission into the plants. It is 

 easy to conceive the useful influence which, in 

 this respect, is exercised on the produce of the 

 fields by the care and industry of the farmer. — 

 But all these labors and efforts do not increase 

 the amount of mineral elements in the field ; in 

 rendering soluble in a given lime, a larger fjuan- 

 tity of the insoluble substances, and olitaining by 

 these means a riclier crop — the time is merely 

 hasteneil, in which the soil liecomes exbausted. 



'I'he experience of centtn ies has shown that, 

 with the help of manure, of the excrements of 

 animals and man, with which we supply those 

 fields which have ceased to pro(hice crops of 

 grain, &c., serving as Ibod for man and animals, 

 in a sufficient quantity, the original fertility can 

 again be restored; an exhausted field which 

 scarcely yielded back the seed, is made to pro- 

 duce a twenty and more fold crop, accrordiug to 

 the proportion of the manure provided. 



Regarding the mode of action of the manure, 

 it haa been observed, that all excrements do not 

 exercise an equal influence on plants. The ex- 

 crements of slieep and cattle, tor instance, in- 

 crease ill most fields the crop of roots and her- 

 baceous plants 10 a far greater degree than those 

 of man and birds, (guano.) The latter act far 

 more favorably on the prodiiciion of the ceielia, 

 especially if tiiey are added lo the animal excre- 

 inenis, and are given to the fields at the same 

 time. 



A field, for example, which has lost its fertility 

 for potatoes and turni(is, but on wlfich peas and 

 beans slill thiive, becomes fu' more ll-rlile, by a 

 supply of the cxcrenients of horses and cows, 

 for a new crop of potatoes and turnips, tliaii by 

 mannring it wiih the excrements of man or with 

 guano. 



The most accurate experiments and analyses 

 have pointed out that the excrements of man 

 and animals contain those substances, lo the 

 presence of wliicli the (eriilily of the soil is due. 

 The I'erlilizing power of iiianuie can be deler- 

 miiied by weight, as its effect is in a diiect ralio 

 to ils aiiioiuit in the mineral elements of the food 

 of plants. The triith of the result of these 

 chemical analyses must be evident lo every one 

 who inquires into Ibe oiigin of excrements. 



All llie excremenis of n an anil animals are 

 derived from the plants of our fields; in the oats 

 ami bay, whirli serve as food lo the horses, in 

 the roots which are coiisuined by a cow, there 

 are a certain ipiantily of mineral ingredients. 

 A horse, in consuming 15 lbs. ol' hay and 4i lbs. 

 of oats per day, consumes il\ oujices of lluise 

 snhslances which the hay and oats look from the 

 fields; he consumes annually 480 Ib.s. of these 

 conslitnent eleuienls of the soil, bill only a very 

 small poriion of them remains in his body. If a 

 horse during one year, increases 100 lbs. iir 

 weighl. Ibis increase cr.nlains only 7 lbs. of those 

 mineral substaiu'cs which were coiilained in ibe 

 food. IJnt what has become of Ibe 473 lbs. 

 which we cannot detect m his bodv ? 



The analysis of the fluid and solid excrements 

 which the horse gives out daily, shows lliat the 

 ingreilients of ihe soil which do not remain in 

 the body of the animal are contained in ils ex- 

 cremenis ; it shows that in a-i adult animal, 

 which from day to day does uciiher increase nor 

 deciva.^e in weight, the amount of ihc mineral 

 ingredients of ilie excremenis is eipial in weight 

 to the mineral ingrcdienis of llie food. 



As Willi ihe horse, so it is wiih all animals. — 

 In nil nilidl {iiniiKils llie ercritmeiiln cuntain Ihe iii- 

 gnJieiila uf lite soil nccou/iiifr lo Ihe ijiunilitics tind 

 reitilive pio/ioitions in which Ihey are conlained in 

 their food. 



The inineral snhstaiices of the food which 

 have remained in the body of the animals, and 

 served to increase their weight, are linmd again 

 in the bones and excremenis of inuii who cou- 

 suiiies the flesh of these animals. 



The excrements of man contain the elemenls 

 of ibe soil, of bread or of grain, of vegetables 

 and niHal. 



These discoverie.s explain, in a tnost simple 

 and saiisfaciory manner, the fertilizing efl'ecl 

 which maniiie produces on our fields. 



It is now obvious wiiy manure renders again 

 fertile llie exhausted fields ; why, by its means, 

 their prodnciiveness can be auginenled ; why the 

 latter is in a direct ratio to the quantiiy of ma- 

 nure adminislered. 



The exhaustion of the soil liy subsequent 

 crops, — its decrease in fertilily, — is produced by 

 ihe gradual removal of the mineral elements, in 

 a soluble stale, which are necessary for the de- 

 velopment of our eullivaled plants. By a sup- 

 ply of maniiie they are again restored to thai 

 stale suited to serve as noiuishnient to a new 

 vegetation. If the supply of the removed ele- 

 menls of the soil, by means of manure, be suffi- 

 cient; if llie (piaiilily taken away he restored, 

 the original fertilily re-appenis ; if Ihe supply he 

 greater, the produce increases; a defective sup- 

 ply gives a smaller produce. 



It is now explained why the difterciit kinds of 

 mtinnre exercise an unequal efl'ect upon the 

 fields. 



The excrements of man, and the L'uano con- 

 taining esiiecially the mineral ingieilienls of 

 grain and meat, exercise liir greater inniieiice on 

 the amount of produce in grain in a field in 

 which these ingri'dieiils are waiuiug, even il 

 ihose of the leaves and stalks are present in suf- 

 ficient quanliiy, than the cxcrenieiiis of an ani- 

 mal which feeds on roots or green foilder. The 

 excreineiils of the latter contains the inineral 

 elements of the leaves, stalks, and roots, in pre- 

 vailing qnalilily, and have a greater value for the 

 production of roots and fbliaceons plants than 

 those of man or birds, which contain only a 

 small qnaulily of those mineral substances which 

 they reipiire lor their development. 



If we compare, (in- instance, the composition 

 of guano with the excremenis of the cow — solid 

 and fluid exi^remenls in the same state of dry- 

 ness — it is found, that in an equal weight, the 

 latter coiilaiu five lo seven times more of the 

 mineral ingredients of turnips and potatoes, than 

 the former. Ilj in a soil, which is deprived of all 

 these mineral subslunces, we w isli to force a crop 

 of liirnips by means of guano, we require al 

 least five times more ol" guano than dung of 

 cattle. 



The same thing happens, though iii'ce versa, if 

 we wish to produce a rich crop of grain by 

 incans of animal excrements ; in this case, one 

 pait of guano and five pans of animal excre- 

 ments produce ihe same effect, as 13. 15 parts of 

 animal excrenieiils. 



To nndersiand the proper meaning of these 

 iiumerii'al proportions, ii is sufficient to menliou, 

 that 4U0 pounds ol bouts contain as much phns- 

 phoric acid as 1000 pounds of wheal ; these 40'0 

 pounds of bones can furnish suflicieiit phospho- 

 ric acid to 8 acres. 



If we take the inqiorl.ition of linnes into Great 

 liritain, in the last ten years, to amount to one 

 niilboii of Ions, enough phosphoric acid has been 

 supplied to the fields for 25 millions of tons of 

 ubeal ; but (uily a small proportion of the phos- 

 pliuric acid of the bones is in a state to be ;is- 

 siinilaled by the plants and applicable to the for- 

 malioii of the grain. The plants, in order to 

 apply tin; other far greater part of that phospho- 

 ric acid to llieir fornialion, must hud a cerlain 

 (piaiilily of alkaline bases bi;sideslbc bone earth, 

 w hicli ari! not given lo ihe plants in the bones, 

 because they contain neither potash nor soda. 



'I'o have increased the li'rtilily of the fields in 

 the rii;ht pioporlion, 800,000 tons of potash 

 ought lo have been added lo the one million ot 

 tons of bones, in a suilable form. 



The same is the case with guaiio; (iO to lOO 

 pminds ol it are sufficient to furnish pbosphorii' 

 acid 10 one acre ol' turnips; but the four lo eight 

 fold (pianiity is required lo liunish the turnips 

 Willi llif necessary alkaline bases, end il is slill 

 doublfnl whither lliey can be at all provided 

 Hilli the latter, by means of the salts with alka- 

 line buses, whicli the guano coiituins. 



At a lime, when the necessity of (he mineral 

 substances for the grovMh and development of 

 the plants, and the direct relation whicli the ef- 

 fect of maiime has to its amount of the same 

 substances, had not been ascertained, a promi- 

 nent value was ascribed lo the organic mailers 

 which it contains. For a long time it was 

 thought that the produce of a field of those sub- 

 stances, coulainiiig nitrogen, which serve as food 

 tor man and animals, stood in a direct proportion 

 to the nilrogeii coiilained in maiiure. It «as be- 

 lieved that its commercial value, or its value as 

 manure, might be expressed in per cents by ils 

 proportion of nitrogen, but laler and morecon- 

 viiiciug observations have induced me to contra- 

 dict this opinion. 



If the nitrogen and carbonic acid formed by 

 the decay and decomposition of the vegetable 

 ingredients of manure, were the cause of its fer- 

 tiliiiing power, this ought also lo be seen if the 

 mineral snbslances are excluded. Direct expe- 

 riments have shown, that the nitrogen of the ex- 

 crements can be assimilated by ihe plains, in the 

 form of ammonia : but that amniouia as well as 

 carbtmic acid, alibough il in indispeiisaiile for the 

 development of all plaiit.s, can accelerate ibe 

 growth of plains and increase llie produce of a 

 field of grain, tools, anil lubercles only, if at the 

 same lime, the mineral ingredients contained in 

 the maiinre which is applied, are in a stale in 

 which ihey are suited lor assimilation. If the 

 latter are excluded, carliouic acid and ammonia 

 have no efl'ect on vegelatioii. 



On the other hand, experience has shown that 

 on many fields the produce which is rich in car- 

 bon ami ammonia, can be increaseil to an extra- 

 ordinary amount without any supply of such 

 matters as (urnisli these substances. 



Oil fields which are provided with a certain 

 quanliiy of marl or slacked lime, or with lioiie 

 earth and gypsum, substances u hicli cannot give 

 up to the plants eiiher carbon iior nitrogen — rich 

 crops are obtained in many places, of grain, tu- 

 bers, and roots, entirely in contradiction w iih the 

 view which ascribes Ihe efFrct of llie niaimre lo 

 ils amount of ingredients coutaiuiug nitrogen or 

 carbonic acid. 



To ex|ilaiii this process, whicli is so opposite 

 to the common opinion, the marl, the lime, ilia 

 gypsum, Ihe alkalies, and the bone earth were 

 regariled as stimulants, w liich acted on the plants 

 like sjiices <ui the (iiod of man, of which it was 

 believed thai they increased the power of assim- 

 ilation, and allowed the individuals to consume 

 larjier quantities of food. 



This view is contradicted, if we consider that 

 slimnlaiits mean such substances as do not 

 serve (i>r Ibe noiu'ishmeui of llie organism or for 

 the formation of organic elemeni.s, and can only 

 increase llie weight of the body, if at the same 

 lime a cerlain increase of food is given. In sup- 

 plying the fields wiih the above mentioned sub- 

 stances, the weight of the plains became in- 

 creased in all llieir separate parl.s, wilhonl their 

 having been provideil with the quantity of food, 

 which accordiiii; to theory, was necessary to this 

 extraordinary increase, viz., with carbonic »oid 

 and ammonia. 



Chemical analysis shows ihat these so called 

 stimulants are eiiher actual iu;:redients of nia- 

 nine, as gypsum, bone e.irlh, and the active sub- 

 stances of the marl, or that they are the means 

 liy which the mineral elements conlained in the 

 soil are resolved inlo a slain adapted for being 

 assimilated by Ihe plants; this is generally eflic- 

 led by the application of slacked lime. They 

 consequently exercise on the vital process of the 

 plains not a ineie stimulus like the spices, but 

 are consumed for the development of the leaves, 

 seeils, tools, >S^c. ; they become cousliliienl pai is 

 of tlii^m, as can be shown w illi eirlaiuiy by 

 chemical annl_\ ses. 



The success which has followed ihe applica- 

 tion of these sniislances to the fields has explain- 

 ed, ill a mosi striking manner, the origin of die 

 carbon and nilrogeii ill the plains. 



In the marl, in the bone earth, in the gypsum, 

 in the niliale of soda, no carbon is providid to 

 the fields; and yet, ill many cases, the same pro- 

 duce, in some even a higher one was obtained, 

 than by the application ol a 4jianure cniilaining 

 carbon and nilrogeii. .As the soil, after the crop, 

 does not cmitaiu less caiboiiaceons or nilro^i:- 

 iioiis substances, it is evident that these proilncls 

 which had been obtained without any carbonic 



