22 



MONTHLY JOURKAL OF AGRICULTURE. 



adapted i'or hcuig assimilated by the phmts ; 

 this is generally otTectcd by the application 

 of slaked lime. They consequently exci-cise 

 on the vital process of the plants not a mere 

 stiumlas like the spices, but ai'e consumed for 

 the development of the leaves, seeds, roots, 

 &c., they become constituent parts of them, 

 as can be shown with certainty by chemical 

 analysis. 



The success which has followed the appli- 

 cation of these substances to the fields has 

 explained, in a most strikmg manner, the ori- 

 gin of the carbon and nitiogen in the plants. 



In the marl, in the bone-earth, in the gyp- 

 sum, in the nili'ate of soda, no carbon is pro- 

 vided to the fields ; and yet, in many cases, 

 the same produce, in some even a higher one, 

 is obtained, than by the apphcation of a ma- 

 nure containing carbon and niti'ogen. As the 

 soil, after the crop, does not contain less car- 

 bonaceous or niti'ogenous substances, it is evi- 

 dent that these products, which had been 

 obtained without any carbonic or azotic ma- 

 nures, must have got the carbon ajid nitrogen 

 of their leaves, roots and stalks from the at- 

 mosphere ; it follows, therefore, that the pro- 

 ductiveness of the fields cannot be increased 

 in proportion with a supply of carbonaceous 

 and azotic substances, l^ut that the fertility 

 depends only on the supply of those ingre- 

 dients wliich should bo provided by the soil. 



The soil not only serves the purpose of fix- 

 ing the plants and their I'oots ; it participates 

 in vegetable life tluougli the absorption of 

 certain of its elements. If these elements are 

 present in snflicient fpiantit^-, and in appropri- 

 ate propoitions, the soil contains the condi- 

 tions wliich render the plant capable of ab- 

 sorbing carbonic acid and ammonia from tiie 

 air, which is an inexhausrible storehouse for 

 them, and renders their elements capable of 

 being assimilated by their organism. 



Tlie agriculturist must, therefore, confine 

 himself to giving to the field the composition 

 necessaiy to the development of the plants 

 which he intends to grow ; it must be his 

 principal task to 8up[)ly and restore all the 

 elements required in the soil, and not only one, 

 as is so fi'equently done ; the ingredients of 

 the air, carbonic acid and ajnmonia, the plants 

 can, ill most cases, procure without man's in- 

 terference ; he must take care to give to his 

 field that physical condition which renders 

 possible and increases the assimilation of these 

 ingredients by the plant ; he must remove the 

 impediments which diminish their effect. 



The favorable influence which bone-earth, 

 gypsum, nitrate of soda, exercise on the fields 

 has uiduced many fanners to the belief, that 

 in applying them they can dispense with ma- 

 nure or with the other elements of the soil ; 

 it requires, however, only little attention to 

 see the gi-eat error of this opinion. We ob- 

 Berve that the effect of these substances is not 

 equal on all fields ; in one place the amount 

 of produce is increased by the lime, by the 

 bone-earth, and by g>'psum ; in another coun- 

 try, or on other fields, these substaiices in no | 



(70) 



way favor vegetation. From this aiise the 

 contradictory views of fanners regarding 

 these matters as manm-es. If one fanner 

 thinks the liming of his fieULs quite indispen- 

 sable for rendeiing them fertile — another de- 

 clares tliat lune produces no effect at all. 



The reason of this difference is very sim- 

 ple. The examination of a soil upon which 

 lime has had no effect, shows that it was al- 

 ready rich in this suljstance : it farther shows 

 that its efiec t extends only to those kinds of soil 

 in which lime is wanting, or in which it is 

 found in too small a quantity, or in a condition 

 which is not suited to its assimilation by the 

 plant. Lime especially sei-ves for resolving the 

 sihcates of alumina (clay) £uid consequently it 

 cannot fertilize soils in which clay is wanting, 

 for instance, sandy soils. It must be apparent 

 to every one, that on the calcareous and gyp- 

 seous fields of France and England one-half 

 per cent, of gj'psum or lime can have no in- 

 fluence at all on vegetation. This can be 

 said with equal justice of bone ashes, and of 

 eveiy other mineral substance serving for the 

 nourishment of plants. 



If these substiinces exercise a favorable ef- 

 fect, some of the constituents of the soil or 

 manure are restored, which are indisj'cnsable 

 to the nourishment of plants, and which have 

 been wanting in the soil. If this be the case 

 the other bodies, equally necessary, nKist be 

 present in sufficient quantity. On a field in 

 which sulphate of lime has acted favorably, 

 but in which clover had been cultivated 

 without it, the crop was 2,200 pounds of clo- 

 ver-hay, in which 53 pounds of potash were 

 removed. On the same field, after it had 

 been dressed with g>'psum, 8,000 pounds of 

 hay were produced, which contained 191 

 pounds of potash. If this potash had not 

 been present in the soil, the gjpsum would 

 ha\e had no effect — the crop would not have 

 been increased. On fields which are richly 

 proN-ided with all other mineral ingi'edients, 

 with the exception of gypsum, the latter is 

 applied with the greatest success. But if 

 gypsum is present in the soil, the same effects 

 are produced by ashes and lime, as is the 

 case in Flanders. On fields in which phos- 

 phate of lime is wanting, bone ashes increase 

 the i)roduce of grain, clover, or grass, and on 

 argillaceous soil, lime produces a decided im- 

 provement. All these substances act only on 

 those fields which are defective in tliem, and 

 if the other elements of the soil are j)resent. 

 The latter cause the former to come into ac- 

 tion, and vice versa. The fanners who 

 thought that by using lime, gj'psum, bone- 

 earth, &c., they might dispense with animal 

 manure,very soon observed that their fields de- 

 tcrioi-ated. They observed that after a thii-d or 

 fourth successive manuiing with those snnple 

 substances the produce decreased ; that, as 

 is the common expression, the soil became 

 tired of the manure, that at last the field 

 scarcely produced the seed. 



It is evident ft-om this, what is the action of 

 the mineral elements in the soil. If in fact, 



