THE FARMERS' REGISTER. 



429 



the piirfare of the. soil. This deposife of vpfjetn- 

 ble extract is one ol' the cniisee why venjeiahle, 

 inoui'l is mo8l abundant at and near the PiirlHce 

 or soils, and assists in prodiioinij "the hiack atid 

 brown rich vejielahle nioiilil." in which Davy 

 Bays "the earttis seem to he in combinMiion with 

 a peculiar extractive matter aflonled durinij the de- 

 coniposiMon of vcnjetahlep." Hence there would 

 seem to be a continual accumulation of L^eine and 

 other vegetable matters ai and near the surface, 

 so Ions as the quantity of such matters- furnished 

 by decaying vegetaiion exceeds that which was 

 con%umed by the frrowini; plants. In the course 

 of lime, this accumulation of vetretable matter, at 

 the surlace of the earth, would become very great 

 if there were no means of carrying it off. Jn cal- 

 careous soils there is a chemical agency, which 

 exerts great energy in retaining and confining 

 this superabundance of vejjelable food, so that 

 the accumulation becomes very considerable. But 

 in soils which are destitute of calcareous earth no 

 such conf:idcrable accumulations are found. This 

 is probably owing in part to the nature of the ve- 

 getable crowth, whii'h may be incapable of draw- 

 ing much of its Ibod from the atmosphere, and 

 consequently the decaying vegetation may furnish 

 no more vegetable matter to the soil than it drew 

 from it lor its own nourishment. But as exhaust- 

 ed lands, even in the poorest soil, when suffered 

 to grow up in timber, are found to increase slowly 

 in lertility, it follows as a necessary consequence, 

 that in the course ol time there would be a con- 

 siderable accumulation of vegetable matter on 

 the surface ot" the soil, unless some agency is at 

 work to carry off' the superabundance. What 

 that agent is, and what are the best means o( 

 counteracting its effi^cts. is an important inquiry. 

 From the tenor of your ' Essay on Calcareous Ma- 

 nures,' It is obvious you suppose the effect is pro- 

 duced by certain vegetable acids neutralizing any 

 lime which may Ibrnierly have composed one of 

 the ingredients of the soil, and then combininsr 

 with gcine and other vetretable products, and 

 thereby rendering them unfit for vegetable food 

 for the more useful plants. If your views on this 

 subject are correct, if would seem to follow ihat 

 there is in fact no loss ol' vegetable food from the 

 want of a soil to fix and retain it, hut that it is 

 only rendered inefR.-ient in consequence of its 

 combination with certain acids in tfie soil. And 

 it would seem thai, if it were all retained in com- 

 bination with acids, by the application of a due 

 proportion of carbonate of lime the accumulated 

 Ibod of plants would immediately become availa- 

 ble, and the soil be restored to ihe highest degree 

 of fertility of which it was capable. These views 

 are very encouraging, and you have sustained 

 ihem by such prools and illustrations as to render 

 them extremely probable.* 



* The opinion expressed in the last passage we 

 consider as sound and true within certain limits — but 

 not to such extent as supposed by our correspondent. 

 "Vegetable matters, the remains of plants previously 

 grown there, do, from several causes, greatly accumu- 

 late on naturally poor lands, left at rest, and especially 

 on forest lands. But this accumulation has a limit, 

 which is fixed in each case by the circumstances of 

 the soil ; and when that limit i.s reached, we infer that 



The recent discovery of geinr. or hvmin, and 

 the acid found under certain circiimsinncfs by the 

 combination ol oxygen wilh this base, seema to 

 prove that the existence of an acid in a soil is not 

 iihcays prejudicial to ilie grovvih of useful veijela- 

 tion. Proiessor Kennie, a8 quoted in your essay, 

 says, "humic acid, however, which I may re- 

 mark is not sour to the taste, readily combines 

 with many of the substances iound in soils and 

 u'anures, and not only renders them, but itself 

 also, easy to he dissolved in water, which in their 

 separate slate could not lake place. In this way 

 humic acid will combine wilh lime, polaKu and am- 

 monia, in the form of humates, and the smallest 

 portion of these will render it soluble in water and 

 fit to be taken up by the spongelels of the root 

 fibres." 



He, farther remarks, "It appears to Iiave been 

 from ignorance of tlie important action of the hu- 

 mic acid in thus lielpinu to dissolve earthy mat- 

 ters, that the older writers were so puzzled to dis- 

 cover how lime and potass got into plants." Pro- 

 lessor Rennie says humin or (as called by Ber- 

 zelius) gefrje is composed of carbon and hydro- 

 gen, and the addition of oxygen to this base to 

 lorm humic or geic acid. This, I apprehend, can 

 no more render it poisonous to plants than the ad- 

 dition of oxygen to carbon, thereby forming car- 

 bonic acid, can render that substance prejudicial 

 to the growth of vegetation. This acid, so far Horn 

 being prejudicial, is the principal source of the 

 supply of lood for vegetables Irom the atmosphere. 



Berzelius says thai"i/u' carbonaceous mould, 

 which changes a part of the air [atmosphert] in- 

 to carbonic acid, is itself changed by the air into 

 geine and into the extract of mould ; and it is up- 

 on this transformation Ihat appears to depend, in 

 part, the advantages derived Irom the ullage of 

 the soil, which is divided by the action of the 



the value of all subsequent additions is lost, as regu- 

 larly as received. Thus, we suppose that the common 

 poor pine and whortleberry ridges ot lower Virginia, 

 which will scarcely produce more than 10 bushels of 

 corn, in their new and best state, actually have at first 

 vegetable raanure enough to produce 2.5 or 30 bushels ; 

 and which vegetable manure might have been made 

 useful, be fixed, and become permanent in the soil, sim- 

 ply by adding enough of calcareous manure, at or be- 

 fore clearing the land, and giving time for the two to 

 combine together, and both with the soil. But no 

 more than the supposed maximum of vegetable mat- 

 ter (in its various and progressive states of decompo- 

 sition,) could remain uncombined viWh the poor soil; 

 and if left for 1000 years without cultivation, we sap- 

 pose that there would be not only no further increase 

 of fertihty, but also, in our warm and dry climate, no 

 greater accumulation of vegetable matter. The ex- 

 cess would rot, and go off in gases, the final products 

 of decomposition. 



But, notwithstanding the exception stated, and 

 others unnecessary to state here, the views presented 

 by Jucige Beatty are certainly correct, and such as we 

 meant to maintain within very extensive limits ; and so 

 extensive as to afford as much encouragement to the 

 improver of soil, as need be desired. — Ed. F. R. 



