272 



FARMERS' REGISTER 



[No. 5 



Berne, where the primitive formation, consisting: 

 of granite, gneissi, mica-slate, and similar rocks, 

 abounds, the larch is indigenous, growing luxuri- 

 antly, and attaining to a great size." 



Clay, sand, gravel, and peat, combined in vari 

 ■ous proportions, Ibrni a base or soil, in the inter- 

 Slices of which, materials, capable of atTordinir 

 nourishment to plants, are rendered fit to be turned 

 to account in their economy. Plants, as well as 

 animals, require for their support a due supply of 

 the elements of which they are composed, and 

 these they obtain from amongst the earthv parti- 

 cles in which their fibres are imbedded. The soil, 

 in fact, is to a plant what the stomach and intes- 

 tines are to animals. It is the laboratory in which 

 a variety of sui)stances are so altered and prepared 

 by mechanical and chemical agency, as to be ca- 

 pable of entering into the composition of veireta- 

 bles. and conducing to their growth. All organ- 

 ized bodies are resolvetl after death, by the chemi- 

 cal process termed putrefaction, into a number of 

 simpler forms, six of which — ^water, nitrogen, car- 

 bonic acid, humic acid, liine^ and potass — are es- 

 sentially necessary for the constitution ol' plants, 

 and are, tlierefore, to be found in greater or less 

 abundance in every soil which is capable of sup- 

 porting them. The first three substances are im- 

 bibed by plants from the surrounding atmosphere, 

 besides being ILirnished by the soil ; but the quan- 

 tity so absorbed hy the leaves is trifling when 

 compared with that which is continually assimila- 

 ted by the roots. Humic acid, on the other hand, 

 is peculiar to vegetable and animal matters, and is 

 indispensable to soils ; lor, apart from its proper- 

 ties as a nutriment lor plants, it is invaluable as 

 being the solvent which enables lime and potass 

 to enter into their composition. Though the agri- 

 cultural chemistry of these bodies is, to a certain 

 extent, a dull and stale subject, it is necessarv that 

 it should be pretty well understood, in order to (a- 

 cilitate the explanation and comprehension of other 

 departments, and, therelbre, our titne will not be 

 badly spent m taking a short survey of the points 

 most worthy of attention. 



The moisture of soils is derived from several 

 sources ; it may be formed hy the decomposition 

 of organized substances, into an explanation of 

 which process, however, we need not enter; or it 

 may be conveyed to the surface of the earth, ei- 

 ther by deposition from the air, as in the case of 

 fogs, dews, and showers, or by filtration through 

 lower strata, as is usual in springs. In whatever 

 way it originates, it serves the important end of 

 holding in solution the other requisites for vegeta 

 tion : without it, in (act, the other ingredients of 

 soils could not be available. It is not only an in- 

 dispensable constituent of a soil, but also a princi- 

 pal component of every plant, — 23 out of every 

 25 tons of globe turnips, for example, being calcu- 

 lated to consist entirely of water. The experi- 

 ments of Da Hamel and Bonnet, who reared plants 

 on moes and sponges moistened with water only, 

 led to the conclusion, that simple water is all that 

 is necessary for their growth ; but in these inves- 

 tigations they forgot that the materials of which 

 they had constructed their mimic soil, contained 

 many things which would, unknown to them, be 

 taken up by the fluid, and carried to the plant. A 

 ealad can certainly be grown and brought to tole- 

 rable perfection in a wetted blanket, and bulbous 

 roots will sprout, and even fiower, when aided only 



bj'^ a supply of wa'er ; but growth proceeds just 

 so long as the nutritive matter which is contained 

 in every seed and bulb, remains unexhausted, and 

 cannot, therelbre, be owing entirely to the mois- 

 ture. 



Wafer that has been much in contact with the 

 air, is always superior in fertilizing properties to 

 such as has not be(m incorporated with it. This 

 is owinir 'o water being of itself incapable of serv- 

 ing as l()od lor plants, and only acting as a promo- 

 ter of fertility in proportion as it contains less or 

 more of other substances. Atmospheric air, toge- 

 ther with carbonic acid (a eras which that air al- 

 ways holds in limited quantity,) are of great utility 

 in tile economy of plants, and are usually Ibund in 

 combination with water. But the proportions in 

 which these ixa^es unite with water, vary accord- 

 iniT to their facilities II>r intermixture ; and. as agi- 

 tation is fivorablp to their intimate contact, tfie 

 water of rivers which have run a long and rapid 

 course, is nyuch niore. beneficial to veirelation, than 

 that which has remained for some time sraornant. 

 Hence the profits to be derived from irrigation arc 

 enhanced by causing the water to flow, in prefer- 

 ence to allowing it to stagnate on the soil. In ad- 

 dition to these gases, water which has passed 

 through a lengthy channel, holds in suspension va- 

 rious earthy and organic particles, frequently cal- 

 culated to ameliorate a soil, and to become a 

 source of nourishment to plants. Accordinir to 

 Sir II. Davy, (Kli-ments of Agricultural Chemis- 

 try, 2 Edit. p. 352,) it may be taken as a general 

 principle, that water containing salts of iron, 

 thoiiirh posspssi'd of fertilizing effects when ap- 

 plied to so'ls impreirnated with lime, is always in- 

 jurious to soils which do not effervesce with acids; 

 and that calcareous wafers, which are known by 

 the earthy deposite they aflord when boiled, 

 are of most use on sandy soils, or other soils con- 

 laininij no remarkable quantity of chalk. 



Nitrogen and carbonic acid, though combined 

 with many ingredients of soils, are only found in 

 nuantity in the compound termed humic acid. 

 This acid, when resolved by the operations of the 

 chemist into ifs ultimate elements, is Ibund to be 

 composed of oxy<;en, hvdrocren. carbon, and ni- 

 trotren, besides a few saline and earthy n)atters, 

 which are not considered essential to if, Piima- 

 rily, it may be viewed as made up of a base called 

 humin, united to the great ■,\cii.\\\\'\niy: pnncip)e, ox- 

 ygen. Himnn, or as it is occasionally termed, 

 vegetable ninuld, is a dark-colored unctuous sub- 

 stance, without either taste or smell, which has 

 been Ibund by several French chenjists of celebri- 

 ty to constitute the leading principle in soils and 

 manures. It is formed by the slow decomposition 

 of vegetable and animal matter, and varies slight- 

 ly in quality accordinir to the nature of the sources 

 from which it has been derived. To it is owing 

 the fertility of soils, and therefore, as we would 

 naturally expect, it is met with in greatest abun- 

 dance in the earth of gardens, and old well rotted 

 dunghills. Chemistry can avail nothing in the 

 formation ofhumin, for it is a product only obtaina- 

 ble from bodies that have been at one time posses- 

 sed of life; and, therefore, it cannot be imitated by 

 the dexterity of^ man. Every thing gifted with an 

 organized formarion is converted, so soon as it 

 has ceased to live, and has been deposited in a 

 suitable locality, in this peculiar matter. The ex- 

 posure to the atmosphere of dead animal or ve- 



