CEOR5 SIAN URES. ] 



CHEMISTRY. 



425 



purposes. In Lincolnshire and Cambridgeshire we see 

 heavy corn crops, owing to the land containing the es- 

 sential constituents in the soil. 



Soils differ greatly, not only in their chemical consti- 

 tution, but also in respect to their physical characteristics. 

 A solid clay will not permit water to pass through it, 

 whilst sand allows that fluid to percolate most readily. 

 Now, generally speaking, the clay is rich in all the sub- 

 stances which are required to produce the plant, whilst 

 sand is comparatively deficient ; and yet a better crop 

 shall be produced from sand soil than from heavy clay. 

 This fact shows that we must not depend solely in the 

 results of a chemical analysis to direct us in the choice of 

 a soil. Indeed, we have seen in Invernesshire and Nairn- 

 shire, in the north of Scotland, soils (if they deserve the 

 name) consisting of nothing but unmixed sea-sand, in 

 their natural state, but which, by means of manures, 

 afford excellent crops of wheat, barley, and oats. An 

 excess of moisture in soils checks vitality equally with 

 droughts ; therefore, not only is a clay improved, in a 

 chemical point of view, by admixture with sand and lime, 

 but its physical character is altered, and it becomes more 

 readily drained, "warmer," and therefore fitter for the 

 production of any kind of crops. 



After one kind of plant has been grown in a soil, it 

 will be found to have abstracted such parts of that soil 

 as have been required to afford it nourishment ; and thus 

 the soil has become deteriorated. Now, it is a remark- 

 able fact, that the absence of an ingredient will entirely 

 ] irevent the production of seeds and fruit. Lime is essen- 

 tially necessary for this purpose ; in fact, pea and bean 

 plants will bear flowers but not seed in its absence. We 

 have at this moment before us a luxuriant crop of beans, 

 grown in a soil in which the same kind of seed was sown 

 yuar, but, in the absence of lime, was absolutely un- 

 productive. 'At the early part of the present year, the 

 soil was well dug up and limed, and now every stem is 

 loaded with pods. On another soil, we tried precisely the 

 same experiment some years ago ; half was limed, and 

 the other half was exhausted : the latter bore plenty of 

 leaves, but not a pod ; while the former afforded abun- 

 dant crops, the same kind of seed being sown in each. 

 It is true that such are extraordinary examples ; but the 

 farmer has plenty of them, although not so distinctly 

 marked as these. Poor crops generally indicate that their 

 producer has failed in his duty and practical knowledge. 

 This is the great secret of the success which attends 

 farming in the north of England and in Scotland. There 

 the climate is everything that can be against the farmer, 

 but his practical experience overcomes the natural defi- 

 ciencies of the soil and climate ; and thus he can produce 

 crops on land which, in the south of England, farmers 

 would only compare to those of a stone wall, as to its 

 probabilities of producing power. We have seen oats 

 growing on a limestone rock, on which the soil rarely ex- 

 ceeded four inches in depth. There the soil had to be 

 brought to the rock ; whilst in the southern counties, 

 rit-h loam, extending many feet in depth, may be found. 

 \\ 'In -n a deep soil is superficially exhausted, it may be 

 improved by being deeply ploughed. By this means the 

 subsoil is brought to the surface, and so mixes with and 

 replaces that which had been exhausted by the crops that 

 had ;rown on it. In a similar manner, the rotation of 

 crops benefits a soil ; for if turnips, for instance, be grown 

 where wheat has been reaped, they merely take up water ; 

 whilst the cereal has withdrawn silex, alumina, lime, <tc. 

 The atmosphere then has time to break up and decom- 

 pose such elements into a soluble state, and so fit the 

 soil, by a kind of reproductive process, for a repetition 

 of the cereal growth after a lapse of time. Herein con- 

 sists the advantage of allowing the fallowing of land. 

 The soil is left to itself for a year or two ; the atmosphere 

 and moisture decompose the felspar and other minerals 

 of which it is composed, and thus render it fit for grow- 

 ing various crops in succession. 



Another point of great importance is the degree of 

 pulverisation of land. As a plant grows it shoots out 

 from the main root a vast number of radicles, by means 

 of which it absorbs, from a thousand sources, its mineral 



VOL. I. 



food. If these radicles are confined by a close soil, the 

 plant droops and dies ; whilst if the soil be porous, and 

 finely divided, these little roots can extend in all direc- 

 tions, and so become feeders for the main root and the 

 plant. Ploughing, digging, harrowing, the burrowing of 

 animals, as moles, worms, <fec., the decay of vegetable 

 fibres, all make such channels in the soil, and also assist 

 in its drainage ; and many manures, such as straw, and the 

 like, thus effect a physical as well as a chemical im- 

 provement in land. This is a matter of great impor- 

 tance ; although we feel sure that it is systematically 

 neglected, and generally by pure accident only obtained. 

 Burning clay has lately been much resorted to for this 

 purpose ; and, where coal is cheap, is an excellent prac- 

 tice. The retention and close character of the clay is 

 destroyed, and the soil rendered into a finer state of 

 division, and therefore more porous. 



MANURES ANALYSIS OF SOILS. An experienced 

 farmer will readily guess as to the nature of the sub- 

 stances abstracted from a soil by any crop ; but chemical 

 analysis more certainly points out this, and also suggests 

 what kind of manure maybe required to restore fertility. 

 We shall not enter into minute details of the plan of 

 analysis, as that has already been done at page 394, and 

 succeeding pages. We shall only give directions as to 

 the preliminary part of the process. 



It will generally happen that more than one kind of 

 soil is contained in a field, or many fields may consist 

 of the same kind. An average of the soil should, there- 

 fore, be gathered, and the various samples mixed to- 

 gether. The first point to ascertain will be the amount 

 of moisture which the soil contains. For this purpose 

 all stones should be removed, and the earth may be 

 weighed. It is then to be exposed for some hours to a 

 temj>erature not exceeding 212 Fah. This will drive off 

 all absorbed water, and the loss of weight will indicate 

 the amount present. 



The absorbing power of a soil may be learned by dry- 

 ing and weighing samples as above. They may then be 

 well wetted, and left till all loose water has drained off. 

 Their comparative weights being then ascertained, their 

 absorptive power will also be learned. 



After the amount of water in the soil has been ascer- 

 tained, the next step will be to find out how much 

 soluble matter it contains. This may be done by agitat- 

 ing the specimen for some time with cold water, when 

 the soluble parts may be removed and tested, in the way 

 directed at page 398. The insoluble portion may then 

 be digested with hydrochloric acid, to remove iron, <fcc. , 

 and the remainder of the analysis carried out in the way 

 suggested at the page referred to, et seq. By such a 

 method, and following the instructions already given, 

 any one of ordinary intelligence may gain sufficient know- 

 ledge of the constituents of a soil, and distinguish the 

 earths and metallic oxides it contains. A quantitative 

 analysis requires considerable knowledge and experience, 

 and is better left to the professional chemist. 



Having discovered what substance the soil is deficient, 

 of, the next step is to supply the required material. 

 This is done by manures ; and tha choice of the proper 

 one is decided by the results of ."the analysis. Such a 

 multitude of these preparations fe offered at the present 

 day, and each is stated to be the'" verv best," that a 

 farmer will, in many cases, be in a state of perplexity as 

 to what he should choose. We shall not increase his 

 difficulties by giving directions, which, at the best, would 

 be but suggestive, if of use at all. So much depends on 

 drainage, climate, and other physical circumstances, 

 besides those of a chemical character, that it would be 

 impossible for us to specify a universal panacea for all 

 the ills that earth is heir to. We shall, therefore, simply 

 name the proximate elements essential, and the manures 

 which contain them, and leave to practical experience 

 their choice and application. In purchasing any kind 

 of manure, we may warn the farmer that he may be 

 jreatly deceived. The practice of adulterating guano with 

 land, &c. , is very common ; and, in every case, a certifi- 

 cate of analysis should be insisted on at the time of pur- 

 chase. Many respectable houses always furnish this. 



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