Page images
PDF
EPUB

a

more

while the land was also longer kept in heart, nate husbandry could only be partially inby alternating a green crop with one of troduced. The next step was so to dry, and corn, the temptation to the evil practice loosen, and mellow these soils, as to fit them was removed, and the alternate husbandry for the growth of green crops. This was carried the day among all intelligent men, accomplished by the introduction of a sysand wherever the land was consislered fitted tem of thorough draining, by which the exfor the growth indifferently of either crop. cess of water was carried off, and the air

5. Meanwhile, this new husbandry de- was permitted to enter the soil. Experimanded constant and careful ence has shown, that such a system of drain

: working of the soil. New modes required age does loosen the stiffest soils, and many new instruments; these new instruments be- practical men assert, that there is no clay ing contrived and made by men familiar so stiff in which a skilful farmer may not with all the resources of modern mechanical now be able to raise a profitable crop of skill, to accomplish a definite end at the turnips. least cost of material, and with the least ex- To the drain succeeds the subsoil plough. penditure of physical force, brought into There are few soils upon which it ought not glaring prominence the defects of the older to be called in to perfect the stirring of the agricultural machinery. Hence the heavy land; there are as few, we believe, by which wooden gave place to the lighter iron ploughs the expense of using it will not be amply re--the lumbering four-horse wagon was suc-paid. ceeded by the quicker two or one-horse cart To this stage of improvement the practi-and gradually the grubber, the improved cal agriculturists of Great Britain inay be (Finlayson's and others) harrow, the horse- said to have generally advanced. Nearly hoe, and the scarifier, began to do portions all now concede the value of the drain, and of the work of the plough, and thus to admit many acknowledge the efficacy of the subof the spring seed being put in upon clay soil plough. They have obtained admission lands at an earlier period of the year. into large tracts of country, and they are Those who are familiar with the tillage of struggling hard to force an entrance into Essex, Hertford, and Suffolk, are aware of many more. In a former article, we showthe benefits which, in these counties, have ed how wide a field lay open for the expenbeen derived from sowing barley upon their diture of capital in the general drainage of clay lands in January and February, instead the country-how profitable such an outlay of, as formerly, in April and May.

was likely to be to the individual cultivator 6. These lighter implements suggested -and how important to the nation at large. quicker work. The drill and the horse-hoe It is interesting to bear in mind, that the could not be permitted to linger in the land, introduction of the turnip has given rise to like the old Berkshire plough, nor the hind the entire series of improvements to which to drag his slow foot behind them as his fa- we have adverted, and the culture of the ther had done in ploughing his ancient fur- turnip is still the immediate object for the row. Thus horses of a quicher step were more general attainment of which these sought for, and improved breeds, like the latest improvements are sought to be introCleveland coach-horse, uniting a quick step duced. with great strength and endurance, gradu- All the improvements above adverted to ally replaced, in improving districts, the old, are connected either with the improvement heavy, and cumbersome races. My fa- of the live stock, or of the machinery and ther,” said a Staffordshire farmer to us once, mechanical operations of the farm. But a when speaking of this subject—"My father new start has lately been taken by the art of kept fourteen farm-horses, and was always culture in this country; and it is beginning behind with his work. On the same farm, to vindicate to itself something of the digI employ only eight, but they have a little nity of a science. blood in them, and my work is never be- The practical cultivator does not readily hind."

see how science is to lessen his labor and 7. We have said that the alternate hus- anxiety, to enlighten his path or to increase bandry was introduced wherever the land his profits. The uninstructed proprietor was considered suitable indifferently for ei- understands as little how science is to benther

crop. On stiff and wet lands, which efit him, while the public at large are by no abound in many countries, it was found that means aware how much the general welfare the turnip could not be grown with advan. of the country is likely to be promoted by tage; upon such soils therefore, the alter the extended application of the results of

a

a

a

scientific research to the cultivation of the In the soil, however, the organic matter soil. What is the nature, then, of this sci- rarely exceeds, and is usually considerably entific knowledge, which is to be brought to less than one-tenth of the whole weight; bear upon the general improvement of agri- while in the plant and the animal it is rarely culture? Of what real value is it likely to less, and is usually more, than nine-tenths prove to the practical man? Of what ben- of the whole. While there is a general reefit to the country at large? These ques- semblance in composition, therefore, there tions will be, in some measure, answered is also an important special difference beby the following sketch :

tween the soil, and the plants and animals that live

upon

it. The soil is the first care of the hus- But let us study the soil a little more parbandman. This he tills, and labors, and ticularly. Whence are soils derived ? Of weeds, and from this he reaps the reward of what do they essentially consist? What is his labors. The plants are his reward; they the nature of the differences which prevail grow upon the soil; their kind and quantity amongst them? Upon what do their differare regulated by it. The nature of the soil ent agricultural values and capabilities de and the growth of the plant are therefore pend? intimately connected.

The visiter to Edinburgh who walks along Again, the plant feeds the animal. On Salisbury Crags sees a long sloping bank vegetable food ultimately all animal life beneath him, consisting of fragments of the appears to depend. The animal, therefore, crumbling rock, which, through Japse of is inseparable from the plant. The soil time, have accumulated at the base of the might exist without the vegetable, and the cliff, and formed this sloping talus. The latier might live and die though there were air, and rain, and frost, have torn down the no animals to feed upon it; but the animal solid rock, and sent its rolling fragments is the creature, as it were, and the conse- into the valley below. The seeds of plants quence of both. It may be likened to the have grown up among the loose materials roof of a structure, of which the plant forms their roots have often penetrated into the the walls and the soil the foundation. The very substance of the fragments, and have dead earth, the living plant, and the moving caused them to crumble still further. These animal are thus intimately connected. Man, plants have died, as well as the insects that the highest of living things, not only treads lived upon and among them, and have left upon the dead earth, but grows out of it, their remains intermingled with the rocky and is separated from it only by the inter- dust. Thus a soil of mingled earthy and vention of vegetable life. How truly is the organized matter has been produced ; and earth our mother, and we children of in a similar way the soils of Arthur's Seat, clay!

of the Queen's Park, of the Calton Hill, of But not only are they thus mutually de- the Pentland range, and of the Ochils and pendent, but they actually resemble each Lomonds beyond the Forth, have all been other in their nature. Take up a particle formed. of soil, and burn it in the fire; its color Such is the general history of all soils. will change and it will diminish in weight. The solid rocks have furnished their inorA part of it burns away, but the greater pro- ganic or incombustible part—the remains of portion resists the action of the fire and re- animals or vegetables have furnished the ormains behind. Take a plant of any kind, ganic part which disappears or burns away

put it in the fire ; it will nearly all dis- in the fire. appear, but a small quantity of ash will re- But rocks differ essentially in their namain, which the fire does not affect. Do ture. Some consist of granite, like the the same with the bone or flesh of an ani- heights of Dartmore, or the Wicklow mounmal, and the result will be the same. It tains, or the Highlands of Aberdeenshire will burn like the plant, but, like it, will —others of trap or basalt, like Arthur's leave something behind which defies the ac-Seat and the Giant's Causeway-others of tion of the fire. Thus the soil, the plant, numerous beds of slate, like much of Cornand the animal, alike consist of two kinds of wall, North Wales, and Southern Scotland matter : one which burns away, or is com- -and others again of limestone, like the bustible-another, which does not burn blue rocks of Northumberland and the Penaway, or is incombustible. To the former nine chain, or the yellow Dolomites, which chemists give the name of organic—to the stretch from Durham to Nottingham, or the latter, that of inorganic matter.

white chalks which cover so large a portion

and

a

of Wiltshire, Hampshire, and others of our rine. Soils which require no manure are southern counties.

thus constituted, and there are many such If rocks thus differ in their nature, it is among the virgin soils of all our colonies. obvious that the loose materials which are From whatever quarter of the world such formed by their decay must differ in like soils are brought, they are found to contain manner-must resemble, that is, in their all these substances, some of them in large, nature and composition, the rocks on which others in small, but all of them in sensible they rest and from which they have been quantity. derived. Hence the natural differences On the other hand, such soils as require to which are observed among soils of different be manured—which will not naturally grow districts, and hence also the striking simi- good crops, or which will not grow crops at larities by which soils are sometimes found all-such soils have been found either to be to be characterized over very large areas. wholly devoid of one or more of those sub

From the crumbling of a limestone is stances, to contain them in too small proporformed a calcareous soil ; from the frag- tion, or to have some of them present in too ments of a sandstone an open and often a great an excess. Thus the nature of the hungry sandy soil; from a slate rock a clay chemical, and consequently the main cause more or less cold, stiff, and impervious; of the practical differences being known, the from a trap an open loam, usually reddish, method of removing these differences springs rich, and fertile. Thus, a geological map up of itself almost without an effort of which represents by its different colors the thought. Make the soils chemically and areas covered by rocks of different kinds physically alike, and you will make them and ages, represents also the general nature, agriculturally equal. Add what is wanting capabilities, and limits of the several soils in the less productive, and bring it into the to which the fragments of these rocks have same physical condition, and you will make given rise. And this is the basis of a close, it equal to the more productive. Take a very interesting, and a practically useful away what is in excess in the one, and you connection between agriculture and geology, will make it as valuable as another from which we cannot now dwell upon, but which which it differs only by this excess. If it our readers will find illustrated and brought contain too great an abundance of saline out in the works of Professor Johnston, of matter—as the plains of Egypt, of India, which the titles are prefixed to the present and of Attica, in many places do-remove article.

this saline matter, and you enable the eleBut this general knowledge of the origin ments of fertility which the soil contains at and main cause of the differences in agri- once to manifest themselves. Thus, there cultural value which are observed among is no soil so hopelessly barren—if parching different soils, is not sufficient to guide the drought and binding frost be absent-on practical man in his economical operations. which the traces of human skill and indusThe rocks differ, and the soils differ with try may not be successfully and profitably them. But in what respects do the rocks left. really differ? What chemical diversities On these principles, though unknown to prevail among the worn and weathered frag- him, the successful farmer has always acted. ments which form our soils? These ques- If a soil, which when left unaided, gave no tions have been answered by the chemical remunerating return to the cultivator, yet analysis of numerous soils of varied qualities, gave him when regularly manured an abunand from all parts of the world. These dant harvest, it was because the manure analyses laid the foundation of that distinct added to the soil those things in which it was though still imperfect perception we now deficient, and brought it up for the time to possess of the differences and capabilities of something like the composition of more natsoils, and of the means by which they are urally favored spois. Or if the addition of severally to be improved.

one substance only to his land--of gypsum, Thus, it has been found, that a soil which of wood-ash, of nitrate of soda, or of burned is so naturally fertile that it will grow a long bones—was often effectual without other succession of crops without any addition of manure, in causing good crops to grow manure, always contains in its inorganic part where they had refused to grow before, it a notable quantity of ten or eleven different was because the absence or deficiency of chemical substances. These are potash, one only of the ten ingredients of a fertile soda, lime, magnesia, alumina, silica, iron, soil was sufficient to render his fields unmanganese, sulphur, phosphorus, and chlo-productive.

.

But further, soils change in character by taken up by the roots from the soil. Other continued cropping. The most naturally portions of their nourishment-much of fertile decline gradually in value and pro- that, for example, which forms their organductiveness. They sink slowly down into ic part-plants draw from the air, but that the class of soils which yield abundant crops which produces their inorganic part is deonly when they are regularly and abundant- rived wholly from the soil. This fact is ly manured. What was the cause of this ? connected with a further series of experiDid the soil gradually lose some of its con- | mental results, by which light has been stituents ? Did the manure constantly re-thrown upon agricultural practice and exstore them? If so, which of its constituents perience. Some plants, as we have said, had the soil lost during this degenerating leave more ash than others, and in some process? What had carried them off? parts of the same plant it is more abundant Where had they gone to? Could they be than in other parts. A ton of leaves, for recovered? How, and in what form did example, often contains ten times as much the manure restore them?

as a ton of the wood of the same tree, and Again, why were all these constituents a ton of straw contains five or six times necessary to the sertility of a soil ? It had as much as a ton of grain. But if it be been discovered by analysis, that the most wholly taken from the soil, that plant, or fertile soils always did contain all these sub- that part of a plant which contains the stances. But must it of necessity contain most, must exhaust the soil the most. Thus, them all? If so, why were they necessary, one clear reason appeared for what had what purpose did they serve?

been so long observed by practical men. All these questions, and many more of a Crops exhausted the soil, because they ackindred character, were answered by a care- tually took up and carried off a portion of ful study of the plants themselves, which its inorganic substance—and one crop exgrow naturally, or which are raised by art hausted the soil more than another, beon our various soils. Let us turn our atten- cause it robbed it of a larger proportion of tion, then, to the plant.

these inorganic substances. All vegetable substances, as we have al- Of what kinds of matter did this ash conready seen, consist of a combustible and an sist? It was taken up from the soil, but incombustible part. This incombustible was it taken up indiscriminately and at part—the ash they leave behind when they random from the whole soil ? Or were are burned-forms, in general, only a small certain substances selected by the roots, proportion of their weight. A hundred and sucked up out of the soil in preference pounds of wheat leave when burned some- to others? These questions suggested two thing less than two pounds of ash, the same inquiries to the analytical chemist. First, weight of dry wood often leaves less than what is the general composition of the ash ? half a pound, while straw and hay leave and second, what special differences exist from five to ten pounds from every hundred. among the ashes of different plants, and of Thus the proportion of ash varies from half different parts of the same plant? a per cent. to 10 per cent. of the weight of The nature of the ash. When subthe dried plant.

jected to a rigorous chemical analysis, the Is this small quantity of incombustible ash of the plant, like the incombustible matter really necessary to the plant, and es- part of the soil, was found to contain nine sential to its growth? If 100 lbs. of dry oak or ten different substances. These were wood leave only six ounces of ash when potash, soda, lime, magnesia, silica, iron, burned, can these few ounces really be of manganese, sulphur, phosphorus, and chloessential moment to the existence and health rine—the same exactly as are present in the of the tree? The analysis of the plant an- inorganic part of the soil. They are to be swers that this ash is never absent, and is detected in greater or less proportion in the therefore, without doubt, in some way ne- ash of all our cultivated crops, and they are cessary to the growing crop. How it is wholly derived from the soil

. Here at once necessary, and why—with a view to what a bright light casts itself back upon the important natural end—was deduced from constitution of the soil itself. All fertile a beautiful train of research, subsequently soils—so careful analysis had said-did entered upon, and to which we shall by and contain a notable proportion of all these by advert.

substances; but the reason did not appear. But whence do plants derive this inor- This reason now breaks in upon us of itganic matter they always contain? It is self. The plants contain all these things;

Ist.

they form a part—a necessary part, as we proportion characterizes the grain, while shall afterwards see-of its substance; and that of silica in large proportion characteras it can get them only from the soil, it is izes the straw. clear that the soil must contain them, if the Similar results are obtained by the explant is to grow in a healthy manner upon it. amination of the ash of different plants.

But there is a special difference between Some contain more lime and magnesia, the soil and the ash of the plant, which it is others more potash and soda, others more interesting to notice. Among the constitu- sulphur, or phosphorus, or chlorine; and ents of the soil, alumina—the substance thus the general law appears to hold, that which gives their stiffness and tenacity to under precisely the same circumstances one clays-holds a prominent place. In the kind of crop will usually take up from the plant it is rarely found, and always in in- soil more of one kind of inorganic matter, considerable quantity. The presence of another crop more of another kind. this substance, therefore, is a character by In its relations to practical agriculture, which the soil is distinguished from the ash this result of experiment involves two disof the plant.

Its functions in relation to tinct conclusions. the growth of plants are very important, but 1. As different parts of the same plant these functions are chiefly performed in require different proportions of these inorthe soil itself.

ganic substances, they must, at different 2d. Special differences in the quality of seasons of their growth, draw these subthe ash. But though every plant we culti-stances in different proportions from the vate, taken as a whole, leaves an ash, in soil-more of one thing at one time, more which all the above substances are to be of another thing at another. They may found, yet that which is left by different flourish, therefore, on a given soil, at one parts of the same plant contain them in period of their growth, and not at another. very different proportions.

That soil which clothes the tree with luxWe have already seen that the absolute uriant verdure, may yet not be able to ripen quantities of ash left by the leaves and the its fruit—that which causes the straw to stems, by the straw and the grain, are very rush up to early maturity may refuse to fill different, but the nature of the ash left by the ear. these different parts also varies. It has 2. As different plants also draw from the been found, for example, that the same soil the same substances in unlike proporsample of Hopeton oat ga ve fromits several tions, they will grow with unlike vigor in parts an ash which in 100 lbs. contained different soils. Hence that which bears a respectively of sulphuric acid and alkaline profitable crop of one kind, is ofter: unable matter, the following very different propor- to yield a good return of another— hence tions :

also the varied flowers and herbage which

diversify the surface of all our fields.

Sulphuric Acid Grain, 31.15

2.54

The beautiful principle involved in these Straw, 18.24

23.00

conclusions, is susceptible of so many inLeal, 15.68

15.23 teresting applications—explains so many Chaff, 4.36

6.51 practical points long known, though little

understood—and is so rich in suggestions And not only are the proportions of the for the future improvement of every branch several substances unlike, but in certain of husbandry, that we may be permitted to parts of the plant some of them are almost pause a little here with the view of present entirely absent. Thus, the grain and the ing to our readers one or two of the more straw of wheat leave an ash which contains intelligible of the illustrations which start of phosphoric acid* and silica respectively, up in crowds before us.

Thus, in regard to exhaustion—the naPhosphoric Acid. Grain,

ture of which we have already, in some 50 per cent. None. Straw, 1 to 3

30 to 60

measure, learned to understand—this prin

ciple showed that it might be of two kinds, The presence of phosphoric acid in large produced in different ways, and demanding

each its peculiar mode of cure at the hands * Phosphoric acid is produced when phosphorus of the economical farmer. It might be a is burned in the air. The white fumes given off by a lucifer match, when it first kindles, consist general exhaustion, by which, through long of phosphoric acid. This acid exists largely in cropping of various kinds, the soil had bebones,

come generally poor in all those varieties of

Potash and Soda.

[ocr errors]

Silica.

.

per cent.

« ՆախորդըՇարունակել »