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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 considered 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 a more constant and careful ence has shown, that such a system of drainworking 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 -and gradually the grubber, the improved (Finlayson's and others) harrow, the horsehoe, and the scarifier, began to do portions of the work of the plough, and thus to admit of the spring seed being put in upon clay lands at an earlier period of the year. Those who are familiar with the tillage of Essex, Hertford, and Suffolk, are aware of the benefits which, in these counties, have been derived from sowing barley upon their clay lands in January and February, instead of, as formerly, in April and May.

To this stage of improvement the practical agriculturists of Great Britain may be said to have generally advanced. Nearly all now concede the value of the drain, and many acknowledge the efficacy of the subsoil plough. They have obtained admission into large tracts of country, and they are struggling hard to force an entrance into many more. In a former article, we showed how wide a field lay open for the expenditure of capital in the general drainage of the country-how profitable such an outlay 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 could not be permitted to linger in the land, like the old Berkshire plough, nor the hind to drag his slow foot behind them as his father had done in ploughing his ancient furThus horses of a quicker step were sought for, and improved breeds, like the Cleveland coach-horse, uniting a quick step with great strength and endurance, gradually replaced, in improving districts, the old, heavy, and cumbersome races. My father," said a Staffordshire farmer to us once, when speaking of this subject-" My father kept fourteen farm-horses, and was always behind with his work. On the same farm, I employ only eight, but they have a little blood in them, and my work is never behind."

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7. We have said that the alternate husbandry was introduced wherever the land was considered suitable indifferently for either crop. On stiff and wet lands, which abound in many countries, it was found that the turnip could not be grown with advantage; upon such soils therefore, the alter

It is interesting to bear in mind, that the introduction of the turnip has given rise to the entire series of improvements to which we have adverted, and the culture of the turnip is still the immediate object for the more general attainment of which these latest improvements are sought to be introduced.

But a

All the improvements above adverted to are connected either with the improvement of the live stock, or of the machinery and mechanical operations of the farm. new start has lately been taken by the art of culture in this country; and it is beginning to vindicate to itself something of the dignity of a science.

The practical cultivator does not readily see how science is to lessen his labor and anxiety, to enlighten his path or to increase his profits. The uninstructed proprietor understands as little how science is to benefit him, while the public at large are by no means aware how much the general welfare of the country is likely to be promoted by the extended application of the results of

scientific research to the cultivation of the soil. What is the nature, then, of this scientific knowledge, which is to be brought to bear upon the general improvement of agriculture? Of what real value is it likely to prove to the practical man? Of what benefit to the country at large? These questions will be, in some measure, answered by the following sketch:

The soil is the first care of the husbandman. This he tills, and labors, and weeds, and from this he reaps the reward of his labors. The plants are his reward; they grow upon the soil; their kind and quantity are regulated by it. The nature of the soil and the growth of the plant are therefore intimately connected.

Again, the plant feeds the animal. On vegetable food ultimately all animal life appears to depend. The animal, therefore, is inseparable from the plant. The soil might exist without the vegetable, and the latter might live and die though there were no animals to feed upon it; but the animal is the creature, as it were, and the consequence of both. It may be likened to the roof of a structure, of which the plant forms the walls and the soil the foundation. The dead earth, the living plant, and the moving animal are thus intimately connected. Man, the highest of living things, not only treads upon the dead earth, but grows out of it, and is separated from it only by the intervention of vegetable life. How truly is the earth our mother, and we children of clay !

In the soil, however, the organic matter rarely exceeds, and is usually considerably less than one-tenth of the whole weight; while in the plant and the animal it is rarely less, and is usually more, than nine-tenths of the whole. While there is a general resemblance in composition, therefore, there is also an important special difference between the soil, and the plants and animals that live upon it.

But let us study the soil a little more particularly. Whence are soils derived? Of what do they essentially consist? What is the nature of the differences which prevail amongst them? Upon what do their different agricultural values and capabilities depend?

The visiter to Edinburgh who walks along Salisbury Crags sees a long sloping bank beneath him, consisting of fragments of the crumbling rock, which, through lapse of time, have accumulated at the base of the cliff, and formed this sloping talus. The air, and rain, and frost, have torn down the solid rock, and sent its rolling fragments into the valley below. The seeds of plants have grown up among the loose materials— their roots have often penetrated into the very substance of the fragments, and have caused them to crumble still further. These plants have died, as well as the insects that lived upon and among them, and have left their remains intermingled with the rocky dust. Thus a soil of mingled earthy and organized matter has been produced; and in a similar way the soils of Arthur's Seat, of the Queen's Park, of the Calton Hill, of the Pentland range, and of the Ochils and Lomonds beyond the Forth, have all been formed.

But not only are they thus mutually dependent, but they actually resemble each other in their nature. Take up a particle 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 and 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 chemists give the name of organic-to the latter, that of inorganic matter.

nine chain, or the yellow Dolomites, which stretch from Durham to Nottingham, or the white chalks which cover so large a portion

of Wiltshire, Hampshire, and others of our southern counties.

If rocks thus differ in their nature, it is obvious that the loose materials which are formed by their decay must differ in like manner-must resemble, that is, in their nature and composition, the rocks on which they rest and from which they have been derived. Hence the natural differences which are observed among soils of different districts, and hence also the striking similarities by which soils are sometimes found to be characterized over very large areas.

rine. Soils which require no manure are thus constituted, and there are many such among the virgin soils of all our colonies. From whatever quarter of the world such soils are brought, they are found to contain all these substances, some of them in large, others in small, but all of them in sensible quantity.

On the other hand, such soils as require to be manured-which will not naturally grow good crops, or which will not grow crops at all-such soils have been found either to be wholly devoid of one or more of those substances, to contain them in too small proportion, or to have some of them present in too great an excess. Thus the nature of the chemical, and consequently the main cause of the practical differences being known, the method of removing these differences springs

From the crumbling of a limestone is formed a calcareous soil; from the fragments of a sandstone an open and often a hungry sandy soil; from a slate rock a clay more or less cold, stiff, and impervious; from a trap an open loam, usually reddish, rich, and fertile. Thus, a geological map up of itself almost without an effort of which represents by its different colors the areas covered by rocks of different kinds and ages, represents also the general nature, capabilities, and limits of the several soils to which the fragments of these rocks have given rise. And this is the basis of a close, a very interesting, and a practically useful connection between agriculture and geology, which we cannot now dwell upon, but which our readers will find illustrated and brought out in the works of Professor Johnston, of which the titles are prefixed to the present article.

But this general knowledge of the origin and main cause of the differences in agricultural value which are observed among different soils, is not sufficient to guide the practical man in his economical operations. The rocks differ, and the soils differ with them. But in what respects do the rocks really differ? What chemical diversities prevail among the worn and weathered fragments which form our soils? These questions have been answered by the chemical analysis of numerous soils of varied qualities, and from all parts of the world. These analyses laid the foundation of that distinct though still imperfect perception we now possess of the differences and capabilities of soils, and of the means by which they are severally to be improved.

thought. Make the soils chemically and physically alike, and you will make them agriculturally equal. Add what is wanting in the less productive, and bring it into the same physical condition, and you will make it equal to the more productive. Take away what is in excess in the one, and you will make it as valuable as another from which it differs only by this excess. If it contain too great an abundance of saline matter-as the plains of Egypt, of India, and of Attica, in many places do-remove this saline matter, and you enable the elements of fertility which the soil contains at once to manifest themselves. Thus, there is no soil so hopelessly barren-if parching drought and binding frost be absent-on which the traces of human skill and industry may not be successfully and profitably left.

On these principles, though unknown to him, the successful farmer has always acted. If a soil, which when left unaided, gave no remunerating return to the cultivator, yet gave him when regularly manured an abundant harvest, it was because the manure added to the soil those things in which it was deficient, and brought it up for the time to something like the composition of more naturally favored spots. Or if the addition of 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 a ton of straw contains five or six times as much as a ton of grain. But if it be wholly taken from the soil, that plant, or that part of a plant which contains the most, must exhaust the soil the most. Thus, one clear reason appeared for what had been so long observed by practical men. Crops exhausted the soil, because they actually took up and carried off a portion of its inorganic substance-and one crop exhausted the soil more than another, because it robbed it of a larger proportion of these inorganic substances.

Again, why were all these constituents necessary to the fertility of a soil? It had been discovered by analysis, that the most fertile soils always did contain all these substances. But must it of necessity contain them all? If so, why were they necessarywhat purpose did they serve?

All these questions, and many more of a kindred character, were answered by a careful study of the plants themselves, which grow naturally, or which are raised by art on our various soils. Let us turn our attention, then, to the plant.

All vegetable substances, as we have already seen, consist of a combustible and an incombustible part. This incombustible part-the ash they leave behind when they are burned-forms, in general, only a small proportion of their weight. A hundred pounds of wheat leave when burned something less than two pounds of ash, the same weight of dry wood often leaves less than half a pound, while straw and hay leave from five to ten pounds from every hundred. Thus the proportion of ash varies from half a per cent. to 10 per cent. of the weight of the dried plant.

Is this small quantity of incombustible matter really necessary to the plant, and essential to its growth? If 100 lbs. of dry oak wood leave only six ounces of ash when burned, can these few ounces really be of essential moment to the existence and health of the tree? The analysis of the plant answers that this ash is never absent, and is therefore, without doubt, in some way necessary to the growing crop. How it is necessary, and why-with a view to what important natural end- -was deduced from a beautiful train of research, subsequently entered upon, and to which we shall by and by advert.

Of what kinds of matter did this ash consist? It was taken up from the soil, but was it taken up indiscriminately and at random from the whole soil? Or were certain substances selected by the roots, and sucked up out of the soil in preference to others? These questions suggested two inquiries to the analytical chemist. First, what is the general composition of the ash? and second, what special differences exist among the ashes of different plants, and of different parts of the same plant?

1st. The nature of the ash. When subjected to a rigorous chemical analysis, the ash of the plant, like the incombustible part of the soil, was found to contain nine or ten different substances. These were potash, soda, lime, magnesia, silica, iron, manganese, sulphur, phosphorus, and chlorine-the same exactly as are present in the inorganic part of the soil. They are to be detected in greater or less proportion in the ash of all our cultivated crops, and they are wholly derived from the soil. Here at once a bright light casts itself back upon the constitution of the soil itself. All fertile soils-so careful analysis had said-did contain a notable proportion of all these 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;

they form a part-a necessary part, as we shall afterwards see-of its substance; and as it can get them only from the soil, it is clear that the soil must contain them, if the plant is to grow in a healthy manner upon it. But there is a special difference between the soil and the ash of the plant, which it is interesting to notice. Among the constituents of the soil, alumina-the substance which gives their stiffness and tenacity to clays-holds a prominent place. In the plant it is rarely found, and always in inconsiderable quantity. The presence of this substance, therefore, is a character by which the soil is distinguished from the ash of the plant. Its functions in relation to the growth of plants are very important, but these functions are chiefly performed in the soil itself.

2d. Special differences in the quality of the ash. But though every plant we cultivate, taken as a whole, leaves an ash, in which all the above substances are to be found, yet that which is left by different parts of the same plant contain them in very different proportions.

We have already seen that the absolute quantities of ash left by the leaves and the stems, by the straw and the grain, are very different, but the nature of the ash left by these different parts also varies. It has been found, for example, that the same sample of Hopeton oat ga ve fromits several parts an ash which in 100 lbs. contained respectively of sulphuric acid and alkaline matter, the following very different proportions:

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proportion characterizes the grain, while that of silica in large proportion characterizes the straw.

Similar results are obtained by the examination of the ash of different plants. Some contain more lime and magnesia, others more potash and soda, others more sulphur, or phosphorus, or chlorine; and thus the general law appears to hold, that under precisely the same circumstances one kind of crop will usually take up from the soil more of one kind of inorganic matter, another crop more of another kind. In its relations to practical agriculture, this result of experiment involves two distinct conclusions.

1. As different parts of the same plant require different proportions of these inorganic substances, they must, at different seasons of their growth, draw these substances in different proportions from the soil-more of one thing at one time, more of another thing at another. They may flourish, therefore, on a given soil, at one period of their growth, and not at another. That soil which clothes the tree with luxuriant verdure, may yet not be able to ripen its fruit-that which causes the straw to rush up to early maturity may refuse to fill the ear.

2. As different plants also draw from the soil the same substances in unlike proportions, they will grow with unlike vigor in different soils. Hence that which bears a profitable crop of one kind, is often unable to yield a good return of another-hence also the varied flowers and herbage which diversify the surface of all our fields.

The beautiful principle involved in these conclusions, is susceptible of so many interesting applications-explains so many practical points long known, though little understood-and is so rich in suggestions for the future improvement of every branch of husbandry, that we may be permitted to pause a little here with the view of present ing to our readers one or two of the more intelligible of the illustrations which start up in crowds before us.

Thus, in regard to exhaustion—the nature of which we have already, in some measure, learned to understand-this principle showed that it might be of two kinds, produced in different ways, and demanding each its peculiar mode of cure at the hands of the economical farmer. It might be a general exhaustion, by which, through long cropping of various kinds, the soil had become generally poor in all those varieties of

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