XXXIX.
SCIENCE IN AGRICULTURE.
I am not a scientific farmer; it is not probable that I ever shall be. I have no such knowledge of Chemistry and Geology as any man needs to make him a thoroughly good farmer. I am quite aware that men have raised good crops—a good many of them—who knew nothing of science, and did not consider any acquaintance with it conducive to efficiency or success in their vocation. I have no doubt that men will continue to grow such crops, and to make money by agriculture, who hardly know what is meant by Chemistry or Geology; and yet I feel sure that, as the years roll by, Science will more and more be recognized and accepted as the true, substantial base of efficient and profitable cultivation. Let me here give briefly the grounds of this conviction:
Every plant is composed of elements whereof a very small portion is drawn from the soil, while the ampler residue, so long as the plant continues green and growing, is mainly water, though a variable and often considerable proportion is imbibed or absorbed from the atmosphere, which is understood to yield freely nearly all the elements required of it, provided the plants are otherwise in healthful and thrifty condition. Water is supplied from the sky, or from springs and streams; and little more than the most ordinary capacity for observation is required to determine when it is present in sufficient quantity, when in baleful excess. But who, unaided by Science, can decide whether the soil does or does not contain the elements requisite for the luxuriant growth and perfect development of Wheat, or Fruit, or Grass, or Beets, or Apples? Who knows, save as he blindly infers from results, what mineral ingredients of this or that crop are deficient in given field, and what are present in excess? And how shall any one be enlightened and assured on the point, unless by the aid of Science?
I have bought and applied to my farm some two thousand bushels of Lime, and ten or a dozen tuns of Plaster; and I infer, from what seemed to be results, that each of these minerals has been applied with profit; but I do not know it. The increased product which I have attributed to one or both of these elements may have had a very different origin and impulse. I only grope my way in darkness when I should clearly and surely see.
An agricultural essayist in Maine has recently put forth a canon which, if well grounded, is of great value to farmers. He asserts that the growth of acid plants like Sorrel, Dock, etc., in a field, results from sourness in the soil, and that, where this exists, Lime—that is, the ordinary Carbonate of Lime—is urgently required; whereas the application of Plaster or Gypsum (Sulphate of Lime) to that field must be useless and wasteful. If such be the truth, a knowledge of it would be worth millions of dollars to our farmers. But I lack the scientific attainment needed to qualify me for passing judgment thereon.
There is great diversity of opinion among farmers with regard to the value of Swamp Muck. One has applied it to his land to good purpose; so he holds Muck, if convenient, the cheapest and best fertilizer a farmer can add to his ordinary barn-yard manure; another has applied cords upon cords of Muck, and says he has derived therefrom no benefit whatever. Now, this contrariety of conclusion may result from imperfect judgment on one side or the other, or from the condition precedent of the diverse soils: one of them requiring what Muck could supply, while the other required something very different from that; or it may be accounted for by the fact that the Muck applied in one case was of superior quality, and in the other good for nothing. Where Muck is composed almost wholly of the leaves of forest-trees which, through thousands of years, have been blown into a bog, or shallow pond, and there been gradually transformed into a fine, black dust or earth, I do not see how it can possibly be applied to an upland, especially a sandy or gravelly soil, without conducing to the subsequent production of bounteous crops. True, it may be sour when first drawn from the stagnant pool or bog in which it has lain so long, and may need to be mixed with Lime, or Salt, or Ashes, and subjected to the action of sun and frost, to ripen and sweeten it. But it seems to me impossible that such Muck should be applied to almost any reasonably dry land, without improving its consistency and increasing its fertility. But all Muck is not the product of decayed forest-leaves; and that which was formed of coarse, rank weeds and brakes, of rotten wood and flags, or skunk cabbage, may be of very inferior quality, so as hardly to repay the cost of digging and applying it. Science will yet enable us to fix, at least approximately, the value of each deposit of Muck, and so give a preference to the best.
The Analysis of Soils, whereof much was heard and whence much was hoped a few years since, seems to have fallen into utter discredit, so that every would-be popular writer gives it a passing fling or kick. That any analysis yet made was and is worthless, I can readily concede, without shaking in the least my conviction that soils will yet be analyzed, under the guidance of a truer, profounder Science, to the signal enlightenment and profit of their cultivators. Here is a retired merchant, banker, doctor, or lawyer, who has bought a spacious and naturally fertile but worn-out, run-down farm, on which he proposes to spend the remainder of his days. Of course, he must improve and enrich it; but with what? and how? All the manure he finds, or, for the present, can make on it, will hardly put the first acre in high condition, while he grows old and is unwilling to wait forever. He is able and ready to buy fertilizers, and does buy right and left, without knowing whether his land needs Lime, or Phosphate, or Potash, or something very different from either. Say he purchases $2,000 worth Of one or more of these fertilizers: it is highly probable that $1,500 might have served him better if invested in due proportion in just what his land most urgently needs; and I unflinchingly believe that we shall yet have an analysis of soils that will tell him just what fertilizers he ought to apply, and what quantity of each of them.
Science has already taught us that every load of Hay or Grain drawn from a field abstracts therefrom a considerable quantity of certain minerals—say Potash, Lime, Soda, Magnesia, Chlorine, Silica, Phosphorus—and that the soil is thereby impoverished until they be replaced, in some form or other. As no deposit in a bank was ever so large that continual drafts would not ultimately exhaust it, so no soil was ever so rich that taking crop after crop from it annually, yet giving nothing back, would not render it sterile or worthless. Sun and rain and wind will do their part in the work of renovation; but all of them together cannot restore to the soil the mineral elements whereof each crop takes a portion, and which, being once completely exhausted, can only be replaced at a heavy cost. Science teaches us to foresee and prevent such exhaustion—in part, by a rotation of crops, and in part by a constant replacement of the minerals annually borne away: the subtraction being greater in proportion as the crop is more exacting and luxuriant.