Читать книгу What I know of farming: - Greeley Horace - Страница 14

While few can have failed to realize the important part played by Water in the economy of vegetation, I judge that the question – "How can I secure to my growing plants a sufficiency of moisture at all times?" – has not always presented itself to the farmer's mind as demanding of him a practical solution. To rid his soil and keep it free of superfluous, but especially of stagnant water, he may or may not accept as a necessity; but that, having provided for draining away whatever is excessive, he should turn a short corner and begin at once to provide that water shall be supplied to his fields and plants whenever they may need it, he is often slow to apprehend. Yet this provision is but the counterpart and complement of the other.

I had sped across Europe to Venice, and noted with interest the admirable, effective irrigation of the great plain of Lombardy, before I could call any land my own. I saw there a region perhaps thirty miles wide by one hundred and fifty along the east bank of the Po, rising very gently thence to the foot of the Austrian Alps, which Providence seems to have specially adapted to be improved by irrigation. The torrents of melted snow which in Spring leap and foam adown the southern face of the Alps, bringing with them the finer particles of soil, are suddenly arrested and form lakes (Garda, Maggiore, Como, etc.) just as they emerge upon the plain. These lakes, slowly rising, often overflow their banks, with those of the small rivers that bear their waters westward to the Po; and this overflow was a natural source of abiding fertility. To dam these outlets, and thus control their currents, was a very simple and obvious device of long ago, and was probably begun by a very few individuals (if by more than one), whose success incited emulation, until the present extensive and costly system of irrigating dams and canals was gradually developed. When I traversed Lombardy in July, 1851, the beds of streams naturally as large as the Pemigewasset, Battenkill, Canada Creek, or Humboldt, were utterly dry; the water which would naturally have flowed therein being wholly transferred to an irrigating canal (or to canals) often two or three miles distant. The reservoirs thus created were filled in Spring, when the streams were fullest and their water richest, and gradually drawn upon throughout the later growing season to cover the carefully leveled and graded fields on either side to the depth of an inch or two at a time. If any failed to be soon absorbed by the soil, it was drawn off as here superfluous, and added to the current employed to moisten and fertilize the field next below it; and so field after field was refreshed and enriched, to the husbandman's satisfaction and profit. It may be that the rich glades of English Lancashire bear heavier average crops; but those of Lombardy are rarely excelled on the globe.

Why should not our Atlantic slope have its Lombardy? Utah, Nevada, and California, exhibit raw, crude suggestions of such a system; but why should the irrigation of the New World be confined to regions where it is indispensable, when that of the Old is not? I know no good reason whatever for leaving an American field unirrigated where water to flow it at will can be had at a moderate cost.

When I first bought land (in 1853) I fully purposed to provide for irrigating my nearly level acres at will, and I constructed two dams across my upland stream with that view; but they were so badly planned that they went off in the flood caused by a tremendous rain the next Spring; and, though I rebuilt one of them, I submitted to a miscalculation which provided for taking the water, by means of a syphon, out of the pond at the top and over the bank that rose fifteen or twenty feet above the surface of the water. Of course, air would work into the pipe after it had carried a stream unexceptionably for two or three days, and then the water would run no longer. Had I taken it from the bottom of the pond through my dam, it would have run forever, (or so long as there was water covering its inlet in the pond;) but bad engineering flung me; and I have never since had the heart (or the means) to revise and correct its errors.

My next attempt was on a much humbler scale, and I engineered it myself. Toward the north end of my farm, the hill-side which rises east of my lowland is broken by a swale or terrace, which gives me three or four acres of tolerably level upland, along the upper edge of which five or six springs, which never wholly fail, burst from the rocks above and unite to form a petty runnel, which dries up in very hot or dry weather, but which usually preserved a tiny stream to be lost in the swamp below. North of the gully cut down the lower hill-side by this streamlet, the hill-side of some three acres is quite steep, still partially wooded, and wholly devoted to pasturage. Making a petty dam across this runnel at the top of the lower acclivity, I turned the stream aside, so that it should henceforth run along the crest of this lower hill, falling off gradually so as to secure a free current, and losing its contents at intervals through variable depressions in its lower bank. Dam and artificial water-course together cost me $90, which was about twice what it should have been. That rude and petty contrivance has now been ten years in operation, and may have cost $5 per annum for oversight and repairs. Its effect has been to double the grass grown on the two acres it constantly irrigates, for which I paid $280, or more than thrice the cost of my irrigation. But more: my hill-side, while it was well grassed in Spring, always gave out directly after the first dry, or hot week; so that, when I most needed feed, it afforded none; its herbage being parched up and dead, and thus remaining till refreshed by generous rains. I judge, therefore, that my irrigation has more than doubled the product of those two acres, and that these are likely to lose nothing in yield or value so long as that petty irrigating ditch shall be maintained.

I know this is small business. But suppose each of the hundred thousand New-England farms, whereof five to ten acres might be thus irrigated at a cost not exceeding $100 per farm, had been similarly prepared to flow those acres last Spring and early Summer, with an average increase therefrom of barely one tun of Hay (or its equivalent in pasturage) per acre. The 500,000 tuns of Hay thus realized would have saved 200,000 head of cattle from being sent to the butcher while too thin for good beef, while every one of them was required for further use, and will have to be replaced at a heavy cost. Shall not these things be considered? Shall not all who can do so at moderate cost resolve to test on their own farms the advantages and benefits that may be secured by Irrigation?