IRRIGATION
This is a topic on which a book might be written. The reader will draw a sigh of relief, however, on learning that I shall content myself with giving a few facts and suggestions, since I am well aware that, in spite of its title, this chapter will be dry to many.
The first rays that fall from the lamp of history reveal vast systems of irrigation in full operation. In many parts of the globe artificial watering is absolutely essential, and there are few agricultural regions which might not be rendered far more productive if the supply of moisture could be regulated in accordance with the needs of each crop. The question, as we shall consider it, is a practical one. In California and other sections, the land must be irrigated; here, and wherever the rainfall is more equally distributed throughout the year, we can water if we find the practice remunerative. The increased yield from the proper application of water is often marvellous. Mr. James Neilson, in a paper read before the New Jersey State Board of Agriculture, gives some interesting facts observed abroad. In regions along the Cavour Canal, the people were able to mow in one season six heavy burdens of grass, and in the vicinity of Edinburgh, by the use of sewage water, five or six crops of grass annually. In Belgium, "sandy, barren land (resembling the pine barrens of New Jersey) was put into profitable cultivation when it could be irrigated." The plain of Gennevilliers, near Paris, seemed utterly worthless for cultivation. It consisted almost wholly of coarse gravel, and bore no rent. No land owner would make any effort to use water, so the city of Paris bought about twenty-five acres and turned upon it part of the sewage. It now rents for nearly $50 per acre, with sewage supplied. In parts of Spain, land is worth $2,500 irrigated, and but $125 without the privilege of water. The enormous and long-continued crops of strawberries raised in California prove that water is equally effective in our new land, where the climate is similar, as in the older countries. Will irrigation pay in our latitude, where we hope for seasonable rains? I think that in many sections it will, and occasionally I hear of remarkable results obtained by the free use of water. In one instance a gravelly hillside, almost worthless for ordinary cultivation, became the wonder of the neighborhood, so large were the crops of strawberries secured by irrigation.
Mr. Chas. W. Garfield, Secretary of the Michigan State Pomological Society, gives an interesting account of his visit to Mr. Dunkley, a successful gardener, at Kalamazoo: "A force," he writes, "were picking strawberries from rows of vigorous plants, and as we opened the vines in advance of the pickers, a more delightful strawberry prospect we had never seen. The varieties were Monarch, Seneca Chief, and Wilson, and under the system of irrigation employed they were just prime for market, after all the other berries in the vicinity had ripened and were gone. Very remunerative prices were thus secured. His vines were vigorous and independent of the rains. Every berry that set reached perfection in size and form." The abundant moisture greatly increases the size of the fruit, but retards the ripening. When the fruit has reached the proper stage for maturity, the water is withheld, and then the berries ripen fast, but in their perfect development are firm, and are shielded from the sun by the luxuriant foliage. "We water," said Mr. Dunkley, "only to supplement the rain. If the season is wet, we employ our artificial system but little, or not at all, and in such seasons get no profit from our investments; but generally, sometime during a season there is a drought that shortens some crop; then we irrigate, and have the advantage of neighboring gardeners." This statement suggests the practical question, Do droughts or dry seasons occur with sufficient frequency to warrant the outlay required for irrigation? In a very interesting paper read before the Massachusetts Horticultural Society, Mr. W. D. Philbrick gives much information on the subject of artificial watering, and its need in our latitude and section, and I quote from him freely:
"The amount of water required will depend largely on the rainfall, velocity of the wind, atmospheric humidity, soil, etc. A loose, sandy soil will require much more water than a retentive clay. In general, however, it may be assumed that in the warm, growing months of May, June, July, August and September, most vegetation requires an inch in depth over the entire surface of the land every five days. This is, of course, only an average. This quantity, estimated as needed by our gardens, would be equivalent to six inches per month of rainfall. If we compare this amount with the actual rainfall, we shall arrive at an idea of what is to be supplied artificially.
"The rainfall at Boston for the past six years (to 1878), for the five growing months named, varies from a maximum of 10.5 inches, in August, 1872, to a minimum of 0.65 inch, in June, 1873. During these six years there was not a single season when we did not suffer more or less from drought during some portion of the summer. Twenty-one of the thirty months in question had less rainfall than six inches per month, and the average of these twenty-one months was about 3.02 inches per month, or only about half of what was needed. Some of the protracted seasons of drought were almost entirely rainless for six weeks, during which the weather was excessively hot and windy, and vegetation suffered extremely in consequence."
Mr. Philbrick estimates that 27,000 gallons, or 108 tons, of water are needed per acre at each watering, which, in a dry period, should be repeated every five days. This enormous quantity leads him to suggest that—
"before embarking in an enterprise of irrigation, it would be best to make sure that the source can be depended upon for a sufficient supply of water in the driest seasons; for it is precisely at such times that the most water is needed. Ordinary springs and wells, therefore, are entirely inadequate to furnish water for anything more than a small patch or garden. The only sources to be depended upon for large areas are unfailing streams, lakes, and ponds. There are few gardens so favorably situated that the water can be drawn from canals and ditches directly from some pond or stream. When this can be done it is by far the cheapest method; and it is in this way that the extensive irrigating works of Lombardy, Spain, France, California, and Colorado are constructed. Where this system is adopted, considerable expense is required to grade the land into inclined beds, so as to distribute the water easily and evenly; but, once done, the water is applied at a very trifling cost—so cheaply that it is used for farm crops in Lombardy and the South of France."
In most instances, however, our land is so located that we cannot irrigate it by a natural flow and fall of water. In this case, it may be distributed by water-carts and by hand. This can be done only on a very small scale. The cost in time and labor would be much too great for profitable returns, and the ground would be so beaten and trampled as to cause much injury. Such methods may answer very well for small and well-mulched fruit gardens, making the home supply certain and large, but it is inadequate from a business point of view. Distributing water through pipes laid underground, beneath the plow, does not work well at all, practically, and is not in accordance with nature. Most of the water is wasted.
Mr. Phil brick continues: