Crops and Methods for Soil Improvement

by Alva Agee

Underdrainage.—There are great swamps, and small ones, whose water should be carried off by open ditches. Our present interest is in the wet fields of the farm,—the cold, wet soil of an entire field, the swale lying between areas of well-drained land, the side of a field kept wet by seepage from higher land,—and here the right solution of the troubling problem lies in underdrainage. An excess of water in the soil robs the land-owner of chance of profit. It excludes the air, sealing up the plant-food so that crops cannot be secured. It keeps the ground cold. It destroys the good physical condition of the soil that may have been secured by much tillage, causing the soil particles to pack together. It compels plant-roots to form at the surface of the ground. It delays seeding and cultivation. An excess of water is more disheartening than absolute soil poverty. The remedy is only in its removal. The level of dead water in the soil must be below the surface—three feet, two and one half feet, four feet,—some reasonable distance that will make possible a friable, aërated, warm, friendly feeding-ground for plant-roots. Only under drainage can do this.

Counting the Cost.—Thorough underdrainage is costly, but it is less so than the farming of fields whose productiveness is seriously limited by an excess of water. The work means an added investment. Estimates of cost can be made with fair accuracy, and estimates of resulting profit can be made without any assurance of accuracy. The farmer with some wet land does well to gain experimental knowledge, and base future work upon such experience. He knows that he cannot afford to cultivate wet land, and the problem before him is to leave it to produce what grass it can produce, sell it, or find profit in drainage. He has the experience of others that investment in drainage is more satisfactory than most other investments, if land has any natural fertility. He has assurance that debt incurred for drainage is the safest kind of debt an owner of wet land can incur. He has a right to expect profit from the undertaking, and he can begin the work in a small way, if an outlet is at hand, and learn what return may be expected from further investment. Almost without fail will he become an earnest advocate of underdrainage.

Drain tile.

Where Returns are Largest.—The total area of land needing drainage is immense. Swamps form only a small part of this area. Yields of much old farm land are limited by the excess of water during portions of the year. As land becomes older, the area needing drainage increases.

The owner of wet land does well to gain his first experience in a field where a swale or other wet strip not only fails to produce a full crop, but limits the yield of the remainder of the field by delaying planting and cultivation. This double profit often is sufficient to repay cost in a single year.

Material for the Drains.—Doubtless there are places and times when stone, or boards, or brush should be used in construction of underdrains, but they are relatively few in number. Such underdrains lack permanency, as a rule, though some stone drains are effective for a long time. If drain tile can be obtained at a reasonable price, it should be used even in fields that have an abundance of stone. Its use requires less labor than that of stone, and when properly laid on a good bottom, it continues effective. There is no known limit to the durability of a drain made of good tile.

The Outlet.—The value of any drainage system is dependent upon the outlet. Its location is the first thing to be determined. If the land is nearly flat, a telescope level should be used to determine elevations of all low points in the land to be drained. The outlet should permit a proper fall throughout the length of the system, and it should not require attention after the work is completed. If it is in the bank of a stream or ditch, it should be above the normal level of the water in the stream. In times of heavy rainfall water may back up into the main with no injury other than temporary failure to perform its work, but continuous submersion will lead to deposits of silt that may close the tile.

Locating Main and Branches.—There are various systems of drainage. Wherever a branch or lateral joins the main, the means of drainage is duplicated within the area that the main can drain, and the system should call for the least possible waste of this sort. It usually is best that the main take the center line of the low land, laterals being used to bring the water to the main from both sides, but there is less duplication of work when the main can be at one side of the wet land. Branches of the main may be needed to reach remote parts of the area.

The Laterals.—Small lines of tile are used to bring the water to the main when the wet land extends beyond the influence of the main. The distance between these laterals depends upon their depth and the nature of the land. A tight clay soil will not let water pass laterally more than a rod or 20 feet, compelling the placing of the drains not over 40 feet apart, while an open soil may permit a distance of 60 or more feet between laterals.