GENERAL PRACTICE DRAINING SOILS. 35 



from an inch upwards, but the usual size for land drains is two inches in diameter, and 

 one foot long ; the main drain-pipes are usually four inches in diameter. All are without 

 sockets or flanges of any kind, those appendages not being needed in land draining. 

 Well-burned pipes are the best, and they should not be warped or twisted in burning, 

 but be as straight as possible. 



The first point to be determined in draining is the outlet ; this should always be 

 at the lowest point of the land, or such as will afford a sufficient fall for the water. 

 The outlet pipe should not be at the immediate bottom of a ditch but above the water 

 ordinarily running in it. The main drain or drains must be at the lowest part in the 

 line of the greatest slope, no matter how uneven the surface, and all the minor drains 

 must enter the mains diagonally in the same direction as the run of the water, and 

 not at right angles. A four-inch main drain is usually sufficient to carry off the water 

 from five to seven acres, but where the land is springy larger mains or more of them 

 are required. 



The drains should not be less than three feet deep, and where there is sufficient fall 

 they are better three and a half to four feet deep. A smooth even fall and certain 

 outlet must be provided. A sharp fall is not necessary. The distance of the drains 

 will be determined by the nature of the soil. Sandy, gravelly or silty subsoils draw 

 well, and the drains for such should be 24 feet apart ; for medium-textured subsoils, 

 21 feet; for stiff loams, 18 feet; and for retentive clay subsoils, 15 feet apart. Some 

 persons make a difference in the depth of drains according as the soil is. light and open, 

 or heavy and tenacious, assuming that in one case the water should be kept three to 

 four feet from the surface, and in the other only two feet. This is erroneous, as for a 

 fruit tree to flourish it must have one foot in depth of ameliorated soil, and another foot at 

 least below it of stirred soil ; so with drains two feet deep the soil is saturated through 

 the ascent of water by capillary attraction, little benefit accruing to the trees, and the 

 subsoil is not opened up as a source of plant food. Something worse may also happen, 

 for shallow drains are quickly choked by the roots entering them. What is sought for 

 in draining is not only a workable surface but an increase of the soil's resources 

 by chemical changes as the result of aeration. 



In tenacious soils it is a good plan to fill the trench with stones up to the level of 

 the disturbed or trenched soil, as the water finds its way readily through trenched 

 ground ; but for soils that are springy, as happens in sand, a little straw on which to 

 lay the pipes is necessary, covering them with the softer portions of hedge brushings to 



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