DRAINAGE OF lEEIGATED LAND. 



29 



leather belting around a cylindrical wooden rod, first having driven 

 the belting full of nails of such length that the outside diameter of the 

 completed brush is somewhat smaller than the inside diameter of the 

 tile to be cleaned. These devices may be operated most conveniently 

 by means of jointed sewer rods. The latter are made up in 3 or 4 foot 

 sections which are fitted with couplings so arranged that they may 

 be joined when two sections are placed at right angles, and are locked 

 together when the two sections are in hne. Working in a manhole 4 

 feet square, a man can easily put together and operate several hun- 

 dred feet of rod in a tile line. Figure 22 shows a set of sewer rods and 

 cleaning devices that have given satisfaction in operation. 



SUBSEQUENT TREATMENT OF LAND. 



While drainage is essential to the reclamation of water-logged and 

 alkaU lands, subsequent work is necessary for the complete redemp- 



FiG. 22.— Sewer rods and tfle-cleaning devices. 



tion of the soil. The alkah salts which may have accumulated in the 

 upper portions of the soil must be removed and the proper physical 

 condition of the soil itseK must be restored. Humus must bo increased 

 and it will be necessary that steps be taken to reduce evaporation, to 

 maintain a downward movement of the salt solution, and to prevent 

 any future rise of the latter. 



The salts, being soluble, will usually be removed in time by the 

 action of ordinary pn^.-ipitation, and this latter is always an important 

 factor in the subsequent treatment; however, the natural method is 

 often too slow and is sometimes (^tirely ineffective, due to the fact 

 that the. precipitation is sufficient to saturate only a foot or so of the 

 soil, and the (^xc(!Ssivo evaporal ion immediately returns the salts to 

 the surface. 



If (•xy)f(lition })e dc^sinul, a gocxl-sized stream of irrigation water 

 should \>c tuHHul on th(i land and allowed to percolate through the 

 soil tt8 rapidly as possihlf!. This is best acconipHshed by diking the 



