TILE DKAINAGE. 13 



But where the pores in the soil and subsoil are very small, 

 with few of the larger spaces, the hydrostatic pressure is 

 nearly overcome by capillarity, and hence is very slow in its 

 action. This is the case in compact and tenacious clayey 

 soils, especially when not tiled. The water from heavy rains 

 and snows is a long time in soaking into and through the 

 ground, almost making impossible the profitable tillage and 

 growing of root crops and cereals ; for, first, the soil can not 

 be tilled early enough in spring nor soon enough after each 

 rain for good results ; and, second, the top level of complete 

 saturation (hydrostatic water) is so near the surface of the 

 ground that the plants get little depth of root. On damp 

 clays, maple and apple tree roots run almost or quite on 

 the surface, not for lack of plant food, but from too much 

 water. " Drowned out," we say correctly. 



Second. The first point just made, is, that surplus mois- 

 ture must be removed. The second, now to be considered, is, 

 that it must, to secure real success, be removed down through 

 the soil and not off along its surface. This is just what un- 

 derdrainage does for clayey soils and subsoils; and so the 

 full discussion of this point will pretty nearly cover the 

 theory and state the facts of tile drainage ; that is, will an- 

 swer the question that stands at the head of this chapter ; 

 viz., u Why do we tile-drain land ? " 



The point we wish to make is, that the surplus water 

 should be removed down through the soil, as by tile drainage, 

 and not off along its surface, as where there is no underdrain- 

 age natural or artificial. The following are a few of the 

 reasons : 



First, because it makes all tillage and harvesting opera- 

 tions easier and more rapid, physically and mechanically. 

 Surface drainage is better than none ; but it greatly inter- 

 feres with all farming operations. If the surface drains are 

 natural, that is, simply made by water action, they will usu- 

 ally be crooked brooks or gulleys, cutting up the field into 

 awkward shapes for cultivation , as in Fig. 5. This repre- 



