70 TILE DRAINAGE. 



a narrow strip over each tile-drain. The result will be, that, 

 so far as this surface-drainage is successful, it thwarts the 

 purpose of tile drainage. The water will, as stated before, 

 even work large holes straight dow r n to the tiles, and you 

 will have little iiltering arid a final stoppage of the drains. 

 Let me once more emphasize the fact that the water should 

 enter the drains from their sides and bottom, and after fil- 

 tration through the entire soil, and not straight down from 

 the surface, unfiltered. The latter thwarts the purpose and 

 prevents the benefits of tile drainage. 



RAPIDITY OF ABSORPTION AND FILTRATION. 



I have spoken of this (Chapter II., section 3), and of the 

 fact that the soil of my farm absorbed and filtered, and my 

 drains carried away, about ten inches of rainfall in Februa- 

 ry and March, 1>91, with no surface wash, gullying, or loss 

 of fertility. I have this week been again reminded of the 

 great absorbing power of a tile-drained soil. We are plow- 

 ing a 36-acre field for wheat, across three plats one timothy, 

 one wheat stubble, thick with young clover, and one heavy 

 clover where wheat was harvested (36 bushels per acre) in 

 1890. Tuesday, Aug. 11, the ground was rather dry to plow 

 -^driest in the strong clover turf, and next driest in the tim- 

 othy turf, dampest in the stubble and young clover. (I had 

 special reasons that justified wheat after wheat, and plo wing- 

 under the young clover, usually and justly considered bad 

 farming.) Tuesday noon, exactly one inch of rain fell in 

 about an hour, soon followed by 0.26 of an inch ; and on 

 Friday by 0.91 of an inch ; total, 2.17 inches. The ground 

 took it all in as fast as it came. The first inch did not soak 

 down over three inches into the clover turf not yet plowed, 

 and the whole 2.17 simply soaked down about seven inches 

 and made it scarcely damp enough to plow best. I judge 

 that the soil and subsoil would hold four inchesgiwre , where 

 tile- drained, before the drains would begin to flow. Soil 

 and subsoil, where drained, are like a vast sponge, quick in 



