SUB-IRRIGATION AND SUBSOILIXG. 



to the land by means of a pipe which is laid directly 

 across the tile at the highest point, and a faucet is 

 arranged so that water may be turned into each line of 

 tile at the same time. The tile may be stopped at the 

 lower end, thus allowing the water to seep out of the 

 joints until the land is sufficiently moist. Many persons 

 would suppose that the water would descend, but it nat- 

 urally rises to the surface. It is essential that a drain- 

 age ditch should be provided at the lower end of the 

 field to serve as an outlet for the tiles, which should be 

 so arranged that they can be drained during the winter, 

 as otherwise they might be cracked by the freezing of 

 the water that they would contain. Upon stiff soils 

 with impervious hardpan, the lines of tile can be placed 

 considerably deeper. 



In order to sub-irrigate a tract with a wind- 

 mill, one should have a reservoir or tank that will hold 

 at least 800 or 1000 barrels, and unless one is reasonably 

 sure of sufficient wind to fill the tank within three days 

 at all times throughout the summer, a corresponding 

 increase would be necessary. A reservoir that will hold 

 3000 or 4000 barrels would, in many places, be advisable. 

 The amount of water and the frequency of application 

 would depend upon soil condition and the character of 

 the season, but ordinarily the application of 800 or 1000 

 barrels of water to the acre at intervals of six or seven 

 days in spring and two or three days during the hot, dry 

 weather of summer, would probably suffice. 



The Gravel Trench. This plan is very simple 

 and quite cheap. Trenches may be dug six or eight 

 inches wide and two feet deep, running with the slope of 

 the land, and forty or fifty feet apart, connecting at the 

 upper end with a head ditch somewhat wider than the 

 others. Into these trenches put six to eight inches of 

 gravel or crushed stone and then fill with earth. If for 

 orchards, the trenches could be dug so as to go under 



