220 IRRIGATION FARMING. 



Sub-Irrigation. It is about a dozen years since a 

 patent was granted for a system of perforated tiles laid 

 under the surface for watering land, but it was found 

 that the common drain tiles would answer the same pur- 

 pose in every respect. There is no doubt that for straw- 

 berry culture this mode of irrigation would pay exceed- 

 ingly well. Tiles are laid in precisely the same maniur 

 as for draining but not so deep and not so far apart. It 

 depends on the nature of the soil how much water is to 

 be supplied, and much pressure is not necessary. With 

 as much as twenty-five pounds to the inch, which is equal 

 to a head of fifty-five feet, the probability is that the 

 water would be forced above the surface and flow on the 

 top. This is not desirable, but only to keep the subsoil 

 moist enough to supply the crops in a dry time. Rows 

 of tiles twelve feet apart have been found sufficient in a 

 light sandy soil, and in a clay it would doubtless be 

 necessary to provide drainage for the surplus, or the dis- 

 tribution must be very carefully made. A small head, 

 three feet for instance, is quite enough to secure the 

 even distribution of the water. As in drainage, the water 

 supply is carried to the small tiles in larger ones, esti- 

 mated as to size by the area to be supplied. In fact, it 

 is simply drainage reversed, and thus everything about 

 it is reversed precisely; the feeding source being equiva- 

 lent to the outlet of the drains and the discharge' corre- 

 sponding to the collecting tiles in the drains. 



Irrigating from Water Mains. In describing 

 an experiment with irrigation in Eastern Kansas, B. F. 

 Smith of Lawrence, says: "I laid iron pipe on top of 

 the ground along the roadways through a strawberry 

 patch of two and one-fourth acres. Three hundred of the 

 five hundred feet of pipe used is common inch iron, and 

 two hundred feet is half-inch galvanized iron pipe. At 

 intervals of about one hundred feet are water cocks, or 

 faucets, for attaching a three-fourths inch rubber hose. 



