SUB-IRRIGATION AND SUBS01LING. 289 



In his book, "The New Agriculture, " the following 

 description appears: "The land is a hillside, along the 

 eastern front of which runs a wayside gutter. Parallel 

 with this and from forty to fifty feet apart, and across 

 the land to its highest boundary, he caused a series of 

 trenches two and a half feet wide and four and a half to 

 five feet deep to be dug, and filled to within eighteen 

 inches of the surface with coarse large stones, covered 

 with loose flat stones, for subterranean water reservoirs; 

 these were connected by numerous shallow and smaller 

 trenches partially filled with small stones at about eight- 

 een inches from the surface, designed to carry off all 

 surface water." The water which naturally fell from 

 the heavens was caught in these trenches and filtered 

 one from the other in such a way as to render the sub- 

 soil constantly moist and friable. Mr. Cole said: " The 

 advantage of such a system for market gardening will 

 commend itself to those who grow or aim to grow large 

 and valuable crops upon small areas of land." 



Greenhouse Irrigation. This is the modern idea 

 in greenhouse construction, and the writer is impressed 

 with the system described by Professor L. A. Taft, in 

 the American Agriculturist, and shown by sectional view 

 in Figure 95. 



A durable greenhouse bench for sub-irrigation can 

 be built of cement, at small cost, especially if it is to be 

 at the same level as the wall. When the bed is desired 

 at the hight of three or more feet, supports must be pro- 

 vided. When the natural level of the soil is where the 

 bottom of the bed should come, one has only to excavate 

 walks, and run up the walls. In a house twenty feet 

 wide it will be easier to make two wide benches, with a 

 walk in the center and two quite narrow ones next to 

 the outer walls of the house. Having provided for 

 benches, the sub-irrigation may be secured by means of 

 two or three rows of two and one-half inch drain tiles 

 19 



