1 88 



IRRIGATION FARMING. 



Open ditches. Sometimes a substantial flume of brick 

 is laid in place of one of wood, and a square vitrified 

 pipe with openings in the side is also highly thought 

 of. A sedlion of this terra-cotta head ditch is pre- 

 sented in Fig. 54. 



Into this flume is turned from the ditch an irrigat- 

 ing head of 20, 25 or 30 inches of water, generally 

 about 20 inches. This is divided by the holes into 

 streams of from one-sixth to one-tenth of an inch, 



FIG. 54 — SECTION OF VITRIFIED HEAD DITCH. 



making from 120 to 200 .streams. These are run 

 across the tradl in small furrows leading from each 

 hole. From five to seven furrows are made between 

 two rows of trees, two between rows of grapes, one 

 furrow between rows of corn, potatoes, etc. It may 

 take from fifteen to twenty hours for one stream to 

 get across the tra(5t. They are allowed to run from 

 eighteen to seventy-two hours. The ground is thor- 

 oughly wet in all diredlions and oftentimes three or 

 four feet deep. As soon as the ground is dry enough, 

 cultivation is begun and kept up from six to eight 

 weeks before water is used again. For trees a year 



