HORTICULTURE 111 



culty in this mode of furrow irrigation arises in withdrawing water 

 from the ditch and in distributng it equally among a large number 

 of furrows. A skilled irrigator may adjust the size and depth of the 

 ditch bank openings so as to secure a somewhat uniform flow in the 

 furrows, but constant attention is required in order to maintain it. 

 If the water is permitted to flow for a short time unattended the dis- 

 tribution is likely to become unequal. Parts of the ditch bank 

 become soft, and, as the water rushes through, the earth is washed 

 away, permitting larger discharges and lowering the general level of 

 the water in the ditch so that other openings may have no discharge. 

 Some of the orchardists of San Diego County, Cal., insert in niches 

 cut in the bank pieces of old grain sacks or tent cloth. The water 

 flows over these without eroding the earth. Another device is to use 

 a board pointed at the lower end and containing a narrow opening or 

 slot through which the water passes to the furrow. Shingles are also 

 used to regulate the flow in the furrows. The thin ends of these are 

 stuck into the ground at the heads of furrows. 



Short Tubes in Head Ditches. In recent years short tubes or 

 spouts have been used in many of the head ditches of orchards to 

 divert small quantities of water to furrows. These tubes are usually 

 made of wood, but pipes made of clay, black iron, galvanized iron, 

 and tin are occasionally used. 



For nurseries and young trees especially, and also for mature 

 trees, a cheap and serviceable tube may be made from pine lath, such 

 as are used for plastering. The 4-foot lengths are cut into two equal 

 parts and four of the pieces are nailed together to form a tube. One 

 of these tubes when placed with its center 2 inches below the sur- 

 face of the water in the head ditch discharges nearly three-quarters 

 of a miner's inch of water, and if placed 4 inches below the surface 

 will discharge more than 1 miner's inch. In southern Idaho the 

 lumber mills manufacture a special lath for this purpose. It is % 

 inch thick, 2 inches wide, and 36 inches long. If such tubes when 

 thoroughly dry are dipped in hot asphalt they will last a much 

 longer time. In some of the deciduous orchards of California a still 

 larger wooden tube or box is used to bring about the same result. 

 It is made of four pieces of % by 3% inch redwood boards of the de- 

 sired length. The flow through this tube is regulated by a cheap 

 gate, consisting of a piece of galvanized iron fastened by means of a 

 leather washer and a wire nail. 



The orchardist who lives near a manufacturing town or city can 

 often purchase at a low figure pieces of worn-out and discarded 

 piping varying from % to 2 inches in diameter. Such pipes when 

 cut into suitable lengths make good substitute for wooden spouts. 

 Tin tubes one-half inch in diameter and of the proper length have 

 been used with good success. In compact soils, through which water 

 passes very slowly, the furrows must be near together, and under 

 such conditions small tin tubes are to be preferred. 



In making use of tubes of various kinds to distribute water to 

 furrows it is necessary to maintain a constant head in the supply 

 ditch. This is done by inserting checks at regular distances. These 



