TEE IRRIGATION AGE. 



81 



so as to secure a fairly uniform flow, but constant at- 

 tention is required in order to maintain it. If the 

 water is permitted to flow- for half an hour unat- 

 tended the distribution is likely to become unequal. 

 The banks of the temporary ditch absorb water and 

 become soft, and as the water rushes through the' 

 openings erosion enlarges them, permitting larger dis- 

 charges and lowering the general level of the water in 

 the ditch so that other openings may have no discharge. 

 Even if it were possible to divide the flow of the ditch 

 equally between a certain number of furrows the diffi- 

 culty would not be overcome, because the number of 

 divisions would invariably be too small. In using 

 such crude methods it is difficult to divide a stream of, 

 say, forty miner's inches into more than about ten 

 equal parts, but good practice frequently calls for a 

 flow .in each furrow of from one-fifth to three-fourths 

 of a miner's inch, which can not be secured by this 

 method. 



In irrigating such crops as corn, potatoes, sugar 



the stream flows down each furrow without damming 

 and flooding a portion of the crop. As soon as the 

 soil is sufficiently dry the furrows are filled in and the 

 space' between the rows cultivated. 



Fig. 11 shows a sketch of the "V" scraper or 

 "crowder." This is one of the most convenient and 

 serviceable home-made implements for making head 

 ditches, whether permanent or temporary. In the 

 sketch shown the shorter arm is hinged to the longer 

 and the "V" can be adjusted to suit ditches of different 

 sizes. 



Some consideration is given to the best way of 

 watering a field at the time of planting. If the steep- 

 est slope is likely to cause erosion, the rows are run 

 diagonally. When the surface is rolling, the rows, 

 particularly if they consist of fruit trees, follow the 

 contours on the desired grade. 



In this kind of furrow irrigation one man will 

 irrigate from two to six acres in a day, and the cost of 

 one irrigation, including the making of furrows and 



Implement for makiEK furrows in orange orchard. 



beets and vegetables, all of which are planted in rows, 

 the usual practice is to make furrows midway between 

 the rows with a light plow or cultivator. Openings are 

 then made in the ditch bank at the head of each fur- 

 row. Sometimes, however, one opening feeds two or 

 more furrows. The latter is the common practice when 

 the head ditch is permanent. Before water is admitted 

 to the furrows on the strip to be irrigated a check 

 dam is placed in the head ditch opposite the lowest fur- 

 row of the strip. The check dam may consist of earth 

 or of manure and earth combined, but it is more likely 

 to be a canvas dam or some one of the many kinds of 

 tappoons. The purpose of this check is to hold the 

 water in the head ditch at the desired elevation and 

 to distribute the flow between the furrows. The num- 

 ber of furrows which should receive water at one time 

 will depend on the crop, the TOlume of water in the 

 head ditch and the smoothness and texture of the soil. 

 With the crude appliances of this method constant at- 

 tention is required in order to distribute the water 

 somewhat equally among the furrows and to see that 



head ditches, will vary from about 50 cents to $1.50 

 per acre. 



THE USE OF SHORT TUBES IN FURROW IRRIGATION. 



In furrow irrigation, as ordinarily practiced, one 

 of the worst defects, as has been already stated, is the 

 difficulty of dividing a stream equally among a large 

 number of furrows. A simple remedy, which is both 

 cheap and effective, is described below, and its general 

 adoption in all sections of the West where no better 

 appliances are in use is recommended. Short tubes 

 or boxes are inserted in the lower bank of the head 

 ditch a trifle below the surface of the water, and each 

 tube furnishes a supply for one or more furrows. In 

 permanent ditches with a clearly defined high-water 

 mark the boxes are placed at the same distance below 

 this mark, but in a new ditch, where there is no such 

 mark, the boxes may be placed so that the bottom of 

 the openings will be slightly above the bottom of the 

 ditch. The flow is rendered fairly constant by means 

 of a small gate at the upper end of each tube. The 

 tubes are usually made of wood, are from twelve to 



