THE IRRIGATION AGE. 



107 



in orchards are spaced from two to three feet apart. 

 For grain and forage crops the spacing will depend 

 chiefly on the ease and rapidity with which water 

 spreads sideways in the soil. 



Furrow irrigation has several advantages over 

 other methods. It requires less water than any form 

 of flooding, because the water surface exposed to evapo- 

 ration is confined to a small fraction of the total land 

 surface, seldom more than 5 per cent. Again, the water 

 is applied from three to twelve inches below the surface 



< 3" * j" > 





IZ 



18' 



Fig. 17 Cross Section 10-inch Cement Flume. 



and is distributed through the soil by capillarity rather 

 than by gravity, and plants seem to thrive best when 

 they receive moisture, in this way. When water is ap- 

 plied in the bottom of V-shaped furrows the surface 

 soil is not saturated and baking is prevented. By the 

 furrow method the surface soil is kept tolerably dry, 

 excessive evaporation is avoided, there is little dis- 

 placement of surface soil, and a tendency toward deep 

 rooting in the plant is promoted. Finally, it is cheap 

 and convenient. 



In seeking to improve on present methods of ap- 

 plying water by furrow irrigation one is tempted to 

 recommend the best appliances, regardless of cost, but 

 such recommendations would be followed only in rare 

 cases. Local conditions have always to be considered. 



Fig. 18 Furrower. 



If one assumes that pipes are the best means of dis- 

 tributing water, he is at once met with the objection 

 that the large majority of irrigators could not afford to 

 lay pipes for that object. It is questionable, also, if 

 cement-concrete flumes could be used in the colder por- 

 tions of the West on account of the severity of the 

 frosts and the tendency of the ground to heave when 



frozen. There is also the same objection that applies 

 to pipes, viz., the first cost, Even wooden flumes are 

 considered by the majority of water-users to be too 

 expensive for the mere purpose of dividing an irriga- 

 tion stream equally among a number of furrows. 



THE BASIN METHOD OF IRRIGATION AS PRACTICED IK 

 THE SANTA CLARA VALLEY, CALIFORNIA. 



Owing to the light rainfall since the dry year of 

 1898 most of the Santa Clara Valley orchards are now 



Fig. 19 Adjustable Ridger. 



irrigated. The water supply comes chiefly from wells 

 by the use of pumps, but the various creeks also fur- 

 nish the gravity canals with considerable volumes dur- 

 ing the rainy months from January to April. About 

 four-fifths of all the irrigated orchards are watered by 

 means of small basins. The basin method may, there- 

 fore, be regarded as not only the most prevalent, but 

 as having attained in the Santa Clara Valley its great- 



FiR. 20 -Steel Ridger. 



est perfection. The same system is extensively prac- 

 ticed in the walnut orchards of Orange County, in 

 California; but since the implements used and the 

 manner of making basins and applying water are much 

 the same in both sections, as well as elsewhere, the de- 

 scriptions which follow under this heading will be con- 

 fined to Santa Clara Valley. For much of the infor- 



