IRRIGATION 



257 



A ridge is thrown up around each tree, thus forming a small 

 basin. This basin is filled with water from a supply ditch 

 which comes in on a ridge or by means of pipes. 



Furrow method. The furrow method (Fig. 215) is used in 

 irrigating crops planted in rows, such as garden truck, 

 bushes, and small fruits. The water is carried in the supply 

 ditch along the upper side of the field. Furrows are formed 

 with a small plow or other tool and the water permitted to 

 flow down to where it is absorbed by the ground between 

 the furrows. These are placed sufficiently close together 

 so that the proper quantity of moisture will be taken up by 

 the soil. In crops such as potatoes and garden truck raised 



After Irrigation Investigations, U. S. Dept. Agri. 



Fig. 214. Basin method of irrigating a prune orchard 



in rows close together a single furrow between each row is 

 sufficient. In widely planted crops a furrow close to and 

 along either side of each row may be necessary. This 

 method does not saturate the surface of the soil, which is 

 an advantage in growing some crops. A large quantity of 

 water is not lost by evaporation, but in an open, porous soil 

 much water may be lost by downward percolation, since 



