248 SEEDING AND PLANTING 



In the portable method of installation a single line of overhead 

 f-inch pipe 100 feet long with nozzles at 4-foot intervals is sup- 

 ported on iron standards about 1 foot above the ground. A small 

 two-wheeled iron cart at one end of the line supports a small 

 motor driven by water which slowly causes the pipe to rotate. 

 The spray reaches to a distance of about 25 feet on each side of 

 the line. The water is brought to the system through an ordi- 

 nary garden hose from near-by hydrants. The pipe can be quickly 

 uncoupled into short lengths and transferred to a frame on the 

 cart, after which it can be easily transported to any part of the 

 nursery. 



19. FLOODING. Special attention should be given to the con- 

 struction of the beds in order to make the application of water 

 by flooding effective. Each bed should be as nearly level as pos- 

 sible, and the paths surrounding it should be from 4 to 6 inches 

 above the general level. The water is permitted to flow over the 

 depressed beds as required, usually to the depth of from 2 to 4 

 inches. The ground becomes thoroughly saturated by this method 

 of irrigation. It is used chiefly in regions of scanty summer rain 

 or where for other reasons large quantities of water are required. 1 

 The chief objection to flooding arises from the fine sediment that 

 it leaves on the surface of the small plants and the hard crust 

 formed on the surface of the bed after the water is taken up by 

 the soil. Where flooding is practiced the seed should be sown in 

 drills so that the soil between the rows can be worked after each 

 irrigation. 



20. PERCOLATION FROM FURROWS. The water may be ap- 

 plied so as to reach the plants by percolation through the soil. 

 By this method of irrigation the water is made to flow in small 

 furrows between the rows of seedlings or transplants or between 

 narrow beds when the seed is broadcasted. The water will readily 

 percolate for a distance of two or more feet at either side of the 

 furrow in loose, permeable soil when the nursery is graded and 

 suitably arranged. This is an excellent, inexpensive, and efficient 

 method of irrigation. Its great advantage over flooding is in the 

 non-formation of a surface crust, and its advantage over sprinkling 

 is in its reduced cost and decreased loss of water through evapo- 

 ration. It is particularly acceptable for irrigating transplants and 



1 Bates, C. G. and Pierce, R. G. : Forestation of the sand hills of Nebraska 

 and Kansas. (U. S. Forest Service, Bui. 121, p. 26. 1913.) 



