SOILS FERTILIZERS. 215 



a main drain 2,010 ft. in length, and laterals 3,050 ft. in length, was installed. 

 The main drain emptied into a snmii from which the drainage water was lifted 

 by a pnmi). 



"On account of the extreme height to which the ground water rises at cer- 

 tain seasons and of the difficulties previously experienced with hardpjin and 

 (luicksand it was decided to place the tiles at an average depth of 3 ft. The 

 water table each year rose much higher than this depth, and it was feared that 

 the drainage system placed at a greater depth would be swamped b.v the rush ( f 

 water from surrounding farms and would prove ineffectual. Six-inch tiles were 

 secured for the mains, but a large number of 3-in. tiles had to be used in the 

 laterals." 



The results of the experiments extending over three seasons are sunnnarized 

 as follows : 



" It has been found that alkali can be washed out of these white-ash soils, 

 where no hardpan occurs close to the surface, during one irrigating season. It 

 should then be fit to produce paying crops. 



"The alkali at Fresno in the white-ash soils consists mainly c,f black alkali. 

 To remove this alkali rapidly and effectivel.v, it has been found necessary to 

 hold water continually for several months over the soil at a depth of about 1 

 ft. When this is done, black alkali need not be feared. 



" The amount of tiling necessary to drain these alkali lands for reclamation 

 has been determined to be far less than formerly thought necessary. Natural 

 stream channels and the great porosit.v of these soils made it possible to place 

 drains several hundred feet apart, thus materially reducing the cost of 

 reclamation. 



" Efficient drainage systems, together with pumps of small capacity, have been 

 found to remove easily and permanently a sufficient quantity of ground water to 

 keep the water table below^ the danger limit throughout the irrigating season. 

 These pumps may be readily driven by power furnished by water wlieels in the 

 canals. Cheap electricity also soon promises to be available for this purpose 

 where water power is not to be had. 



" When installing drainage systems, a competent engineer should be em- 

 ployed in order that the drains may be correctly laid on a proper and uniform 

 grade. A contour survey of the surface of the land, together with one of the 

 hardpan, is necessary to avoid the heavy cost of digging through hai"dpan and 

 at the same time to secure the best drainage. 



" In placing the tiles in the trench great care should be taken to crowd them 

 clo.sely together to exclude silt and sand. Silting is a serious problem in many 

 alkali soils, but may be overcome readily by placing cables in the drains and 

 drawing brushes through them. 



" The time necessar.v to drive alkali out of the freer soils by continuous deep 

 flooding may be as short as G weeks. Heavier soils require more time, but 

 usually not more water. 



"The practical trench test, to determine when the alkali has been sufficiently 

 removed and when flooding should cease, should be used. A grain crop should 

 follow during the next winter season. Any spots showing alkali can then be 

 readily detected and treated in the following spring and sununer. 



" With the experience gained by the Bureau of Soils as a guide no insur- 

 mount.ible difficulty in freeing land from alkali should be encountered by 

 farmers. The success attained in draining individual farms at the Toft-IIanseu 

 tract and other places clearly denjonstrates that such drainage is a permanent 

 and financial success. That such individual work will in time solve the problem 

 of alkali reclamation seems highly probable." 



