158 



THE IRRIGATION AGE. 



It will be noted that the water analyses made 

 by the Division of Agricultural Chemistry, Uni- 

 versity of California, show the removal of consid- 

 erable Na 2 SO 4 , but the soil analyses made by the 

 Division of Soil Chemistry and Bacteriology, Uni- 

 versity of California, do not indicate the presence 

 of appreciable amounts in the soil. This is due to 

 the method of analysis used by the Division of 

 Soil Chemistry and Bacteriology, as no quantitative 

 analyses were made for Na 2 SO 4 unless a qualitative 

 analysis gave a sulphate reaction. 



It is interesting to note that water samples 

 taken on the same dates in 1915 from the Houghton 

 Canal and from a pumping plant about two miles 

 distant on the Kearney Park Experiment Station 

 tract, show an average alkali content as follows : 



parts per 

 million 



1. Kearney Vineyard experimental drain. . .301.88 



2. Houghton Canal 33.43 



3. Kearney Park Experimental Station 98.82 



These figures would indicate that no great 

 amount of alkali was added to the tract through the 

 water used in flooding, and also that considerable 

 more was removed in the drainage water than is 

 found in the usual ground water. 



The average alkali content for the tract has 

 been materially reduced, as found after the 1915 

 tests, and is now much less than is usually consid- 

 ered detrimental to crops. Alkali tests made on 

 areas where the 1916 crops were not satisfactory 

 indicate that the alkali is not wholly responsible. 

 There seems to be little doubt but that the physical 

 condition of the soil is very poor in these spots and 

 investigations are now under way to determine, if 

 possible, a remedy for this condition. 

 Operations During 1916 



During December, 1915, the west half of the 

 tract was sown to oats. Owing to weather condi- 

 tions it was not possible to plant the remainder of 

 the tract until February, 1916, which was then sown 

 to barley. 



During the early part of April it 



became necessary to irrigate the 

 barley planted on the east eighty 

 acres. This operation took about one 

 week and no more water was added 

 until late in the season, this being 

 done to facilitate the preparation of 

 the land for alfalfa. 



In 1916 one hundred and eighty 

 tons of hay were obtained from the 

 tract, an average of almost 1.2 tons 

 per acre. 



Summary 



The tract of land chosen for this 

 experiment was formerly a profitable 

 vineyard, but because of a rising 

 water table and the accompanying 

 accumulation of alkali, passed from 

 a vineyard through the stages of 

 decline of an alfalfa and grain field 

 to a poor pasture of foxtail and alkali 

 weed. For two or three years previous to 1913 no 

 crops were grown. 



Preliminary investigations indicated the pres- 

 ence of alkali in dangerous quantities over a con- 



siderable portion of the tract. At certain times of 

 the year the water table was less than two feet from 

 the surface and during most of the growing season 

 was dangerously high. 



The installation of the drainage system in 1913 

 was the first step toward reclamation. Shortly after 

 operations were started in 1914, several errors in 

 design were discovered, the principal ones being a 

 too small and poorly-designed pumping equipment 

 and too small carrying capacity of the main drain. 

 These have been remedied. Aside from these 

 changes made during the spring and summer of 

 1914, it became apparent that fewer and less expen- 

 sive silt wells would have served the purpose and 

 the canal crossings could have been omitted 

 entirely. 



The reclamation of this tract has involved the 

 expenditure of $100 per acre, which is a large ex- 

 pense, but it must be remembered that the entire 

 expenses incidental to putting this land into an 

 irrigable condition and the eradication of Bermuda 

 grass, amounting to approximately $20 per acre, 

 would have been necessary under any circumstances 

 and cannot be properly chargeable to drainage ; in 

 many cases of reclamation it will not be necessary. 

 The duplicate expenses for pump and tile can be 

 eliminated from future undertakings of this char- 

 acter, and this, together with changes in design that 

 will favor economy in construction, will reduce the 

 first cost by an additional $20 per acre, making a 

 total possible reduction of about $40 per acre. 



From measurements taken of the pump dis- 

 charge, it is evident that drainage systems under 

 similar conditions should be designed to remove at 

 least one cubic foot per second for each 100 acres, 

 especially where the drained tract is entirely sur- 

 rounded by undrained land. 



Indications are that the lateral drains might 

 have been placed 400 feet apart. It would have been 

 better had the lateral tile lines been placed six and 

 one-half or seven feet deep, instead of five and three- 

 quarters feet. The hardpan, which was known to 



Fig. 11 Oat hay on west half of drained tract. May, 1916. 



exist, has not proved to be a material hindrance to 

 the movement of water. 



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