RURAL ENGINEERING. 283 



all sides. Further general information is given regarding the building of canal 

 embankments, the distribution of water from canals, and for drilling and 

 casing wells. The vertical centrifugal pump has been found to give the best 

 satisfaction in all re.spects and is said to be almost universally used. 



Experiments conducted to determine the effect of water containing different 

 percentages of sea salts on growing rice are also reported, the percentages of 

 salt in the water varying from 0.0-5 to 1 per cent. It was found that water 

 with more than 0.3 per cent of salt when applied every two weeks after the 

 rice had stooled in fresh water killed the rice. Rice irrigated with water 

 containing 0.2 and 0.3 per cent of salt made only short heads and small grains. 

 When salt water was applied only once and fre.sh water was applied at the 

 next irrigation the injury was not so great as when the rice was irrigated 

 with salt water several times, and when salt water and fresh water were 

 j;pplied alternately every two weeks during the season the rice was not injured 

 quite so much as when only salt water was applied. 



" Two-tenths per cent or more of salt in the irrigation water will cause some 

 of the leaves and hulls of the rice plants to turn brown. The more salt there 

 is in the water beyond a certain percentage the greater is the injury ; 0.15 or 

 0.1 per cent of .salt in water will cause the rice to grow better than 0.0.5 per 

 cent, which shows that the.se small amounts of sea salt act as fertilizers. 

 Larger percentages of salt can be used if there is rain or If there is considerable 

 fresh water on the field to dilute the salt water." 



Further general information is given regarding the preparation of a rice 

 field for irrigation, including particularly the application of water, the location 

 and building of levees, and the value of irrigation as a means of controlling 

 insects and rice plant diseases. 



Drainage and reclamation (California Sta. Rpf. 1915, p. IS). — Experiments 

 on drainage of alkali soils made in cooperation with the Office of Experiment 

 Stations of the U. S. Department of Agriculture are reported. 



Four miles of 10- and 12-in. tile drains with 6-in. laterals laid at a depth of 

 a little less than 6 ft. in a quarter-section of vineyard soil rendered unproduc- 

 tive by alkali were found to remove approximately 97,580,000 gal. of drainage 

 water the first season, containing 151.5 tons of alkali, mostly common salt. 

 " Extensive tests of the soil show a very decided decrease in common salt but 

 no material change in the black alkali. A rather unsatisfactory crop of 

 Pigyptian corn was grown on the east half of the area. After one season's 

 flooding the alkali weed, which was so abundant, has almost wholly disap- 

 peared and Bermuda grass is so rapidly taking its place as to become an 

 important factor in the cost of reclamation. The cost of the drainage system, 

 including pump and motor, was somewhat less than $70 per acre, while leveling 

 the land and operating expenses, including pumping, have cost during the year 

 $15 per acre additional." 



Land drainage by means of pumps, S. M. Woodwabd, revised by C. W. Okey 

 (V. S. Dept. Agr. Bid. 304 (1915), pp. 59, pis. 8, figs. 3).— This bulletin repre- 

 sents the results of a revision of the bulletin previously noted (E. S. R., 26, p. 

 589) with special reference to the upper Mississippi Valley. 



It is stated that a pumping plant should have a capacity sufficient to remove 

 as a minimum amount in 24 hours a quantity of water sufficient to cover the 

 entire district to a depth of 0.3 in. " Since it has been shown that the average 

 depth of water to be pumped from such districts per year will be about 15 in., 

 with well-designed and carefully operated plants the total cost per acre of drain- 

 age area per year should not exceed 80 cts. for a mean lift of 5 ft. and $1.20 

 for a mean lift of 10 ft. The administration of the business of the district 

 should be placed in the hands of a competent engineer who is familiar with 



