728 EXPERIMENT STATION RECORD. [Vol.41 



It is concluded that this inliibition of shoot formation and the favoring of 

 root formation are factors concerned in the determination of the polar character 

 of regeneration. 



On certain shoot-bearing tumors of eucalypts and angophoras, and their 

 modifying influence on the growth habit of the plants, J. J. Fletchee and 

 C. T. MussoN (Proc. Linn. Soc. N. S. Wales, 43 {1918), pt. 1, pp. 191-233, pis. 

 2Jf). — This is an account of the presence and apparent relations of tumors dis- 

 cussed herein as found on eucalypts and angophoras, but mentioned also as 

 occurring on about 10 species of other genera, observations regarding whicli 

 cases are also to be published. The presence in some species of water-storing 

 roots is also briefly discussed. 



FIELD CROPS. 



Irrigation of field crops in Nevada, C. S. Knight and G. Hakdman (Nevada 

 Sta. Bid. 96 (1919), pp. 5-^2, figs. i9).— This bulletin comprises a discussion of 

 irrigation practice in Nevada, the water supply and drainage areas of the State, 

 factors affecting the duty of v^^ater, and experimental work with irrigated field 

 crops, including alfalfa, wheat, potatoe.s, red clover, and sugar beets, already 

 reported on from time to time (E. 3. R., 41, p. 231). 



Approximately 1.3 per cent of the area of the State was irrigated in 1918, 

 of which about 145,000 acres was in alfalfa, 80,000 acres in wheat, and 15,000 

 acres in potatoes, these being the most important cultivated crops grown under 

 irrigation. The Humboldt, Truckee, Carson, Walker, and Muddy are said to be 

 the principal rivers supplyirig water for irrigation, and more than 50 per cent 

 of the irrigated area received its water from the Humboldt River. The greater 

 portion of the alfalfa and grain is irrigated by the border method of flooding, 

 while the furrow method is used in the irrigation of potatoes and other simi- 

 larly cultivated crops. The important factors aifecting the duty of water in 

 Nevada are designated as soil type, topography, hardpan near the surface, 

 annual rainfall, and evaporation, the type of soil causing greater variation in the 

 amount of water required under general field conditions than any other one 

 factor. 



The average results of early investigations with alfalfa, 1906-1911, show a 

 total irrigation of 3.27 aci'e-ft. of water, producing a yield of 5.93 tons per 

 acre. During the 5-year period 1914-1918, inclusive, practically no precipita- 

 tion was received during the gi-owing season that was sufficient to affect the 

 moisture content of the soil. The irrigation water was measured into each 

 plat through calibrated galvanized-iron pipes 2 in. in diameter, while check 

 plats were used to prevent, as far as possible, any errors due to variation in 

 soil. Alfalfa allowed to reach the wilting point before irrigation produced a 

 relatively low yield per acre, but excellent returns v.ere realized when irriga- 

 tion was withheld until the plants turned dark green in color. The most eco- 

 nomical use of water with alfalfa was accomplished with a total irrigation of 

 3.5 ft., applied when plants showed need of water by the dark-green color of the 

 foliage, producing 5.59 tons per acre. 



Soil-moisture determinations showed that 70 per cent of the 6-in. applications 

 was retained in the first 4 ft. of soil. The use on this plat was equivalent dur- 

 ing the period of irrigation to a deliv,ery of water at the rate of 1 second-ft. for 

 85 acres, or 0.47 miner's in. per acre. The highest yield of alfalfa, 6.18 tons 

 per acre, was obtained with an application of 81 in, of water when the crop 

 was irrigated before plants showed need of water, but this was accompanied by 

 the lowest yield per acre-ft., 1.03 tons. Soil-moisture determinations showed 

 that only 25 per cent of the 12-in. application was retained in the first 4 ft. of 



