41 



water by saltgrass, wire rush, willow, Bermuda grass, tules, and 

 cattails grown in tanks with different depths to ground water. 



Study of soils and soil-moisture conditions in the lower 

 Santa Ana River Valley led to selection of a plot in a level 

 10-acre field 4 miles west of Santa Ana and about 7 miles inland 

 from the Pacific coast. The field was free of windbreaks and 

 shade, and was generally suitable for consumptive-use studies. 

 Soil was of alluvial origin, classified as a fine, sandy loam, 

 grading into a coarse, yellow sand at a depth of 6 to 7 feet. 

 It lacked humus and contained a small amount of alkali. An ample 

 supply of good water for use in the experiment tanks was found at 

 a depth of a few feet. The climatic conditions at this point are 

 representative of the coastal climate of southern California. 

 Summers are warm and dry and winters are moderate and wet. Coast- 

 al fogs are frequent, tending to modify evaporation from water 

 surfaces and transpiration by plants. Figure 5 is a sketch of the 

 station showing arrangement of tanks. 



Saltgrass . --In all saltgrass tanks water tables were held 

 at definite predetermined depths by means of Mariotte supply tanks. 

 A general outline of the tank set-up is shown in Figure 1, and a 

 description of the Mariotte apparatus is given on page 19- Fif- 

 teen soil tanks of the double-shell type, each 23 inches in diame- 

 ter and 6 feet deep, were filled with a fine sandy loam soil. In 

 12 tanks the soil was captured in place undisturbed, but in three 

 others it was loosely settled in water. Six tanks of undisturbed 

 soil had an original crop of saltgrass on the soil column with 

 root systems fully developed. Later in the investigation salt- 

 grass was transplanted into all other tanks so that eventually 

 all tanks supported saltgrass growth. 



To reduce the hazard of inaccuracies which might occur in a 

 single tank the entire group was divided into sets of three, each 

 set having a different depth to water. In four sets consumptive- 

 use measurements were made with water tables at depths of 1 , 2, 3, 

 and 4 feet respectively. A summary of the data obtained from the 



