to the south-southwest, and the 30 acres of alfalfa In the field 

 are surrounded by small irrigated fields, dry- farmed grain, and 

 native vegetation. Prevailing winds in the area are from the west 



Initially, three rows of five access tubes were installec 

 73 feet apart, with the tubes spaced in the rows 15 feet apart. 

 In September 1959^ four more tybes were installed in one of the 

 rov;s, and the other two rows abandoned, reducing the plot to nine 

 tubes. This enabled the plot to be irrigated in two days, rather 

 than the three to four days required for the sprinklers to pass 

 over the original three rows of access tubes. 



Irrigation water is applied by a portable sprinkler 

 system, using full circle (360 degrees) rotating sprinklers. The 

 sprinklers sometimes stuck in one position, and irrigation applica 

 tion, as a result, was not uniform enough to determine applied wat< 

 from pumping records. This plot was subjected to somewhat deficit 

 irrigation, which left a dry zone generally below a depth of 8 fee' 

 For this reason, the soil moisture measurements can be used with 

 confidence as estimate of evapotranspiration. 



Neutron moisture depletion measurements were made during 

 1959 and 196O at another alfalfa site 3 miles west of the Pittvill«' 

 plot. Due to apparent excessive moisture movement, however, the rt 

 suits of these measurements are not included in the report. 



Arvin Neutron Probe Moisture Depletion Measurements . 

 These measurement sites are in the southern San Joaquin Valley, 

 near the 35 degree latitude, located at an elevation of about hkO 

 feet. The plot sites are on broad, smooth, recently formed fans 



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