to obtain adequate evapotransplratlon data from soil moisture de- 

 pletion measurements, attempts to modify Irrigation were initiated. 



It was observed that weekly visits to plot sites ad- 

 verseley affected the crop cover and soil conditions by trampling 

 the crop. To overcome these undesirable effects, a portable 

 sampling platform v/as built in 1956 to sample one of the plots. 

 This was the forerunner of platforms which were used later with 

 neutron probes. 



In 1957^ the water use studies were expanded to other 

 areas of the State, Alfalfa fields were sampled in Stanislaus 

 and Kings Counties. These plots were abandoned because data ob- 

 tained from them were not considered reliable for estimating evapo- 

 transplratlon because of excessive moisture movement that resulted 

 from overirrigation at the Stanislaus County plots and unfavorable 

 soil conditions at the plots in Kings County. 



In 1958, one man was stationed in Kern County following 

 a reconnaissance for plot sites. Plots of alfalfa, grapes, and 

 plums were sampled. Problems of two kinds were encountered. On 

 plots receiving lesser quantities of irrigation, the crops ex- 

 tracted moisture from below the zone sampled, while on plots re- 

 ceiving very frequent irrigations, considerable moisture movement 

 occurred between sampling. 



No further gravimetric samples were taken following the 

 adoption of neutron scattering equipment in the spring; of 1959. 

 While complete detailed records were kept and calculations made 

 for each of the gravimetric sampling sites, the results of these 

 measurements are not Included in this report, 



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