technique appears to promise a reasonable means of estimatlnf 

 with precision heretofore unknovm, evapotransplratlon rates I 

 crops In the various geographic areas of California. 



Conclusions 



1. Correlation of evaporation with evapotransplratlf 

 appears to promise a reasonable means of estimating evapotranS' 

 plratlon within the various agricultural area of the State. 



2. Reasonable estimates may be obtained by using 

 either pan, or atmometer coefficients. 



3. Pan and atmometer coefficients are strongly in- 

 fluenced by percent of ground cover, particularly for ground 

 cover percentage less than (60^o) sixty percent. 



^1-. Estimated values presented In this report are 

 based upon only two years of record, and so should be used 

 with considerable judgment. 



5. On the basis of the agroclimatic data collected, 

 no definite segregation of the State into areas of uniform 

 evaporation is possible at present. Inland areas appear to ha 

 more uniform evaporation rates than expected, although effect 

 of microenvlronment cause large differences of evaporation be- 

 tween individual measurement sites. 



6. It may be found that the len,^;th of growing seaso: 

 is the most Important factor affecting seasonal evapotransplra 

 tlon in inland areas. 



■ 74- 



