IKHKiATIOX EXPEEIMBNTS IN IDAHO. 

 FALL PLOWING. 



43 



An oxperimont was carried on at the Gooding experiment station 

 to determine tho effect of fall versus spring plowing on the duty of 

 water and yield produced, with the results that are shown in Table 

 XXI. 



Table XXI. — -Results of full versus spring plowing, Gooding experiment station. 



Sub- 

 plot 

 No. 



Area. 





Acre. 



1 



0.314 



2 



.315 



3 



.314 



4 



.314 



5 



.304 



6 



. 305 



Treatment of subplot. 



Water 



applied 



per 



acre. 



Acre- 

 feet. 



Fall plowed, minimum irrigation 0. 376 



Spring plowed, minimum irrigation 376 



Fall plowed, average irrigation . 962 



Spring plowed, average irrigation | . 962 



Fall plowed, maximum irrigation ' 1.533 



Spring plowed, maximum irrigation I 1. 533 



Yield of grain. 





Per 



Per 



acre- 



acre. 



foot of 





water. 



41.18 

 32.88 

 43.65 

 39.77 

 47. 54 

 45. 26 



Bush. 

 109.5 

 87.5 

 45.5 

 41.4 

 31.0 

 29.5 



Weight 



of 



grain 



per 



bushel. 



Pounds. 

 38 

 38 

 41 

 41 

 42 

 42 



A study of Table XXI makes it apparent that too much emphasis 

 can hardly be placed on the many advantages of fall plowing. 



MEASUREMENT OF WATER USED ON FARMS AND UNDER COMPLETE 



CANAL SYSTEMS. 



It is believed that the supply of water has been varied upon a 

 sufficient number of tracts in this investigation and that the in- 

 vestigation has covered a sufficient number of seasons to furnish a 

 correct idea of the irrigation requirements of" the soils and crops in- 

 cluded, but as an investigation of this sort alone furnishes no in- 

 formation (1) of the water required for domestic purposes, (2) of the 

 transmission losses and other general w T astes, or (3) of the average 

 use of water on typical Idaho farms when such use is unrestricted, it 

 was thought best to investigate also the use of water both upon 

 typical farms and under complete canal systems of the State. The 

 investigation was therefore extended so as to include a careful 

 measurement of the quantities used by a large number of typical 

 farmers and by seven complete canal systems in 1911 and eight com- 

 plete canal systems in 1912. 



The water used on the farms investigated was measured by auto- 

 matic water registers which were installed on weirs in the feed ditches 

 leading to the tracts or farms in question. The type of water registers 

 used and the method of their installation in connection with the weirs 

 are shown in Plate III, figure 1. 



The volume of water diverted and used by the canal systems was 

 determined by daily gage readings and a large number of current- 



