TRRIGATION EXPERIMENTS IN IDAHO. A3 
FALL PLOWING. 
An experiment was carried on at the Gooding experiment station 
to determine the effect of fall versus spring plowing on the duty of 
water and yield produced, with the results that are shown in Table 
XO. 
TaBLe X XI.—Results of fall versus spring plowing, Gooding experiment station. 
Yield of grain. 
Sub- Wiater " Bae: 
plot | Area. Treatment of subplot. oepied Per | grain 
No. a a Per acre- per 
; acre. | foot of | bushel. 
water. 
Acre- 
Acre. Feet Bush. | Bush. |Pounds. 
1| 0.314] Fall plowed, minimum irrigation..................-.---- | 0.376 | 41.18 | 109.5 38 
2 .315 | Spring plowed, minimum irrigation.........-...-.------ .376 | 32.88 87.5 38 
3 .314 | Fall plowed, average irrigation.........---------------- -962 | 43.65 45.5 41 
4 314 | Spring plowed, average irrigation.........--....-------- 2962) Sonat 44 41 
5 .304 | Fall plowed, maximum irrigation......-.....---.------ 1.533 | 47.54 31.0 42 
6 .305 | Spring plowed, maximum irrigation.........-.....---.- 1..5337|> 45.26 29.5 42 
A study of Table X XI makes it apparent that too much emphasis 
ean 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 (i) of the water required for domestic purposes, (2) of the 
transmission losses and other general wastes, or (3) of the average 
use of water on typical Idaho farms when such use is unrestricted, it 
was thought best to mvestigate also the use of water both upon 
typical farms and under complete canal systems of the State. The 
vestigation 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 
Jeading 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- 
