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Show CONSUMPTIVE USE OF WATER IN IRRIGATION Snelson's Alberta Work.-Working on field plots in Brooks, Alberta, Canada, Snelson (18) used moderate quantities of water in single applications and made careful measurements of soil moisture to a depth of 6 ft. at the beginning and the end of the growing season. Under his methods percolation loss in all probability was very small if not zero, and hence it seems safe to assume that U is equal to Uf. If percolation losses were zero, then according to Snelson's experiments with wheat on the more fertile soil the consumptive use varied from 0.85 ft. to 1.82 ft. as the crop yield varied from 10 to 50 bushels per acre. For oats on the more fertile plots the consumptive use ranged from 0.72 ft. to 1.75 ft. as the yield varied from 40 to 135 bushels per acre. Barley required a consumptive use from 1.25 to 1.60 ft. for yields ranging from 40 to 51 bushels per acre, and for alfalfa the use varied from 1.00 to 2.62 ft. for yields ranging from 1.0 to 5.7 tons per acre. Powers' Oregon Work.-Powers (16, 17) has made many field plot measurements of consumptive use in Oregon. Experimenting with alfalfa in the Willamette Valley during 1911, using moderate irrigation he found values from 1.4 to 2.Q ft., accompanying yields of 4.1 to 5.2 tons per acre. The consumptive use for clover was approximately the same as that for alfalfa. Moisture determinations were made to a depth of 6 ft. at the outset in the Willamette Valley work, but as most of the borings showed a water penetration to only 4 ft., the later borings were not made below this depth except in connection with a few very heavy irrigations. Powers was convinced that there was "practically no loss by percolation" apparently because dry soil was frequently encountered in the lower depths and also because these lower depths in many instances gained in moisture content during the period following one irrigation and preceding the next following. It is doubtful whether this is conclusive since the increase in the lower depths may have been caused by a movement of capillary water downward from the moist surface to the dryer sections below. If such were the case, some percolation probably occurred and Powers' measurements would represent Uf instead of U. If, on the other hand, the moisture did rise in significant quantities from below the zone of soil sampling, then the value of the consumptive use as measured by Powers is too small as there was an unmeasured source of water. In reporting the Western Oregon work, Powers is silent concerning the depth of the water-table. Further measurements were made in Eastern Oregon by Powers (17), but it is beyond the scope of this report to give them in detail. Utah, Work by Harris.-Further field plot work at the Utah Agricultural Experiment Station by Harris (6) and associates from 1911 to 1919 gives additional information concerning consumptive use. The results of this work, together with the work done by Widtsoe, have been reported in detail in fifteen Station Bulletins which were published as the work progressed. Finally, in one paper (6), Harris has brought together the results of seventeen years' work. This Bulletin contains six charts, each representing a different crop, which show the relation between the yield and the quantity of water applied. Two curves are platted on each chart, the actual average yields for |