SEASONAL CONSUMPTIVE USE OF WATER BY CROPS GROWN IN SOUTHERN ALBERTA AND ITS RELATIONSHIP TO EVAPORATION

Abstract

Irrigation water was applied to 13 crops, commonly grown in southern Alberta, whenever the available moisture within the root zone was depleted to the 75, 50, and 25 per cent levels during the seasonal growth period. The average consumptive use, associated with the maximum yield treatments, during this 12-year study, was highest for alfalfa and pasture grass (26 and 24 inches, respectively) and lowest for tomatoes and canning peas (14 and 13 inches, respectively). Other crops produced maximum yields with an average use of water, in inches, as follows: sugar beets, 22; potatoes, 20; soft wheat, 19; hard wheat, 18; oats and barley, 16; and flax and corn, 15. The range of water use data reported in this study is generally somewhat lower than the practical water requirements (including measured and estimated consumptive use) indicated in earlier reports by other investigators.The consumptive use-evaporation ratios were highest for forage crops and lowest for row crops. These relationships were determined for the 4-foot sunken pan, the class "A" pan, and the black Bellani plate atmometer.