RELATIONSHIP BETWEEN EVAPOTRANSPIRATION BY WHEAT AND THE STAGE OF CROP DEVELOPMENT, BELLANI-PLATE EVAPORATION, AND SOIL MOISTURE CONTENT

Abstract

Mean weekly evapotranspiration by spring wheat at Brandon, Man. (1955–1959) was dependent on the stage of development of the crop. It increased from 0.70 in. per week at the 3-leaf stage to 1.45 in. per week at the flowering stage and decreased to 0.60 in. per week as the crop reached maturity. Evapotranspiration was correlated positively with Bellani-plate evaporation when the soil was moist to the surface and correlated negatively when the surface soil was dry, but total soil moisture was greater than 50% of field capacity. When the soil moisture was less than 50% of field capacity evapotranspiration was not correlated with Bellani-plate evaporation. Evapotranspiration was correlated positively with total soil moisture plus rainfall. This emphasizes the importance of moisture stress in limiting evapotranspiration in a semi-arid region.