Abstract
The fraction of short‐wave radiation reflected from agricultural crops was measured from May till September 1958 using two portable solarimetric thermopiles. Maximum reflection coefficients for grass, lucerne, potatoes, sugar beet, and spring wheat were between 0·25 and 0·27. Lower values found in the early stages of crop development, and for spring wheat even at maturity, can be correlated with low leaf areas and mutual shading of the leaves, also reduced reflection. Data by Billings and Morris (1951) have been used to compute total reflection coefficients for different types of vegetation including two desert species and to explain why these do not normally differ as much as the coefficients for the visible component.