R. Leuning et al., RAINFALL INTERCEPTION AND EVAPORATION FROM SOIL BELOW A WHEAT CANOPY, Agricultural and forest meteorology, 67(3-4), 1994, pp. 221-238
Components of the seasonal pattern of water use by a wheat crop at Wag
ga Wagga, N.S.W. are presented. Total evapotranspiration was estimated
using a combination of Time Domain Reflectometry and Neutron Moisture
Meter measurements. Miniature lysimeters were used to measure evapora
tion from soil below the canopy. Evaporation of intercepted rain was c
alculated using an aerodynamic technique in conjunction with a canopy
storage coefficient. Detailed measurements of soil evaporation and rai
nfall interception commenced 80 days after sowing (DAS), when L approx
imately 1, until 165 DAS. Interception losses accounted for 33% of rai
n during this period (114 mm), while soil evaporation was 48% of rainf
all. Combined interception and soil evaporation losses for the whole g
rowing season accounted for 49% of total evapotranspiration. Scope exi
sts to reduce soil evaporation by managing crops for early canopy clos
ure, but this will mean greater rainfall interception losses and reduc
ed replenishment of soil water.