Abstract : Intercepted solar radiation by each leaflet in two field grown soybean communities was measured by integrated solarimeter films for two consecutive days. These solarimeters are pieces of film (70 mg, 12 mm X 35 mm) , and measure radiation by percentages of remaining dye after the exposure to radiation. These solarimeters were placed on every leaflet surface of two plants each of the two determinate cultivars. The experiments were done at the flowering and the young pod stages. In both experiments, the mean intercepted radiation of each layer tended to be decreased gradually toward the base of the canopy. There were several leaflets which intercepted similar radiation as compared with the global solar radiation. The portion of intercepted radiation by leaves on branches was about 60% of the total intercepted radiation at the flowering stage, and increased to about 70% at the young pod stage. Terminal leaflets intercepted more radiation ranging from 4 to l0% as compared with the side leaflets.

Key words : Canopy structure, Integrated solarimeter films, Light interception, Soybean