SOLAR RADIATION IN CROP CANOPIES.

The paper analyzes penetration of total solar, T, near infrared and photosynthetically active radiation (PAR). PAR, measured by tube solarimeters at Rothamsted, England in five different crops, includes sugar beet, field beans, kale, and spring wheat. The measurements are used to obtain the sunfleck parameters in Monteith's theory. Crop transmission parameters calculated from the daily radiation totals changed little when crop cover was full.