TY - JOUR T1 - Sunlight Interception by Vineyards JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 141 LP - 147 DO - 10.5344/ajev.1973.24.4.141 VL - 24 IS - 4 AU - Richard E. Smart Y1 - 1973/01/01 UR - http://www.ajevonline.org/content/24/4/141.abstract N2 - A numerical model of grapevine light interception was developed and adapted for computer analysis. The effects of the variables — plant shape, size, planting distance, row orientation, cloudiness, and latitude — were evaluated. The dominant component of illumination under clear skies was direct light absorbed by vine tops and walls, with diffused sky light of less importance. Light interception was maximal for tall, closely spaced, north-south rows. Patterns of interception were similar over the latirude range 12°S to 43°S, and cloud cover reduced the advantages of north-south rows. The advantages and shortcomings of the computer model are discussed. ER -