The objective of this work was to quantify the growth rates, dry matter production and distribution of summer squash grown in raw rice husk medium with recirculating nutrient solution, in two crop seasons: spring-summer 2005 and summer-autumn 2006, which are periods characterized by high and low solar radiation availability, respectively. Each treatment corresponded to a sampling date and dry matter production was evaluated at 18, 32, 46 and 68 days after setting (DAS) in spring-summer, and 15, 29, 43 and 55 DAS in the summer-autumn crop season. Dry matter production was highest in high solar radiation availability conditions. In those conditions, fruits were characterized as the largest drains of the crop, which did not happen in low solar radiation availability. The growth rates (crop, fruits, shoot organs and relative crop rates) also were higher in high solar radiation availability conditions. Leaf area ratio and specific leaf area showed similar dynamics to the relative crop rate, decreasing according with the time-course of the crop.
Cucurbita pepo L.; dry matter production; hydroponics; leaf area; solar radiation; growth analysis
