SHADING AND AIR VELOCITY INFLUENCE ON GREENHOUSE MICROCLIMATE

A comprehensive experimental study was initiated to investigate the effects of shading rates as solar interceptors and air velocity on the greenhouse crop environment.
The 50% shade nets reduced evapotranspiration (ET) rates by 22% while solar energy loads were reduced by 45%. For the 50% shaded greenhouse, increasing air velocities above plant from 0.1 to 0.6 m/s significantly increased ET rates by 16%; for the 0% shade, ET rates were not significantly increased by air velocity.
For the 0% shaded greenhouse, top leaf temperatures were approximately 1°C higher than air temperatures when air velocities were approximately 0.1 m/s.
When air velocities across the plants were approximately 0.6 m/s, top leaf temperatures were nearly equal to or slightly less than air temperatures.
For the 50% shade, both leaf temperatures at the top and within the plant canopy were consistently lower than air temperatures.

International Symposium on Greenhouses, Environmental Controls and In-house Mechanization for Crop Production in the Tropics and Sub-Tropics

I. Al-Arafi

greenhouse environment, shading rates, ventilation, evapotranspiration (ET), leaf temperature

https://doi.org/10.17660/ActaHortic.2006.710.22