Combination of Black Shading Nets and Its Effect on Radiation Intensity and Quality

Abstract

The use of shading nets in agronomy is a common method to create protected environments for plant acclimation and production. Climate changes increased the use of shading nets and it is common to find builds with combined or overlapped layers whereas the resulting attenuation is unclear. This work aimed to study the radiation intensity and attenuation inside shaded environments created by combining black shading nets. Shading environments were build with a base 30% black shading net and the combinations of 30%+50% and 30%+70% nets, plus, shaded environments were compared to unshaded condition. The experimental design was completely randomized with four treatments and five replicates. Radiation intensity was measured with a spectroradiometer at ultraviolet (Uv), photosynthetically active radiation (PAR) and near infrared (IR) bands. Ultraviolet radiation was further studied at UvA, UvB and UvC bands. Attenuation was calculated for each shading condition as compared to unshaded treatment. The combination of shading nets reduced radiation intensity of PAR, IR and UvA bands. UvC and UvB bands were unaffected by the shading nets used. Shading capacities of individual shading nets were summed but   attenuation was lower then predicted. Thus, combination of shading nets provides partial summation of individual shading capacities and is effective to improve attenuation of UvA, PAR and IR bands; however, combination of shading nets had no effect for UvC and UvB bands.