Effects of External Coloured Shade Nets on Sweet Peppers Cultivated in Walk-in Plastic Tunnels

Attila Ombódi,Hajnalka Ledóné Darázsi4,,András Kovács,Zsuzsanna Tóthné Taskovics,Lajos Helyes,Péter Szuvandzsiev,Zoltán Pék,Ambrus Koházi-Kis

doi:10.15835/nbha4329863

Abstract

Shading effect of external nets of different colours (white, green, yellow and red) on the yield of two â€œkapijaâ€ pepper (Capsicum anuum L.) cultivars was examined in walk-in plastic tunnels in Hungary under real cultivation circumstances. Shading nets decreased incoming radiation by 23-39% and reduced photosynthetically active radiation by 32-46%. The highest retention was obtained by yellow and green nets, in the range of 450-550 nm and 550-670 nm, respectively. Relation was reported between the degree of shading and the average air temperature of the tunnels, however, treatments did not decrease tunnel air temperature significantly, compared to that of unshaded and paint-shaded control tunnels. This can be explained by the applied proper ventilation and mist irrigation. A strong and negative relation was noted between the intensity of shading and the relative chlorophyll content (SPAD value) of leaves. Shading net treatments did not increase yields, yellow and green nets even decreased it. Instead of tunnel air temperature, yield was mainly affected by photosynthetically active radiation in the experiment. Strong positive linear relation was declared between the chlorophyll content of the leaves and the yield. Results of the current research led to the conclusions that under Hungarian climatic conditions the use of shading nets was less justified if proper cooling techniques (ventilation and mist irrigation) were applied; even under the relatively high incident radiation experienced during the trials. In greenhouses of less favourable climatic conditions, red or white shading nets are recommended instead of commonly used green ones in Hungary.

Highlights

Low-cost walk-in plastic tunnels are still very commonly used for vegetable – including pepper (Capsicum anuum L.) – cultivation in East-Central Europe (FruitVeB, 2013)
Results of the current research led to the conclusions that under Hungarian climatic conditions the use of shading nets was less justified if proper cooling techniques were applied; even under the relatively high incident radiation experienced during the trials
The combined effects resulted in better crop yields and lower susceptibility to decay during post-harvest storage compared to traditional shading methods (Stamps, 2009; Shahak, 2014)

Summary

Introduction

Low-cost walk-in plastic tunnels are still very commonly used for vegetable – including pepper (Capsicum anuum L.) – cultivation in East-Central Europe (FruitVeB, 2013). According to the literature photoselective shading nets of red, pearl and yellow colour markedly increased productivity, improved fruit quality of different cultivated vegetables and reduced the crop infestation by pests and diseases. Yellow coloured mesh shades increased open field pepper yield and quality compared to traditional black nets (Fallik et al, 2009), while both yellow and pearl coloured nets reduced the occurrence of Alternaria and improved post-harvest qualities of the product (Goren et al, 2011). Numerous studies focused on the use of shading nets in open field pepper cultivation, less result was obtained from the investigation on the effect of photoselective meshes on greenhouse sweet pepper production. The current study aimed to contribute to the knowledge on the effect of different coloured shading nets on the incident radiation and air temperature of walk-in tunnels and on the yield of pepper cultivated in the tunnels

Materials and Methods

Results and Discussion

Conclusions