Articles
ZEBRA NET, TITANIUM NET, TRANSPARENT NET AND NEW GREY HAIL NET ¿ THE NEW GENERATION OF HAIL NETS: LARGE MESH SIZE, STRONGER FIBERS AND LARGE PORTION OF CRYSTALLINE TRANSLUCENT FIBERS IMPROVE LIGHT TRANSMISSION AND DURABILITY
Article number
1058_38
Pages
321 – 326
Language
English
Abstract
The first generation of black hail nets provided insufficient light transmission (ca. 80% PAR), which led to reduced fruit colouration in the fruit growing regions along 50°N similar to the second generation of coloured hail nets.
Hail nets in Europe typically comprise two interwoven longitudinal fibers (parallel to the tree row) and a single transverse fiber (perpendicular to the tree row); fibers are HD-PE mono-filaments.
In the third generation, an intelligent design, viz., combination of few thicker black fibers (> 0.32 mm) and a large portion of translucent crystalline fibers and large mesh size, enable greater light transmission, as well as better strength and durability.
Light transmission was measured as PAR in situ in July on both sunny and overcast days, 0.5 m underneath the hail nets spread flat and horizontally on a frame.
Their fine structure was examined by a stereoscan microscope with the following results: The zebra hail net (Fruit Security Co., Austria./MaBo) with the largest mesh size of 3.0 x 8.8 mm consisted of longer (95 cm) patches of white and shorter (30 cm) patches of transversal black fibers (8 %) and transmitted ca. 85% PAR. The new grey hail net (Fruit Security, MaBo; BayWa, Germany), also with the largest mesh size of 2.9 x 8.8 mm, consisted of two interwoven, translucent and a single transverse black fiber, which also transmitted ca. 85% PAR. The titanium hail net (Helios Co., Italy) uses translucent fibers with a medium mesh size of 2.8 x 8.2 mm and UV-stabilizes only the single, white, transverse fiber with titanium, and transmitted ca. 86% PAR. The transparent hail net (Brändlin Co., Germany) combined translucent fibers with the smallest mesh size of 3.0 x 7.0 mm and reinforced only the edges with black longitudinal fibers to achieve a large light transmission of ca. 88% PAR.
Hail nets in Europe typically comprise two interwoven longitudinal fibers (parallel to the tree row) and a single transverse fiber (perpendicular to the tree row); fibers are HD-PE mono-filaments.
In the third generation, an intelligent design, viz., combination of few thicker black fibers (> 0.32 mm) and a large portion of translucent crystalline fibers and large mesh size, enable greater light transmission, as well as better strength and durability.
Light transmission was measured as PAR in situ in July on both sunny and overcast days, 0.5 m underneath the hail nets spread flat and horizontally on a frame.
Their fine structure was examined by a stereoscan microscope with the following results: The zebra hail net (Fruit Security Co., Austria./MaBo) with the largest mesh size of 3.0 x 8.8 mm consisted of longer (95 cm) patches of white and shorter (30 cm) patches of transversal black fibers (8 %) and transmitted ca. 85% PAR. The new grey hail net (Fruit Security, MaBo; BayWa, Germany), also with the largest mesh size of 2.9 x 8.8 mm, consisted of two interwoven, translucent and a single transverse black fiber, which also transmitted ca. 85% PAR. The titanium hail net (Helios Co., Italy) uses translucent fibers with a medium mesh size of 2.8 x 8.2 mm and UV-stabilizes only the single, white, transverse fiber with titanium, and transmitted ca. 86% PAR. The transparent hail net (Brändlin Co., Germany) combined translucent fibers with the smallest mesh size of 3.0 x 7.0 mm and reinforced only the edges with black longitudinal fibers to achieve a large light transmission of ca. 88% PAR.
Publication
Authors
M.M. Blanke
Keywords
apple (Malus domestica Borkh.), crystal net, hail net, light, durability, PAR, polyethylene (HD-PE), UV, resource conservation, sustainability, tearing strength
Online Articles (87)