Over the last decade, the use of net structures to protect horticultural and fruit crops has been widely deployed in the Southeast of Spain, mainly because of the advantages provided by this type of structure, such as shading in summer, protection against pests, as well as protection against hail.
Half of the 13,000 hectares (ha) of protected crops currently registered in the Region of Murcia are plastic greenhouses and the other half are net structures. The most important areas of nets are concentrated in the Guadalentin Valley (including Mazarron and Aguilas) with 3,600 ha, Vegas Alta y Media Del Segura with 1,700 ha and Vega Baja- Campo de Cartagena, with 1,000 ha.
A study carried out in Cartagena determined that moderate shading, which reduces light transmission by 20%, is optimal for growing peppers in summer, achieving a 70% increase in productivity compared to the same crop in the open air.
Most likely this is due to increased radiation scattering under net structures, associated with changes in the spectral distribution of light, and decreased stress due to excess light (photo-inhibition) that promote higher yields of plants grown in these structures.
Similar results have been obtained with cucumber, and possibly also with tomato, since it has a similar physiological behavior to bell pepper.
The study has also revealed that water use efficiency, i.e., the ratio between production and the amount of water used by the crop, is also higher in crops grown under net structures, which also improve the efficiency of light use.
The severe stress conditions found outdoors or in unshaded greenhouses were substantially reduced under the net structures.
Net structures with an optimized design and adequate transmission and porosity are one of the most economical and sustainable means to increase the productivity of horticultural crops in Mediterranean regions.
Anti-insect netting is less porous in order to prevent the entry of virus vectors. Depending on the species grown, shading can be strong (50%, for ornamental plants), medium (between 50% and 25%) and moderate (25%) for horticultural or fruit crops. From the structural point of view, they are less investment-intensive than plastic greenhouses, as no windows are required for ventilation. It offers the added advantage that netting has a minimum life span of five years, which is longer than the three seasons of the plastic films usually used as greenhouse coverings.
This is a pioneering study on the subject, as there was no information on the optimum shading percentage for horticultural crops, particularly peppers, an important tradition in Murcia.
In GrennNets we offer you for your horticultural crops, our 7×5.5 thread/cm2 (17 mesh) mosquito netting, available in clear, gray and black, or our 5×4 threads/cm2 (13 mesh) anti-hail netting, available in white, black and clear.
Source: https://www.upct.es