•The use of protective netting to reduce fruit sunburn, hail and wind damage is gaining momentum in apple production.•Under high light environments, protective netting can reduce light stress and ...improve plant growth and performance.•Protective netting can change the orchard microclimate thereby altering tree water-use, growth and overall productivity.
The use of protective netting (also called shade nets or anti-hail nets) is being increasingly adopted in apple (Malus × domestica) production. Protective netting is mainly used to prevent fruit sunburn and protect trees against hail damage. Netting can also be used for protection against damage from birds, fruit bats, insects, wind and sand storms. In recent times, protective nets have been modified into photoselective nets by incorporating chromatic elements into the netting material. These change the spectral characteristics of the solar radiation reaching the tree canopy below the net and can affect physiological pathways that respond to the altered light spectra. Protective netting primarily modifies light quantity and quality underneath by reducing light intensity by an approximately pre-determined percentage. Protective netting has also been reported to reduce wind speed and soil temperature with minimal impact on canopy temperature and relative humidity. Quantifying the influence of protective netting on tree gas exchange has been difficult due to variations in the environmental conditions at the time of measurement. Reductions in light intensity due to protective netting result in increased leaf area, shoot length, and total shoot fresh weight that increases as the net shading percentage increases. Fruit set, return bloom, and flower induction are all affected by protective netting. Ultimately, fruit quality is the critical factor determining whether protective netting is suitable for apple production. The reported results on the effect of protective netting on fruit quality have not been conclusive. It has been suggested that changes in fruit quality under protective netting are often more influenced by the environmental conditions in that specific growing season than the netting itself. For example, typical shade responses under netting can be exacerbated when the natural overall light intensity is reduced on cloudy days. In conclusion, protective netting provides an alternative to traditional approaches to protecting apple from sunburn, mechanical injury from hail and wind, and abiotic stress that limits tree productivity. However, the inconsistent reported results suggest a targeted approach is needed to identify specific physiological responses of apple under protective netting, and more specifically, photoselective netting as a strategy to protect apple orchards from adverse environmental conditions.
•Hail net offsetting the negative effects caused by heat and drought stress in apple production.•Integrating the effects of hail net on the water supply and some of the parameters of photosynthesis ...of apple orchard.•Differences between the response of Golden Reinders and Early Gold varieties on the effect of hail net.
Apple production accounts for 60–65 % of all fruit production in Hungary, as one of the most important areas of the fruit production sector. Extreme weather conditions in the continental climate can cause significant problems in apple production. The most important solutions to decrease their effects are irrigation and hail net. In addition to protection against hail damage, the hail net has effect on microclimatic factors, its shading effect has a positive effect on the growth of fruit trees and it reduces the risk of sunburn and transpiration. The aim of our research was to evaluate the effect of hail net on the water balance of Early Gold and Golden Reinders microclimatic factors on the basis of thermal imaging, water potential measurement, canopy dry matter content and to analyze the effect on pigment content. The research was carried out on a weekly basis in July and August 2019 at the Horticultural Unit of Pallag, University of Debrecen, Hungary. Based on our results, the air temperature was 2.91 % lower (p = 0.150) and the relative humidity was 3.16 % higher (p = 0.0001) under the hail net. Results also revealed that the foliage temperature was 7.28 % lower (p = 0.006), the water potential value of the foliage was 20.80 % higher (p = 0.399) under the hail net, while the dry matter content of the leaf was 4.76 % lower than in orchards outside the hail net. Canopy chlorophyll concentration was 10.24 % (p = 0.066) higher and carotenoid values were also higher (16.24 %, p = 0.004) in hail net protected circumstances. Based on the results, the hail net has a favorable effect on the water balance of apple orchards and pigment content of apple leaves through microclimatic conditions, partially offsetting the negative effects caused by summer heat and drought stress.
Traditional small-sized vineyards are especially sensitive to different impacts, including the arrival of new pests. The adults of the yellow-legged hornet (Vespa velutina), an invasive alien species ...present in the Iberian Peninsula since 2010, feed on sugary foods, causing crop losses in vineyards. However, present management techniques for the control of V. velutina are limited, and they do not provide effective control in agricultural settings. This work aims to evaluate the use of an exclusion system in a traditional non-mechanized vineyard of a highly invaded area by V. velutina in NW Spain (Protected Geographical Indication of Betanzos, Galicia) as a method to mitigate the damage caused by hornets. Anti-hail nets were used in a factorial design experiment with groups of netted and unnetted vines of two white wine cultivars in order to address the vineyard production loss. In particular, we aim to 1) asses the effectiveness of anti-hail netting on preventing grape yield loss, 2) assess the impact of anti-hail netting on grape ripening and incidence of bunch fungal infection, and 3) study the potential relationship between the damage caused by V. velutina and grape fungal diseases. Results show that the tested exclusion system increases the crop yield, since it prevents effectively both the damage caused by hornets and birds. No significant correlation between the damage caused by V. velutina and the incidence of bunch fungal diseases was found in either cultivar. However, netting increased slightly the final sugar content in one of the cultivars, as well as the incidence of bunch fungal damage. We discuss the management implications of this exclusion method within the framework of agricultural land abandonment and the loss of traditional landscapes.
•The invasive hornet Vespa velutina can notably reduce crop yield of small vineyards.•Anti-hail netting prevents grape yield losses by hornets and birds.•Netting might alter grape ripening and the bunch fungal diseases of some cultivars.•Economic costs and mechanization needs might reduce acceptance of netting.•Vineyard abandonment is a potential outcome of V. velutina invasion.
Microclimatic and soil management studies emphasize that roofing above the canopy or soil mulching contributes to reduce water losses from horticultural cropping systems and, at the same time, to ...increase water use efficiency. The aim of this 2-year on-farm study, carried out on a late ripening peach (cv. California) orchard, was to investigate the combined effect of water supply (full or deficit irrigation, DI), incoming light (hail or shading net), and soil management (tilling or mulching) on: microclimate; fruit growth; yield; irrigation water use productivity (WP
I
); and soil water stress coefficient (Ks). Shading hail net reduced air temperature (−1°C), wind speed (−57%), solar radiation (−32%), while increased relative air humidity (+9.5%). Compared to the control treatment (hail net coverage, soil tillage, and full irrigation), the innovative management (DI + shading hail net + mulching) reduced seasonal volumes of irrigation water (−25%) and increased both final yield (+36%) and WP
I
(+53%). Saving water resources without losing yield is an achievable goal by peach orchards growing under the Mediterranean climate if the DI agro-technique is adopted conjointly with shading hail net and soil mulching.
•High tunnels altered microclimatic conditions surrounding blueberry plants.•Leaf stomatal conductance decreased together with elevating VPDl.•Net photosynthesis was during whole day measurements ...higher under the high tunnel.•Microclimatic changes during the day decreased Fv’/Fm’ similarly at both sites.•At noon, higher zeaxanthin and VAZ were measured in leaves under the high tunnel.
In a two-year experiment, the aim of our study was to evaluate the physiological and chemical response of highbush blueberry (Vaccinium corymbosum L.) ‘Duke’ plants to changed microclimatic conditions that may occur during production in a protected environment—in this case, high tunnels and a hail net. Measurements were performed from 7.00 a.m. to 7.00 p.m. on days with different weather conditions in 2020 and 2021. In the second year of the experiment, both photosynthetic pigments and phenolics were measured in the leaves. The air temperature, relative humidity, photosynthetic photon flux density (PPFD), substrate temperature, and water content were dramatically altered by the protected environment. Along with an increased air temperature and VPDl (leaf vapor pressure deficit), significant reductions in net photosynthesis (Pn), stomatal conductance (gs), and Fv’/Fm’ (actual PS II efficiency) were detected under both protected environments, with higher values under the high tunnel. Elevated zeaxanthin and AZ/VAZ concentrations were detected in the leaves from 7.00 a.m. to 12.00 p.m., after which these concentrations reduced and continued to do so until the evening. Significance was also observed between high-tunnel and hail-net conditions. Individual and total phenolic concentrations in the leaves did not significantly change during the daytime, but significantly higher values were detected under the hail net. Our results indicate that, regarding photosynthetic pigments and phenolics, modified microclimatic conditions, i.e. elevated air temperature and reduced light quantity under different types of protected environments strongly affect the physiological status of highbush blueberry ‘Duke’ plants and the chemical composition of leaves.
Anti-hail nets are the best way to mitigate the effects of hailstorms in the orchards. Apple trees covered with nets may exhibit a variety of vegetative and reproductive responses, inclusive of ...changes in tree vigour, cropping, sugar contents, and fruit colour. The present study was conducted to assess the effect of timing of installation and colour of anti-hail net on cropping and fruit quality in high-density apple orchard for two consecutive seasons (2021 and 2022). White and blue colour nets of size (9 m × 30 m) 80 GSM (square mesh with non-sliding threaded, leno weave, and < 30% shading factor) were installed at three different time intervals (15 days before estimated full bloom, at full bloom, and 15 days after full bloom) on apple cultivar ‘Jeromine’. The installation at different time and colour of anti-hail nets significantly exhibit variability in cropping, fruit quality, and bio-chemical metrics. The significant highest cropping (fruit yield, productivity, and yield efficiency) and fruit biochemical parameters (total soluble solids) were recorded in T
3
C
2
(15 days after full bloom + white colour anti-hail net) followed by T
2
C
2
(installed at full bloom + white colour anti-hail net). Hence, white colour anti-hail nets installed 15 days after full bloom increased fruit production and improved quality in comparison to blue colour anti-hail net in apple under high-density plantations.
With the increasing use of hailnets and decrease in light availability in the ripening period of apple fruit, insufficient light exposure often causes poor colouration viz anthocyanin synthesis on ...certain parts of the fruit and on certain fruit within the tree. The aim of this study was to investigate the potential of improving anthocyanin synthesis, in terms of fruit colouration, the major incentive for a consumer. Therefore, the reflective ground cover Lumilys® was spread between ‘Braeburn Mariri Red’ apple rows under a crystalline hailnet seven weeks prior to harvest and colour measured on 240 attached apple fruit. The reflective ground cover increased the reflected light by 1.6 to 3.9 times 1.0 m above ground. The improved light utilization led to an improved peel colouration, especially on the shaded side of the apple fruit and fruit in the lower inner part of the canopy, A coloured visualization from orange (high light intensity), yellow (medium) to green (low light intensity) as a result of the individual PAR measurements every 20 cm inside the canopy showed how the reflective mulch influences the light penetration into the different parts of the tree canopy.
The use of plastics in horticulture is reviewed with respect to its sustainability based on the traditional criteria of triple Rs (reduce, reuse, and recycling) plus a re-place strategy, taking into ...account possible alternatives. Hail (and insect) nets made of HD-PE, with their long-term use mostly on apple and polytunnels of LD-PE for cherry and strawberry as well as solarisation mulches (reuse), were found to be relatively sustainable solutions for their needs and are currently without alternatives. In contrast, standard black mulch, with its largest share among horticultural plastics, had the widest range of sustainable alternatives, ranging from biodegradable to spray mulch; few sustainable alternatives are available for fleeces and reflective mulches. For the third sustainable option, pilot recycling schemes were examined, such as PolieCoTM (Italy), MAPLATM (Spain), and ERDETM (Germany); they collect 30–50% of the agricultural plastics used in their respective areas, with a successful retrieval growth rate of ca. 20% per year in the case of ERDETM. For the fourth new R option (replace), future sustainability perspectives for the predominant black mulch are research into and development of better, biodegradable, non-fossilbased plastics, sprayable mulch; microbes for the digestion of deployed polyolefins and, for a certain limited range (on shade tolerant crops or in high-light intensity environment), hail nets and polytunnels that are equipped/substituted by/with solar panels (“agri pv”) for the concomitant sustainable production of green renewable energy.
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