Innovative Strategies for the Use of Reflective Foils for Fruit Colouration to Reduce Plastic Use in Orchards

Abstract

(1) Background: Plastic in fruit orchards represents an environmental issue due to large CO2eq emissions associated with its production from fossil fuel and disposal (often incineration). (2) Materials and methods: Apple cv. “Braeburn Hillwell” trees on M9 rootstocks under a hail net were used at Campus Klein-Altendorf (CKA), Germany (50 °N) in 2018. In order to reduce the use of plastics to improve the red colouration of fruit particularly under hail nets, three alternatives to the current use of reflective mulch in each alleyway between the tree rows were explored, with uncovered grass alleyways as control. About 2800 colour measurements were done in the four weeks prior to harvest on 720 attached fruit below and above 1 m height in the field, and ca. 6900 additional colour measurements were conducted at harvest. (3) Results: The underlying regulatory mechanisms contrasted between the diffusive reflection of the white woven ground cover (such as LumilysTM or ExtendayTM) in the alleyways and aluminium foil under the trees with regular (straight) light reflection. Good fruit colouring and a plastic reduction were achieved (a) through spreading the white woven ground cover in every other row, and (b) through substituting the white ground cover with aluminium foil (80% recycled). Both methods can reduce greenhouse gas (GHG) emissions (75–110 kg CO2eq/ha for the first option a). (4) Conclusion: Plastic use in fruit orchards can be reduced by multiple use of the material in the same or several years, spreading it in every other row or substituting it by another reflective material, a relevant step towards an environment-friendly sustainable horticulture.

Spatial and Temporal Enhancement of Colour Development in Apples Subjected to Reflective Material in the Southern Hemisphere

“…Satisfactory colour of apple fruit requires a certain amount of available sunlight. Therefore, fruit or fruit parts grown in shade will not turn red during ripening due to a lack of anthocyanin synthesis, particularly under hail nets [11,12]. This may be due to providing a longer exposure to light during the time, when anthocyanin synthesis, PAL activity and MYB 1 and MYB 10 gene expression in the apple peel starts ca.…”

“…Fruit in the first pick are mostly from the outer and upper periphery of the tree canopy. Because the main influence of the reflective mulches can be observed and explained on fruit from the inner part of the tree canopy [12], their portion enhances in the first pick. Sometimes fewer picks have to be carried out to retrieve all fruit from a tree.…”

Advances in the Sustainable Use of Plastics in Horticulture—Perspectives, Innovations, Opportunities, and Limitations

“…Reflective mulches are mo in Washington State (US), Chile, and China and to a lesser extent in Sout and New Zealand (Figure 6). Sustainability aspect: In the search for sustainable alternatives to Extend et al (2021) [14] at Klein-Altendorf (University of Bonn) developed two so spreading of the reflective mulch in every other row; or (b) silver foil made aluminum. The authors' LCA showed savings in GHG emissions in the ord CO2e/ha.…”

“…Partial defoliation originates from viticulture an more sustainable approach than plastic or aluminum (Figure 7). Sustainability aspect: In the search for sustainable alternatives to Extenday & Co., Hess et al (2021) [14] at Klein-Altendorf (University of Bonn) developed two solutions: (a) the spreading of the reflective mulch in every other row; or (b) silver foil made from recycled aluminum. The authors' LCA showed savings in GHG emissions in the order of 0.7-1.1 t CO 2e /ha.…”

Sustainable Fruit Growing: From Orchard to Table-Editorial Commentary

“…To be sustainable, an apple farm must produce adequate yields of high quality, be profitable, protect the environment, conserve resources, and be socially responsible in the long term [4,5]. For example, the use of plastic in apple orchards can be reduced by using the material several times in the same year or years, by using it in every other row, or by replacing it with another reflective material-an important step toward environmentally friendly, sustainable horticulture [6]. Thanks to the changes that have taken place in recent years in the field of image analysis methods and computational performance, it is possible to develop solutions for automatic fruit counting based on registered digital images and predict yield, which contributes to better planning of harvest [7].…”