This study aimed to evaluate the chemical composition, identify the bioactive compounds and measure the antioxidant activity present in blackberry, red raspberry, strawberry, sweet cherry and blueberry fruits produced in the subtropical areas of Brazil and to verify that the chemical properties of these fruit are similar when compared to the temperate production zones. Compared with berries and cherries grown in temperate climates, the centesimal composition and physical chemical characteristics found in the Brazilian berries and cherries are in agreement with data from the literature. For the mineral composition, the analyzed fruits presented lower concentrations of P, K, Ca, Mg and Zn and higher levels of Fe. The values found for the bioactive compounds generally fit the ranges reported in the literature with minor differences. The greatest difference was found in relation to ascorbic acid, as all fruits analyzed showed levels well above those found in the literature.

Determination of the bioactive compounds, antioxidant activity and chemical composition of Brazilian blackberry, red raspberry, strawberry, blueberry and sweet cherry fruits

Agrivoltaic systems to optimise land use for electric energy production

The world consumption of plastics in agriculture amounts yearly to 6.5 million tons. In addition to conventional polymers used in agriculture for greenhouses and mulches such as PE, PVC, EVA, photo-selective and luminescent polymers have been used, in order to improve the quality of crops. For the same reason plastic nets are used mainly in countries with tropical and Mediterranean climates. For an environmentally friendly agricultural activity, an alternative strategy can be represented by bio-based agricultural raw materials. For low environmental impact applications, biodegradable materials for agricultural films are nowadays produced. An overview of the main methods for the disposal and recycling of plastic materials are presented with the results of mechanical and radiometric tests on recycled plastics. The strategies to reduce the burden of plastics in agriculture are: a correct procedure for the collection, disposal and recycling of post-consumption plastics; the increase of lifetime duration and performance; and the introduction and promotion of bio-based materials.

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Plastic materials in european agriculture: actual use and perspectives

Environmental problems, such as global warming and plastic pollution have forced researchers to investigate alternatives for conventional plastics. Poly(lactic acid) (PLA), one of the well-known eco-friendly biodegradables and biobased polyesters, has been studied extensively and is considered to be a promising substitute to petroleum-based polymers. This review gives an inclusive overview of the current research of lactic acid and lactide dimer techniques along with the production of PLA from its monomers. Melt polycondensation as well as ring opening polymerization techniques are discussed, and the effect of various catalysts and polymerization conditions is thoroughly presented. Reaction mechanisms are also reviewed. However, due to the competitive decomposition reactions, in the most cases low or medium molecular weight (MW) of PLA, not exceeding 20,000-50,000 g/mol, are prepared. For this reason, additional procedures such as solid state polycondensation (SSP) and chain extension (CE) reaching MW ranging from 80,000 up to 250,000 g/mol are extensively investigated here. Lastly, numerous practical applications of PLA in various fields of industry, technical challenges and limitations of PLA use as well as its future perspectives are also reported in this review.

Poly(lactic Acid): A Versatile Biobased Polymer for the Future with Multifunctional Properties-From Monomer Synthesis, Polymerization Techniques and Molecular Weight Increase to PLA Applications.

At the moment, there are a large number of agricultural net types on the market characterized by different structural features such as type of material, type and dimensions of threads, texture, mesh size, porosity / solidity and weight; by radiometric properties like color, transmissivity/reflectivity/shading factor; by physical properties like air permeability and several mechanical characteristics such as tensile stress, strength, elongation at break, and durability. Protection from hail, wind, snow, or strong rainfall in fruit-farming and ornamentals, shading nets for greenhouses and nets moderately modifying the microenvironment for a crop are the most common applications. A systematic review of the current state-of-the-art of structural parameters, standard and regulations, most common agricultural net applications, and their supporting structures has been developed by means of a literature study, technical investigations, concerning characteristics and use of nets. As a result, the survey highlighted that in many cases different, not even similar, net types were adopted for the same application and the same cultivations by various growers. Results show that neither growers nor net producers have clear ideas about the relationship between the net typology optimization for a specific application and the construction parameters of the net. The choice often depends on empirical or economic criteria and not on scientific considerations. Moreover, it appears that scientifically justified technical requirements for nets used in specific agricultural applications have not been established yet.

/pdf/plastic-nets-in-agriculture-a-general-review-of-types-and-ifgxhohert.pdf

Plastic nets in agriculture ; a general review of types and applications

During the last years, European government remuneration polices promoted the realisation of photovoltaic systems integrated with the structures instead of on ground photovoltaic (PV) plants. In this context, in rural areas, greenhouses covered with PV modules have been developed. In order to interdict the building of greenhouses with an amount of opaque panels on covering not coherent with the plant production, local laws assigned a threshold value, usually between 25% and 50%, of the projection on the soil of the roof. These ranges seem not to be based on scientific evaluation about the agricultural performances required to the building but only on empirical assessments. Purpose of this paper is to contribute to better understand the effect of different configurations of PV panels on the covering of a monospan duo-pitched roof greenhouse in terms of shading effect and energy efficiency during different periods of the year. At this aim, daylighting and insolation analysis were performed by means of the software Autodesk ® Ecotect ® Analysis (Autodesk, Inc., San Rafael, CA, USA) on greenhouse model with different covering ratio of polycrystalline photovoltaic panels on the roof.

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Photovoltaic greenhouses: evaluation of shading effect and its influence on agricultural performances

Wind pressures on permeably and impermeably-clad structures

Relationship between Solidity Ratio, Colour and Shading Effect of Agricultural Nets

Plastic netting is most commonly used in agriculture to protect greenhouses, fruit-trees and ornamental plants from solar radiation, insects, birds, hail, wind, snow or heavy rainfall. There are many net typologies on the market with different construction parameters. It appears that there are no shared criteria for choosing the net typology which best fulfils a specific requirement, but that the choice generally depends on empirical or economic criteria, not on scientifically relevant considerations. In order to investigate the influence of net construction parameters on their radiometric properties, a set of field tests were performed using a spectroradiometer (GER2600) with a wavelength range of 250-2500 nm. Transmittance was calculated in field tests in the following wavelengths: UV (300-380 nm); Visible (380-760 nm); PAR (Photosynthetically active radiation 400-700 nm); NIR (760-1500 nm). Tests were carried out on 25 different kinds of commercial nets. An experimental setup of 120 x 120 x 50 cm was used to evaluate the radiometric properties of the nets tested. In addition, trials were performed on a full scale shade-house (9.60 x 4.40 x 30.00 m) covered with 4 different kinds of shading nets. Experimental test results made it possible to define the influence of net colour, porosity, shading factor and solar angle on the evaluation of transmittance in the UV, PAR and visible light wavelengths.

Sergio Castellano

Papers

Plastic nets in agriculture ; a general review of types and applications

Photovoltaic greenhouses: evaluation of shading effect and its influence on agricultural performances

Wind pressures on permeably and impermeably-clad structures

Relationship between Solidity Ratio, Colour and Shading Effect of Agricultural Nets

The Influence of Construction Parameters on Radiometric Performances of Agricultural Nets