Soil biodegradation of nutrients enriched cellulose- and chitosan-derived mulching films for sustainable horticulture

In 2019, global plastics production reached 370 million tons, of which 58 million tons were in Europe[1]. If the plastic use in agriculture accounts for 2% of the global production[2], more than 7 million tons of plastic were used in 2019 in the agricultural sector. Mulch films represent the major source of plastic contamination in agricultural soils[3]. The agricultural surface area covered by plastic films in Europe is four times larger than that covered by greenhouses and six times that of low tunnel hoops. Over the past decades, biodegradable biopolymer mulching films (BPMFs) have been developed to reduce soil pollution by non-biodegradable plastic debris[4] and to expand the circular bioeconomy[5]. In Europe, since 1999, low density polyethylene mulches (LDPMs) have to be dismissed after their use to remove source of pollutants that can reach up to 200 kg ha-1[6] and decline soil quality, crop growth, and yield[7]. BPMFs are a sustainable alternative to conventional LDPMs. Unlike LDPMs, BPMFs, at the end of their lifetime, are tilled into soil where they are expected to be biodegraded by soil microorganisms[8]. Moreover, BPMFs show an estimated saving of about 500 kg of CO2 equivalent per hectare in comparison with LDPMs. Conversely, the impact of LDPMs in intensive horticulture could result higher than weed control by herbicides as by life cycle assessment (LCA)[9]. BPMFs can be obtained by thermo-plasticizing, solvent casting and spraying processes by using renewable and biodegradable raw materials such as starch, cellulose, chitosan, alginate, glucomannan[10] and glycerin as plasticizer[11]. Cellulose and chitosan, being the two most abundant natural biopolymers on Earth, have been proposed as the best candidates for BPMFs production. Unfortunately, the high tendency for intra- and intermolecular hydrogen bonding confers undesirable mechanical properties. The addition of plasticizer as well as fillers overcome this problem[12] modifying mechanical and functional properties of the materials. To sum up, biopolymer blending is an effective strategy to reuse cellulose and chitosan-containing by-products and develop materials with novel mechanical characteristics[13]. Moreover, the functional properties of these materials can be tuned by doping them with suitable compounds[14]. Based on what stated above, and considering that soil fertility, crop growth and yield, are generally N and P limited, the core idea of this project is the preparation of N- and P-enriched BPMFs for soil mulching, in order to slowly release soluble nutrients into soils upon their biodegradation. The latter aspect is of great importance because a proper C:N:P ratio can lead to an increase of soil-dwelling organisms thus contributing to nutrient cycling in the soil-plant system, soil C sequestration and biological fertility status[15]. Moreover, repeated additions of BPMFs over long term can increase the amount of nutrients, thus reducing the use of external inputs (e.g. synthetic fertilizers) within a circular economy perspective. The specific aim of the proposed research are: i) to set up a method for the preparation of suitable BPMFs enriched with N and P; ii) to characterize novel BPMFs and evaluate their structure, degradation kinetics, and isotopic composition iii) to assess the impact of the innovative BPMFs on soil nutrient cycling and crop growth and yield; iv) to evaluate the effect of the innovative BPMFs on soil prokaryotes and micro-arthropods communities; v) to speed-up the biodegradation of the innovative BPMFs by spraying them at the end of their lifecycle with selected microorganisms and by adding the recipient soil with earthworms; vi) to evaluate the innovative BPMFs using the LCA methodology and to investigate its role within the circular economy. Bibliography [1] Plastic Europe, 2020. Website https://www.plasticseurope.org/it/resources/publications/4312-plastics-facts-2020 accessed on 05.01.2021 [2] Vox, G., Loisi, R.V., Blanco, I., Mugnozza, G.S., & Schettini, E. (2016). Agriculture and Agricultural Science Procedia, 8, 583-591. [3] Wenqing, H., Enke, L., Qin, L., Shuang, L., Turner, N., C. & Changrong, Y. 2014. World Agriculture, 4, 3236. [4] Sanchez-Hernandez J.C., Capowiez Y. & Ro K.S., 2020. ACS Sustainable Chemistry & Engineering, 8, 4292-4316. [5] Karan, H., Funk, C., Grabert, M., Oey, M., & Hankamer, B., 2019. Trends in Plant Science, 24, 237-249. [6] Razza, F., Guerrini, S., & Impallari, F.M., 2019. Acta Horticulturae, 1252, 77-84. [7] Hou, L., Xi, J., Chen, X., Li, X., Ma, W., Lu, J., Xu J. & Lin, Y. B, 2019. Journal of Hazardous Materials, 378, 120774. [8] Kyrikou, I., & Briassoulis, D., 2007. Journal of Polymers and the Environment, 15, 125–150 [9] Tasca, A. L., Nessi, S., & Rigamonti, L., 2017. Journal of Cleaner Production, 140, 725-741 [10] Santagata, G., Malinconico, M., Immirzi, B., Schettini, E., Scarascia Mugnozza, G., & Vox, G., 2014. Acta Horticulturae 1037(1037), 921-928. [11] D’Avino, L., Rizzuto, G., Guerrini, S., Sciaccaluga, M., Pagnotta, E., & Lazzeri, L. (2015). Industrial Crops and Products, 75, 29-35. [12] Chen, P., Xie, F., Tang, F., & McNally, T. (2021). Influence of plasticiser type and nanoclay on the properties of chitosan-based materials. European Polymer Journal, 144, 110225. [13] Bajpai, A.K., Shukla, S. K., Bhanu, S., & Kankane, S., 2008. Progress in Polymer Science, 33(11), 1088-1118 [14] Sohaimy, M.I.H.A., & Isa, M.I.N.M. et al., 2020. Polymers. 12, 2487 [15] Cleveland, C.C., & Liptzin, D., 2007. Biogeochemistry 85, 235–25

Effetto della copertura castanicola sulla qualità del suolo e sul contenuto di sostanze umiche. (Repertorio n. 12/2021 prot n. 167708 del 27/09/2021)

Con lo scopo di valorizzare il contributo ecosistemico forestale, il progetto intende valutare l'effetto della copertura castanicola sulla qualità del suolo e sul contenuto di sostanze umiche. A questo fine saranno oggetto di studio suoli forestali opportunamente individuati e campionati in zona Monti Cimini (regione Lazio) e Valle Anticolana (regione Lazio). Verranno utilizzati campioni di suolo già in suo possesso in quanto precedentemente oggetto di studio di un dottorato di ricerca. • caratterizzazione chimica dei suoli • frazionamento dei prodotti di umificazione • caratterizzare la struttura della comunità microbica dei suoli (PLFA). • determinare il contenuto di carbonio nelle frazioni umiche ottenut

Mechanisms of arsenic assimilation by plants and countermeasures to attenuate its accumulation in crops other than rice.

Arsenic is a ubiquitous metalloid in the biosphere, and its origin can be either geogenic or anthropic. Four oxidation states (−3, 0, +3 and + 5) characterize organic and inorganic As- compounds. Although arsenic is reportedly a toxicant, its harmful effects are closely related to its chemical form: inorganic compounds are most toxic, followed by organic ones and finally by arsine gas. Although drinking water is the primary source of arsenic exposure to humans, the metalloid enters the food chain through its uptake by crops, the extent of which is tightly dependent on its phytoavailability. Arsenate is taken up by roots via phosphate carriers, while arsenite is taken up by a subclass of aquaporins (NIP), some of which involved in silicon (Si) transport. NIP and Si transporters are also involved in the uptake of methylated forms of As. Once taken up, its distribution is regulated by the same type of transporters albeit with mobility efficiencies depending on As forms and its accumulation generally occurs in the following decreasing order: roots > stems > leaves > fruits (seeds). Besides providing a survey on the uptake and transport mechanisms in higher plants, this review reports on measures able to reducing plant uptake and the ensuing transfer into edible parts. On the one hand, these measures include a variety of plant-based approaches including breeding, genetic engineering of transport systems, graft/rootstock combinations, and mycorrhization. On the other hand, they include agronomic prac- tices with a particular focus on the use of inorganic and organic amendments, treatment of irrigation water, and fertilization

Use of Air-Classification Technology to Manage Mycotoxin and Arsenic Contaminations in Durum Wheat-Derived Products

Mycotoxins are the most common natural contaminants and include different types of organic compounds, such as deoxynivalenol (DON) and T-2 and HT-2 toxins. The major toxic inorganic elements include those commonly known as heavy metals, such as cadmium, nickel, and lead, and other minerals such as arsenic. In this study, micronisation and air classification technologies were applied to durum wheat (Triticum turgidum ssp. durum L.) samples to mitigate inorganic (arsenic) and organic contaminants in unrefined milling fractions and final products (pasta). The results showed the suitability of milling plants, providing less refined milling products for lowering amounts of mycotoxins (DON and the sum of T-2 and HT-2 toxins) and toxic inorganic elements (As, Cd, Ni, and Pb). The results showed an As content (in end products) similar to that obtained using semolina as raw material. In samples showing high organic contamination, the contamination rate detected in the more bran-enriched fractions ranged from 74% to 150% (DON) and from 119% to 151% (sum of T2 and HT-2 toxins) as compared to the micronised samples. Therefore, this technology may be useful for manufacturing unrefined products with reduced levels of organic and inorganic contaminants, minimising the health risk to consumers

Arsenic accumulation in grafted melon plants: Role of rootstock in modulating root-to-shoot translocation and physiological response

The bio-agronomical response, along with the arsenic (As) translocation and partitioning were investigated in self-grafted melon ′’Proteo′’, or grafted onto three interspecific (’‘RS841′’, ‘‘Shintoza′’, and ′’Strong Tosa′’) and two intraspecific hybrids (′’Dinero′’ and ′’Magnus′’). Plants were grown in a soilless system and exposed to two As concentrations in the nutrient solution (0.002 and 3.80 mg L−1, referred to as As− and As+) for 30 days. The As+ treatment lowered the aboveground dry biomass (−8%, on average), but the grafting combinations differed in terms of photosynthetic response. As regards the metalloid absorption, the rootstocks revealed a different tendency to uptake As into the root, where its concentration varied from 1633.57 to 369.10 mg kg−1 DW in ′’Magnus′’ and ‘‘RS841′’, respectively. The high bioaccumulation factors in root (ranging from 97.13 to 429.89) and the low translocation factors in shoot (from 0.015 to 0.071) and pulp (from 0.002 to 0.008) under As+, showed a high As mobility in the substrate–plant system, and a lower mobility inside the plants. This tendency was higher in the intraspecific rootstocks. Nonetheless, the interspecific ‘‘RS841′’ proved to be the best rootstock in maximizing yield and minimizing, at the same time, the As concentration into the fruit