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Phenol oxidases (POs) are a group of soil extracellular oxidoreductase enzymes, which are involved in oxidative processes related to nutrient cycling. This class of enzymes has multiple functions at both the organism and ecosystem level and can trigger either positive or negative feedback loops between soil organisms and soil organic matter. The purpose of this study was to evaluate: (i) whether PO activities have a trend different from those of microbial biomass and activity; and (ii) whether PO activities are enhanced or reduced by fertilizer application. Soil samples were taken from plots in a 14-year-old experimental walnut orchard, subjected, since planting, to three fertilizer treatments: organic (compost) or mineral (urea) fertilization at the same rate of nitrogen application (100 kg N ha − 1 ), or left unfertilized. Soil samples were divided according to sampling depth (0–20 cm and 20–40 cm). Results showed that the application of compost significantly increased C and N pools. qCO 2 and DHD/C ext data indicated that the biota at 20–40 cm soil depth was more stressed or mainly composed of microorganisms with low substrate utilization efficiency. Phenol oxidase, tyrosinase, and catechol oxidase activities were significantly promoted in the surface layer by compost addition. In contrast, laccase activity showed a large increase in the deeper soil layer when supplied with mineral N, whereas compost addition led to increased activity in the surface layer. These findings suggest that soil phenol oxidases play a part in the determination of soil functionality, but they need to be investigated in greater depth in order to understand the mechanisms regulating their activities. [ABSTRACT FROM AUTHOR]

In agriculture, the use of soil biodegradable mulch films could represent an eco-friendly alternative to conventional plastic films. However, soil biodegradable mulch films incorporated into the soil through tillage, being not only a physical but also a biogeochemical input, is expected to influence the soil quality by affecting its functions. Therefore, the eco-compatibility of these biodegradable plastics needs to be evaluated for their impact on different soil functions. To understand the effect of biodegradable plastics on soil quality (i.e. microbial biomass, nitrogen cycle, and activity of soil enzymes involved in the biochemical processes of carbon and nitrogen), we added increasing quantities of biodegradable plastics in two different soils: a loamy (Cambisol) and sandy (Arenosol) soil. The results highlight that the carbon added through the biodegradable plastics influenced the processes linked to carbon and nitrogen cycles. Significant effects were observed mainly with the highest dose of biodegradable plastics added (1%), resulting in a higher growth of microbial biomass, increased carbon mineralisation, and increased immobilisation of available nitrogen. The results also underline the importance of evaluating the impact of biodegradable plastics in different soils because all the processes considered are also influenced also by soil physicochemical characteristics. [Display omitted] • Biodegradable mulch films as eco-friendly alternative in agriculture • Biodegradable mulch films incorporation could affect soil functionality. • Significant impact of biodegradable plastics on soil microbial biomass and activity • Biodegradable plastics influenced the processes linked to soil C, N and P cycles. • Importance of considering soils with distinct characteristics [ABSTRACT FROM AUTHOR]

Organic management aims to maintain and/or enhance the soil quality by adopting crop rotation, reduced tillage, and application of organic fertilizers. Several studies highlight the advantages of organic management in terms of soil quality and soil fertility, the key themes in sustainable agronomy. The aim of this study was to understand whether there were differences in soil quality between two different approaches of organic management. Soil quality was assessed using a set of biochemical parameters individually or in combination, in simple and complex indexes, respectively. Soil samples were procured from a long-term field experiment area located in Monsanpolo del Tronto (Central Italy) in which conventional (Conv), and two different organic managements (Org1, organic traditional; Org2, organic agroecological) were followed, and were assessed for soil quality. Results from individual soil properties, simple and complex indexes highlighted that Conv and Org1 were similar in terms of acquisition activity indicating that both mineral and organic fertilizers supply C, N, and P equally to agro-ecosystems. However, in Org2, despite theoretical imbalances in terms of C:N:P, microbial activity efficiently filled this imbalance without affecting soil organic carbon content. The indexes showed a positive metabolic response and a higher soil quality in both the organically managed plots, indicating that organic management, independent of the agronomic approach, maintains the soil quality despite the differences in biochemical processes. Moreover, simple and complex soil quality indexes were sensitive enough to discriminate the two organic management strategies. [Display omitted] • Conventional and organic management effects on soil quality were evaluated. • Soil organic C and microbial biomass were enhanced by the organic managements. • Specific hydrolytic enzyme activities increased in the conventional management. • Soil quality indexes highlight differences between the two organic managements. • Soil quality indexes help in understanding the soil biochemical processes. [ABSTRACT FROM AUTHOR]

The extent to which different agricultural strategies may affect the uptake of potentially toxic elements (PTEs) by cropped plants is not entirely understood at a field scale. This study addresses the effect of seasonality, Trichoderma inoculation alone, or combined with different applications of commercial-grade clinoptilolite (i.e., foliar action, fertigation, and pellet) on the PTE content of early- and late-ripening cultivars of Cucumis melo L. Two similar field experiments were performed in spring and summer. For each cultivar/treatment combination, the input of PTEs [namely, chromium (Cr), copper (Cu), and lead (Pb)] into the soil-crop system through irrigation water, fertilizers, pesticides, and treatment products (i.e., Trichoderma and clinoptilolite products), as well as the PTE content of melon stem, leaves, and fruit, were measured through inductively coupled plasma-optic emission spectrometry (ICP-OES). Neither Trichoderma alone nor with clinoptilolite had a visible effect on PTE uptake by plants, whereas early season cultivation was strongly associated with reduced uptake of Cu and Pb. The high correlation of Cu and Pb content with stem and leaf calcium (Ca) content (used as a proxy for different transpiration rates under different growing seasons) indicated a possible uptake of these metals through Ca nonselective cation channels as a defense against drought stress. Reduced Cu and Pb concentrations were found in early-ripening fruit cultivated in spring. Concerning Cu and Pb risk management, in case of significant contamination in Mediterranean calcareous soils, early-ripening Cucumis melo L. cultivars are suggested instead of lateripening ones. [ABSTRACT FROM AUTHOR]

Agricultural land abandonment is an emerging problem in European Union (EU), and about 11% of agricultural EU land is at high risk of abandonment in the coming 10 years. Land abandonment may have both positive and negative effects in ecosystems. Due to the potential for land abandonment to increase soil fertility, the study of vegetation succession effects on soil quality is of great importance. In this study, we investigated an abandoned vineyard where, after a period of 30 years, rows and alleys were characterized by two different forms of vegetation succession: natural recolonization by trees along the rows and by herbaceous vegetation in the alleys. No-tilled alleys covered by herbaceous vegetation of a neighboring conventionally cultivated vineyard were used as a comparison. Soil samples were chemically characterized (pH, extractable element, and available and total metals), and analyzed for the determination of carbon (C) and nitrogen (N) pools; hydrolytic and phenol oxidizing (PO) enzyme activities involved in C, N, and phosphorus (P) cycles; and the enzyme ratios. Results highlighted that natural recolonization by trees increased the organic C and N soil pools by 58% and 34%, respectively, compared to the natural recolonization by herbaceous vegetation. Moreover, natural recolonization by trees reduced β-glucosidase by 79%, urease by 100%, alkaline phosphastase by 98%, acid phosphatase specific hydrolytic activities by 50%, and catechol oxidase and laccase specific oxidative activities by 127% and 119%, respectively, compared to the renaturalization by herbaceous vegetation. In addition, the natural recolonization by trees reduced the C (βglu):C (PO) enzymes ratio by 16% compared to that of the conventional vineyard. Comparing the natural recolonization by herbaceous vegetation with that of the conventional vineyard revealed little significant difference (15% of the measured and calculated parameters); in particular, PO activities significantly decreased in the renaturalized vineyard with herbaceous vegetation by 49% (catechol oxidase) and 52% (laccase), and the C (βglu):C (PO) enzyme ratio showed a reduction (−11%) in the vineyard naturally recolonized by herbaceous vegetation compared to the conventional vineyard. This highlights that the type of vegetation succession that takes place after land abandonment may have a significant impact in terms of soil fertility and C accrual potential. These results help to focus attention on the practices used in agro-forestry that should be adopted in abandoned agro-ecosystems to increase their biodiversity, soil C stock, and soil quality, because these indicators are affected by the type of vegetative coverage. [ABSTRACT FROM AUTHOR]

Understanding the complex relationships among soil quality, crop productivity, and management practices would help to develop more sustainable agricultural production systems. In this study, we investigated the combined effects of crop rotations and fertilization treatments on soil quality and crop yield in a long term (about 50 years) field experiment. Crop rotations included continuous corn (Zea mays L.), a 2 year corn-wheat (Triticum aestivum L.) rotation, and a 9 year corn-wheat-corn-wheat-corn-wheat-alfalfa-alfalfa-alfalfa (Medicago sativa L.) rotation. Fertilization treatments included control, mineral fertilization with urea and triple superphosphate, and amendment with cattle manure. Crop rotations and fertilization treatments were combined in a factorial experimental design with two replications for each rotation and six replications for each fertilization treatment. The continuous corn and the corn-wheat rotations had negative effects on the main soil quality indicators considered (carbon (C) and nitrogen (N) pools, microbial biomass and activity). On the contrary, the 9 year rotation had positive effects on soil organic carbon (+24%) and total nitrogen (+23%) but resulted in impoverished available P (−5%). Positive effects on soil microbial biomass (+37% of microbial biomass C and +23% of microbial biomass N) and activity (+19%) were also observed. Soil amendment with manure built up soil organic carbon (+13%), increased nutrient content (+31% of extractable C and +19% of extractable N), including that of available P (+47%), and stimulated microbial growth (+34%) and activity (+8%). As compared to manure, mineral fertilization increased the soil nutrient content to a lesser extent. This study showed that the combined use of rotations, including legume forage crops, and soil amendment with manure may help preserve soil quality and crop productivity in the long term. [ABSTRACT FROM AUTHOR]

A leaching experiment was designed to study the effects of a commercial nitrification inhibitor containing nitrapyrin on nitrification, microbial nitrogen (N) immobilization, and nitrate leaching. Soil columns were treated with 100 mg N kg−1 from pig slurry, cattle slurry, and anaerobic digestate in a mixture with or without the nitrification inhibitor. Destructive sampling was carried out after 0, 7, and 28 days of incubation in the dark at 18 °C. At each sampling date, artificial rain (200 mm of 0.01 M calcium chloride over 4 h) was added to the soil columns. The leachate was collected, and the soil was removed from the columns and sectioned into 5 cm segments. Results indicated that after 28 days of incubation, nitrapyrin enhanced ammoniacal N accumulation in the top layers of the soil columns and reduced the nitrate concentration in the leachates with pig slurry and anaerobic digestate. Furthermore, in the soil columns treated with anaerobic digestate, nitrapyrin promoted microbial N immobilization. These findings suggest that the use of nitrapyrin in a mixture with animal slurry and anaerobic digestate has the potential to reduce nitrate leaching and increase N retention in the topsoil, affording both environmental and economic advantages. [ABSTRACT FROM AUTHOR]

Intensive conventional farm management, characterized by high agrochemicals input, could alter the composition of microbial communities with potential negative effects on both functional traits and the ecosystem services provided. In this study, we investigated the gut microbial composition of a high ecological relevance carabid Pseudoophonus rufipes, sampled in two fields subjected to conventional and organic management practices. Carabids' gut microbiota was analyzed via qPCR and NGS. Profound differences between the microbial composition of organic and conventional samples were detected: the abundance of Tenericutes and Proteobacteria was significant higher in organic and conventional samples, respectively. Spiroplasmataceae and Bifidobacteriaceae families were significantly more abundant in samples from organic management, while Enterococcaceae, Morganellaceae and Yersiniaceae were more abundant in samples from conventional management. The diverse gut microbial composition of insects between the two management systems is related to the pressure of environmental stressors and it may representing an important bioindication of ecological functions and services provided by a carabid species. [ABSTRACT FROM AUTHOR]

The intensification of highly specialized viticulture has led to a dramatic decrease of soil fertility that can be restored by increasing soil organic matter using organic fertilizers. The aim of the present experiment was to evaluate the effect of different organic amendments on vine vegetative growth and nutritional status, soil N availability and microbial biomass, as well as on yield and grape quality. The experiment was carried out in 2020 and 2021, on cv. Sangiovese (Vitis vinifera L.) vines grafted on 110 Richter (V. berlandieri × V. rupestris) planted in February 2019. Plants were fertilized yearly in spring with (1) mineral fertilization (MIN), (2) municipal organic waste compost (MOW), and (3) sewage sludge compost (SS). The application of SS increased nitrate availability in both years, while the supply of organic matter (no matter the source) enhanced soil microbial biomass content. Plant nutritional status was in the optimal range for all treatments, with an increase of N in SS and K in MOW. Fruit yield in 2020 was not influenced by treatments, while in 2021 it was enhanced by MIN and MOW, which also induced a higher berry quality. Plant vegetative growth was stimulated by the application of SS. In conclusion, from these preliminary results we observed a higher N availability as a consequence of SS supply that resulted in a higher plant biomass, but reduced yield and berry quality, supporting the theory that for vineyards, N should be carefully managed to reach an equilibrium between vegetative and reproductive activity. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to valuate, after 14 years, the impact of annual compost applications on micronutrient and potentially toxic trace elements on nectarine tree uptake and soil fertility. The study was performed in the Po valley, Italy, on the variety Stark RedGold (grafted on GF677). Since orchard planting, the following treatments were applied, in a randomized complete block design, with four replicates: 1. unfertilized control; 2. mineral fertilization (N was supplied as NO 3 NH 4 at 70–130 kg ha−1 year−1); 3. compost at 5 t DW ha−1 year−1; 4. compost at 10 t DW ha−1 year−1. The actual rate of application was 12.5 (LOW) and 25 (HIGH) t ha−1, since compost was concentrated in the tree row. Compost was made from domestic organic wastes mixed with pruning material from urban ornamental trees and garden management and stabilized for 3 months. The supply of compost HIGH induced an enrichment of soil total Cu, Zn and Cd, and a decrease of Fe and Co concentration; with values always below the European threshold limits for heavy metals in the soil. In addition, compost (at both rates) increased availability (DTPA-extractable) of Fe, Mn and Zn, Cd, Ni, and Pb in the top soil (0–0.15 m). Total micronutrient and trace element tree content was not affected by fertilization treatments; however, the recycled fraction returned to the soil at the end of the season through abscised leaves and pruned wood of Cu, Fe, Mn and Zn was increased by mineral fertilization; Fe and Zn also by compost HIGH. Our data show that the introduction of compost at both 12.5 and 25 t ha−1 year−1 in the row did not increase the risk of pollution related to potentially toxic trace elements and at the same time increased the bioavailability of Fe, Mn and Zn. Unlabelled Image • Impact of yearly compost supply on micronutrient and potentially toxic trace elements on nectarine tree uptake and soil fertility was evaluated. • Total Cu, Zn and Cd soil concentration was enhanced by addition of compost HIGH, Cu and Zn also incresaed with compost LOW; Fe and Co decreased. • Availability Fe, Mn and Zn in the top soil (0-0.15 m), was positively influenced by compost supply. • Total micronutrient and trace element tree content was not affected by fertilization. • The supply of compost at 5 and 10 t ha-1 year-1, representing a rate of 12.5 and 25 t ha-1 year-1in the row, did not increase the risk of soil pollution. [ABSTRACT FROM AUTHOR]

The search for sustainable source of N, the need of soil organic matter restoration, along with the call for recycling of organic wastes has led to a rise of the use of organic fertilizers. The aim of the present experiment was to evaluate: the effectiveness of compost application as a N fertilizer, the impact on N distribution in soil and plant and on tree performances, in a long-term experiment (14 years). The study was carried out in the Po valley, Italy and, since orchard planting (2001), the following treatments were applied: 1. unfertilized control; 2. mineral fertilization; 3. compost at a rate of 5 t DW ha−1 yr−1; 4. compost at a rate of 10 t DW ha−1 yr−1. Soil total N, potentially mineralizable, microbial and extractable N were higher in compost in comparison to mineral (fertilizer). The effect was found both in the row and in the inter-row and the rise of N fractions was evident in the shallowest soil layer of the row. Soil mineral, potentially mineralizable N was increased by mineral (11.1 mg kg−1) and compost 10 (12.4 mg kg−1) fertilization compared with control (6.7 mg kg−1). Vegetative growth and yield were increased in trees treated with mineral and compost 10; moreover, these plants were able to recycle (66.1 and 70.5 kg ha−1 yr−1, respectively) and remobilize (41.5 and 48.7 kg ha−1 yr−1, respectively) a higher amount of N than those of control and compost 5. In conclusion, organic fertilization strategy promoted the buildup of soil N reserve, meaning a capacity of the ecosystem to sequestrate N. The application of compost 10 showed a similar effect on plant growth and production as mineral fertilization, but introduced the advantage of the use of a cheap, renewable waste material, providing a new insight on N fertilization management. Unlabelled Image • Application of compost increased soil N fraction. • Vegetative growth increased in compost and mineral fertilized plants. • Compost 10 and mineral plants recycled and remobilized more N than other treatments. • N removed was not influenced by the fertilization strategy. • Organic fertilization promoted the build-up of N reserves. [ABSTRACT FROM AUTHOR]

Abstract: Persistent recruitment of neutrophils in the bronchi of cystic fibrosis patients contributes to airway tissue damage, suggesting the importance of intervening on the expression of the neutrophil chemokine IL-8. Extracts from plants have been investigated to select components able to reduce IL-8 expression in bronchial epithelial cells challenged with Pseudomonas aeruginosa. Extracts and purified components have been added to cells 24h before pro-inflammatory challenge with P. aeruginosa and IL-8 transcription was quantified in the IB3-1 CF cells in vitro. P. aeruginosa-dependent IL-8 mRNA induction was increased by Argemone mexicana and Vernonia anthelmintica whereas no significant modification of transcription was observed with Aphanamixis polystachya, Lagerstroemia speciosa and Hemidesmus indicus. Finally, inhibition of IL-8 was observed with Polyalthia longifolia (IC50 =200μg/ml) and Aegle marmelos (IC50 =20μg/ml). Compounds from A. marmelos were isolated and identified by GC–MS. No significant effect was observed with butyl-p-tolyl sulphate, whereas the inhibition obtained with 6-methyl-4-chromanone concentration was accompanied by an anti-proliferative effect. On the contrary, 5-methoxypsoralen resulted in IL-8 inhibition at 10μM concentration, without effects on cell proliferation. In synthesis, 5-methoxypsoralen can be taken into consideration to investigate mechanisms of neutrophil chemotactic signalling and for its potential application in modulating the excessive CF lung inflammation. [Copyright &y& Elsevier]