1,720,968 research outputs found
Effect of the Growing Season, Trichoderma, and Clinoptilolite Application on Potentially Toxic Elements Uptake by Cucumis melo L
Full text linkThe 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
Compost improves plant and soil macronutrient content in a 14-years orchard
Full text linkAdequate plant nutritional status and soil fertility preservation can be achieved through sustainable agricultural management techniques. The challenge of intensive orchard cultivation, besides the risk of nutrient decline, is to prevent the loss of soil fertility that could lead to soil degradation with a consequent negative impact on yield and fruit quality. The use of organic amendments could be a sustainable strategy to combine high plant performance with soil fertility improvement. This work aims at shedding light on the effects of compost addition with respect to an unfertilized control and a mineral fertilization treatment on macronutrient (K, Ca, Mg, and S) dynamics in plants and soil of a commercial nectarine orchard planted in 2001. In the first 0.15 m of soil, compost addition resulted in higher values (26–42%) of all the parameters. Both fertilization treatments induced a 28% increase in roots’ S content compared to the control but did not induce macronutrient content variation in plant skeleton, pruned wood, and thinned fruits. In autumn leaves, all the macronutrients resulted in higher values (24–45%) with both mineral and compost fertilization, and the same was observed in fruit at harvest (increases of 15–31%). In our study, the treatment with compost satisfied plants' nutrient demands as much as the mineral fertilizer. In addition, compost treatment also improved soil nutrient content while preserving yield. Our results show that it is possible to reconcile plant nutrient needs with the preservation of soil fertility with the aim of improving sustainability of agriculture
Assessing the Fertilizing Potential of Two Tannery Bio-Wastes Through Short-Term Soil Incubation and Plant Rhizosphere Bioassay
No full textThe tannery industry is a significant global manufacturing sector, producing over 4 million tons of tannery bio-wastes (TBWs) annually, and to reintegrate TBWs into the productive cycle offers a significant alternative to landfill disposal. Despite TBWs are rich in organic matter, nitrogen (N), and carbon (C) they pose important environmental risks, such as the presence of heavy metals like chromium (Cr) that can be released into the environment. This study aimed at evaluating the fertilizing potential of two TBWs-based fertilizers through a complementary laboratory-scale approach by using a short-term soil incubation experiment and the Rhizotest (ISO16198: 2015) bioassay. Two TBWs-based fertilizers, Tannery Sludge (TS) and Integrated Leather Meal (ILM), were subjected to 42 days of soil incubation and to Rhizotest bioassay. Nitrogen release, chemical and biochemical indicators were assayed after the soil incubation. Tomato plants uptake of heavy metals and rhizosphere enzyme activities were assayed after Rhizotest. TS and ILM released 11% and 35% of their total N content respectively, with TS acting more as a slow-release fertilizer. Heavy metal contamination was negligible, except for Cr, which however remained in the soil in its trivalent form and was not absorbed by plants. Rhizotest allowed to highlight that TS and ILM stimulated broad and specific enzyme activities in the rhizosphere soil. This complementary approach enabled rapid, reproducible, and sensitive characterization of organic fertilizers produced from TBWs, which have the potential to be employed as organic fertilizers safely
Biodegradable plastics: Effects on functionality and fertility of two different soils
Full text linkIn 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
Conventional versus organic management: application of simple and complex indexes to assess soil quality
Full text linkOrganic 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
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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