1,720,974 research outputs found
INTRODUCING CONSERVATION AGRO-ECOSYSTEMS TO ENHANCE SOIL QUALITY AND SUSTAIN FOOD PRODUCTION
No full textL’introduzione di agro-ecosistemi conservativi viene indicata come strategia per aumentare il sequestro del carbonio organico nel suolo (SOC) e migliorarne la fertilità.
La continua applicazione di concimi organici, come il compost e il sovescio, favorisce il sequestro di SOC (+ 1.3 ÷ 2.5 Mg C ha-1 anno-1) e l'accumulo di azoto totale del suolo (STN) (+ ~ 1 Mg N ha-1 anno-1). Tuttavia, quando le fertilizzazioni organiche vengono interrotte, il SOC diminuisce rapidamente.
Negli agro-ecosistemi intensivi, il no till (NT) garantisce rese comparabili a quelle dei sistemi convenzionali (CT) immediatamente dopo la transizione. Il NT aumenta la sostanza organica (SOM) e il STN principalmente nei primi 5 cm di terreno, sebbene la cover crop di segale assicuri l'accumulo di SOM fino a 30 cm di profondità (+ 30% rispetto alla CT). Il NT e la minima lavorazione (MT) portano ad un aumento del SOC e del STN nei primi 30 cm di suolo, rispetto al CT. Gran parte di tale aumento è dovuto ai macroaggregati, all'interno dei quali, i pool di C e N associati ai microaggregati (mM) rappresentano tra il 41 e il 65% del contenuto totale di C e N nei sistemi NT e MT.The introduction of conservation agro-ecosystems has been suggested for increasing soil organic carbon (SOC) sequestration and enhancing soil fertility.
Continuous organic fertilization such as compost distribution and cover crops incorporation promotes SOC sequestration (+1.3÷2.5 Mg C ha-1 yr-1) and soil total nitrogen (STN) accumulation (+~1 Mg N ha-1 yr-1). However, when the organic fertilization is stopped, SOC rapidly decreases.
In intensive agro-ecosystems, no till (NT) can ensure yields comparable to conventional tillage (CT) immediately after transition. The major contribution of NT to soil organic matter (SOM) and STN increase is detected in the top 5 cm of soil, although the cultivation of rye as cover crop ensures SOM accumulation down to 30 cm depth (+30% than CT). No till and minimum tillage (MT) may increase SOC and STN levels in the 0-30 cm soil layer, both as concentration and as mass, compared with CT. Most of such a SOC and STN increase is due to C- and N-rich macroaggregates. Within macroaggregates, microaggregates (mM) are of primary importance for soil organic matter stabilization since C and N pools associated to mM account for between 41 and 65% of total C and N content in the NT and MT systems
Gli attori della produzione e della trasformazione
No full textIl capitolo esemplifica i motivi del successo del pomodoro da industria nel territorio piacentino attraverso 7 casi-studio, identificandone un denominatore comune nella capacità innovativa dei protagonisti. Da questa breve analisi condotta sulle esperienze personali degli imprenditori, nasce facilmente la necessità di puntare proprio sull'innovazione tecnica per rilanciare il pomodoro piacentino, nel rispetto della sostenibilità.The chapter exemplifies the reasons for the success of processing tomato in the province of Piacenza, through 7 study-cases, identifying the innovation ability of the protagonists as a common denominator. From this brief analysis of entrepreneurs' personal experiences, it is easy to see that focusing on technical innovations is necessary to revive tomato production system in Piacenza, while respecting sustainability
Effects of no-till on root architecture and root-soil interactions in a three-year crop rotation
Full text linkNo-till (NT) has repeatedly been reported to result in several environmental advantages, including the reduction of soil erosion, sequestration of carbon from the atmosphere and increase of water retention in soils. However, experimental evidences to date show negative effects of NT on soil physical parameters (i.e., increasing penetration resistance and soil bulk density) and root development of plants, thus reducing crop yield. A three-year field study (2014–2016) was conducted to assess the effects of NT vs conventional tillage (CT) on root growth in maize, soybean, and winter wheat, on a silty clay soil in the Northern Italy. Root length density (RLD), diameter class length (DCL), root dry weight (RDW) and roots composition (C and N) in the top 60 cm of soil were measured. The total amount of root C (TRC) was calculated by multiplying RDW by root C content. Relationships among root traits, soil bulk density (BD) and penetration resistance (PR) were investigated using the non-parametric Spearman rank coefficient. RLD was significantly increased under NT compared to CT in the topsoil (0–5 cm) in maize (6.37 vs. 2.03 mg cm−3) and winter wheat (5.38 vs. 2.90 cm cm−3), while it was lower in NT than in CT in the deeper soil (5–15 cm) only in maize (3.19 vs. 4.53 cm cm−3). RDW was increased under NT compared to CT in the 0–5 cm layer in maize (3.86 vs.0.50 mg cm−3), soybean (4.33 vs. 0.43 mg cm−3), and winter wheat (0.96 vs. 0.38 mg cm−3). NT significantly reduced root C:N ratio of maize (-9%), increased C:N ratio of soybean (+14%), and did not affect C:N ratio of winter wheat. This was mainly related to the effect of NT on coarse roots, which decreased average roots N content. A negative correlation between root traits (RLD, RDW) and soil physical parameters (BD, PR) was found in this study under NT while no correlation occurred for CT. This corroborates the hypothesis that when tillage is abandoned roots are major drivers and detectors of soil physical conditions, which in turn affects roots growth again. Moreover, these results showed that BD did not always represent the main factor affecting root development and the increase of soil strength and particle density under NT did not reduce downwards root growth, which suggests that stability of continuous biopores as induced by NT in well-structured soils is probably much more relevant than the total amount of pores to affect root traits
Driving crop yield, soil organic C pools, and soil biodiversity with selected winter cover crops under no-till
No full textNo-till (NT) and cover crops (CCs) have been repeatedly recommended for building-up resilience of agro-ecosystems, enhancing soil biodiversity, and steering efficient nutrients cycling and yield. Yet, the overall impact of CCs on soil properties and dynamics during transition may highly change depending on CC species and interactions with field condition. In the present 3-yr field study, we (i) examined how selected CCs (i.e. rye [Secale cereale L.]; phacelia [Phacelia tanacetifolia Benth.] + white mustard [Sinapis alba L.]; Italian ryegrass [Lolium multiflorum Lam.] + crimson clover [Trifolium incarnatum L.] + Persian clover [Trifolium resupinatum L.]; hairy vetch [Vicia villosa Roth] + crimson clover) affect yield performance in a crop sequence of maize (Zea mays L.), soybean (Glycine max L. Merr.), and maize under NT, and (ii) assessed the effects of CCs on inputs to the soil (i.e. biomass, carbon [C], and nitrogen [N]), soil organic C (SOC) and pools, as well as microarthropods and earthworms abundance and diversity. Grain yield during the initial 2-yr period was on average reduced with CCs by 1–23% in maize, and 1–33% in soybean. This effect was less evident with CC residues having low C:N ratio ([removed]3-yr term. We concluded that CC mixtures that allow the best compromise between the high amount of residue and the low residue C:N ratio should be preferred for: (i) reducing possible detrimental effects on grain yield of maize and soybean, and (ii) enhancing soil C cycling and biodiversity. Therefore, selecting appropriate CC species in mixtures represents the main challenge at the field level for pursuing both objectives in the shortest timeframe. Within all options in summer crop sequences, here we reported that mixtures including leguminous cover crops might be primarily considered
Orobanche nel pomodoro: strategie di contenimento
No full textlivello nazionale, la diffusione delle infestazioni di orobanche sta interessando un numero sempre maggiore di areali agricoli, vocati storicamente alla coltivazione del pomodoro da industria. Questa rapida espansione viene senz’altro favorita dalla facilità di diffusione dei semi, di piccolissime dimensioni (inferiori a 0,5 mm), prodotti in notevolissima
quantità (da 5.000 fi no a 500.000 per pianta). La prova condotta in provincia di Parma nel 2014 ha evidenziato che la Solfonilurea SS2452
(sostanza attiva ancora in fase di
registrazione) ha garantito un controllo pressoché completo di Phelipanche ramosa, limitando
fortemente il numero dei turioni per
metro quadro (sempre inferiore a 10). Il glifosate ha mostrato un discreto controllo dell’infestazione (50-100 turioni/m2) ma ha ridotto drasticamente la produzione.
Tutte le altre tesi di trattamento, invece, hanno fatto segnalare un leggero controllo, ma non si sono discostate significativamente dalla classe d’infestazione media delle parcelle testimone
Prime esperienze di coltivazione della Quinoa (Chenopodium quinoa Willd.) in Pianura Padana
No full textChenopodium quinoa Willd. è una pianta originaria della zona andina, classificata come pseudocereale (Fleming e Galwey, 1995). La quinoa è una coltura alimentare che contiene tutti gli aminoacidi essenziali ed è ricca di oligoelementi (Krivonos, 2013). Dalla granella si ottengono farine di buon tenore proteico (13-18%) e gluten-free, quindi utili nella dieta delle persone celiache. Inoltre, grazie all’elevata adattabilità e rusticità dimostrata anche in ambienti diversi da quelli di origine, la quinoa può rappresentare una coltura alternativa di fronte ai cambiamenti climatici (Jacobsen, 2003) e avere un certo ruolo nel contribuire alla sicurezza alimentare globale. Nella ricerca di colture alternative e di alimenti ad alto valore nutrizionale, è stato intrapreso uno studio sperimentale sull’adattabilità della quinoa in Italia Settentrionale. Il primo compito è quello di individuare le cultivar più idonee alle condizioni pedo-climatiche padane e la tecnica colturale appropriata per il suo inserimento in agrosistemi intensivi sostenibili di pianura e di collina. Nei campi dimostrativi, Real Blanca e Real Roja hanno esibito un ciclo di 130 e 150 giorni dall’emergenza, rispettivamente a Val di Nizza e a Castelnovetto. La resa di Real Roja in quest’ultima località è stata di 1040 kg ha-1 di granella secca, mentre a Val di Nizza sono stati prodotti 370 e 448 kg ha-1 rispettivamente per Real Roja e Real Blanca. Nel campo catalogo, l’altezza media della pianta era di 205 (±48) cm, la lunghezza media della pannocchia era di 73 (±10) cm, mentre la resa andava da 106 a 1290 kg ha-1. La cultivar più produttiva è stata Flc 6. Solo 12 cultivar, tra le 24 appartenenti alla collezione varietale, hanno raggiunto la maturazione fisiologica (in media in 171 giorni), mentre le restanti non sono andate oltre lo stadio di fioritura, poiché il loro ciclo vegetativo è risultato troppo lungo. Tra i problemi emersi, è da evidenziare la forte competizione con alcune infestanti, in particolare con Chenopodium album, Echinochloa crus-galli e Sorghum halepense. Sono stati riscontrati anche alcuni attacchi di Peronospora spp. Questi risultati suggeriscono che alcune cultivar di quinoa possono essere coltivate con successo in Italia Settentrionale, ma è necessario continuare la ricerca delle varietà più idonee, nonché della tecnica colturale più adatta
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
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