Mulch-based no-tillage effects on weed community and management in an organic vegetable system

Weeds can cooperate with the agroecosystem\u2019s functioning by providing ecosystem services. Effective weed management should mitigate negative weed\u2013crop interference, while maintaining a functional and balanced weed community. In a two-year trial, the in-line/roller crimper (RC) was used to terminate an agroecological service crop (ASC; here barley, Hordeum vulgare L.) before organic zucchini (Cucurbita pepo, L.) and compared with green manure (GM) ASC and tilled no-ASC with Mater-Bi mulch on the rows (No_ASC). Zucchini yield, soil N availability, weed density/cover, biomass, and community composition were assessed. Analysis of variance, exploratory statistical analysis, and non-parametric inferential approaches were run, respectively, on agronomic data, species-specific weed frequencies, and Shannon diversity. Zucchini yield was the highest in No_ASC, due to soil N immobilization under high C:N barley residues in GM and RC. Multivariate analysis discriminated RC from tilled systems, outlining a specific ensemble of weed species correlated to Shannon diversity. From zucchini fruit set, RC selectively favored Polygonum aviculare L. and Helminthotheca echioides (L.), reasonably because of their oligotrophy and creeping habit. Their dominance finally caused low RC weed control. Results highlight strong weed selective pressure by the mulch-based no-tillage. Understanding the mechanisms underpinning the impact of soil management practices on weed community can drive towards a tailor-made and more effective weed management

EFFECTS OF COVER CROP MANAGEMENT AND COMPOST APPLICATION ON SOIL FERTILITY OF ORGANIC MELON

A field experiment was carried out in Central Italy on growing melon (Cucumis melo L.) after barley (Hordeum vulgare L.). Three different systems of cover crop termination (green manure, roller crimper and fallow, as control) were combined with three doses of compost (0, 15 and 30 t ha-1 d.m.) in a strip plot design. The main objective of the research was to evaluate their effects on organic melon production and on short and long term soil nitrogen (N) fertility. Marketable yield and quality and soil N availability along the melon cycle were determined and a simplified N budget calculated. Green manure (GM) treatment showed the highest total and marketable yield, followed by fallow (FA), while roller crimper (RC) was characterized by a significant lower yield respect to the other two treatments (45% and 62% of the marketable yield of GM and FA, respectively). On the other side, long term soil N fertility of GM and FA were characterized by N deficit unless combined with compost application at the dose of 15 t ha-1 d.m

Ecological Sustainability of an Organic Four-Year Vegetable Rotation System: Carabids and Other Soil Arthropods as Bioindicators

A four-year investigation comparing organic and conventional horticultural vegetable rotation systems was carried out in Central Italy using soil arthropods as bioindicators. The indexes of biodiversity showed, in general, higher values on organic in comparison with conventional management, but the differences were strongly affected by the crops. An index specifically designed to select the Carabid species, which benefit from organic versus conventional, was calculated in order to understand faunistic data on this group. Our data demonstrated that the spray intensity adversely affects the Carabid species richness, as proved by the lowest diversity values recorded in the conventional plots. The experiment, planned by following a \u201csystem approach research,\u201d was suitable to understand the ecological sustainability in organic farming in comparison with conventional. The better conservation of arthropod fauna in the organic seems to be coherent also with the enhancement of organic matter in this system. For this reason, a holistic effect of the organic system can provide a reasonable interpretation of the better conservation of the living component and, in particular, of Carabid beetle biodiversity, during the four-year period

Agro-ecosistemi a confronto: biologico e convenzionale

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Casi di studio

L'analisi attraverso lo studio di casi aziendali ha comportato qualche rischio per il buon esito della ricerca. Come \ue8 noto, infatti, le analisi qualitative in genere e quelle condotte attraverso casi di studio in particolare consentono un maggiore approfondimento nell\u2019analisi, ma al tempo stesso soffrono di una scarsa estendibilit\ue0 dei risultati. Il riferimento ad un numero ridotto di casi aziendali e la loro selezione con metodiche non riconducibili ad un processo di campionamento statistico impediscono, in effetti, che le informazioni acquisite sui soggetti osservati possano essere estese anche agli altri soggetti della medesima popolazione. E' pur vero, tuttavia, che lo studio approfondito di un\u2019azienda, della sua storia, del suo essere e del suo fare consente di comprendere appieno quali siano i fattori che ne hanno determinato il successo ed anche i limiti che ne condizionano lo sviluppo, fino a minacciarne, talvolta, l\u2019esistenza futura