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IVES 9 IVES Conference Series 9 Caratteristiche fisico-chimiche dei suoli coltivati a vite e loro influenza nella diffusione del mal dell’esca

Caratteristiche fisico-chimiche dei suoli coltivati a vite e loro influenza nella diffusione del mal dell’esca

Abstract

[English version below]

Il mal dell’esca é una malattia della vite della quale sono state studiate sintomatologia, eziologia, patogenesi ed epidemiologia. Essendo una malattia che colpisce soprattutto la parte epigea delle piante, le caratteristiche dei suoli non sono mai state considerate fra le responsabili della sua insorgenza e diffusione. In questo lavoro abbiamo studiato suoli di vigneti in cui il mal dell ‘esca présenta un ‘elevata incidenza e suoli di vigneti dove tale incidenza è scarsa o nulla. Le osservazioni morfologiche ed i risultati analitici indicano che i vigneti più danneggiati dalla malattia sono quelli i cui suoli presentano condizioni idromorfe a minima profondità, fra i 35 ed i 65 cm. Al contrario, i terreni dove l’incidenza é scarsa non presentano segni di idromorfia.
La difficoltà di percolazione, con conseguente instaurarsi di condizioni asfittiche, può essere imputata a due cause: 1) diminuzione di porosità totale negli orizzonti inferiori e 2) preponderante presenza di microporosità dovuta all’eccessivo contenuto di argilla e limo (dal 48 al 76%). Inoltre, l’argilla è costituita da minerali in grado di espandersi in presenza di acqua e, quindi, di rallentare ulteriormente il drenaggio del suolo. Al tri fattori che favoriscono la formazione di orizzonti asfittici sono: 1) i bassi tenori di carbonio organico non sufficienti a prevenire la migrazione dell ‘argilla; 2) la scarsa efficienza delle opere di drenaggio e 3) le lavorazioni meccaniche. Nei suoli ben drenati il contenuto di argilla e limo non supera il 45%, i minerali a reticolo espandibile sono presenti in tracce e, di conseguenza, non vi sono difficoltà di percolazione. Dalle nostre osservazioni risulta quindi che i vigneti maggiormente soggetti al mal dell ‘esca sono quelli che tendono a sviluppare condizioni di scarso drenaggio.

Studies have been conducted on the symptomatology, aetiology, pathogenesis and epidemic of the esca, a disease that affects grapes. Since Esca attacks mostly the above ground parts of the plants, the soil has not been considered relevant in the development and spreading of this disease. In this work we have investigated vineyard soils with a high incidence of esca, and others with a low or no incidence. Our morphological observations and analyses have shown that those vineyard affected by esca also manifest poorly drained conditions at a depth of about 35-65 cm. On the contrary the soils where the occurrence of the disease is less manifested are well drained.
The irnpeded drainage, with the attendant unoxy conditions, can be attributed to two causes: 1) a decreasing porosity in the lower horizons and 2) the prevailing micro porosity due to the high content of clay and silt (from 48 to 76%). Moreover, the clay is made of minerals that, once hydrated, tend to expand, further reducing the porosity and, thus, the drainage. Others factors that additionally cause a deterioration of the drainage are 1) the low organic matter content that prevent aggregation; 2) the inadequate drainage structures and 3) the continuous mechanical operations. In the well-drained soils the clay plus silt content is always less than 45%, the expandable minerals are presence in traces and, hence, there are not limitations to impede the drainage. We conclude that the vineyards more vulnerable to the esca are those painted on soils which tend to develop poorly drained conditions.

DOI:

Publication date: March 2, 2022

Issue: Terroir 1998

Type: Article

Authors

GIUSEPPE CORTI, FIORENZO C. UGOLINI, ROSANNA CUNIGLIO

Dipartimento di Scienza del Suolo e Nutrizione della Pianta
Piazzale delle Cascine, 15 – 50144 Firenze

Tags

IVES Conference Series | Terroir 1998

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