Gaglione, Salvatore Agostino (2014) Fattori di controllo della fungistasi: il ruolo della sostanza organica e della microflora tellurica. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Resource language: Italiano
Title: Fattori di controllo della fungistasi: il ruolo della sostanza organica e della microflora tellurica
Gaglione, Salvatore
Date: 30 June 2014
Number of Pages: 128
Institution: Università degli Studi di Napoli Federico II
Department: Agraria
Scuola di dottorato: Scienze agrarie e agro-alimentari
Dottorato: Agrobiologia e agrochimica
Ciclo di dottorato: 26
Coordinatore del Corso di dottorato:
Bonanomi, GiulianoUNSPECIFIED
Date: 30 June 2014
Number of Pages: 128
Keywords: ammendanti organici, funghi,lettiere
Settori scientifico-disciplinari del MIUR: Area 07 - Scienze agrarie e veterinarie > AGR/12 - Patologia vegetale
Date Deposited: 02 Jul 2014 11:04
Last Modified: 27 Jan 2015 13:38

Collection description

Soilborne plant pathogens are among the most important limiting factors for the productivity of agro-ecosystems. Identifying reliable and effective control methods is crucial for efficient biological control. Soil fungistasis is the capability of soils to inhibit the germination and growth of soil-borne fungi in presence of optimal abiotic conditions. The first aim of this PhD thesis was to clarify the relationships between soil amendments with plant residues spanning a wide range of biochemical quality with soil fungistasis. Microcosms experiments were performed with 42 different plant residues and the effect on soil fungistasis was assessed by using four different fungi (Aspergillus niger, Botrytis cinerea, Pyrenochaeta lycoperici and Trichoderma harzianum). We measured soil respiration and soil enzymatic activity and compared classic litter proximate chemical analysis with 13C-CPMAS NMR spectroscopy to define plant residues biochemistry. Results showed that the quality of organic amendments is a major controlling factor of soil fungistasis. The dramatic relief of soil fungistasis when soil was amended with lignin poor, but labile carbon rich, substrates gives strong support to the competition-based hypothesis. The positive correlation between soil respiration and fungal growth further supports the competition hypothesis. Finally, 13C-CPMAS NMR results showed clear-cut relationships between soil fungistasis and the biochemical quality of plant residues, and provided a quantitative assessment of the time required for fungistasis restoration after organic materials application. The second aim of this work was to assess the effects of different soil amendment histories, in terms of amendment types and amounts, on fungistasis. The few studies concerning the history of soil amendment pointed out its effect on basic soil functions such as respiration, enzymatic activities, carbon and nitrogen mineralization. Previous studies demonstrated that soils with a long-term (i.e. months to years) application history of organic amendments, compared with unamended soils, have a higher and more active microbial biomass and enhanced enzymatic activities. It is not know however, because of the lack of experimental evidences, whether and how a story of organic amendments affects fungistasis. The aforementioned considerations about basic soil processes and soil amendment history drove the hypothesis to us that training a soil with organic carbon, by stimulating the activity of the resident microbial community can positively affect soil fungistasis. With this background, aim of this study was to assess the effects of different soil amendment histories on fungistasis in terms of amendment types and amounts. For this purpose microcosm experiments were performed by training a soil with different amounts and types of organic sources covering a wide range of biochemical qualities (glucose, alfalfa and wheat straw). Thereafter, the fungistasis response was assessed by using four different fungi (Aspergillus niger, Botrytis cinerea, Pyrenochaeta lycoperici and Trichoderma harzianum). Trained soils were characterized for microbial activity (respiration) and functional diversity by the BIOLOG EcoPlates™ method. Results showed that, irrespectively of fungal species and amendment types, frequent supplies of organic C reduce fungistasis relief (i.e. increase fungistasis resistance to organic matter pulse) as well as the time required for fungistasis restoration (i.e. increase fungistasis resilience). Moreover, the frequent addition of organic carbon as a result of the continuous supply of easily decomposable organic compounds enhance soil respiration and its specific catabolic capabilities. In conclusion, organic amendment applications create a soil functionally distinct from its not amended counterpart, with greatly enhanced fungistasis resistance and resilience. Finally, the third aim of this work was to provide the first monitor of soil fungistasis in the Campania Region. Soil quality, especially in the presence of reduced organic inputs, degrades in a few years with the following negative effects: the increased incidence of soil-borne pathogens, the traditional chemical methods loses its effectiveness for the development of strains resistant to fungicides, the efficiency of the fertilizer use is lowered, and the soil food webs become simplified. In order to mitigate these effects is necessary to test innovative farming techniques. In both biological and conventional agriculture, to the recovery of the quality of the soils, it has been proposed to use organic amendments. In this context, the aim of this work was to assess the level of fungistasis in different soils sampled in the Campania Region, from both agro-ecosystems and natural ecosystems. In general, we wanted to assess the combined effect of soil type and a different management on fungistasis. To this end, the analysis included a wide spectrum of types of soils to better understand the relationships between physico - chemical-microbiological characteristics of soils and their fungistatic activity. Since the quality of the soil depends on multiple factors, and the same fungistasis is dependent on several processes and properties of the soil system, in order to evaluate the power fungistatic of soils sampled and to differentiate them according to their ability to induce or less fungistasis and thus inhibit or slow the development of soil-borne fungi, it is necessary to measure a variety of parameters, chemical, physical, biological and microbiological processes. In this multidisciplinary study were compared 12 different soils from different ecosystems and collected in different geographical areas of the Campania Region. Each soil has been subjected to chemical, physical, microbiological, enzymatic analysis, fungistasis assessment with three fungi (Aspergillus niger, Botrytis cinerea and Trichoderma harzianum). The hypothesis to be tested was that soils with higher organic matter content and higher microbial activity showed higher levels of fungistasis. Contrary to the initial hypothesis there was no evidence correlation between microbial biomass and fungistasis, but for the metabolic profile of the telluric microorganisms. The monitoring showed that there are significant differences in the fungistatic power of the different soils, it allows us to classify soils on the basis of their ability to inhibit or slow the development of soil-borne fungi.


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