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Heltai G.,Szent Istvan University | Anton A.,MTA Agrartudomanyi Kutatokozpont | Hoffmann S.,University of Pannonia | Szili-Kovacs T.,MTA Agrartudomanyi Kutatokozpont | And 6 more authors.
Agrokemia es Talajtan | Year: 2013

Soils from selected treatments in a long-term comparative experiment on the effect of organic and mineral fertilizers, set up in Keszthely in 1963, were used in pot experiments together with undisturbed soil columns taken from the border plots. The aim was to determine how mineral fertilizer, farmyard manure (FYM) and the ploughing in of plant residues influenced the dynamics of CO 2 and N2O gas production and their accumulation in the soil air during the vegetation period.Pot experiments of mesocosm size were conducted in 2008, 2009 and 2010. For the soil from treated plots, gas traps were installed in the pots at a depth of 20 cm to collect soil air samples. In the case of the undisturbed soil columns, the production of CO2 and N2O was studied at depths of 20, 40 and 60 cm.The CO2 concentration stagnated at the start of the growing period, after which one or more peaks were observed before the concentration dropped to the original level in both experimental systems. These changes exhibited good correlation with changes in the mean daily temperature.Changes in N2O production exhibited no clear trend over time in the soil columns, while an increase in the concentration was only observed in the pots until the 6th day after sowing.The CO2 concentration in the undisturbed soil columns rose significantly up to a depth of 40 cm, while little further change was observed between 40 and 60 cm. A similar tendency was observed for the changes in N2O concentration with depth, but this was not as clear, since the measurements were less reliable. In the pots the CO2 concentrations recorded in the gas traps at a depth of 20 cm were of the same order of magnitude as the values found at the same depth in the soil columns. In the unfertilized treatments the presence of plants increased the production of CO2 and N2O both in the soil columns and in the pots. In response to fertilizer treatments the production of both gases decreased in the soil columns. In the presence of plants this reduction was less intense when organic manure was applied than in the case of mineral fertilizer. In the pot experiments the presence of plants caused an increase in the CO2 and N2O production in the soil in the fertilized treatments. This increased in the same order as the yield-increasing effect of the treatments: FYM mineral fertilizer FYM + mineral fertilizer.In summary it can be concluded that the conditions influencing the production of CO2 and N2O and their emission from the soil differ in undisturbed and cultivated soil, and that the presence of metabolising plants has a substantial effect on this process. The database created from the experimental results will allow the CO2 and N 2O emission from agricultural soils in the case of diverse methods of fertilization and cultivation to be realistically estimated using mathematical models.

The aim of this review is to give a brief evaluation about the DNA-based diagnostic and typing methods for the most important foodborne pathogens, based on the available literature and on the authors' experiences with considerations for the adaptability of the present methods and for the need of faster and more specific tests. Main aspects of this evaluation are: cost and time effectiveness, sensitivity/specificity and internationally accepted standardization. Further important aspect is the compatibility to international databases so that these methods could also serve as widely available tools for molecular risk analysis. Some of the molecular methods reported here are already indispensable tools for diagnostic and typing studies in food safety. Through their data inputs for international databases, these molecular methods will be increasingly important in the future. However, the use of internationally standardized official (ISO) methods for systematic isolation and detection of representative pathogenic strains can not be replaced by the molecular detection methods yet.

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