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Wskaźniki opadu atmosferycznego w rejonie Puczniewa

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Wskaźniki opadu atmosferycznego w rejonie Puczniewa. Susze są jednymi z groźniejszych zjawisk atmosferycznych powodujących szczególnie duże straty w plonach roślin uprawnych. W artykule dokonano oceny intensywności oraz wieloletniej zmienności suszy w okresie wegetacyjnym (IV–IX) na terenie Puczniewa, wyznaczonej na podstawie względnego wskaźnika opadu (RPI) oraz wskaźnika standaryzowanego opadu (SPI). Analizie poddano dobowe sumy opadów z okresu 1953–2002. Większą częstość występowania okresów wegetacyjnych z silną suszą wykazał wskaźnik RPI niż wskaźnik SPI.
The paper describes the filter-paper method as an indirect method for the estimation of the pF characteristics. In this method, no direct measurements of soil water potential (pF) are performed, but the latter is determined on the basis of the gravimetric moisture content of the filter paper, which is in contact with the analysed soil samples. Therefore, there is a need to establish a calibration equation that would express the relationship between the value of the soil water potential (pF) and the gravimetric moisture content of the filter paper. The calibration procedure was performed using standard measurement methods of determining pF curves (sand box, pressure plates) and filter paper (Whatman no 42). Based on the research conducted, calibration curves were developed for the filter-paper method, for the analysed sapric (drainic) histosoles, developed from moss and alder peats of medium (hemic) and strong (sapric) degree of decomposition, originating from the mid-basin of the Biebrza river. The proposed calibration curves were presented as 3-degree polynomial equations. The aforementioned equations can be used for the estimation of retention characteristic for sapric (drainic) histosoles, showing similar properties and comparable degree of secondary decomposition of the peat mass.
Our paper presents an analysis of the water retention characteristics of mineral soils for select forest soils in Poland. Direct measurement of the soil retention characteristics is relatively complicated and time consuming, therefore often indirect methods are sought instead. The main objective of the paper was to establish statistical relationships between the soil basic physical properties and the moisture content at predefined soil matrix potentials (e.g. pF curves). The relationship between individual soil texture classes, bulk density, specific density, and organic matter content at certain soil suction (pF values) were analyzed. The empirical models were described by multiple regression equation. The research covers 62 mineral forest soil layers of a diverse textured composition, from sand to clays. They were classified as Haplic Podzols and Cambisols representing pine and spruce ecosystems. For verification of the used method, calculated and measured values of total available water content were compared. The relationships between examined properties and the soil moisture content at certain pF value was provided statistically. The obtained data set can be a valuable representation of water retention characteristics and physical parameters of forest soil in pine and spruce ecosystems across Poland.
Assessment of the possibility of applying selected pedotransfer functions for indicating the retention of forest soils in Poland. Landscape retention influences the water balance of a catchment and the course of flooding events. The degree of retention capabilities of forest soils are much less known than the retention of land used for agriculture. Soil retention capacity influences the formation of a given forest habitat type, floristic species composition, as well as the type and quality of the stand of trees. The analysis was carried out for a regression model dedicated to selected forest soils within the area of Poland, as well as van Genuchten’s and Wösten’s, and Varallyay’s and Mironienko’s models. In order to assess the fit of the models, an independent series of forest soils were used. The models prepared for soils used for agricultural purposes do not result in statistically acceptable fit when it comes to the analyzed forest soils. The analysis of measured and calculated values of total available water indicate good fit of the regression model developed for the analyzed group of podzolic and brown forest soils.
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