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An equation to describe vertical gradients of element concentrations in soils under beech and spruce stands
No full textA description of element gradients in organic layers and the uppermost parts of the mineral soil may give information on their storage and cycling in forest ecosystems. The objectives were to describe vertical gradients of C, N, P, S, NA, K, Ca, Mg, Mn, Fe, and Al contents under beech (Fagus sylvatica L.), spruce (Picea abies (L.) Karst.), and mixed beech-spruce stands and-to obtain an easy method for the estimation of nutrient stocks and their distribution in the organic layer at a regional scale. Organic layers and upper 5 cm of mineral soil from 90 profiles were cut centimeterwise. Samples were analyzed for contents of C and N and P, S Na, K, Ca, Mg, Mn, Fe, and Al after pressure digestion in HNO3, Contents of C, N, P, S, Ca, and Mn decreased whereas contents of Na, K, Mg, Fe, and Al increased with depth. The gradients of C, N, P, S, Na, K, Mn, Fe, and Al were described satisfactorily using the following equation after transforming the maximal height of the organic horizon to 0 cm: E(d) = E-M + (E-L - E-M)/[1+(alpha X d)(beta)]((1-1/beta)) where E(d) is the element concentration at depth d, EL and Em are the concentrations of the element in the L layer and in the mineral soil at 5 cm depth, respectively, and alpha and beta of are fitting parameters. Linear, correlation coefficients (r,) measured against modeled element contents were greater than or equal to 0.8 and 1.2 (with the regression coefficients (a) varied between 0.8 exception of P, Fe, and Na for some profiles) The parameters a and P depended on the height of the organic horizon. An effect of the tree species on the parameters was found only for Mn and Fe. The equation enabled the estimation of the stocks of C, N, P, and S in organic horizon with satisfying accuracy (r greater than or equal to 0.8, 0.8 less than or equal to a less than or equal to 1.0), after measuring only the height of the organic horizon. However, the prediction of the stocks of other elements was less satisfactory
Hot water extractable C and N in relation to microbiological properties of soils under beech forests
No full textHot water extraction is sometimes recommended as an easy method to estimate the readily mineralizable fractions of total C (C-t) and total N (N-t) in arable soils. However, the usefulness of this method for forest soils has not been adequately studied. The objectives of this study were to relate the hot water extractable C (C-hw) and N (N-hw) to microbiological and chemical properties of the forest soils under beech (Fagus sylvatica L.) stands and to test the ability of near infrared spectroscopy (NIRS) to predict chemical and microbial properties of these soils. Soils differing in humus type, soil type and soil texture were collected from five locations and five depths. In all soils the amount of C-hw was higher than the microbial biomass C (C-mic) indicating that a considerable part of C-hw was of non-microbial origin. The amount of C-hw in mineral soil correlated significantly (r =-0.30-0.53) with C-mic, basal respiration (BAS) and C-t/N-t ratio but was not related to C-mic/C-t ratio. The amount of N-hw was correlated with C-mic, BAS, C-mic/C-t ratio, and C-t/N-t ratio (r =-0.59-0.78). However, C-t and N-t values showed better relationships (r =-0.42-0.88) with all the parameters, indicating no advantage in using C-hw and N-hw in forest soils. NIRS predicted satisfactorily C-t, N-t, C-hw, N-hw, C-mic, C-mic/C-t ratio and BAS in the mineral soils [the regression coefficients (a) of linear regression (measured against predicted values) ranged from 0.84 to 1.17 and the correlation coefficients (r) ranged from 0.86 to 0.94] indicating the applicability of NIRS to estimate these properties
Near infrared spectroscopy for determination of total and exchangeable cations in geologically heterogeneous forest soils
No full textSustainable forest management requires information on a number of soil properties. Therefore fast methods of soil analysis are needed. The objective of this study was to test the ability of near infrared (NIR) spectroscopy to predict the total and exchangeable Na, K, Ca, Mg, Mn, Fe and Al, the cation exchange capacity (CEC), the base saturation (BS) and the total contents of Zn, Cu, Cd and Ph in geologically heterogeneous forest soils. The samples (n = 100) were collected from five sites covered by beech (Fagus sylvatica L.) forest stands and from four depths. The soils were analysed for total contents of Na, K, Ca, Mg, Mn, Fe, Al, Zn, Cu, Cd and Ph after pressure digestion in HNO(3) and for contents of exchangeable Na, K, Ca, Mg, Mn, Fe and Al in NH(4)Cl. The spectra were recorded between 400 and 2500 run at 2 nm intervals. Principal components analysis revealed significant spectral differences among the samples from different sites. The global NIR models predicted well the mean values of the total contents of all cations, Zn, Pb, the exchangeable K, Mg, Fe and BS in upper (0-10 cm) and lower (10-20 cm) layers of the studied soils: the correlation coefficients (r(2)) of the linear regression (measured against predicted values) varied between 0.90 and 1.00 and the regression coefficients (a) ranged from 0.94 to 1.07. The contents of Cu, CEC and the exchangeable Na, Ca and Al were predicted satisfactorily (r(2)=0.874.98, a=0.86-1.14). The global models overestimated the values of total Ca and exchangeable Ca, Mn and Fe in the lower parts of their ranges resulting in biased estimations of the means at some of the considered sites. Splitting the sample population into spectrally similar groups enabled the development of local calibrations, which improved the prediction accuracy (lower standard errors of prediction) for most of the analysed constituents and removed the bias in the estimations of exchangeable of total Ca and Ca, Mn and Fe. The obtained results indicated the usefulness of NIR spectroscopy for determination of a number of soil constituents in geologically heterogeneous forest soils
Use of near infrared spectroscopy to determine biological and chemical characteristics of organic layers under spruce and beech stands
No full textThe chemical composition of organic layers of forest soils shows a high spatial variability and fast methods may be required for its study at a landscape level. The objective was to assess the applicability of near infrared spectroscopy (LAIRS) to measure several chemical and biological properties of organic layers in spruce, beech, and mixed spruce-beech stands. Spectra in the VIS-NIR region (400-2500 nm) were recorded for 406 samples representing Oi, Oe, and Oa layers of forest soils from Solling (Germany), 195 of them were used for calibration and 211 for validation. The calibration equations for each constituent were developed using the whole spectrum (0(th) to 3(rd) derivative). Humus samples were analyzed for contents of C and N and contents of P, S, Na, K, Ca, Mg, Mn, Fe, and Al after pressure digestion in HNO3. Additionally, basal respiration and microbial C (C-mic) were measured. LAIRS predicted well the contents of C, N, P, S, Ca, Na, K, Fe, and AI and C/N and C/P ratios: the regression coefficients (a) of a linear regression (measured against predicted values) ranged from 0.9 to 1.1, and the correlation coefficients (r) were greater or equal 0.9. C-mic (a = 0.87, r = 0.83) was predicted satisfactorily, whereas the prediction of the basal respiration (a = 0.74, r = 0.87) was less satisfactory. Due to liming of some of the plots LAIRS failed to predict contents of Mg (a = 1.27, r = 0.68). For all chemical and biological characteristics the best prediction performances were achieved using the whole sample population. Splitting the samples into smaller groups according to a dominant tree species or an organic layer did not improve the predictions
Erfassung von Humusmengen und qualitäten in organischen Auflagen in Rein- und Mischbeständen von Buchen und Fichten unterschiedlichen Alters
No full textErfassung von Humusmengen und qualitäten in organischen Auflagen in Rein- und Mischbeständen von Buchen und Fichten unterschiedlichen Alters
No full textNear infrared spectroscopy for determination of total and exchangeable cations in geologically heterogeneous forest soils
No full textSustainable forest management requires information on a number of soil properties. Therefore fast methods of soil analysis are needed. The objective of this study was to test the ability of near infrared (NIR) spectroscopy to predict the total and exchangeable Na, K, Ca, Mg, Mn, Fe and Al, the cation exchange capacity (CEC), the base saturation (BS) and the total contents of Zn, Cu, Cd and Ph in geologically heterogeneous forest soils. The samples (n = 100) were collected from five sites covered by beech (Fagus sylvatica L.) forest stands and from four depths. The soils were analysed for total contents of Na, K, Ca, Mg, Mn, Fe, Al, Zn, Cu, Cd and Ph after pressure digestion in HNO(3) and for contents of exchangeable Na, K, Ca, Mg, Mn, Fe and Al in NH(4)Cl. The spectra were recorded between 400 and 2500 run at 2 nm intervals. Principal components analysis revealed significant spectral differences among the samples from different sites. The global NIR models predicted well the mean values of the total contents of all cations, Zn, Pb, the exchangeable K, Mg, Fe and BS in upper (0-10 cm) and lower (10-20 cm) layers of the studied soils: the correlation coefficients (r(2)) of the linear regression (measured against predicted values) varied between 0.90 and 1.00 and the regression coefficients (a) ranged from 0.94 to 1.07. The contents of Cu, CEC and the exchangeable Na, Ca and Al were predicted satisfactorily (r(2)=0.874.98, a=0.86-1.14). The global models overestimated the values of total Ca and exchangeable Ca, Mn and Fe in the lower parts of their ranges resulting in biased estimations of the means at some of the considered sites. Splitting the sample population into spectrally similar groups enabled the development of local calibrations, which improved the prediction accuracy (lower standard errors of prediction) for most of the analysed constituents and removed the bias in the estimations of exchangeable of total Ca and Ca, Mn and Fe. The obtained results indicated the usefulness of NIR spectroscopy for determination of a number of soil constituents in geologically heterogeneous forest soils
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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