BC of soils (van Breemen et al., 1983). Soil acidification may be defined as the loss of ANC and does not neces-In Slovakia H ؉ input into soils is increasing because alkaline dust sarily result in the decrease of the soil equilibrium pH emissions have been reduced since 1990. Our objectives were to exam-(van Breemen et al., 1983). Sü sser (1987) described ine (i) the metal release in H ؉ buffer reactions of Slovak soils and (ii) the impact of the proton buffering on heavy metal partitioning. buffer reactions in soils during pH stat experiments as the We used 10 soils (pH 7.4-3.6) in a batch pH stat experiment. Released sum of two independent reactions both following firstions were adsorbed to an ion-exchange resin, while pH was kept order kinetics.
Among energy crops, short-rotation coppices (SRC) are recommended to provide renewable energy. Compared to annual crops, willows and poplars are regarded as plants with low requirements for nutrients, herbicides, pesticides, and soil maintenance. However, only little is known about N-fertilizer effects on SRC and the few studies are even inconsistent. Therefore, we studied the effects of N on yields of willows and poplars in a field experiment. The effects of N fertilization on nitrate leaching and nitrous oxide emissions from the loamy-sand soil were also measured. Cuttings of willows (Salix viminalis clone Inger) and poplars (Populus maximovizcii × P. nigra clone max 4) were planted on farmland in 2008. The experiment was arranged in a random block design with three levels of N fertilizer (0, 50, and 75 kg N ha -1 y -1 ). After 2 y, the trees were harvested for the first time. Fertilization did not affect the yields of willows or poplars. However, the application of 75 kg N ha -1 y -1 caused an average increase of N leaching in the willow and poplar plots of 25 kg N ha -1 y -1 and 40 kg N ha -1 y -1 , respectively. Emissions of N 2 O were increased by a maximum of only 0.2 kg N ha -1 y -1 . Further, the N fertilizer stimulated the growth of the weed biomass in case of the willow plots by 46% and of the weed N content by 52% (r = 0.53). In conclusion, in the first 2 y, SRC could be produced in a more effective and environmentally friendly manner without mineral fertilizer.
Empirical studies which examine the theory of newsworthiness and the predictability of news coverage in transnational or developing countries still remain on the agenda of journalism research. Therefore, this study examines the influence of news factors on the foreign news coverage of three Mexican newspapers. Two main questions guide the research. First, is the theory of newsworthiness a valid approach for predicting news selection in a cultural context that is significantly different from western industrialized countries? Secondly, which are the relevant news factors that predict foreign news coverage in the Mexican press and thus shape the image of foreign nations? The results of a quantitative content analysis confirm the hypotheses of selection, additivity, and replication as they were originally postulated by Galtung and Ruge and thus prove the external validity of the theory of newsworthiness beyond western journalism.
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