The effect of experience on choosing where to go: an application to a choice experiment on forest recreation

The main objective of this paper is to investigate the impact of experience on the choice of visits to forests in a stated discrete choice experiment. Recent literature has indicated that experiences with the environmental services valuated may increase the respondents' certainty in their choice of hypothetical alternatives. We apply two indicators of experiences: the number of visits and the number of different forests visited during the last year. Applying the generalized multinomial logit model, we find that an increase in the number of visits to forests makes respondents' choices more predictable. However, the number of different forests visited reduces the predictability of choices. Furthermore, we investigate the relationship between respondents' experience of forest recreation and the self-reported choice certainty, controlling for respondents' social-demographics and other design characteristics. Finally, we show that self-reported choice certainty is positive correlated with the scale factor, as expected.     

Phosphorus speciation in sequentially extracted agro-industrial by-products: evidence from X-ray absorption near edge structure spectroscopy

The phosphorus (P) in agro-industrial by-products--a potential source of freshwater eutrophication but also a valuable fertilizer--needs to be speciated to evaluate its fate in the environment. We investigated to what extent X-ray absorption near edge structure (XANES) spectroscopy at the P K- and L2.3-edges reflected differences in sequentially extracted filter cakes from sugarcane (Saccharum officinarum L.) (FIC) and niger seed (Guizotia abyssinica Cass.; NIC) processing industry in Ethiopia. The P fractionation removed more labile (54%) and H2SO4-P (28%) from FIC than from NIC (18% labile, 12% H2SO4-P). For the FIC residues after each extraction step, linear combination (LC) fitting of P K-edge spectra provided evidence for the enrichment of Ca-P after the NaOH-extraction and its almost complete removal after the H2SO4-treatment. The LC-fitting was unsuccessful for the NIC samples, likely because of the predominance of organic P compounds. The different proportions of Ca-P compounds between FIC (large) and NIC (small) were more distinctive in L2-than in the K-edge XANES spectra. In conclusion, the added value of complementary P K- and L2.3-edge XANES was clearly demonstrated, and the P fractionation and speciation results together justify using FIC and NIC as soil amendments in the tropics.     

Organic Farming and Soil Carbon Sequestration: What Do We Really Know About the Benefits?

Organic farming is believed to improve soil fertility by enhancing soil organic matter (SOM) contents. An important co-benefit would be the sequestration of carbon from atmospheric CO₂. Such a positive effect has been suggested based on data from field experiments though many studies were not designed to address the issue of carbon sequestration. The aim of our study was to examine published data in order to identify possible flaws such as missing a proper baseline, carbon mass measurements, or lack of a clear distinction between conventional and organic farming practices, thereby attributing effects of specific practices to organic farming, which are not uniquely organic. A total of 68 data sets were analyzed from 32 peer-reviewed publications aiming to compare conventional with organic farming. The analysis revealed that after conversion, soil C content (SOC) in organic systems increased annually by 2.2% on average, whereas in conventional systems SOC did not change significantly. The majority of publications reported SOC concentrations rather than amounts thus neglecting possible changes in soil bulk density. 34 out of 68 data sets missed a true control with well-defined starting conditions. In 37 out of 50 cases, the amount of organic fertilizer in the organic system exceeded that applied in the compared conventional system, and in half of the cases crop rotations differed between systems. In the few studies where crop rotation and organic fertilization were comparable in both systems no consistent difference in SOC was found. From this data analysis, we conclude that the claim for beneficial effects of organic farming on SOC is premature and that reported advantages of organic farming for SOC are largely determined by higher and often disproportionate application of organic fertilizer compared to conventional farming.     

教育性建筑物中的能源效率设计和可再生能源的利用:MEDUCA项目

MEDUCA(教育性建筑模式)项目包括7个国家的8个示范项目.这些项目分布在挪威的格龙(65°);瑞典的哥德堡(58°N);瑞典的Falkenberg(57°N);丹麦的巴勒鲁普(56°N);德国的新明斯特(54°N);西班牙的阿尔梅里亚(36°50'N);意大利的Bagheria(38°N);和希腊的Legraina(38°N).     

Zoobenthos as indicators of ecological status in coastal brackish waters: a comparative study from the Baltic Sea

A new method for classifying soft-bottom zoobenthic assemblages along the Finnish coasts (northern Baltic Sea) is presented and tested against traditional physicochemical monitoring data in the complex Archipelago Sea. Although multivariate methods for assessing the state of the marine environment have become widely used, few numerical indices can operate over a wide salinity range. We compare indices currently in use and propose a new index, BBI (brackish water benthic index), for the low-saline and species-poor Baltic coastal waters. BBI offers a salinity-corrected tool for classification of the soft-bottom zoobenthos under the demands of the European Union Water Framework Directive.     

Size effect on the mineralogy and chemistry of <Emphasis Type="Italic">Mytilus trossulus</Emphasis> shells from the southern Baltic Sea: implications for environmental monitoring

Mussels have the ability to control biomineral production and chemical composition, producing shells with a range of functions. In addition to biological control, the environment also seems to influence the process of biomineralization; thus, shells can be used as archives of ambient water parameters during the calcium carbonate deposition. Past and present environmental conditions are recorded in the shells in the form of various proxies including Mg/Ca or Sr/Ca ratios. For such proxies to be accurate and robust, the influence of biological effects including the size of studied organism must be examined and eliminated or minimized, so that the environmental signal can be efficiently extracted. This study considers mineralogy and elemental composition of shells representing four size classes of Mytilus trossulus from the Baltic Sea. Obtained results suggest that mineralogy and chemical composition change throughout the shell development due to most likely a combination of environmental and biological factors. The content of aragonite increases with increasing shell size, while the bulk concentrations of Na, Cd, Cu, U, V, Zn and Pb were found to decrease with increasing height of the shells. Therefore, using mussels for environmental monitoring requires analysis of individuals in the same size range.     

Fluorescence imaging applied to tracer distributions in variably saturated fractured clayey till

The study of mechanisms controlling preferential flow and transport in variably saturated fractured clayey till is often hindered by insufficient spatial resolution or unknown measuring volume. With the objective to study these mechanisms while circumventing the obstacles, tracer experiments with two fluorescent tracers Acid Yellow 7 (AY7) and Sulforhodamine B (SB) were performed at three different rain events for a fall and a summer season. Irrigated areas were excavated down to depths of 2.8 m and the movement of both tracers in the exposed profiles was delineated simultaneously by high spatial resolution apparent concentration maps (pixel approximately 1 mm(2)) obtained with an imaging device. The device consists of a light source and a CCD camera, both equipped with tracer-specific-filters for fluorescent light. The fluorescence images were corrected for nonuniform lighting, changing surface roughness, and varying optical properties of the soil profile. The resulting two-dimensional apparent concentration distribution profiles of the tracers showed that: (i) relative low water content in the upper 10 cm of the irrigated till in summer had a pronounced retardation effect on the AY7-migration and no effect on the SB-migration; (ii) the dead-end biopores were not activated in the fall season; (iii) only 3D fracture-plans connected to hydraulically active 1D-biopores contributed to the leaching; (iv) the tracer migration primary followed macropores during both seasons, though AY7 also followed a topsoil piston transport in summer; (v) the highest tracer pixel apparent concentrations were often found in macropores and most pronounced in the summer season; and (vi) 3D-dilution in fractures seems to play a dominating role in AY7-migration in the fall season.