Groceries delivered by mistake: an experimental study of customers’ honesty

Purpose – The purpose of this paper is to examine how perceived performance risk moderates consumers' evaluations of different types of promotions, including extra free product promotions (e.g. buy‐one‐get‐one‐free deals or BOGOFs) and price discounts (e.g. 50 per cent off). Some evidence shows that consumers prefer extra free products to discounts because of mental accounting, and the way that these different types of promotions are framed. This research explores a new moderating link in the consumer behaviour literature by showing that perceived performance risk, through its effect on a consumer's tendency to stockpile, moderates consumers' evaluations of extra free product promotions and price discounts.Design/methodology/approach – This research uses a cross‐sectional experiment to manipulate perceived performance risk, type of promotion and promotion size, and measures consumers' value perceptions and purchase intentions. The experimental method provides greater internal validity and addresses calls ...

A comfortable indoor thermal environment plays a crucial role in preserving occupant health and productivity. In most office building today, the indoor thermal environment is regulated by heating, cooling, and air-conditioning(HVAC) systems with static schedule-based rules. While prevalent, this control strategy has resulted in low thermal satisfaction rates and energy waste. A growing number of researchers are focusing on occupant-centric buildingcontrols and applying various advanced control methods to improve thermal comfort and energy efficiency. However, it is still challenging to integrate occupants’ personalized requirements into a control system with a capabilityof learning from the environment. This thesis has developed a bio-sensing and reinforcement learning control system for continuously integrating occupants’ bio-signals into the operation of different heating, cooling, and ventilationsystems, learning through interaction to achieve personalized thermal comfort and energy savings.A bio-sensing and reinforcement learning control (Bio-REAL) system is comprised of a bio-sensing network, multiple Bio-REAL agents, and a negotiator. The bio-sensing network uses smart wristbands to measure occupants wrist temperature in real-time. The Bio-REAL agent initiates the best control actions on behalf of each occupant in response to the wrist temperature, subjective feedback, and environmental conditions. The negotiator resolvesconflicts in the control actions initiated by different Bio-REAL agents to maximize collective thermal comfort and minimize energy consumption. A state-of-art reinforcement learning algorithm, double Q learning with experimentreplay and neural network approximation, is applied to train the Bio-REAL agents. This thesis evaluates the Bio-REAL systems using three types of experimental techniques: simulation experiments, preliminary field and simulationexperiments, and field experiments. The simulation experiment trains a Bio-REAL system with three virtual occupants and an office room with a variable air volume (VAV) system in a heating season. The three virtual occupants are simulated using classic thermal comfort models. The room of a small-sized office building is modeled by the EnergyPlus simulation tool. The preliminaryheating season field and simulation experiments gather data from six occupants, providing inputs to create the personalized occupant models. The experimental test space is a room with water-sourced radiators for heating and modeled by the EnergyPlus tool. The co-simulation with personalized occupant models and EnergyPlus model assesses the performance of the Bio-REAL system. The cooling season field experiment evaluates the real-worldperformance of the Bio-REAL systems with fourteen occupants in a tropical climate, occupying a studio with ambient temperature controls and shared controls of ceiling fans. The three types of experiments each demonstrated that the Bio-REAL system has more advantages for improving thermal comfort and energy efficiencycompared to the conventional control systems based on thermal comfort models and static schedules. With the combinations of bio-sensing and learning capability, the Bio-REAL system was able to derive dynamic and adaptive control policies, mapping occupants’ personalized requests and the changes of indoor and outdoor environmental conditions to optimum control actions. The Bio-REAL system contributes an innovative approach for controllingbuilding conditioning systems, to deliver thermal comfort for each individual at the lowest energy possible, with benefits for occupant health and productivity, as well as sustainability. The Bio-REAL research addresses individualdifferences in thermal comfort for multi-occupant spaces with limited individual controls. It also addresses a range of heating and cooling choices from ambient to task systems. The structure and learning process of the Bio-REAL system, the strategies for the simulations, and the real-world implementation offer creative solutions for building control systems, contributing to the application of the Internet of Things and artificial intelligence in buildings.

We study whether employment history can provide information about a worker’s non-cognitive skills - in particular, about “work attitude,” or the ability to work well and cooperatively with others. We conjecture that, holding all else equal, a worker’s frequent job changes can indicate poorer work attitude, and that this information is transmitted in labor markets through employment histories. We provide support for this hypothesis across three studies that employ complementary lab, field, and survey experiments. First, a laboratory labor market, in which the only valuable characteristic of workers is their reliability in cooperating with an employer’s effort requests, demonstrates that prior employment information allows employers to screen for such reliability and allows high-reliability workers to obtain better employment outcomes. Second, we conduct a field experiment that varies the frequency of job changes in fictitious job applicants’ resumes. Those applicants with fewer job changes receive substantially more callbacks from prospective employers. Finally, a survey experiment with human resource professionals confirms that the resume manipulations in the field study create different perceptions of work attitude and that these account for the callback differences. Our work highlights the potential importance of job history as a signal of worker characteristics, and points to a cost for workers of frequent job changes.

This article uses a novel experimental approach to measure consumer willingness to pay (WTP) for wine attributes. We invited customers of a local supermarket who had selected a bottle of wine to purchase to participate in a valuation experiment. Integrating their original wine choice into the experiment, each participant evaluated six alternative wines, generating a rich set of data on willingness to pay and consumer characteristics. The data from the experiment allow us to compare standard shelf price‐based wine attribute valuation estimates with estimates using WTP data and an increasing amount of information about individual consumers. The full model employs individual fixed effects to estimate WTP parameters without bias from consumer sorting or supply side influences. Our WTP estimates for wine attributes differ markedly from previous attribute value estimates. Consumers in our sample display clear and stable preferences for wine varieties, but less clear preferences for appellations. Our results suggest caution is needed in using market prices to estimate parameters of the consumer valuation function for product attributes.

In spite of significant progress in the development and calibration of new proxies, major challenges still limit our ability to use these indicators to fully understand past environmental changes. Over the past two decades, both field and laboratory experiments have shed light on the importance of trace metals in controlling –through limitation or toxicity - the growth and composition of phytoplankton communities. Nonetheless, there is still a lack of reliable tools to evaluate trace metals–phytoplankton interactions during past environmental and climatic perturbations. In this work, we evaluated the use of the Zn content of silicate shells (frustules) of fossil diatoms to track past changes in Zn bioavailable concentrations of surface waters. This essential element is delivered to both continental and ocean waters via natural and/or anthropogenic inputs. Our approach combined laboratory and field experiments.

Sour rot is a disease complex that causes serious damage in viticulture. The common vinegar fly Drosophila melanogaster (Diptera: Drosophilidae) is associated with sour rot in overripe or otherwise damaged grapes. Drosophila suzukii (Diptera: Drosophilidae) is an invasive species, which is suspected to induce sour rot in previously undamaged grapes due to the flies’ ability to infest healthy, undamaged soft fruits with its serrated ovipositor. As a consequence, infection of healthy grapes by D. suzukii may facilitate the colonization by D. melanogaster. The aim of this study was to investigate the single and combined influence of D. suzukii and D. melanogaster on sour rot development under near-natural conditions in the vineyard, along with laboratory experiments under controlled climate. For that, manipulative experiments with gauze-bagged grapes comprising four different treatments: 1) D. suzukii, 2) D. melanogaster, 3) both Drosophila species combined and 4) without flies as control were performed in 2017 and 2018. Subsequently, sour rot development was determined by measuring the volatile acidity levels. All experiments were performed around the harvest, started with the adding of the flies and ended with the determination of the volatile acid levels (as an indicator for sour rot). Field experiments were set up in a randomized block design: Blocks comprised four different treatments and were repeated 10 times and randomly distributed over the vineyard. For the laboratory experiments, the same experimental set up was chosen with four treatments repeated 10 times and randomly distributed in the climatic chamber. Therefore, one grape cluster per sample was placed in a plastic box. For all experiments n = 40 samples (4 treatments x 10 replicates) were used to check for differences in volatile acidity levels between the treatments performing variance analyses followed by post hoc tests. The raw data supporting the results in the paper are presented in three datasets referring to the five figures in the publication. A legend, explaining the different variables used in the datasets is given in a separate document. Dataset 1 is from the semi-field experiments in 2017 and underlies figure 1, 2 and 3 and related analyses. In two experimental repetitions starting at 30.8.2017 and 6.9.2017 and ending three weeks later at 20.9.2017 and 25.9.2017, grapes were exposed to the four different treatments in gauze sleeves in the field, followed by an incubation in the laboratory. In this experiment, additionally to the volatile acidity of the grape clusters, the fly emergence rates and grape cluster weight were determined. Dataset 2 is from the field experiments in 2018 and underlies figure 4 and related analyses. The experimental setup was same as in dataset 1, but the experiment took place completely in the vineyard. Again, two experimental repetitions were performed starting at 24.8.2018 and 31.8.2018 and ending with the determination of volatile acidity at 13.9.2018 and 20.9.2018. Dataset 3 is from the laboratory experiments in 2018 and underlies figure 5 and related analyses. For that, two laboratory repetitions were performed starting at 29.8.2018 and 4.9.2018 by placing one grape cluster per sample in a plastic box. The experimental setup was the same as in the field experiments with four treatments repeated 10 times and distributed randomly in the climatic chamber. The experiment ended after two weeks with the determination of volatile acidity of the grape cluster at 12.9.2018 and 29.9.2018 respectively.

Field experiment is an experimental research method corresponding to lab experiment. It has received continuous attention in recent years because of its high realism and external validity. However, past research did not reach consensus on the definition of field experiment, which puzzled the readers to understand the meaning of field experiment and to carry out a real field experiment. This research gap motivated the current paper.First, we collect previous scholars’ definitions of field experiment. Based on these past definitions, we put forward a relatively clear definition of and a criterion for field experiment. In the same part, we further distinguish the definitions of field experiment between those of some other related terms such as lab experiment, quasi experiment, field study and realistic experiment in-the-field. This part is followed by introducing two subcategories of field experiment, namely, independent field experiment and collaborative field experiment, and discussing the advantages and disadvantages of field experiment. We argue that although field experiment has disadvantages in uncovering the underlying mechanism, controlling noise, analyzing data, etc, it can improve the realism and external validity of a scholarly work. Importantly, it can increase the publication likelihood of the scholarly work to some extent.Next, we analyze a total of 108 articles which include at least one field experiment in four leading marketing journals, i.e. JCR, JMR, JM and JCP. The time span of these articles ranges from August 2014 to November 2019. Based on the summary of these 108 field experiment articles, we elaborate on the general methods of IV manipulation and DV observation. Specifically, we divide IVs of these 108 articles into several categories: individual characteristics, product stimuli, environmental situations, and other categories, etc. These IVs are mainly manipulated through natural display, actual recording and language highlighting. Regarding DVs, we find that the DVs of these 108 articles are generally observed by adopting the “pay-what-you-want” paradigm, recording participants’ actual choices, recording participants’ food intake quantity and product purchase quantity, counting website visits and clicks, and recording relevant behaviors such as information sharing and information collection, etc.In the following part, we provide a few suggestions on how to conduct two different types of field experiment (independent field experiment and collaborative field experiment). For independent field experiment, researchers can consider designing experiment flexibly, placing extra emphasis on increasing the authenticity of experiment, and avoiding participants’ awareness. While for collaborative field experiment, researchers can consider using a large sample size, understanding the needs of non-academic partners, and bringing practical benefits to non-academic partners, etc. Sometimes researchers also need to meet the anonymity requirements of non-academic partners.In the final part, we discuss when researchers should carry out field experiment and when they should not. We argue that field experiment is not necessary, perfect and omnipotent, so researchers should choose appropriate research methods according to their own research objectives, research characteristics and resource constraints. We hope this paper could provide reference value for domestic researchers who plan to carry out field experiment in the future.

DEVELOPMENT OF SOIL AND LITTER ARTHROPOD ASSEMBLAGES IN RAINFOREST RESTORATION

The field of behavioral economics enhances the ability of social science research to effectively inform socially efficient climate policy at the microeconomic level, in part due to the dependence of climate outcomes upon present and future human consumption patterns. Since the behavioral field is relatively new, environmental and resource economists still have scarce evidence as to why people make particular decisions. For this thesis, I have conducted both field and laboratory experiments to address market failures highly relevant to environmental outcomes, namely international public goods problems and externalities from fuel and resource consumption. My methodology capitalizes upon the benefits of each experimental methodology—laboratory, artefactual, framed, and natural—to capture the effects of particular informational and contextual elements on subsequent behavior. While each methodology has its potential advantages and shortcomings, I contend that the complete toolkit is necessary to study a broad range of relevant environmental contexts. For instance, while natural field experiments are generally considered the “gold standard” in terms of exogeneity and generalizability, many settings in which field experimentation may provide tremendous insight preclude randomization across unknowing subjects. Similarly, researchers may not have access to populations of interest, though lab experimentation may still provide insights into the behavior of these populations or reveal motivations not yet captured in neoclassical utility functions. In this thesis, I will detail results from one of each experimental type, each suited to the context of interest. The natural field experiment in Chapter 2 aims to discern whether there is a role for environmental preferences and cognitive dissonance to play in encouraging individuals to engage in resource-conserving behaviors, and suggests that the latter may be effective in changing the behavior of green consumers. Chapter 3 presents the results of a large-scale framed field experiment comprising all eligible captains in Virgin Atlantic Airways, which tested the impacts of personalized information, tailored targets, and prosocial incentives on captains’ performance of fuel-efficient behaviors. In addition to documenting a substantial Hawthorne effect, we provide intent-to-treat estimates of the three types of feedback to show that tailored targets are the most (cost) effective strategy of those implemented. I introduce a complementary artefactual field experiment in Chapter 4, which allows for detailed scrutiny of captains’ fuel efficiency based on their social preferences as well as preferences and attitudes toward risk and uncertainty. I find that more risk-averse captains are more prone to over-fuel, that prosocial incentives increase captains’ well-being, and that revealed altruism increases responsiveness to prosocial incentives. Finally, Chapter 5 aims to provide insight into the effects of “side deals” in facilitating cooperation on international climate agreements. Using a lab experiment, we find that side deals alter the composition of group contribution to climate change mitigation, eliciting increased effort on the part of players with higher wealth.

This study concerns the longitudinal dispersion of fluid particles which are initially distributed uninformly over one cross section of a uniform, steady, turbulent open channel flow. The primary focus is on developing a method to predict the rate of dispersion in a natural stream. Taylor's method of determining a dispersion coefficient, previously applied to flow in pipes and two-dimensional open channels, is extended to a class of three-dimensional flows which have large width-to-depth ratios, and in which the velocity varies continuously with lateral cross-sectional position. Most natural streams are included. The dispersion coefficient for a natural stream may be predicted from measurements of the channel cross-sectional geometry, the cross-sectional distribution of velocity, and the overall channel shear velocity. Tracer experiments are not required. Large values of the dimensionless dispersion coefficient D/rU* are explained by lateral variations in downstream velocity. In effect, the characteristic length of the cross section is shown to be proportional to the width, rather than the hydraulic radius. The dimensionless dispersion coefficient depends approximately on the square of the width to depth ratio. A numerical program is given which is capable of generating the entire dispersion pattern downstream from an instantaneous point or plane source of pollutant. The program is verified by the theory for two-dimensional flow, and gives results in good agreement with laboratory and field experiments. Both laboratory and field experiments are described. Twenty-one laboratory experiments were conducted: thirteen in two-dimensional flows, over both smooth and roughened bottoms; and eight in three-dimensional flows, formed by adding extreme side roughness to produce lateral velocity variations. Four field experiments were conducted in the Green-Duwamish River, Washington. Both laboratory and flume experiments prove that in three-dimensional flow the dominant mechanism for dispersion is lateral velocity variation. For instance, in one laboratory experiment the dimensionless dispersion coefficient D/rU* (where r is the hydraulic radius and U* the shear velocity) was increased by a factory of ten by roughening the channel banks. In three-dimensional laboratory flow, D/rU* varied from 190 to 640, a typical range for natural streams. For each experiment, the measured dispersion coefficient agreed with that predicted by the extension of Taylor's analysis within a maximum error of 15%. For the Green-Duwamish River, the average experimentally measured dispersion coefficient was within 5% of the prediction.

The aim of this study was to understand the regulatory mechanism of the high diversity of soil living oribatid mites (Acari, Oribatida) which appear to coexist without extensive niche differentiation. I focussed on trophic niche differentiation, perturbation and resource quantity and quality as three putative mechanisms. Two food choice experiments, one stable isotope analysis and two field experiments were conducted. Dark pigmented fungi (‘Dematiacea’) are generally preferred as diet by soil microarthropods, such as collembolans and oribatid mites. I investigated the feeding preferences of ten oribatid mite species among eight ‘Dematiacea’ in a food choice experiment. The investigated oribatid mite species differentially fed on dark pigmented fungal species. Since overall oribatid mites preferred two ‘Dematiacea’ (Alternaria alternata and Ulocladium sp.), I conclude that niche differentiation in oribatid mites in respect to dark pigmented fungi is limited, but nevertheless may contribute to the high diversity of this microarthropod group. Mycorrhizal fungi reach high densities in forest soils and are a potential food resource for oribatid mites. I investigated the feeding preferences of three oribatid mite species among six ectomycorrhizal and one ericoid mycorrhizal fungal species in a food choice experiment. Feeding preferences significantly differed between the oribatid mite species. However, overall, oribatid mites preferred two mycorrhizal species, Hymenoscyphus ericae and Boletus badius. This also supports the hypothesis that trophic niche differentiation in oribatid mites occurs, but appears not to be sufficient to solve the enigma of the large number of oribatid mite species in soil. Trophic niche differentiation of 36 oribatid mite species/taxa from four forests was investigated using stable isotope analysis (15N). The oribatid mite species investigated formed a gradient from phytophagous species over primary and secondary decomposer to predators and scavengers (four trophic levels/feeding guilds). These surprisingly large differences in 15N values of oribatid mite species strongly indicate that oribatid mites occupy different trophic niches in the field. This finding clearly supports the view that trophic niche differentiation is an important mechanism for the maintenance of the high number of oribatid mite species in forest ecosystems. Intermediate disturbances may contribute to the coexistence of large numbers of plant and animal species. Therefore, I investigated the effect of three perturbation levels (single perturbation, perturbation once every two months and once every two weeks) on oribatid mite diversity and density in a field experiment. I hypothesised that the species number of oribatid mites is highest at the intermediate disturbance level (one perturbation every two month). In contrast to this hypothesis, oribatid mite diversity and density continually decreased with increasing perturbation level. These results suggest that the great majority of oribatid mite species are sensitive to disturbances irrespective of intensity and frequency. Therefore, the intermediate disturbance hypothesis presumably does not apply for oribatid mites. The effect of the temporary enhancement of resources of different nutrients (wood, glucose & nitrogen & phosphorous (CNP), pet food, wheat bran) on oribatid mite diversity and density was investigated in a field experiment in the Solling (Germany). I hypothesised that the number and the density of oribatid mite species increase with the amount and quality of resources. The results of this experiment did not support this hypothesis, since the diversity of oribatid mites generally did not respond to the experimental treatments. The density of oribatid mites was slightly higher in the CNP-treatment compared to the pet food treatment. However, this increase likely resulted from indirect effects due to the decrease in earthworm density in the CNP-treatment. The results indicate that the oribatid mite community is not limited by the amount or quality of resources but rather by the burrowing and mixing activity of earthworms. Overall, the results of the present study suggest that the coexistence of the large number of oribatid mites in soil cannot be explained by the presence of intermediate levels of disturbances or the amount and quality of resources but rather by the presence of trophic niche differentiation. The comparison of the results of the laboratory food choice experiments and the field study using stable isotopes indicate that oribatid mites feed on a wide range of substrates (when offered in the laboratory) but occupy rather distinct trophic niches in the field. To understand the factors that form these niches, further studies on the feeding biology of oribatid mites are necessary. In the future, recently established techniques such as the analysis of phospholipid fatty acids and the analysis of gut contents by molecular tools may contribute to the understanding of niche differentiation in oribatid mites.

1. Although the 'Experimental Method' has played a central role in natural scientific investigation, in the field of the social sciences it has remained in a primitive stage. There are many approaches to the problem of experimental methods in sociological research, and marked differences in this respect between German, French and American methodology. (1) German methodology (as, especially, in M. Weber's Verstehende Soziologie or H. Freyer's Soziologie als Wirklichkeitswissenschaft) has emphasized the specific character of sociology and asserted that the essential purpose of sociology can be attained only if the experimental method is excluded from the methods of sociological research. This stand-point may be called the 'essential (ist) ' approach to experimental methods. (2) By contrast, French methodology (as, for example, in E. Durkheim's Les Regles de la Methode Sociologique) has directed attention to the process of logical inference and consequently, following J. S. Mill's system of logic, has claimed that sociological experiment is impossible. (Essentially, Durkheim's 'concomitant method' or 'comparative method' is not experimental.) This standpoint may be called the 'formal logical' approach. (3) Lastly, in American methodology (see, for example, G. Lundberg's Social Research) 'the methods of social research' means 'the techniques of gathering data' and methodology begins and ends with the consideration of methods of research and has thus been largely concerned with the technical difficulties of sociological experiment. This may be called the 'technical' approach. 2. The origin of these different standpoints may be traced back to the traditional character of sociology in these countries and to the peculiar nature of their social structures, but, at all events, these have been the main barriers to experimental sociology. What, then, is experiment ? An experiment consists of two elements : the 'verification of hypotheses' and the 'creation of experimental conditions'. The former is the theoretical aspect and the latter the practical aspect. If we neglect either one we shall fail not only to grasp the essential nature of experiment (as, for example, did E. Greenwood, who neglected the practical aspect and included what he calls 'ex-post-facto experiment' in the category of experiment) but also to understand the nature of inference from individual instances to generalisations, the advance from correlation to causation, or the practical significance of experiment. From these points of view, we must, I think, include only Goode and Hatt's 'quasi-experiment', French's 'field experiment', Greenwood's 'projective experiment' and 'stochastical experiment', in the category of experiment proper, and must exclude from it 'natural experiments' ex-post-facto experiment', 'trial and error experiment' and 'controlled observation study. (These are preliminary stages to experiment itself.) 3. The aim of experimental procedure is the determination of geno-typical phenomena or relationships ; the discovery of 'laws'. If such 'laws' can be discovered they will not only influence sociological concepts and theories, they will bring sociology itself out of the stage of verstehen or 'interpretation' to that of 'application'. For the 'futility' of sociological studies depends not only on their purpose, but also on the character of traditional sociological theories and the type of 'laws' they have been concerned to establish.

Grazer control of periphyton biomass has been addressed in numerous experimental studies in all kinds of aquatic habitats. In this meta-analysis, the results of 865 experiments are quantitatively synthesized in order to address the following questions: (i) Do lotic, lentic, and marine ecosystems differ in their degree of grazer control of periphyton biomass? (ii) Which environmental variables affect the degree of grazer control? (iii) How much does the result of these experiments depend on facets of experimental design? Across all ecosystems, the grazers removed on average 59% of the periphyton biomass, with grazing being significantly stronger for laboratory (65%) than for field (56%) experiments. Neither field nor lab experiments showed a significant difference among lotic, lentic, and coastal habitats. Among different taxonomic consumer groups, crustaceans (amphipods and isopods) and trichopteran larvae removed the highest proportion of periphyton biomass. Grazer effects increased with increasing algal biomass, with decreasing resource availability and with increasing temperature, especially in field experiments. Grazer effects also increased with increasing total grazer biomass in field experiments but showed the opposite trend in lab experiments, indicating a tendency toward overcrowded lab experiments. Other aspects of experimental design, such as cage type, size, and duration of the study, strongly affected the outcome of the experiments, suggesting that much care has to be placed on the choice of experimental design.

The impacts of lateral movement of soil organic carbon (SOC) by soil erosion on global carbon (C) cycling and climate change have been the subject of a controversial debate for decades. Because of the limited availability of data on SOC erosion history, the effects of erosion on CO2 emissions have mostly been calculated by determining SOC inventories at sites of erosion and comparing against depositional sites. The use of SOC inventories to calculate C fluxes relies on the assumption that sediment properties are temporally and spatially stable during erosion events. However, on eroded lands, it always involves a temporal-dynamic pattern of SOC content, as well as a spatial enrichment and/or depletion of SOC in sediment that differs from original soils. Therefore, the approach of using SOC inventories at the slope-scale to back-calculate C fluxes caused by erosion would result in a biased assessment. Improving our assessment of soil erosion and its impact on C cycling thus requires a better understanding of the behavior of eroded SOC during transport and deposition across agricultural landscapes.
\nIn a given water layer, the transport distance of eroded sediment is mainly determined by particle settling velocity. Settling velocity distribution, calculated based on the diameter of dispersed mineral grains, has been used in some erosion models to predict the redistribution of sediment and associated SOC across landscapes. However, most eroded particles are transported in the form of aggregates rather than individual mineral grains. Aggregation dramatically increases the settling velocity of individual mineral grains that are incorporated into aggregates, as well as the transport distance of associated SOC. Consequently, the uncertainties of calculating the lateral redistribution of sediment and associated SOC may further lead to a biased estimate of the vertical C released from eroded SOC during redistribution. Therefore, identifying the settling velocity of natural aggregated-sediment represents an essential step if the redistribution of eroded SOC, as well as further assessing the potential CO2 mineralization, is to be more accurately modeled.
\nSeveral laboratory-based studies conducted on dry-sieved aggregates have examined the transport fate of aggregated sediment and associated SOC based on settling velocity. However, the erodibility of the soil in the field is more temporally and spatially variable due to the impacts of tillage, rainfall, wetting-drying cycles, freezing, and biological effects. For example, rainfall kinetic energy will affect the breakdown of aggregates and the development of crust. It is not entirely clear whether changes in natural surface conditions could impact on the characteristics of sediment and thereby diminish the effect of aggregation on the fate of eroded SOC. Moreover, from the perspective of parametrizing erosion models, it would require a large amount of accurate settling velocity data from a wide range of soils in order to cover the broad spatial heterogeneity that is inherent during soil development. Identifying the settling velocity distribution based on laboratory or field tests with flumes, even if well-designed, are both far too much work to test all soils over a sufficiently wide range of rainfall conditions. Therefore, it is vital to develop a simple proxy to generate quasi-natural sediment in a time and labor-saving manner, and to further identify accurate settling information of sediment that could be incorporated into erosion models.
\nTo address the above knowledge gaps, four objectives were identified in this study. They are: 1) to quantitatively identify the potential fate of SOC eroded from a natural crusted soil surface and further compare the observations with that based on dry-sieved aggregates in the laboratory; 2) to investigate the sensitivity of the sediment settling behavior to increased kinetic energy during a series of rainfall events and thereafter examine the effect of aggregation on the quality of eroded SOC; 3) to develop a simple but efficient proxy method to generate natural or quasi-natural sediment; and 4) to evaluate the feasibility and sensitivity of such a proxy method. In this study, a series of experiments were conducted to attain those four objectives: Field Experiments 1&2 involved investigating the effect of a natural crusted soil surface on SOC transport and mineralization; Laboratory Experiments 1&2 involved developing an approach to identify the settling velocity of quasi-natural sediment.
\nIn Field Experiments 1&2, short term wind driven storms simulated with a modified portable wind and rainfall simulator (PWRS) were conducted on a natural crusted soil surface after harvesting in the village of Witterswil, in northwest Switzerland. The collected sediment was fractionated with a settling tube according to their respective settling velocities. The sediment mass, SOC concentration and cumulative CO2 emission of each fraction were measured. The results show: 1) 53% of eroded sediment and 62% of eroded SOC would potentially deposit across landscapes. This is six times and three times higher compared to that implied by mineral grains, respectively; 2) the underestimation of eroded SOC deposited across landscapes can mainly be attributed to underestimating mineral-associated organic carbon (MOC); 3) the preferential deposition of SOC-rich fast-settling sediment leads to a higher SOC stock than that at a comparable depth of non-eroded original soil. This would potentially release approximately 50% more CO2 than the same layer of the non-eroded original soil; 4) about 15% of SOC could be mineralized during the redistribution process of sediment, especially from the silt and clay fractions; 5) the settling velocity distributions of eroded sediment, as well as the SOC concentration and cumulative mineralization of each fraction, did not change during a series of rainfall events, suggesting settling velocity distribution of eroded SOC could be regarded as a stable parameter during redistribution. The results obtained from Field Experiments 1&2 confirm in general the conclusions drawn from the laboratory-based work and thus demonstrate that aggregation can affect the redistribution of sediment associated SOC under field conditions, including an increase in CO2 emissions compared to bulk soil. This illustrates the need to integrate the effect of aggregation on SOC redistribution into soil erosion models, which could help precisely distinguish SOC potentially re-deposited across landscapes from that possibly transported to aquatic systems, and further assess the impacts on global C cycling. In order to capture the effect of aggregation on settling behavior and thus the redistribution of eroded sediment, in Laboratory Experiments 1&2, a combined Raindrop Aggregate Destruction Device-Settling Tube (RADD-ST) proxy was developed to effectively simulate aggregate breakdown under raindrop impact, and further identify the settling velocity of aggregated sediment and associated SOC. The results show: 1) for an aggregated soil, applying dispersed mineral grain size distribution, rather than actual aggregate distribution, to soil erosion models would lead to an underestimate of deposition of eroded sediment and SOC across landscapes; 2) the RADD-ST designed in this study effectively captures the effects of raindrop impact on aggregate destruction and is thus able to simulate the quasi-natural sediment spatial redistribution; 3) the combined RADD-ST approach is adequately sensitive to measure actual settling velocities of differently aggregated soils; 4) this combined RADD-ST approach provides an effective tool to improve the parameterization of settling velocity input for erosion models. 
\nOverall, the results observed from this study confirm that aggregation effects, even on crusted soil surfaces, considerably reduce the likely transport distance of eroded SOC. It thus potentially skews the re-deposition of SOC-rich coarse sediment fractions towards terrestrial systems and contributes additional CO2 to the atmosphere. Therefore, current erosion models urgently need to be optimized by the development of a computable parameter integrating aggregated sediment settling velocity and the associated SOC distribution. The RADD-ST approach developed in this study has the potential to provide actual settling information generated under relatively simple simulated rainfall conditions to optimize the parametrization of sediment behavior and quality in erosion models. If further extrapolated appropriately to a specific erosion scenario, the RADD-ST derived sediment quality parameters can also help improve our understanding of sediment movement through watersheds and thus contribute to reaching consensus on the role of erosion on C cycling.
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Field experiments (2000-2002) were carried out to determine the effect of eyespot caused by Oculimacula yallundae and O. acuformis (formerly known as W-type and R-type, respectively) on yield or lodging resistance of winter wheat and to identify any differences in the development of the two pathogens throughout the season. A field experiment on artificially inoculated wheat was designed to clarify the effects of the two Oculimacula spp. on plant characteristics associated with lodging resistance and on yield of individual shoots and whole crop. Overall yield of winter wheat in the absence of lodging was reduced by 11% and 6% by eyespot caused by O. acuformis and O. yallundae respectively. Both species reduced the stem safety factor associated with lodging resistance, indicating their ability to cause lodging in winter wheat by reducing stem-bending strength. The ability of O. acuformis to cause significant yield loss was demonstrated in a series of fungicide efficacy experiments in early-drilled winter wheat. Oculimacula acuformis developed more and caused greater yield loss in the first winter wheat in which other stem-base pathogens were absent in the early growth stages of the crop. Fungicide mixtures containing cyprodinil were consistently more effective in controlling eyespot caused by O. acuformis in first, second and third winter wheat crops. Positive relationships were observed between DNA concentrations of O. acuformis, O. yallundae and M. nivale throughout the growing season, indicating that these species co-existed within the crop. While the DNA of M. nivale consistently increased more up to GS 39 in different field experiments, DNA of Oculimacula spp. increased at different times in the growing season and these increases were sometimes associated with the relative quantities of DNA of M. nivale at the early growth stages.