German farmers’ intention to use autonomous field robots: a PLS-analysis

Autonomous field robots are a promising technology for solving several problems in agriculture, as they are electrical driven, can control weeds single-plant based mechanically or with microdoses of pesticides and exert less ground pressure on the field. Whether such robots will be applied on a large scale in German agriculture depends on various parameters. Therefore, the factors influencing the behavioural intention of farmers with respect to their future adoption of autonomous field robots were investigated. The analysis applies a structural equation model based on an extended version of the Unified Theory of Acceptance and Use of Technology. The dataset, collected in 2019, consists of 500 German farmers. The results reveal significantly positive effects of farmers’ expected performance, social influence and trust as well as significantly negative effects of farmers’ effort expectancy and anxiety on the behavioural intention to use autonomous field robots. Additionally, moderating effects of age on the relationship of individual constructs to the behavioural intent to use robots could be confirmed. The results provide important information for various stakeholders. Robot suppliers should better inform farmers about the performance of their products, for instance by involving farmers in the development process of the robots. The ecological benefits attributed to field robots could meet public expectations and should be better communicated to address farmers’ social influence on the behavioural intention to use the robots. Policymakers could try to create better framework conditions, for example by establishing a stable legal situation for autonomous systems or promote its use.

     

Historical Contaminated Sediments and Soils at the River Basin Scale

Background, Aims, and Scope  

Data from the Elbe River and its tributaries indicate, despite extensive improvement in water quality during the last 15 years, that the respective sediment situation of many priority pollutants has not reached an acceptable level. For the coming decades, risks for downstream sites and stakeholders will persist, mainly due to secondary sources originating from historical pollution of soils and sediments in the catchment area. In practice, a catchment-wide assessment of historical contaminated soil and sediment should apply a three-step approach: (i) Identification of substances of concern (s.o.c.) and their classification into ’hazard classes of compounds’; (ii) identification of areas of concern (a.o.c.) and their classification into ‘hazard classes of sites’; (iii) identification of areas of risk (a.o.r.) and their assessment relative to each other with regard to the probability of polluting the sediments in the downstream reaches. The conversion of this concept has to consider the underlying philosophy of the EU Water Framework Directive, particularly with respect to the analysis and monitoring of priority substances in solid matrices. However, major deficiencies are still in the assessment and prognosis of resuspension processes, and potential approaches to fill this gap are described both in theory and from examples of the Elbe River.     

Observation of X-ray lines from a gamma-ray burst (GRB991216): evidence of moving ejecta from the progenitor

We report on the discovery of two emission features observed in the x-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 December 1999 by the Chandra X-ray Observatory. These features are identified with the Ly(alpha) line and the narrow recombination continuum by hydrogenic ions of iron at a redshift z = 1.00 +/- 0.02, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, a quantity of iron approximately 0.01 of the mass of the sun at a velocity approximately 0.1 of the speed of light, probably by a supernova explosion.     

Some computer-based developments in sociology

Sociological data sets are now being computer analyzed by means of a variety of sophisticated procedures, to produce results that reflect the intricacy of social life. Computers also are being used to conduct simulations of social processes based on mathematical models and to collect the data for analysis. Portable computers allow computing power to be used in field studies, and the relatively low cost of computers is expanding the range of sociologists who use them. While opening up new research opportunities, computers also bring certain problems for social researchers and teachers.     

The need for new concepts in risk management of sediments historical developments, future perspectives and new approaches

Being part of a highly dynamic system, contaminated sediments are especially in need of an integrated management approach. Due to change in importance from source to diffuse pollution and the variety of chemical substances in the environ-ment, different scientific fields need to cooperate and incorpo-rate their data in a common risk assessment scheme. Public perception of risk that is associated with sediments and with chemical data is low while the acceptance of ecotoxico-logical data with decision makers is often missing. A growing demand of the public to be involved in decision processes and informed about environmental problems demands a change of methods and concepts in the future. Necessity of an integration of risk assessment and management procedures has been suggested in order to increase the efficiency of the process and the early involvement of public concern. As the confidence in experts’ opinions decreases, a strong need for communication with and transparency for all involved parties arises.     

Influence of Soil Organic Carbon on Acute and Chronic Toxicity of Plant Protection Products to Poecilus cupreus (Coleoptera, Carabidae) Larvae (4 pp)

Background, Aims and Scope   Variability of results from terrestrial ecotoxicological tests with arthropods demonstrate the importance of understanding the impact of soil composition has on the bioavailability of pollutants. Beside other soil parameters, the organic C content is known to be relevant to bioavailability. The aim of the present paper was to detect lethal and sublethal effects of plant protection products on soil-dwelling larvae of the carabid beetle Poecilus cupreus under different concentrations of soil organic C. The study was based on a familiar laboratory test method. Methods   Larvae of the laboratory-reared carabid beetle P. cupreus were exposed to dimethoate in a standardised soil (Lufa 2.1), modified to four different concentrations of organic C between 0.5 to 2.8% by admixing peat. Dimethoate was applied to the soil surface at rates ranging between 40 and 250 g a.i./ha. Some larvae were exposed to an application of water to act as a control. One larva was released per test tube, with at least 20 larvae per treatment group. Effects on mortality and developmental time of the larvae and on the hatching weight of adult beetles were recorded. Dimethoate was selected as the test item because some dose-response data for different soils were already available and because the reproducibility of test results with dimethoate had already been shown in a previous ring test. Results and Discussion   With increasing concentration of organic C in the soil substrate, mortality decreased at all tested rates of dimethoate. Consequently, LC50 values increased from 39 to 107 g a.i./ha with increasing organic C content from 0.5 to 2.8%. The results suggest higher bioavailability of dimethoate with decreasing content of organic C. The replication and magnitude of sublethal effects (hatching weight and developmental time) was insufficient to detect a clear interaction between dimethoate and organic C. Conclusion   The results of the experiment reveal that the concentration of organic C in the soil substrate is influential on the effects and, by association, the toxicity of dimethoate to larvae of P. cupreus. For the interpretation of terrestrial ectotoxicological tests with arthropods, the composition of the substrate has to be taken into account. Recommendations and Outlook   For reliable and reproducible test results, a well-defined and thoroughly controlled composition of the test soil is highly recommended. Test results should be used for risk assessments only after having taken the soil composition, especially the organic C content, into account.     

Modelling riverine habitat for robust redhorse: assessment for reintroduction of an imperilled species

A critical component of a species reintroduction is assessment of contemporary habitat suitability. The robust redhorse, Moxostoma robustum (Cope), is an imperilled catostomid that occupies a restricted range in the south‐eastern USA. A remnant population persists downstream of Blewett Falls Dam, the terminal dam in the Pee Dee River, North Carolina. Reintroduction upstream of Blewett Falls Dam may promote long‐term survival of this population. Tillery Dam is the next hydroelectric facility upstream, which includes a 30 rkm lotic reach. Habitat suitability indices developed in the Pee Dee River were applied to model suitable habitat for proposed minimum flows downstream of Tillery Dam. Modelling results indicate that the Tillery reach provides suitable robust redhorse habitat, with spawning habitat more abundant than non‐spawning habitat. Sensitivity analyses suggested that suitable water depth and substrate were limiting physical habitat variables. These results can inform decisions on flow regulation and guide planning for reintroduction of the robust redhorse and other species.