Showing papers by "Swedish University of Agricultural Sciences published in 2022"

Optimum growth temperature declines with body size within fish species

Abstract: According to the temperature-size rule, warming of aquatic ecosystems is generally predicted to increase individual growth rates but reduce asymptotic body sizes of ectotherms. However, we lack a comprehensive understanding of how growth and key processes affecting it, such as consumption and metabolism, depend on both temperature and body mass within species. This limits our ability to inform growth models, link experimental data to observed growth patterns, and advance mechanistic food web models. To examine the combined effects of body size and temperature on individual growth, as well as the link between maximum consumption, metabolism, and body growth, we conducted a systematic review and compiled experimental data on fishes from 52 studies that combined body mass and temperature treatments. By fitting hierarchical models accounting for variation between species, we estimated how maximum consumption and metabolic rate scale jointly with temperature and body mass within species. We found that whole-organism maximum consumption increases more slowly with body mass than metabolism, and is unimodal over the full temperature range, which leads to the prediction that optimum growth temperatures decline with body size. Using an independent dataset, we confirmed this negative relationship between optimum growth temperature and body size. Small individuals of a given population may, therefore, exhibit increased growth with initial warming, whereas larger conspecifics could be the first to experience negative impacts of warming on growth. These findings help advance mechanistic models of individual growth and food web dynamics and improve our understanding of how climate warming affects the growth and size structure of aquatic ectotherms.

Whose transformation is this? Unpacking the ‘apparatus of capture’ in Sweden's bioeconomy

Abstract: This study investigates how and by whom the Swedish (forest) bioeconomy has been shaped so far. We unpack emerging bioeconomies as discursive constructs and use the ‘apparatus of capture’ as a conceptual framework to understand and rethink the Swedish bioeconomy. Based on analysis of empirical data from multiple sources (e.g., online surveys, in-depth interviews, participatory observations), we identify a closed bioeconomy network structure that includes forest industries, major forest owner associations, regional councils and research institutes/universities. The network (re)produces three key storylines that appeal to the majority of parties in the national parliament, defines the boundaries of relevant expertise, and discredits environmental regulation and expertise. Through these storylines the Swedish bioeconomy is turned into an issue of innovation governance, which blurs the boundaries between public and private interests in forests. To counteract future capture, different types of knowledges and forest perspectives need further exploration in Swedish bioeconomy and forest governance.

Competing Transport Futures: Tensions between Imaginaries of Electrification and Biogas Fuel in Sweden:

Abstract: The choice of fuels has frequently been at the center of debates about how a future low-carbon mobility system can be achieved. This paper introduces two visions of biogas fuels and electricity usi...

Biodiversity of the Genus Trichoderma in the Rhizosphere of Coffee (Coffea arabica) Plants in Ethiopia and Their Potential Use in Biocontrol of Coffee Wilt Disease

Abstract: The present study investigated the distribution status and biodiversity of Trichoderma species surveyed from coffee rhizosphere soil samples from Ethiopia and their potential for biocontrol of coffee wilt disease (CWD) caused by Fusarium xylarioides. Trichoderma isolates were identified based on molecular approaches and morphological characteristics followed by biodiversity analysis using different biodiversity indices. The antagonistic potential of Trichoderma isolates was evaluated against F. xylarioides using the dual confrontation technique and agar diffusion bioassays. A relatively high diversity of species was observed, including 16 taxa and 11 undescribed isolates. Trichoderma asperellum, T. asperelloides and T. longibrachiatum were classified as abundant species, with dominance (Y) values of 0.062, 0.056 and 0.034, respectively. Trichoderma asperellum was the most abundant species (comprising 39.6% of all isolates) in all investigated coffee ecosystems. Shannon’s biodiversity index (H), the evenness (E), Simpson’s biodiversity index (D) and the abundance index (J) were calculated for each coffee ecosystem, revealing that species diversity and evenness were highest in the Jimma zone (H = 1.97, E = 0.76, D = 0.91, J = 2.73). The average diversity values for Trichoderma species originating from the coffee ecosystem were H = 1.77, D = 0.7, E = 0.75 and J = 2.4. In vitro confrontation experiments revealed that T. asperellum AU131 and T. longibrachiatum AU158 reduced the mycelial growth of F. xylarioides by over 80%. The potential use of these Trichoderma species for disease management of F. xylarioides and to reduce its impact on coffee cultivation is discussed in relation to Ethiopia’s ongoing coffee wilt disease crisis.

Testing interventions to reduce food waste in school catering

Abstract: Food waste is a problem that needs to be addressed to achieve sustainable development. There is a need for interventions that can reduce food waste, including in organisations already aware of the food waste problem. Swedish school canteens have experience of food waste reduction, but need tools to achieve further reductions. This study tested four interventions (tasting spoons, awareness campaign, a plate waste tracker and a guest forecasting tool) designed to reduce food waste in school canteens. Each intervention was introduced in two school canteens, while seven school canteens acted as a reference group. The interventions were compared with baseline food waste before the intervention and with the reference group. All interventions reduced total food waste (by 6 to 44 g/guest) compared with the baseline, but the reference group also reduced its food waste. The awareness campaign reduced plate waste most, by 13 g per portion, which was 6 g/portion more than the plate waste reduction in the reference group. The forecasting and plate waste tracker interventions reduced serving waste most, by 34 and 38 g/portion, compared with 11 g/portion in the reference group. Some interventions also had an effect on waste fractions they were not designed to target, affecting the total waste by shifting the waste. Interventions should always be seen in a context and be implemented in combinations that increase overall sustainability. Thus forecasting is an effective way to reduce serving waste, plate waste tracker and awareness campaign are effective tools to reduce plate waste in school canteens.

Soil Compaction Due to Agricultural Field Traffic: An Overview of Current Knowledge and Techniques for Compaction Quantification and Mapping

Abstract: Soil compaction caused by agricultural vehicles is a global problem affecting a considerable proportion of all arable land and causing tremendous costs to farmers and society. Soil compaction reduces soil porosity and modifies pore geometry, thereby adversely affecting key soil ecological, hydrological and agronomic functions. This chapter provides an overview of current knowledge on stress propagation, soil compressive behaviour, impacts of soil compaction on soil properties and functions and recovery of soil structure after compaction, and discusses the costs of soil compaction. We provide an overview of non-destructive measurement techniques and approaches for improving description and quantification of soil compaction at spatial scales from the soil pore to the field. Finally, we discuss sensor systems for on-the-go mapping of soil compaction and provide a perspective for future development of sensor fusions for soil compaction identification and mapping.

Sensitivity of soil respiration rate with respect to temperature, moisture and oxygen under freezing and thawing

Abstract: In alpine environments, the decomposition rate of soil organic carbon (SOC) is controlled by several biotic and abiotic factors, which mostly change simultaneously and often lead to freezing and thawing cycles. However, it is highly uncertain whether the temperature sensitivity of decomposition around the freezing point of water is similar as in higher temperature ranges. In this study, we conducted a full factorial incubation experiment using soil samples from a grassland site in the Tibetan Plateau. A manipulative freeze-thaw cycle was imposed to these soils by continuously changing temperature, from −5 to 10 °C. Additional treatments included 4 levels of soil moisture at 15, 30, 60 and 90% of water-filled pore space (WFPS), and two levels of O2 concentration at 0 and 20%. We fitted the Arrhenius equation into the flux data to estimate the activation energy (Ea) and base flux rate (A) for each treatment level. Then, we predicted the dependence and sensitivity of decomposition rate (k) by implementing the Dual Arrhenius and Michaelis-Menten (DAMM) model using a Bayesian optimization approach. While soil temperature had the strongest control on SOC decomposition rate at all soil moisture and O2 levels, its intrinsic temperature sensitivity (Δk/ΔT) remained nearly constant across the entire temperature range except around 0 °C. We found that Ea was higher in nearly dry or anoxic conditions, suggesting that in these extremes more energy is required for microbial activity to take place. These intrinsic sensitivities revealed that temperature (energy) is the main factor that limits decomposition in cold environments provided that moisture and oxygen are sufficiently available. Intrinsic sensitivities with respect to soil moisture and oxygen concentration were only relevant at very narrow ranges, when soils were almost dry or partially anoxic, and small changes within these narrow ranges may lead to very strong changes in decomposition rates.