Lecture – INVESTIGATION ON EFFECT OF CO2 ON PYROLYSIS OF SPRUCE WOOD AND BARK
Liang Wang, Alba Dieguez-Alonso, Maria Nicte Polanco Olsen, ...
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Many greenkeepers and authorities are concerned about the environmental risks resulting from pesticide use on golf courses. We studied leaching and surface runoff of fungicides and metabolites during two winter seasons after fall application of boscalid, pyraclostrobin, prothioconazole, trifloxystrobin and fludioxonil in field lysimeters at NIBIO Landvik, Norway. The applications were made on creeping bentgrass greens (5% slope) that had been established from seed or sod (26 mm mat) on USGA‐spec. root zones amended with Sphagnum peat or garden compost, both with 0.3‐0.4% organic carbon in the root zone. The proportions of the winter precipitation recovered as surface and drainage water varied from 3 and 91% in 2016‐17 to 33 and 55% in 2017‐18 due to differences in soil freezing, rainfall intensity and snow and ice cover. Detections of fungicides and their metabolites in drainage water were mostly within the Environmental Risk Limits (ERLs) for aquatic organisms. In contrast, concentrations in surface runoff exceeded ERLs by up to 1000 times. Greens established from sod usually had higher fungicide losses in surface runoff but lower losses in drainage water than greens established from seed. Presumably because of higher microbial activity and a higher pH that made prothioconazole‐desthio more polar, fungicide and metabolite losses in drainage water were usually higher from greens containing compost that from greens containing peat. Leaching of fungicides and metabolites occurred even from frozen greens. The results are discussed in a practical context aiming for reduced environmental risks from spraying fungicides against turfgrass winter diseases.
Lecture – Long-term monitoring of vegetation and hydrology in headwater catchments and the difficulties to embrace data-oriented and process-oriented approaches
Michael Hauhs, Holger Lange, Henning Meesenburg
In the Bramke valley (western Harz mountains, North Germany), three forested headwater catchments have been monitored since decades. A broad range of observables relevant to forestry, hydrology, hydrochemistry and ecosystem research allows to compare different approaches to environmental monitoring; each of them has its own set of relevant observables. The basic temporal resolution is daily for hydrometeorology and bi-weekly for streamwater chemistry; standing biomass of the Norway spruce stands is measured every couple of years. Tree growth (site index) has changed between and within rotation periods (of up to 129 years); changes in soil nutrient pools are typical variables used to explain this nonstationary forest growth when the spatial-temporal scales match. In hydrology, transport mechanisms of water and solutes through catchment soils are used to model and predict runoff and its chemistry. Given the homogeneity of the area in terms of geology, soils and topography as well as climate, differences between the catchments in the Bramke valley are mostly related to forestry variables. The catchments exhibit long-term changes and spatial gradients related to atmospheric deposition, management and changing climate. After providing a short multivariate summary of the dataset, we present several nonlinear metrics suitable to detect and quantify subtle changes and to describe different behavior, both between different variables from the same catchment, as well as for the same variable across catchments. Soil water potential and solution chemistry are further links between forestry and hydrology. However, at Lange Bramke, similar to other catchment studies, the evaluation of these data sets has not converged to a consistent, realistic model at the catchment scale. We hypothesize that this lack of model integration is due to theoretical rather than technical limits. A possible representation of these limits might be phrased in a category theory approach. How to cite: Hauhs, M., Meesenburg, H., and Lange, H.: Long-term monitoring of vegetation and hydrology in headwater catchments and the difficulties to embrace data-oriented and process-oriented approaches, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7684, https://doi.org/10.5194/egusphere-egu21-7684, 2021.
Migration of ungulates (hooved mammals) is a fundamental ecological process that promotes abundant herds, whose effects cascade up and down terrestrial food webs. Migratory ungulates provide the prey base that maintains large carnivore and scavenger populations and underpins terrestrial biodiversity (fig. S1). When ungulates move in large aggregations, their hooves, feces, and urine create conditions that facilitate distinct biotic communities. The migrations of ungulates have sustained humans for thousands of years, forming tight cultural links among Indigenous people and local communities. Yet ungulate migrations are disappearing at an alarming rate (1). Efforts by wildlife managers and conservationists are thwarted by a singular challenge: Most ungulate migrations have never been mapped in sufficient detail to guide effective conservation. Without a strategic and collaborative effort, many of the world’s great migrations will continue to be truncated, severed, or lost in the coming decades. Fortunately, a combination of animal tracking datasets, historical records, and local and Indigenous knowledge can form the basis for a global atlas of migrations, designed to support conservation action and policy at local, national, and international levels.
Purpose The study measures the technology gap and performance of the Norwegian dairy farms accounting for farm heterogeneity. Design/methodology/approach The analysis was based on a meta-frontier and unbalanced farm-level panel data for 1991–2014 from 417 Norwegian farms specialized in dairy production in five regions of Norway. Findings The result of the analysis provides empirical evidence of regional differences in technical efficiencies, technological gap ratios (TGRs), and input use. Consequently, the paper provides some insights into policies to increase the efficiency of dairy production in the country across all regions.
Lecture – Microplastics in Norwegian agricultural soils via biogas digestate application and plastic mulching
The presentation covers some of the work we are doing on two important sources of plastics and microplastics in Norwegian agricultural soils. The first is through soil amendment with biogas digestate. The second is through plastic mulching with biodegradable plastic film.
Lecture – Mismatch between the optimal ages for ecosystem productivity and net CO2 sequestration in Norway spruce forests
Junbin Zhao, Holger Lange, Helge Meissner
Forests have climate change mitigation potential since they sequester carbon. However, their carbon sink strength might depend on management. As a result of the balance between CO2 uptake and emission, forest net ecosystem exchange (NEE) reaches optimal values (maximum sink strength) at young stand ages, followed by a gradual NEE decline over many years. Traditionally, this peak of NEE is believed to be concurrent with the peak of primary production (e.g., gross primary production, GPP); however, in theory, this concurrence may potentially vary depending on tree species, site conditions and the patterns of ecosystem respiration (Reco). In this study, we used eddy-covariance (EC)-based CO2 flux measurements from 8 forest sites that are dominated by Norway spruce (Picea abies L.) and built machine learning models to find the optimal age of ecosystem productivity and that of CO2 sequestration. We found that the net CO2 uptake of Norway spruce forests peaked at ages of 30-40 yrs. Surprisingly, this NEE peak did not overlap with the peak of GPP, which appeared later at ages of 60-90 yrs. The mismatch between NEE and GPP was a result of the Reco increase that lagged behind the GPP increase associated with the tree growth at early age. Moreover, we also found that newly planted Norway spruce stands had a high probability (up to 90%) of being a C source in the first year, while, at an age as young as 5 yrs, they were likely to be a sink already. Further, using common climate change scenarios, our model results suggest that net CO2 uptake of Norway spruce forests will increase under the future climate with young stands in the high latitude areas being more beneficial. Overall, the results suggest that forest management practices should consider NEE and forest productivity separately and harvests should be performed only after the optimal ages of both the CO2 sequestration and productivity to gain full ecological and economic benefits. How to cite: Zhao, J., Lange, H., and Meissner, H.: Mismatch between the optimal ages for ecosystem productivity and net CO2 sequestration in Norway spruce forests, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4257, https://doi.org/10.5194/egusphere-egu21-4257, 2021.
Mixed-species stands have been found to be more productive than would be expected from the performance of their component species in monocultures due to facilitation and complementarity between species, although these interactions depend on the combination of species present. Our study focuses on monospecific and mixed-species stands of Scots pine and Norway spruce using 20 triplets established in nine countries along a climatic gradient across Europe. Differences in mean tree and stand characteristics, productivity and stand structure were assessed. Basal area increment in mixed stands was 8% higher than expected while volume increment was only 2% greater. Scots pine trees growing in mixed-species stands showed 11% larger quadratic mean diameter, 7% larger dominant diameter, 17% higher basal area and 25% higher stand volume than trees growing in monospecific stands. Norway spruce showed only a non-significant tendency to lower mean values of diameters, heights, basal area, as well standing volume in mixtures than monocultures. Stand structure indices differed between mixed stands and monocultures of Scots pine showing a greater stratification in mixed-species stands. Furthermore, the studied morphological traits showed little variability for trees growing in monospecific stands, except for diameter at breast height, crown length and crown length ratio. For trees growing in mixed stands, all the morphological traits of the trees were identified as different. Some of these morphological traits were associated with relative productivity. Nevertheless, relative productivity in mixed-species stands was not related to site conditions.