Mineralization of vegetable oils used for thermal weed control in arable soils

Hot vegetable oil can be used for weed control as an alternative to the use of herbicides. We analysed the temporal development of vegetable oil mineralization in soil and tested the role of nutrient supply on oil mineralization. Further, we investigated the effect of oil application on mineralization of native soil organic carbon (SOC), i.e. the priming effect. In a laboratory experiment, three oil dosages (0.1, 1.0 and 3.0ml per 35g soil) were applied to three arable soils and soil respiration was measured hourly. Both a C3-sunflower oil and a C4-corn oil were used in order to differentiate oil-derived CO2 from SOC-derived CO2. The results revealed that after 42days of incubation, 9.6 to 39.7% of the applied oil was mineralized which, however, also primed the mineralization of SOC by a factor of 2.2 to 4.2. The higher the applied oil amount, the lower was the percentage of oil-C mineralization, but the higher was the priming effect. The addition of fertilizer (0.29mgNg(-1) soil and 0.048mgPg(-1) soil) increased oil-C mineralization to 39.9 to 50.9%. We conclude that oil can temporarily accumulate in soil, especially in case of low nutrient supply. As the addition of oil stimulates SOC mineralization, a decrease of native SOC stocks may occur, which needs further quantification in long-term field experiments.Peer reviewe

Similar vegetation-geomorphic disturbance feedbacks shape unstable glacier forelands across mountain regions

Abstract Glacier forelands are among the most rapidly changing landscapes on Earth. Stable ground is rare as geomorphic processes move sediments across large areas of glacier forelands for decades to centuries following glacier retreat. Yet, most ecological studies sample exclusively on stable terrain to fulfill chronosequence criteria, thus missing potential feedbacks between geomorphic disturbances and vegetation colonization. By influencing vegetation and soil development, such vegetation-geomorphic disturbance feedbacks could be crucial to understand glacier foreland ecosystem development in a changing climate. We surveyed vegetation and environmental properties, including geomorphic disturbance intensities, in 105 plots located on both stable and unstable moraine terrain in two geomorphologically active glacier forelands in New Zealand and Switzerland. Our plot data showed that geomorphic disturbance intensities permanently changed from high/moderate to low/stable when vegetation reached cover values of around 40%. Around this cover value, species with response and effect traits adapted to geomorphic disturbances dominated. This suggests that such species can act as ?biogeomorphic? ecosystem engineers that stabilize ground through positive feedback loops. Across floristic regions, biogeomorphic ecosystem engineer traits creating ground stabilization, such as mat growth and association with mycorrhiza, are remarkably similar. Nonmetric multidimensional scaling revealed a linked sequence of decreasing geomorphic disturbance intensities and changing species composition from pioneer to late successional species. We interpret this linked geomorphic disturbance-vegetation succession sequence as ?biogeomorphic succession,? a common successional pathway in unstable river and coastal ecosystems across the world. Soil and vegetation development were related to this sequence and only advanced once biogeomorphic ecosystem engineer species covered 40%?45% of a plot, indicating a crucial role of biogeomorphic ecosystem engineer stabilization. Different topoclimatic conditions could explain variance in biogeomorphic succession timescales and ecosystem engineer root traits between the glacier forelands. As glacier foreland ground is widely unstable, we propose to consider glacier forelands as ?biogeomorphic ecosystems? in which ecosystem structure and function are shaped by geomorphic disturbances and their feedbacks with adapted plant species, similar to rivers and coasts

Portugiesische Hamburger und Hamburger Portugiesen

Zu Beginn des 17. Jahrhunderts ließ sich eine Gruppe portugiesischer Juden in Hamburg nieder. Sie spielte eine wichtige Rolle im Geschäftsleben der Stadt und tat sich insbesondere im Handel mit Portugal hervor. Etwa zur selben Zeit gingen annähernd ebenso viele hamburgische Kaufleute nach Portugal, um von dort aus Handel mit ihrer Heimatstadt zu treiben. Aufgrund ihrer unterschiedlichen Migrationsbedingungen und der gegensätzlichen Haltung der aufnehmenden Obrigkeiten in Hamburg und Portugal wiesen die beiden Gruppen nicht nur ein stark divergierendes Sozialverhalten auf, sondern verfolgten auch unterschiedliche Handelsstrategien. Die portugiesischen Kaufleute in Hamburg waren hinsichtlich ihrer sozialen, politischen und wirtschaftlichen Möglichkeiten erheblich benachteiligt und blieben eine segregierte Gruppe. Die hamburgischen Kaufleute in Portugal genossen dagegen eine rechtliche Vorrangstellung und hohes soziales Prestige. Sie integrierten und assimilierten sich relativ schnell und waren wirtschaftlich oft sehr erfolgreich

Clifford-Jacobs Forging Company v. Capital Engineering & (and) Manufacturing Co.: The Continuing Problem within U.C.C. Section 2-207, 16 J. Marshall L. Rev. 589 (1983)

status: accepte

A comprehensive dataset of vegetation states, fluxes of matter and energy, weather, agricultural management, and soil properties from intensively monitored crop sites in western Germany

Data description paperThe development and validation of hydroecological land-surface models to simulate agricultural areas require extensive data on weather, soil properties, agricultural management, and vegetation states and fluxes. However, these comprehensive data are rarely available since measurement, quality control, documentation, and compilation of the different data types are costly in terms of time and money. Here, we present a comprehensive dataset, which was collected at four agricultural sites within the Rur catchment in western Germany in the framework of the Transregional Collaborative Research Centre 32 (TR32) "Patterns in Soil-Vegetation-Atmosphere Systems: Monitoring, Modeling and Data Assimilation". Vegetation-related data comprise fresh and dry biomass (green and brown, predominantly per organ), plant height, green and brown leaf area index, phenological development state, nitrogen and carbon content (overall > 17 000 entries), and masses of harvest residues and regrowth of vegetation after harvest or before planting of the main crop (> 250 entries). Vegetation data including LAI were collected in frequencies of 1 to 3 weeks in the years 2015 until 2017, mostly during overflights of the Sentinel 1 and Radarsat 2 satellites. In addition, fluxes of carbon, energy, and water (> 180 000 half-hourly records) measured using the eddy covariance technique are included. Three flux time series have simultaneous data from two different heights. Data on agricultural management include sowing and harvest dates as well as information on cultivation, fertilization, and agrochemicals (27 management periods). The dataset also includes gap-filled weather data (> 200 000 hourly records) and soil parameters (particle size distributions, carbon and nitrogen content; > 800 records). These data can also be useful for development and validation of remote-sensing products. The dataset is hosted at the TR32 database (https://www.tr32db.uni-koeln.de/data.php?dataID=1889, last access: 29 September 2020) and has the DOI https://doi.org/10.5880/TR32DB.39 (Reichenau et al., 2020).Peer reviewe

Applied research note : biomonitoring of mycotoxins in blood serum and feed to assess exposure of broiler chickens

Because European maximum guidance values of mycotoxins are only available for feed, mycotoxin exposure in animals is mainly monitored by feed analysis. However, proper sample collection is needed to ensure reliable results because of uneven distributions and disproportional spread of mycotoxins in feed which can hamper the evaluation of mycotoxin exposure in animals. A cross-sectional study was performed on 40 randomly selected broiler farms in Belgium. During a farm visit at the animal's age of 28 d, a pooled feed sample at the beginning and the end of the feed line was collected. Feed samples were analyzed by a validated multimycotoxin LC-MS/MS method. Moreover, serum samples were collected from 10 randomly selected chickens per farm. Serum concentrations of mycotoxins and major in vivo phase I metabolites were analyzed quantitatively, whereas the presence of phase II metabolites was determined in a qualitative approach by an UPLC-HRMS method. Deoxynivalenol (DON) was the most frequently occurring mycotoxin, being present in 74% of the feed samples, with an average concentration of 270 +/- 171 mu g/kg and a maximum concentration of 751 mu g/kg in positive samples. Also the acetylated forms 3and 15-acetyldeoxynivalenol (3 and 15ADON) were present in half of the samples, however, at lower concentrations (8 +/- 3 mu g 3ADON and 10 +/- 7 mu g 15ADON/kg). Only in 17.5% of the farms, DON was detected in serum samples at a mean serum concentration and standard deviation (SD) of 11 +/- 19 ng/mL. The maximum serum concentration of 49 ng DON/ mL was detected in broilers which were fed a diet that was contaminated with 191 mu g DON/kg, whereas the maximum concentration of DON in feed was 751 mu g/kg. Besides, 3 and 15ADON were only detected in 10% of the serum samples (max. 1.3 ng/mL). Sulfate conjugates of DON were only detected in a few serum samples. Qualitative screening for phase II metabolites of other mycotoxins showed similar results. Overall, correlations between feed and serum concentrations of all mycotoxins were lacking (R-2 = 0.18 for DON)

Living, dead, and absent trees-How do moth outbreaks shape small-scale patterns of soil organic matter stocks and dynamics at the Subarctic mountain birch treeline?

Mountain birch forests (Betula pubescens Ehrh. ssp. czerepanovii) at the subarctic treeline not only benefit from global warming, but are also increasingly affected by caterpillar outbreaks from foliage-feeding geometrid moths. Both of these factors have unknown consequences on soil organic carbon (SOC) stocks and biogeochemical cycles. We measured SOC stocks down to the bedrock under living trees and under two stages of dead trees (12 and 55 years since moth outbreak) and treeless tundra in northern Finland. We also measured in-situ soil respiration, potential SOC decomposability, biological (enzyme activities and microbial biomass), and chemical (N, mineral N, and pH) soil properties. SOC stocks were significantly higher under living trees (4.1 +/- 2.1 kg m(2)) than in the treeless tundra (2.4 +/- 0.6 kg m(2)), and remained at an elevated level even 12 (3.7 +/- 1.7 kg m(2)) and 55 years (4.9 +/- 3.0 kg m(2)) after tree death. Effects of tree status on SOC stocks decreased with increasing distance from the tree and with increasing depth, that is, a significant effect of tree status was found in the organic layer, but not in mineral soil. Soil under living trees was characterized by higher mineral N contents, microbial biomass, microbial activity, and soil respiration compared with the treeless tundra; soils under dead trees were intermediate between these two. The results suggest accelerated organic matter turnover under living trees but a positive net effect on SOC stocks. Slowed organic matter turnover and continuous supply of deadwood may explain why SOC stocks remained elevated under dead trees, despite the heavy decrease in aboveground C stocks. We conclude that the increased occurrence of moth damage with climate change would have minor effects on SOC stocks, but ultimately decrease ecosystem C stocks (49% within 55 years in this area), if the mountain birch forests will not be able to recover from the outbreaks.Peer reviewe

Microbial carbon use efficiency along an altitudinal gradient

Soil microbial carbon-use efficiency (CUE), described as the ratio of growth over total carbon (C) uptake, i.e. the sum of growth and respiration, is a key variable in all soil organic matter (SOM) models and critical to ecosystem C cycling. However, there is still a lack of consensus on microbial CUE when estimated using different methods. Furthermore, the significance of many fundamental drivers of CUE remains largely unknown and inconclusive, especially for tropical ecosystems. For these reasons, we determined CUE and microbial indicators of soil nutrient availability in seven tropical forest soils along an altitudinal gradient (circa 900-2200 m a.s.l) occurring at Taita Hills, Kenya. We used this gradient to study the soil nutrient (N and P) availability and its relation to microbial CUE estimates. For assessing the soil nutrient availability, we determined both the soil bulk stoichiometric nutrient ratios (soil C:N, C:P and N:P), as well as SOM degradation related enzyme activities. We estimated soil microbial CUE using two methods: substrate independent O-18-water tracing and C-13-glucose tracing method. Based on these two approaches, we estimated the microbial uptake efficiency of added glucose versus native SOM, with the latter defined by 18O-water tracing method. Based on the bulk soil C:N stoichiometry, the studied soils did not reveal N limitation. However, soil bulk P limitation increased slightly with elevation. Additionally, based on extracellular enzyme activities, the SOM nutrient availability decreased with elevation. The C-13-CUE did not change with altitude indicating that glucose was efficiently taken up and used by the microbes. On the other hand, 18O-CUE, which reflects the growth efficiency of microbes growing on native SOM, clearly declined with increasing altitude and was associated with SOM nutrient availability indicators. Based on our results, microbes at higher elevations invested more energy to scavenge for nutrients and energy from complex SOM whereas at lower elevations the soil nutrients may have been more readily available.Peer reviewe