Organic cropping systems maintain yields but have lower yield levels and yield stability than conventional systems – Results from the DOK trial in Switzerland

Sufficient and stable crop yields are the basis for feeding a growing world population. Limited cropland, climate change, degradation of soil quality and loss of biodiversity coupled with excessive use of non-renewable resources require new solutions for future cropping systems beyond existing management practices. Here we analyzed mean yields, temporal yield trends and the stability of organic and conventional cropping systems from the currently longest-lasting cropping system comparison, the DOK long-term systems comparison trial (DOK) comparing biodynamic, bioorganic and conventional cropping systems, over a period of 40 years. We used yield data of winter wheat, potatoes, grass-clover, maize and soybean in a seven-year rotation, where bioorganic and biodynamic farming systems were compared with conventional mixed and sole mineral fertilized systems. System treatments have been established at a reduced half and a regular fertilization level, which corresponds to standard Swiss farming practices. Yields were significantly lower in organic systems in non-legumes between 13% and 34%, depending on the investigated crop, whereas in legumes, no yield reduction was observed in soybean and only 10% was observed in grass-clover. Half the amount of fertilizer reduced yields by around 10% in all systems and crops. Applied mineral N determined yields mainly in winter wheat and potatoes. Temporal yield trends did not differ between organic and conventional systems, nor between half and regular fertilization over all crops. However, in winter wheat, both conventional and biodynamic management with regular fertilization showed a stronger temporal increase in yield, while yield of grass-clover under biodynamic management with half-fertilization decreased. Increased yield differences between systems in single years were due to poor performance of organic systems rather than better performance of conventional systems. Absolute stability (measured by the variance) did not differ, but conventional systems were more stable than organic ones in relative stability, measured by the coefficient of variation, expressing the stability in relation to the yield level. We found no difference in both absolute and relative stabilities between half and regular fertilization. Long-term organic management results in lower yields than conventional management, but not in a decrease of yields over time. The similarity in both stability measures between half and regular fertilization suggests that the variation in relative stability between organic and conventional management might be more related to plant protection than to fertilization intensity

Permanent grasslands in Europe : Land use change and intensification decrease their multifunctionality

Acknowledgments We acknowledge the financial support of this work by European Union Horizon 2020 research and innovation programme, under grant agreement 774124, project SUPER-G (Developing Sustainable Permanent Grassland Systems and Policies).Peer reviewedPublisher PD

Altered energy partitioning across terrestrial ecosystems in the European drought year 2018

Drought and heat events, such as the 2018 European drought, interact with the exchange of energy between the land surface and the atmosphere, potentially affecting albedo, sensible and latent heat fluxes, as well as CO(2)exchange. Each of these quantities may aggravate or mitigate the drought, heat, their side effects on productivity, water scarcity and global warming. We used measurements of 56 eddy covariance sites across Europe to examine the response of fluxes to extreme drought prevailing most of the year 2018 and how the response differed across various ecosystem types (forests, grasslands, croplands and peatlands). Each component of the surface radiation and energy balance observed in 2018 was compared to available data per site during a reference period 2004-2017. Based on anomalies in precipitation and reference evapotranspiration, we classified 46 sites as drought affected. These received on average 9% more solar radiation and released 32% more sensible heat to the atmosphere compared to the mean of the reference period. In general, drought decreased net CO(2)uptake by 17.8%, but did not significantly change net evapotranspiration. The response of these fluxes differed characteristically between ecosystems; in particular, the general increase in the evaporative index was strongest in peatlands and weakest in croplands. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'

The soil organic carbon stabilization potential of old and new wheat cultivars: a ¹³CO₂-labeling study

Over the past decades, average global wheat yields have increased by about 250 %, mainly due to the cultivation of high-yielding wheat cultivars. This selection process not only affected aboveground parts of plants, but in some cases also reduced root biomass, with potentially large consequences for the amount of organic carbon (OC) transferred to the soil. To study the effect of wheat breeding for high-yielding cultivars on subsoil OC dynamics, two old and two new wheat cultivars from the Swiss wheat breeding program were grown for one growing season in 1.5 m deep lysimeters and pulse labeled with ¹³CO₂ to quantify the amount of assimilated carbon that was transferred belowground and can potentially be stabilized in the soil. The results show that although the old wheat cultivars with higher root biomass transferred more assimilated carbon belowground compared to more recent cultivars, no significant differences in net rhizodeposition were found between the different cultivars. As a consequence, the long-term effect of wheat cultivar selection on soil organic carbon (SOC) stocks will depend on the amount of root biomass that is stabilized in the soil. Our results suggest that the process of wheat selection for high-yielding cultivars resulted in lower amounts of belowground carbon translocation, with potentially important effects on SOC stocks. Further research is necessary to quantify the long-term importance of this effect

Can plasma fibrinogen levels predict bleeding after coronary artery bypass grafting?

Background: Fibrinogen is the main biomarker for bleeding. To prevent excessive postoperative bleeding, it would be useful to identify high-risk patients before coronary artery bypass grafting (CABG). Objectives: In order to predicating bleeding after CABG, we sought to determine whether preoperative fibrinogen concentration was associated with the amount of bleeding following CABG. Patients and Methods: A total of 144 patients (mean age = 61.50 ± 9.42 years; 65.7% men), undergoing elective and isolated CABG, were included in this case-series study. The same anesthesia technique and medicines were selected for all the patients. In the ICU, the patients were assessed in terms of bleeding at 12 and 24 hours post-operation, amount of contingent blood products received, and relevant tests. Statistical tests were subsequently conducted to analyze the correlation between preoperative fibrinogen concentration and the amount of post-CABG bleeding. Results: The mean and standard deviation of bleeding at 12 and 24 hours post-operation was 285.37 ± 280.27 and 499.31 ± 355.57 mL, respectively. The results showed that postoperative bleeding was associated with different factors whereas pre-anesthesia fibrinogen was not correlated with bleeding at 12 (P = 0.856) and 24 hours (P = 0.936) post-operation. There were correlations between the extra-corporal circulation time and bleeding at 12 hours post-operation (ρ = 0.231, P = 0.007) and bleeding at 24 hours post-operation (ρ = 0.218, P = 0.013). Conclusions: Preoperative assessment of plasma fibrinogen levels failed to predict post-CABG bleeding

Lutembacher's syndrome associated with meningioma

49-year-old man with Lutembacher's syndrome associated with frontal meningioma referred to our hospital. He also suffered from exertional dyspnea. Transthoracic echocardiography demonstrated mitral valve area of 1.48 cm2, moderate mitral stenosis, and left atrial dimension (LAD) of 5.6 cm with no clot. TEE revealed severe mitral stenosis, mitral valve area of 1.05 cm2 with wilkins 8-10 score, ejection fraction of 50%, and enlarged left atrium (LAD = 5.8 cm) with no clot. Induction of anesthesia was commenced taking into account the patient's specific circumstances, which meant the risk of surgery was high. During surgery, the mitral valve was replaced and the atrial septal defect was repaired without a patch. This case underscores the significance of the adoption of an appropriate therapeutic strategy in the treatment of Lutembacher's syndrome with meningioma before meningioma surgery

Influence of starch deficiency on photosynthetic and post-photosynthetic carbon isotope fractionations

Carbon isotope (^13C) fractionations occurring during and after photosynthetic CO_2 fixation shape the carbon isotope composition (δ^13C) of plant material and respired CO_2. However, responses of ^13C fractionations to diel variation in starch metabolism in the leaf are not fully understood. Here we measured δ^13C of organic matter (δ^13COM), concentrations and δ^13C of potential respiratory substrates, δ^13C of dark-respired CO_2 (δ^13CR), and gas exchange in leaves of starch-deficient plastidial phosphoglucomutase (pgm) mutants and wild-type plants of four species (Arabidopsis thaliana, Mesembryanthemum crystallinum, Nicotiana sylvestris, and Pisum sativum). The strongest δ^13C response to the pgm-induced starch deficiency was observed in N. sylvestris, with more negative δ^13COM, δ^13CR, and δ^13C values for assimilates (i.e. sugars and starch) and organic acids (i.e. malate and citrate) in pgm mutants than in wild-type plants during a diel cycle. The genotype differences in δ^13C values could be largely explained by differences in leaf gas exchange. In contrast, the PGM-knockout effect on post-photosynthetic ^13C fractionations via the plastidic fructose-1,6-bisphosphate aldolase reaction or during respiration was small. Taken together, our results show that the δ^13C variations in starch-deficient mutants are primarily explained by photosynthetic ^13C fractionations and that the combination of knockout mutants and isotope analyses allows additional insights into plant metabolism.ISSN:1460-2431ISSN:0022-095

The soil organic carbon stabilization potential of old and new wheat cultivars: a 13CO2-labeling study

Over the past decades, average global wheat yields have increased by about 250 %, mainly due to the cultivation of high-yielding wheat cultivars. This selection process not only affected aboveground parts of plants, but in some cases also reduced root biomass, with potentially large consequences for the amount of organic carbon (OC) transferred to the soil. To study the effect of wheat breeding for high-yielding cultivars on subsoil OC dynamics, two old and two new wheat cultivars from the Swiss wheat breeding program were grown for one growing season in 1.5 m deep lysimeters and pulse labeled with 13CO2 to quantify the amount of assimilated carbon that was transferred belowground and can potentially be stabilized in the soil. The results show that although the old wheat cultivars with higher root biomass transferred more assimilated carbon belowground compared to more recent cultivars, no significant differences in net rhizodeposition were found between the different cultivars. As a consequence, the long-term effect of wheat cultivar selection on soil organic carbon (SOC) stocks will depend on the amount of root biomass that is stabilized in the soil. Our results suggest that the process of wheat selection for high-yielding cultivars resulted in lower amounts of belowground carbon translocation, with potentially important effects on SOC stocks. Further research is necessary to quantify the long-term importance of this effect.ISSN:1726-4170ISSN:1726-417

Physiological response of Swiss ecosystems to 2018 drought across plant types and elevation

Using five eddy covariance flux sites (two forests and three grasslands), we investigated ecosystem physiological responses to the 2018 drought across elevational gradients in Switzerland. Flux measurements showed that at lower elevation sites (below 1000 m.a.s.l.; grassland and mixed forest) annual ecosystem productivity (GPP) declined by approximately 20% compared to the previous 2 years (2016 and 2017), which led to a reduced annual net ecosystem productivity (NEP). At the high elevation sites, however, GPP increased by approximately 14% and as a result NEP increased in the alpine and montane grasslands, but not in the subalpine coniferous forest. There, increased ecosystem respiration led to a reduced annual NEP, despite increased GPP and lengthening of the growing period. Among all ecosystems, the coniferous forest showed the most pronounced negative stomatal response to atmospheric dryness (i.e. vapour pressure deficit, VPD) that resulted in a decline in surface conductance and an increased water-use efficiency during drought. While increased temperature enhanced the water-use efficiency of both forests, de-coupling of GPP from evapotranspiration at the low-elevation grassland site negatively affected water-use efficiency due to non-stomatal reductions in photosynthesis. Our results show that hot droughts (such as in 2018) lead to different responses across plants types, and thus ecosystems. Particularly grasslands at lower elevations are the most vulnerable ecosystems to negative impacts of future drought in Switzerland. This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.ISSN:0962-8436ISSN:1471-2970ISSN:0080-462