Analyzing Temporal and Spatial Characteristics of Crop Parameters Using Sentinel-1 Backscatter Data

The knowledge about heterogeneity on agricultural fields is essential for a sustainable and effective field management. This study investigates the performance of Synthetic Aperture Radar (SAR) data of the Sentinel-1 satellites to detect variability between and within agricultural fields in two test sites in Germany. For this purpose, the temporal profiles of the SAR backscatter in VH and VV polarization as well as their ratio VH/VV of multiple wheat and barley fields are illustrated and interpreted considering differences between acquisition settings, years, crop types and fields. Within-field variability is examined by comparing the SAR backscatter with several crop parameters measured at multiple points in 2017 and 2018. Structural changes, particularly before and after heading, as well as moisture and crop cover differences are expressed in the backscatter development. Furthermore, the crop parameters wet and dry biomass, absolute and relative vegetation water content, leaf area index (LAI) and plant height are related to SAR backscatter parameters using linear and exponential as well as multiple regression. The regression performance is evaluated using the coefficient of determination (R 2 ) and the root mean square error (RMSE) and is strongly dependent on the phenological growth stage. Wheat shows R 2 values around 0.7 for VV backscatter and multiple regression and most crop parameters before heading. Single fields even reach R 2 values above 0.9 for VV backscatter and for multiple regression related to plant height with RMSE values around 10 cm. The formulation of clear rules remains challenging, as there are multiple influencing factors and uncertainties and a lack of conformity.BMEL, 2815710715, Verbundprojekt: Erzeugung von landwirtschaftlichen Ertragspotenzialkarten durch Fusion von Ertragskartierungen, Fernerkundungsdaten, digitaler Reliefauswer-tung und Bewirtschaftungsdaten (AgriFusion) - Teilprojekt

Stickstoff-Effizienz von Milchkühen bei Fütterung mit und ohne Proteinkonzentrate

In einer ökologischen Milchviehherde in der Schweiz wurden 12 Kühe mit 2.4 kg/Tag und 11 Kühe mit 0 kg/Tag Proteinkonzentraten supplementiert. Der Verzicht auf die Konzentrate führte zu einer signifikanten Steigerung der Grundfutteraufnahme. Der Effekt auf die Milchprotein-Leistung war nicht signifikant. Die Stickstoff-Effizienz war nicht beeinflusst. Diese Daten unterstützen die Hypothese, dass die Protein-Konzentrate in der ökologischen Milchviehfütterung signifikant reduziert werden könnten ohne an Effizienz in der Milchproteinproduktion zu verlieren

Fütterungseinflüsse auf das Fress- und Wiederkäuverhalten von Milchkühen auf einem Biobetrieb

In einer ökologischen Milchviehherde in der Schweiz wurden 23 Kühe mit verschiedenen Rationen gefüttert. Futteraufnahme und Wiederkäuverhalten wurden mit Kausensoren erfasst. Proteinkonzentrate sowie eine separate Heugabe zeigten signifikante Einflüsse auf das Fressen und Wiederkäuen während des Tages, jedoch nicht während der Nacht. Die Daten zeigen das Potential der Erhebung von Fress- und Wiederkäuverhalten zur Beurteilung von Fütterungssituationen mit grundfutterreichen Rationen

Glycolytic Shunts Replenish the Calvin-Benson-Bassham Cycle as Anaplerotic Reactions in Cyanobacteria

The recent discovery of the Entner-Doudoroff (ED) pathway as a third glycolytic route beside Embden-Meyerhof-Parnas (EMP) and oxidative pentose phosphate (OPP) pathway in oxygenic photoautotrophs requires a revision of their central carbohydrate metabolism. In this study, unexpectedly, we observed that deletion of the ED pathway alone, and even more pronounced in combination with other glycolytic routes, diminished photoautotrophic growth in continuous light in the cyanobacterium Synechocystis sp. PCC 6803. Furthermore, we found that the ED pathway is required for optimal glycogen catabolism in parallel to an operating Calvin–Benson–Bassham (CBB) cycle. It is counter-intuitive that glycolytic routes, which are a reverse to the CBB cycle and do not provide any additional biosynthetic intermediates, are important under photoautotrophic conditions. However, observations on the ability to reactivate an arrested CBB cycle revealed that they form glycolytic shunts that tap the cellular carbohydrate reservoir to replenish the cycle. Taken together, our results suggest that the classical view of the CBB cycle as an autocatalytic, completely autonomous cycle that exclusively relies on its own enzymes and CO2 fixation to regenerate ribulose-1,5-bisphosphate for Rubisco is an oversimplification. We propose that in common with other known autocatalytic cycles, the CBB cycle likewise relies on anaplerotic reactions to compensate for the depletion of intermediates, particularly in transition states and under fluctuating light conditions that are common in nature

Detecting Phenological Development of Winter Wheat and Winter Barley Using Time Series of Sentinel-1 and Sentinel-2

Monitoring the phenological development of agricultural plants is of high importance for farmers to adapt their management strategies and estimate yields. The aim of this study is to analyze the sensitivity of remote sensing features to phenological development of winter wheat and winter barley and to test their transferability in two test sites in Northeast Germany and in two years. Local minima, local maxima and breakpoints of smoothed time series of synthetic aperture radar (SAR) data of the Sentinel-1 VH (vertical-horizontal) and VV (vertical-vertical) intensities and their ratio VH/VV; of the polarimetric features entropy, anisotropy and alpha derived from polarimetric decomposition; as well as of the vegetation index NDVI (Normalized Difference Vegetation Index) calculated using optical data of Sentinel-2 are compared with entry dates of phenological stages. The beginning of stem elongation produces a breakpoint in the time series of most parameters for wheat and barley. Furthermore, the beginning of heading could be detected by all parameters, whereas particularly a local minimum of VH and VV backscatter is observed less then 5 days before the entry date. The medium milk stage can not be detected reliably, whereas the hard dough stage of barley takes place approximately 6–8 days around a local maximum of VH backscatter in 2018. Harvest is detected for barley using the fourth breakpoint of most parameters. The study shows that backscatter and polarimetric parameters as well as the NDVI are sensitive to specific phenological developments. The transferability of the approach is demonstrated, whereas differences between test sites and years are mainly caused by meteorological differences.BMEL, 2815710715, Verbundprojekt: Erzeugung von landwirtschaftlichen Ertragspotenzialkarten durch Fusion von Ertragskartierungen, Fernerkundungsdaten, digitaler Reliefauswer-tung und Bewirtschaftungsdaten (AgriFusion) - Teilprojekt

Migrations- und Integrationserfahrungen europäischer Ärztinnen und Ärzte in Deutschland: Ergebnisse einer bundesweiten Umfrage

Im vorliegenden Bericht präsentieren wir erste Ergebnisse unserer Umfrage unter in Deutschland tätigen Ärztinnen und Ärzten mit einer nicht-deutschen EU-Staatsbürgerschaft, die selbst nach Deutschland zugewandert sind. Durchgeführt wurde die Umfrage von der Nachwuchsforschungsgruppe "Transnationalisierung der Gesellschaft, Politik und Wirtschaft" unter der Leitung von Prof.Dr. Céline Teney am Forschungszentrum Ungleichheit und Sozialpolitik (SOCIUM) der Universität Bremen. Die Nachwuchsgruppe ist von der Deutschen Forschungsgemeinschaft (DFG) durch die Exzellenzinitiative der Universität Bremen finanziert und erforscht ökonomische, soziale und politische Dimensionen inner-europäischer Mobilität von hochqualifizierten EU-Bürger/-innen

Suitability of satellite remote sensing data for yield estimation in northeast Germany

Information provided by satellite data is becoming increasingly important in the field of agriculture. Estimating biomass, nitrogen content or crop yield can improve farm management and optimize precision agriculture applications. A vast amount of data is made available both as map material and from space. However, it is up to the user to select the appropriate data for a particular problem. Without the appropriate knowledge, this may even entail an economic risk. This study therefore investigates the direct relationship between satellite data from six different optical sensors as well as different soil and relief parameters and yield data from cereal and canola recorded by the thresher in the field. A time series of 13 years is considered, with 947 yield data sets consisting of dense point data sets and 755 satellite images. To answer the question of how well the relationship between remote sensing data and yield is, the correlation coefficient r per field is calculated and interpreted in terms of crop type, phenology, and sensor characteristics. The correlation value r is particularly high when a field and its crop are spatially heterogeneous and when the correct phenological time of the crop is reached at the time of satellite imaging. Satellite images with higher resolution, such as RapidEye and Sentinel-2 performed better in comparison with lower resolution sensors of the Landsat series. The additional Red Edge spectral band also has advantage, especially for cereal yield estimation. The study concludes that there are high correlation values between yield data and satellite data, but several conditions must be met which are presented and discussed here

Pyruvate: ferredoxin oxidoreductase and low abundant ferredoxins support aerobic photomixotrophic growth in cyanobacteria

The decarboxylation of pyruvate is a central reaction in the carbon metabolism of all organisms. It is catalyzed by the pyruvate:ferredoxin oxidoreductase (PFOR) and the pyruvate dehydrogenase (PDH) complex. Whereas PFOR reduces ferredoxin, the PDH complex utilizes NAD+. Anaerobes rely on PFOR, which was replaced during evolution by the PDH complex found in aerobes. Cyanobacteria possess both enzyme systems. Our data challenge the view that PFOR is exclusively utilized for fermentation. Instead, we show, that the cyanobacterial PFOR is stable in the presence of oxygen in vitro and is required for optimal photomixotrophic growth under aerobic and highly reducing conditions while the PDH complex is inactivated. We found that cells rely on a general shift from utilizing NAD(H)- to ferredoxin-dependent enzymes under these conditions. The utilization of ferredoxins instead of NAD(H) saves a greater share of the Gibbs-free energy, instead of wasting it as heat. This obviously simultaneously decelerates metabolic reactions as they operate closer to their thermodynamic equilibrium. It is common thought that during evolution, ferredoxins were replaced by NAD(P)H due to their higher stability in an oxidizing atmosphere. However, the utilization of NAD(P)H could also have been favored due to a higher competitiveness because of an accelerated metabolism.</p

Approaches to fattening dairy calves

Innovative organic producers have developed alternative systems for fattening calves, bulls and steers from dairy farming. This technical guide presents the systems and shows what to pay attention to when fattening calves