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We report on the first realization of time-dependent quantum detector tomography for commercially available InGaAs avalanche photo detectors. For the construction of appropriate time-dependent POVMs from experimentally measured data, we introduce a novel scheme to calculate the weight of the regularization term based on the amount of measured data. We compare our POVM-based results with the theoretical predictions of the previously developed model by Gouzien et al (2018 Phys. Rev. A 98 013833). In contrast to our measurement-based construction of a time-dependent POVM for photon detectors, this previous investigation extends a time-independent POVM to a time-dependent one by including effects of detector timing jitter and dead time on the basis of particular model assumptions concerning the inner physical mechanisms of a photon detector. Our experimental results demonstrate that this latter approach is not sufficient to completely describe the observable properties of our InGaAs avalanche photo detectors. Thus, constructing the time-dependent POVM of a detector by direct quantum tomographic measurements can reveal information about the detector’s interior that may not easily be included in time-independent POVMs by a priori model assumptions.

Preparing quantum states is essential for quantum information processing since any process must start at a well-defined initial state. State conversion describes techniques to transform a specific initial- into a predefined target state. This dissertation investigates quantum state conversion for two interacting qubits and its specialization to a constrained system where only adjacent levels are connected. Furthermore, it shows its applicability in a system of three qubits supposed to model interacting Rydberg atoms. A general Lie-algebraic approach is discussed, allowing a wide range of unitary transformations of the interacting two-qubit system to be described by two independent pseudospin degrees of freedom. Although restricting the representable transformations, the approach offers a simple description of many different conversion schemes and is well-suited to discuss the mentioned constrained situation. For this constrained Hamiltonian, a specific state conversion scheme is developed, which can be adopted in a reduced system of three qubits. These three qubits are supposed to model a Rydberg-atom trimer, and the developed conversion scheme maps onto the transformation between the three-atomic W state and the corresponding Greenberger-Horne-Zeilinger state. This mapping is achieved by reducing the eight-dimensional system to an effective four-level system. Two possible reduction schemes are presented. One depends on phase-matching conditions and the other on lifting degeneracies and employing multiple separated time scales in the eight-dimensional dynamics. The control over the atomic ensemble is established via the interaction with coherent states of the electromagnetic field. All topics are presented in the framework of quantum optics which is the theoretical foundation of much of the developing field of quantum technologies. The presented research shows how to design quantum state conversion protocols for two interacting qubits and apply such conversion proto

The non-turning or only superficial turning of soil is considered to be a gentle tillage method. Nevertheless, conventional ploughs are widely used in organic farming for crop production reasons. For the further development of reduced tillage, and up to no tillage, the effects of three cover crop species and their incorporation with different tillage intensities on nitrogen (N) dynamics, weed emergence and the yield of the subsequent main crop, oats, were examined in a repeated organic one-year trial. Sinapis alba, Trifolium resupinatum, Vicia sativa and bare fallow were tested and incorporated using (1) a plough (PL), (2) reduced tillage (RT), (3) mulching + drilling (MD) and (4) direct drilling (DD). V. sativa was the most promising cover crop in combination with RT, MD and DD. In Trial 1, the soil mineral N content and oat yields after the introduction of V. sativa were on a similar level as those in the PL treatments, and weeds were not yield-limiting there. In Trial 2, the biomass production of V. sativa was only about half of that of Trial 1 and did not offer sufficient weed control, but V. sativa was still successful in the RT treatments. In both trials, the yield differences were more pronounced between the cover crop treatments after RT than after PL. RT, therefore, was more dependent on an adequate cover crop species than PL. The no-till method was not only dependent on an adequate cover crop species but also on its proper biomass production for sufficient weed control.

In organic farming the control of perennial weed species, in particular Cirsium arvense, can be a major concern for farmers, especially if there is no regulation through perennial forage production. To test whether the stubble cleaner (SC), an enhanced skim plow (PL), is as effective in the control of C. arvense and other weeds as conventional ploughing and perennial forage production, an organic field experiment was established. Three different tillage/crop rotation systems were compared: an SC system and a PL system, both in a cereal-based crop rotation and an additional PL system in a crop rotation that included a perennial alfalfa–grass mixture (PLALF). In the SC system, tillage was carried out solely with the SC, while in the PL and PLALF systems, ploughing was alternated with chiseling. In the fifth year, each main plot was divided into subplots, and seven different cover crop treatments were integrated into each of the three systems. The effects of the three systems and the cover crop treatments on weed cover and density, weed biomass, and weed diversity in the sixth and seventh year of the experiment are the subjects of this paper. The choice of cover crop species was of minor importance for weed control. The PLALF system was generally more effective in controlling C. arvense than the PL and SC systems. No significant differences between the PL and SC systems regarding the control of C. arvense could be identified in four of five assessments. The SC system had significantly higher total weed density than the PLALF and PL systems in both years. However, the differences in weed emergence between the PL and SC systems diminished until the assessment of weed cover and biomass in the main crops, when no significant differences between these two systems (2012) or no differences at all (2013) could be identified. Species richness was not significantly influenced by the tillage/crop rotation system in both years. Evenness and Shannon–Wiener index were significantly

Integration of legumes into European agricultural systems would diversify the highly specialized cropping systems that are dominated by cereals and increase resource efficiency of agricultural systems. By providing high quality protein for food and feed as well as regulating and supporting services, legumes contribute essential ecosystem services. In order to assess the overall effects of legumes in agricultural systems, it is necessary to consider how legumes are integrated in cropping systems and evaluate the impacts of this integration. As legumes influence the production of other crops in the rotation and as the interaction of legumes are multiplex, an assessment of the cropping system that considers multiple criteria is required. The objective of this work was to assess the impacts of changes in crop rotations through the integration of legumes using cropping systems implemented in practice. We used a multi-actor approach to incorporate the knowledge of a range of legume experienced actors representing value chains with soybean, pea, faba bean, lupin and forages for food and feed and evaluate thereby the role of legumes in crop rotations of diverse systems from Ireland in the West to Ukraine in the East. Within the research process we firstly identified region-specific crop rotations with cultivation techniques based on expert opinion in the 17 different study areas. One rotation representing the current farming without legumes and at least one alternative legume-based crop rotation was specified per region. Secondly, a valid set of indicators was developed, including environmental, economic and agronomic indicators. The indicators were calculated for each cropping system at the rotational level, considering pre-crop effects i.e. adapted N fertilizer application rates and yields. Finally, the cropping system assessment compared current farming practices to legume-based alternatives. Trade-offs and synergies between different indicators e.g. gross margins and N

The nitrogen supply can be a yield-limiting factor in organic farming, especially when reduced tillage is applied. An organic field experiment was conducted from 2007 to 2013 to analyse the potential of the nitrogen supply through the efficient use of green manure crops in different tillage systems. Three farming systems were compared: a stubble cleaner system (SC) and a plough system (PL), both in a cereal-based crop rotation, and another plough system in a crop rotation that included alfalfa grass ley (PLALF). In the fifth year of the experiment, the experimental design was extended into a split plot design, and seven green manure treatments (Lolium perenne, Phacelia tanacetifolia, Sinapis alba, a mixture of Sinapis alba and Trifolium resupinatum, Trifolium resupinatum, Vicia sativa, and bare fallow as the control) were integrated into each of the three systems. The effects of the three systems and the green manure treatments on N mineralization, the soil microbial biomass and the yield of the main crops of oats and field beans in the sixth and seventh years of the experiment were analysed. The results showed that the choice of green manure species was of minor importance in the PLALF system. This system generally success- fully supplied N to the oats with oat yields from 3.6 to 5.1 t per ha.Vicia sativa was the most promising green manure crop in the SC and PL systems, with the Nmin values and oat yields (4.0 and 4.6 t per ha) being similar to those in the PLALF system. In the subsequent year, the PLALF system again was more successful in most of the Nmin assessments than the PL and SC systems, which often had rather similar results. In addition, a main crop of field beans was able to compensate for the differences in the Nmin content, and the yields were similar in all three systems (3.1 to 3.7 t per ha). The microbial biomass in the top soil was significantly increased in the reduced tillage system compared to the plough systems. In conclusion, reduced tillage

In der Praxisforschung werden LandwirtInnen als aktiv Handelnde in den Forschungsprozess eingebunden. LandwirtInnen, BeraterInnen und ForscherInnen gestalten Fragen und Inhalte gemeinsam. Dadurch entstehen Synergieeffekte, die Innovationen für eine nachhaltige Landwirtschaft hervorbringen. Durch langjährige Zusammenarbeit in Netzwerken kann erfolgsentscheidenes Vertrauen zwischen den Akteuren aufgebaut werden. In der vorliegenden Untersuchung wurden im April 2018 acht Akteure aus Hessen (LandwirtInnen, BeraterInnen und ForscherInnen) zur Praxisforschung in Hessen befragt. Hierzu wurde die Methode der Fokusgruppendiskussion genutzt. Die befragten Akteure nehmen eine Expertenstellung innerhalb ihrer Akteursgruppe ein. Die Analyse der Fokusgruppendiskussion zeigt, dass zur Zeit nur wenig Praxisforschung in Hessen betrieben wird und die Akteursgruppen schlecht untereinander vernetzt sind. Die Rahmenbedingungen für intensivere Zusammenarbeit sind sehr gut: Finanzmittel stehen zur Verfügung (Ökoaktionsplan), es gibt motivierte Akteure, es sind viele Universitäten ansässig und erfolgreiche EIP-Projekte bieten eine gute Ausgangsbasis. Um Praxisforschung im ökologischen Landbau in Hessen zu etablieren, werden AnsprechpartnerInnen und eine entsprechende Institutionalisierung benötigt. Die VÖL (Vereinigung Ökologischer Landbau in Hessen e.V.) bietet interessante Voraussetzungen für die Koordination eines Praxisforschungsnetzwerks. Die zur Zeit limitierte Versuchstechnik, eingeschränkte zeitliche Kapazitäten und räumliche Distanzen müssen dabei ebenso realistisch berücksichtigt werden wie eine faire Kostenverteilung.

In diesem Workshop sollen sowohl bereits bewährte als auch innovative Anbaustrategien auf ihre Eignung für nachhaltige Getreideerzeugung in ökologischen viehlosen Marktfruchtbetrieben untersucht werden.

Potatoes are one of the most important crops in organic farming with respect to farmers’ income. Yields are often strongly influenced by regional and yearly diffe-rences. Despite the availability of detailed knowledge, it is only now that a crop growth model has been generated which allows for the estimation and prediction of potato yield under organic conditions. The aim of our study was to produce a highly elaborate prediction model based on the utilization and speed of nitrogen uptake as they relate to the yield dynamics of tubers and canopy in combination with late blight dynamics. Therefore, from 2005 to 2014, these parameters were assessed in up to 18 varieties of potatoes comprised of differing maturity groups. The data were ana-lyzed in R using similar algorithms to the Grofit package. Our distinct model included updated mathematical functions to estimate the yield development in organic potato-es. Finally, we demonstrate that at a relatively early time in the season it is possible to estimate the yield of potatoes of various varieties and maturity groups.

Biolandwirte stehen vor der Entscheidung, welche Körnerleguminosen-Art sie auf ihrem Betrieb zur Erzeugung von regionalem Futtermittel anbauen sollen. Die bestehenden Empfehlungen beruhen jedoch meist auf Sortenversuchen und Unter¬suchungen, welche sich mit Anbausystemen befassen. Welche Körner¬leguminosen-Art sich für den jeweiligen Standort unter den Bedingungen des Ökologischen Landbaus am besten eignet und welche den besten Vorfruchtwert für die nachfolgende Kultur aufweist, ist weit¬gehend unerforscht. Daher ist es Ziel dieser Arbeit, verschiedene Körnerleguminosen-Arten im Gemenge und in Reinsaat auf ein und demselben Standort (Colmar-Berg, Luxemburg) miteinander zu vergleichen, sowie ihren Vorfruchtwert auf die Nachfrucht Winter-Weizen zu untersuchen. In zwei aufeinanderfolgenden Jahren wurden verschiedene Körnerleguminosen-Arten (Ackerbohne, Erbse, blaue Lupine, Sojabohne) als Winterung und Sommerung (Ackerbohne und Erbse) sowie in Reinsaat und im Gemenge mit Getreide (Erbse) untersucht. Ertrag, Proteingehalt und Proteinertrag der verschiedenen Anbausysteme und der Nachfrucht Winter-Weizen wurden erfasst. Die Ackerbohnen erzielten in beiden Versuchsjahren die höchsten Proteinerträge und sind trotz der laut Literatur ungünstigen Bodenbedingungen durchaus anbaufähig in der Versuchsregion. Sommer-Erbse, Sommer-Ackerbohne und Blaue Lupine erzielten den höchsten Vorfruchtwert.

Mit dem Projektvorhaben sollten neue Wintererbsen mit einer verbesserten Frosttoleranz, hoher Standfestigkeit, determinierten Wuchs, einem hohen Ertrag und guter Futterqualität entwickelt werden. In den Jahren von 2011 bis 2013 wurden auf hauptsächlich 2 Standorten 12 selektierte Genotypen (1 halbblattloser/violett blühender, 6 halbblattlose/ weiß blühende, 2 vollblättrige/ violett blühende und 3) mit der Referenzsorte EFB33 und 3 weiteren genetischen Ressourcen auf ihre Anbaueignung in Reinsaat und im Gemengeanbau mit Triticale, Roggen, Weizen, Raps und Rübsen unter ökologischen Bedingungen getestet und verglichen. Es wurden die Merkmale Frosttoleranz, Feldaufgang, Lagerneigung, Bodendeckung, unspezifische Krankheitsresistenz, Ertrag und Qualität erhoben. Die durchschnittlich besten Ergebnisse erzielten die Genotypen im Gemenge mit Triticale. Aufgrund der hohen Pflanzenlängen und dem Beikrautdruck ist der Reinsaatanbau von Wintererbsen, selbst von den halbblattlosen, weiterhin nicht zu empfehlen. Gute Futterqualitäten zeigten die vollblättrigen, weißblühenden Genotypen mit sehr geringen Tannin- und hohen Rohproteingehalten.

In den Jahren 2009-2011 wurde auf der seit 2001 ökologisch bewirtschafteten Hessischen Staatsdomäne Frankenhausen (Lehr- und Versuchsbetrieb der Universität Kassel; 698 mm; 8,9°C; mittlerer toniger Schluff) ein Feldversuch mit vier, im Abstand von 10 Tagen durchgeführten Probenahmen zu ausgewählten Fragestellungen der Ertragsbildung, Stickstoffeffizienz, Methoden der Bestimmung des N-Versorgungsstatus und des Unkrautunterdrückungspotenzials von 16 Kartoffelsorten aller vier Reifegruppen bei Verzicht auf Kupfereinsatz durchgeführt. Die Sorten der späteren Reifegruppe wiesen über die drei Versuchsjahre eine geringere Ertragsstabilität auf. Die Ergebnisse bestätigten die Hypothese, dass Sorten mit geringer Knollendichte und gleichzeitig hohen Einzelknollenmassen im Ökologischen Landbau zu bevorzugen sind, weil diese den relativ höchsten Marktwareertrag erwarten lassen. Die Untersuchungen konnten zeigen, dass das geringste Anbaurisiko mit der Wahl einer solchen Sorte verbunden ist, die relativ gesehen, ein überdurchschnittliches Ertragsniveau bei gleichzeitig überdurchschnittlicher relativer Ertragszuwachsgeschwindigkeit aufweist und dies mit einer geringen Streuung über die Jahre. Die Ergebnisse belegen weiterhin, dass im Ökologischen Landbau der maximale Knollenertrag von Sorten der Reifegruppen I bis III bereits 90 Tage nach dem Legen erreicht ist, wenn die Intensität der Krautfäule gering ist. Die Kenntnis des Zeitpunktes, zu dem, bei Unterschreiten eines noch zu erarbeitenden Schwellenwertes (z.B. N-Gehalt des jüngsten voll entwickelten Blattes) auch bei vollem Einsatz von Pflanzenschutz (Kupfer), kein weiterer Ertragszuwachs zu erwarten ist, muss in weiterführenden N-Steigerungsversuchen erlangt werden. Die Verknüpfung des in dieser Studie entwickelten Wachstumsmodells zur Ertragsbildung und der gewonnenen Erkenntnisse zum N-Haushalt der Kartoffel kann eine Grundlage dazu liefern. Bezüglich des Unkrautunterdrückungspotenzials konnte kein eindeutiger Einfluss der R

One of the objectives of the TILMAN-ORG Project is to improve weed management under conservation agriculture (reduced tillage and/or cover crops) in organic arable systems. The shift from ploughing to conservation agriculture should not only maintain crop yield but possibly improve weed community diversity. This paper summarises the results on (1) weed abundance, (2) weed diversity and (3) crop yield obtained in the first year of the project (2012) in 13 trials scattered across Europe.

Field trials on reduced soil tillage under organic farming conditions across Europe were used to compare the soil quality changes over time. Soil organic carbon fractions, soil carbon stocks and microbial community structure were analysed. Most severe differences between plough and reduced tillage were found in the top ten cm of the soil profile. Differences became less or not significant in deeper layers. Analyses are still ongoing and will only be ready to be presented at the conference.