20 Jahre Modellbetrieb für Ökolandbau in Müncheberg. Teil 2: Wie ertragslabil sind Körnerleguminosen im Vergleich zu Getreide und Mais?

Auf dem Modellbetrieb für Ökolandbau in Müncheberg wurden von 1993 bis 2013 Feldversuche zur Ermittlung der Ertragsstabilität von zwei Körnerleguminosen (Schmalblättrige Lupine und Futtererbse), Wintergetreide (Roggen und Weizen), Hafer und Silomais durchgeführt. Zwei orthogonale Datensätze wurden genutzt um die temporären Ertragsschwankungen der Einzelkulturen zu vergleichen. Beide Körnerleguminosen zeigten die geringste Ertragsstabilität von allen untersuchten Kulturen. Dies war sowohl für varianzbasierte als auch für regressionsbasierte Stabilitätsparameter der Fall. Gründe für die geringe Ertragsstabilität sind unzureichend bekannt. Es müssen Strategien für das Management entwickelt werden, um mit den großen Schwankungen umzugehen

Inspiring Farmers For Healthy Farming

"The health and nutritional value of agricultural food products is strongly linked to, and inherently dependent on the production process and farm system. However, there are currently only limited options for transferring and measuring farm-health principles at farm level (Vieweger and Döring, 2015). In our previous work we have shown how organic farmers have developed their own strategies and philosophies for running healthy farming systems and increase the health of soils, plants, animals and humans. Such tacit farmer knowledge and awareness of a holistic systems-approach to health in food production can contribute crucial information and practical understanding for food system sustainability. The current project builds on these earlier findings, using participatory multi-actor approaches to collaborate with the established international network. The farmer groups in Germany, Austria and the UK aimed to 1) conceptualize health criteria on farms, such as ‘Is a nutrient or humus balance calculated?‘, ‘How much time is spent for observation and reflection?’, ‘Are regionally adapted breeds and varieties used?’; and 2) develop a concept for farmer-to-farmer learning, defining most appropriate conditions and methodologies for the multiplication of this knowledge. With a co-learning approach, we aim to allow a flexible integration of farmer knowledge and experience, thereby inspiring farmers to reflect on the potential ways they can improve health in their system, and further develop their individual methods over time; this approach also aims to help research identify general drivers of farm health.

Grain legume yields are as stable as other spring crops in long-term experiments across northern Europe

Grain legumes produce high-quality protein for food and feed, and potentially contribute to sustainable cropping systems, but they are grown on only 1.5% of European arable land. Low temporal yield stability is one of the reasons held responsible for the low proportion of grain legumes, without sufficient quantitative evidence. The objective of this study was to compare the yield stability of grain legumes with other crop species in a northern European context and accounting for the effects of scale in the analysis and the data. To avoid aggregation biases in the yield data, we used data from long-term field experiments. The experiments included grain legumes (lupin, field pea, and faba bean), other broad-leaved crops, spring, and winter cereals. Experiments were conducted in the UK, Sweden, and Germany. To compare yield stability between grain legumes and other crops, we used a scale-adjusted yield stability indicator that accounts for the yield differences between crops following Taylor's Power Law. Here, we show that temporal yield instability of grain legumes (30%) was higher than that of autumn-sown cereals (19%), but lower than that of other spring-sown broad-leaved crops (35%), and only slightly greater than spring-sown cereals (27%). With the scale-adjusted yield stability indicator, we estimated 21% higher yield stability for grain legumes compared to a standard stability measure. These novel findings demonstrate that grain legume yields are as reliable as those of other spring-sown crops in major production systems of northern Europe, which could influence the current negative perception on grain legume cultivation. Initiatives are still needed to improve the crops agronomy to provide higher and more stable yields in future.Peer reviewe

A cropping system assessment framework-Evaluating effects of introducing legumes into crop rotations

Methods are needed for the design and evaluation of cropping systems, in order to test the effects of introducing or reintroducing crops into rotations. The interaction of legumes with other crops (rotational effects) requires an assessment at the cropping system scale. The objective of this work is to introduce a cropping system framework to assess the impacts of changes in cropping systems in a participatory approach with experts, i.e., the integration of legumes into crop rotations and to demonstrate its application in two case studies. The framework consists of a rule-based rotation generator and a set of algorithms to calculate impact indicators. It follows a three-step approach: (i) generate rotations, (ii) evaluate crop production activities using environmental, economic and phytosanitary indicators, and (iii) design cropping systems and assess their impacts. Experienced agronomists and environmental scientists were involved at several stages of the framework development and testing in order to ensure the practicability of designed cropping systems. The framework was tested in Vastra Gotaland (Sweden) and Brandenburg (Germany) by comparing cropping systems with and without legumes. In both case studies, cropping systems with legumes reduced nitrous oxide emissions with comparable or slightly lower nitrate-N leaching, and had positive phytosanitary effects. In arable systems with grain legumes, gross margins were lower than in cropping systems without legumes despite taking pre-crop effects into account. Forage cropping systems with legumes had higher or equivalent gross margins and at the same time higher environmental benefits than cropping systems without legumes. The framework supports agronomists to design sustainable legume-supported cropping systems and to assess their impacts. (C) 2015 The Authors. Published by Elsevier B.V.Peer reviewe

Procollagen Triple Helix Assembly: An Unconventional Chaperone-Assisted Folding Paradigm

Fibers composed of type I collagen triple helices form the organic scaffold of bone and many other tissues, yet the energetically preferred conformation of type I collagen at body temperature is a random coil. In fibers, the triple helix is stabilized by neighbors, but how does it fold? The observations reported here reveal surprising features that may represent a new paradigm for folding of marginally stable proteins. We find that human procollagen triple helix spontaneously folds into its native conformation at 30–34°C but not at higher temperatures, even in an environment emulating Endoplasmic Reticulum (ER). ER-like molecular crowding by nonspecific proteins does not affect triple helix folding or aggregation of unfolded chains. Common ER chaperones may prevent aggregation and misfolding of procollagen C-propeptide in their traditional role of binding unfolded polypeptide chains. However, such binding only further destabilizes the triple helix. We argue that folding of the triple helix requires stabilization by preferential binding of chaperones to its folded, native conformation. Based on the triple helix folding temperature measured here and published binding constants, we deduce that HSP47 is likely to do just that. It takes over 20 HSP47 molecules to stabilize a single triple helix at body temperature. The required 50–200 µM concentration of free HSP47 is not unusual for heat-shock chaperones in ER, but it is 100 times higher than used in reported in vitro experiments, which did not reveal such stabilization

Efficient solvers for nonlinear time-periodic eddy current problems

This work deals with all aspects of the numerical simulation of nonlinear time-periodic eddy current problems, ranging from the description of the nonlinearity to an efficient solution procedure. Due to the periodicity of the solution, we suggest a truncated Fourier series expansion, i.e. a so-called multiharmonic ansatz, instead of a costly time-stepping scheme. Linearization is done by a Newton iteration, where the preconditioning of the linearized problems is a special issue: Since the matrices are non-symmetric, we need a special adaptation of a multigrid preconditioner to our problem. Eddy current problems comprise another difficulty that complicates the numerical simulation, namely the formation of extremely thin boundary layers. This challenge is handled by means of adaptive mesh refinement.

Numerical Analysis of Nonlinear Multiharmonic Eddy Current Problems

This work provides a complete analysis of eddy current problems, ranging from a proof of unique solvability to the analysis of a multiharmonic discretization technique. For proving existence and uniqueness, we use a Schur complement approach in order to combine the structurally di#erent results for conducting and non-conducting regions. For solving the time-dependent problem, we take advantage of the periodicity of the solution. Since the sources usually are alternating current, we propose a truncated Fourier series expansion, i.e. a so-called multiharmonic ansatz, instead of a costly time-stepping scheme. Moreover, we suggest to introduce a regularization parameter for the numerical solution, what ensures unique solvability not only in the factor space of divergence-free functions, but in the whole space H(curl). Finally, we provide estimates for the errors that are due to the truncated Fourier series, the spatial discretization and the regularization parameter.