Pelargonic acid for weed control in onions: factors affecting selectivity

In Zwiebeln (Allium cepa) sind nur wenige Herbizide bewilligt. Aufgrund ihrer aufrecht stehenden Blätter und aufrechten Pflanzenarchitektur bleibt an den Zwiebelpflanzen nach der Applikation weniger Herbizid haften als an breitblättrigen Unkräutern. Außerdem haben sie eine dickere Cuticula. Diese Unterschiede machen einen selektiven Einsatz von Pelargonsäure in Zwiebeln möglich. Das Hauptziel dieser Arbeit war, verträgliche Aufwandmengen für unterschiedliche Wachstumsstadien zu bestimmen. In 5 Feldversuchen wurden 3 Pelargonsäure-haltige Produkte (1 SL- und 2 EC-Formulierungen) mit einem Logsprayer appliziert. Zwischen 0 und 56 kg Aktivsubstanz (a.s.) ha-1 wurden appliziert. Die Zwiebelstadien reichten von BBCH 10 bis 16. Die Verträglichkeit wurde visuell bonitiert. Die Produkte waren verträglich mit jeweils 7.2 und 8.3 ka a.s. ha-1 (BBCH 10-11), 6.1 und 8.9 ka a.s. ha-1 (BBCH 11-12), 8.5 und 20.7 ka a.s. ha-1 (BBCH 13) sowie mit 6.3 und 9.0 kg a.s. ha-1 (BBCH 14-16) für die SL- bzw. die EC-Formulierungen. Die Verträglichkeit hing vom Kulturstadium und den Wetterbedingungen ab. Wichtig für einen selektiven Einsatz in Zwiebeln ist eine intakte Wachsschicht, was eine regenfreie, lichtintensive Periode vor der Applikation bedingt. Pelargonsäure könnte eine wirksame Komponente für eine nachhaltige Unkrautbekämpfung in Zwiebeln werden. Aufgrund der reinen Blattwirkung müssen kleine Unkräuter behandelt werden und es sind mehrere Applikationen notwendig.In onions (Allium cepa) few herbicides are registered. Due to their erect leaf and plant structure, onions retain less herbicide after spraying than broadleaved weeds. Further, onion plants have a thicker plant cuticle. These differences allow a selective use of pelargonic acid in onions. The main aim of this study was to determine the selective dose at different crop growth stages. Five field trials were carried out. Three pelargonic acid containing products (1 SL- and 2 EC-formulations) were applied with a logarithmic sprayer. Dose range was 0 to 56 kg active substance (a.s.) ha-1. The growth stage varied between BBCH 10 and 16. Selectivity was rated visually. The products were selective at 7.2 and 8.3 kg a.s. ha-1 (BBCH 10-11), 6.1 and 8.9 kg a.s. ha-1 (BBCH 11-12), 8.5 and 20.7 kg a.s. ha-1 (BBCH 13) and 6.3 and 9.0 kg a.s. ha-1 (BBCH 14-16) for the SL- and EC-products respectively. Selectivity depended on growth stage and weather conditions. Important for selectivity is an intact cuticle, a rain-free, light-intense period before application. Pelargonic acid could become a component for sustainable weed control in onions. Due to its foliar activity, small weeds need to be targeted and several passes are required

Tuning the structural instability of SrTiO_3 by Eu doping: The phase diagram of Sr_1-xEu_xTiO_3

The phase diagram of Sr_1-xEu_xTiO_3 is determined experimentally by electron paramagnetic resonance and resistivity measurements and analyzed theoretically within the self-consistent phonon approximation as a function of x ([0.03-1.0]). The transition temperature of the structural instability of the system increases nonlinearly to higher temperatures with increasing x. This is interpreted theoretically by a substantial alteration in the dynamics caused by a change in the double-well potential from broad and shallow to narrow and deep.Comment: 15 pages, 5 figure

Gr\"obner bases of syzygies and Stanley depth

Let F. be a any free resolution of a Z^n-graded submodule of a free module over the polynomial ring K[x_1, ..., x_n]. We show that for a suitable term order on F., the initial module of the p'th syzygy module Z_p is generated by terms m_ie_i where the m_i are monomials in K[x_{p+1}, ..., x_n]. Also for a large class of free resolutions F., encompassing Eliahou-Kervaire resolutions, we show that a Gr\"obner basis for Z_p is given by the boundaries of generators of F_p. We apply the above to give lower bounds for the Stanley depth of the syzygy modules Z_p, in particular showing it is at least p+1. We also show that if I is any squarefree ideal in K[x_1, ..., x_n], the Stanley depth of I is at least of order the square root of 2n.Comment: 13 page

Efficacy of herbicides against yellow nutsedge (Cyperus esculentus) plants originating from seeds

Erdmandelgras (Cyperus esculentus) ist ein gefürchtetes Unkraut. Es vermehrt und breitet sich hauptsächlich über Knöllchen aus. Es werden aber auch keimfähige Samen gebildet. Die Samen sind klein und verfügen dementsprechend über wenig Speicherstoffe. Erdmandelgrassämlinge sind zart gebaut und ähneln Süßgräsern (Poaceae). Daher vermuteten wir, dass Erdmandelgrassämlingspflanzen sensibler auf Herbizide reagieren als aus Knöllchen gekeimte Pflanzen. Im Gewächshaus wurden Erdmandelgraspflanzen aus Samen angezogen und mit Glyphosat, Bentazon, Bromoxynil, Pelargonsäure und Clethodim behandelt. Die Herbizidwirksamkeit wurde geschätzt und die Anzahl gebildeter Knöllchen bestimmt. Kein Verfahren zeigte eine volle Wirkung. 4 Wochen nach Behandlung konnte eine Wuchsreduktion um 84 % und 34 % in den Verfahren Glyphosat resp. Bentazon im Vergleich zur unbehandelten Kontrolle beobachtet werden. Bei den anderen Verfahren lag die Wuchsreduktion unter 15 %. In den Verfahren Glyphosat und Bentazon wurden deutlich weniger Knöllchen gebildet als in der unbehandelten Kontrolle. Zusammenfassend konnten wir unsere Hypothese nicht bestätigen. Bereits 6 Wochen nach Keimung waren die Sämlinge robust, vergleichsweise tolerant gegenüber den applizierten Herbiziden mit Ausnahme von Glyphosat und Bentazon und bildeten Knöllchen. Das bedeutet, dass bereits nach sehr kurzer Zeit aus Samen entstandene Erdmandelgrasnester die gleichen Probleme verursachen wie aus Knöllchen entstandene.Yellow nutsedge (Cyperus esculentus) is a troublesome weed. It reproduces and spreads mainly via tubers, but also viable seeds are produced. The seeds are very small and have little resources stored. The seedlings are very fragile and look like grasses (poaceae). We hypothesized that C. esculentus plants originating from seeds are more susceptible to herbicides than plants originating from tubers. Cyperus esculentus plants grown from seeds in the greenhouse were treated with glyphosate, bentazone, bromoxynil, pelargonic acid and clethodim. Herbicide efficacy was rated and produced tubers were counted. None of the treatments achieved full control. Four weeks after application a growth reduction of 84% was observed in the glyphosate treatment, whereas bentazone reduced growth by 34% compared to the control. In the other treatments, growth reduction was < 15%. In the glyphosate and bentazone treatment, considerably fewer tubers were produced than in the control. Concluding, we could not confirm our hypothesis. Already 6 weeks after germination seedlings were well developed, tolerant to the sprayed herbicides, except for glyphosate and bentazone, and produced tubers. This implies, that already after a short time Cyperus esculentus stands originating from seeds pose the same problems as the ones originating from tubers

The challenge to determine a company’s process maturity: a case study from the financial services industry

Purpose. Conducting projects to improve a company’s business processes is of utmost importance in all industries and countries. Many companies have installed specific organizational units to develop guidelines for process design, to document and maintain of these processes, and to further increase the processes’ efficiency. Although these enterprises continually work on improving their processes, they often struggle to answer the question on the current status of the maturity of their processes. Therefore, the purpose of this work is to characterize the methodology, applicability, pitfalls and benefits of analyzing the maturity of processes. Design/Method/Approach. This work is based on mixed-methods research recently conducted in a medium-sized German bank. Findings. The paper defined the benefits of measuring the level of maturity of the company’s processes clearly. This work identified the substantial theoretical drawbacks, such as, for example, the lack of considering of process innovation in the extant models of process maturity. Limitations. Naturally, a research limitation is the analysis of a specific company in the financial services sector. Theoretical implications. From a theoretical point of view it is critical to choose the appropriate model out of a variety of available process maturity models. In fact, the selection of the model influences the data, the subsequent interpretation of these data, and the conclusions to be drawn for the company. Originality/Value. The paper is novel as it presents–based on empirical data–the measurement of process maturity including the derivation of implications from both an academic and a practical perspective. In addition, the impact of process maturity on perceived process performance could be shown.  Paper type – empirical

Activity of comets: Gas Transport in the Near-Surface Porous Layers of a Cometary Nucleus

The gas transport through non-volatile random porous media is investigated numerically. We extend our previous research of the transport of molecules inside the uppermost layer of a cometary surface (Skorov and Rickmann, 1995; Skorov et al. 2001). We assess the validity of the simplified capillary model and its assumptions to simulate the gas flux trough the porous dust mantle as it has been applied in cometary physics. A new microphysical computational model for molecular transport in random porous media formed by packed spheres is presented. The main transport characteristics such as the mean free path distribution and the permeability are calculated for a wide range of model parameters and compared with those obtained by more idealized models. The focus in this comparison is on limitations inherent in the capillary model. Finally a practical way is suggested to adjust the algebraic Clausing formula taking into consideration the nonlinear dependence of permeability on layer porosity. The retrieved dependence allows us to accurately calculate the permeability of layers whose thickness and porosity vary in the range of values expected for the near-surface regions of a cometary nucleus.Comment: 25 pages, 9 figure

Validation of yellow nutsedge (Cyperus esculentus) control strategies in maize in an on-farm, large-scale field trial

A large on-farm field trial was carried out between 2013 and 2015 to investigate the effect of repetitive maize cropping on Cyperus esculentus infestation over time. Intensive control strategies, developed and investigated in small-scale trials, were validated. Four C. esculentus treatment strategies were installed. Soil samples were taken each year put in the greenhouse and the number of C. esculentus sprouts was assessed. Initial infestation was patchy. Field areas were flooded several times due to heavy rainfall. Despite the inherent variability and the adverse weather conditions following conclusions can be drawn: Growing maize combined with intensive weed control (2-4 passes), reduced infestation on average by 80%. Principal components for Cyperus esculentus control strategies are hoeing, the active substances S-metolachlor, mesotrione, terbuthylazine, rimsulfuron, bentazone, and a herbicide containing foramsulfuron, thiencarbazone and iodosulfuron. Growing maize combined with high intensity weed control is an effective approach to manage and reduce C. esculentus infestation. Yield depressions due to this highly intensive weed control cannot be rule out. Nevertheless, farmers in the affected region have adopted these approaches