Ecomat und Dammkultur – Alternative Bodenbearbeitungssysteme im Ökologischen Landbau – Erste Ergebnisse aus einem Exaktversuch

In the interdisciplinary research project a field experiment of alternative tillage systems in organic farming was installed. Ridge till system from Turiel-Major and Ecomat-system from Kverneland will be compared with conventional ploughing system. Within the project, located on the experimental farm of the University of Kassel, regular yearly workshops are led. Due to the regular contact with farmers, advisers, developers and scientists knowledge of practice will be carried into scientific research, the transfer of knowledge will be carried on. The change to the Ecomat-system is simple. Take notice that after very shallow till-age, like stubble cultivation (short stubble) or turning grass-clover, the following tillage has to be done a few cm deeper. In the year of implementing the Ecomat-system there were no decreases in yields. The mineralization of Nitrogen was the same as in the ploughing system. When changing to the ridge till system the width of the dams (90 cm) must fit to the track width, planting and harvesting equipment. After stubble cultivation in the ridge till system mineralization of N increased. This N was taken up by the catch crop. Leaching of N is not expected. Even in the first year after changing the tillage systems the alternative systems Eco-mat and ridge till showed higher saturated hydraulic conductivity than the conventional ploughing system. This leads to much lower susceptibility of soil erosion when using these soil layer conservation systems

Samenfeste Sorten oder Hybriden - Untersuchungen an Speisemöhren aus einem Anbauvergleich an zwei Standorten des Ökologischen Landbaus

An zwei Standorten des Ökologischen Landbaus (Neu-Eichenberg, Nordhessen: mittlerer bis schwerer Boden; Queck, Osthessen: leichter Boden) wurden Feldversuche mit Möhren durchgeführt, um sechs samenfeste Sorten und sechs Hybriden auf ihre Anbautauglichkeit zu prüfen. Außer der Roh- und Handelswarenerträge wurden die Einheitlichkeit des Erntegutes (cv%) bestimmt und die Gehalte an Mineralstoffen (K, Ca, P, Mg) und Zuckern (D-Glucose, D-Fructose, Saccharose) analysiert. Auch sogenannte Bildschaffende Methoden (Kupferchloridkristallisation, Steigbild, Rundfilterchromatogramm) kamen zur Anwendung. Die untersuchten Hybriden erzielten Mehrerträge von 25 bis 29% und in den meisten Fällen auch gleichmäßiger lange Rüben als die Samenfesten. Die Inhaltsstoffuntersuchungen zeigten höhere Mineralstoffgehalte und niedrigere Quotienten von Mono- zu Disaccharide bei den samenfesten Sorten. Mithilfe der Bildschaffenden Methoden konnten die Proben blind klar in zwei unterschiedliche Gruppen differenziert werden: Die Bilder der samenfesten Sorten waren im Vergleich zu denjenigen der Hybriden geprägt durch einen höheren Grad an Formintensität und Reife

Samenfeste Sorten oder Hybriden - Anbauvergleich von Möhren unter den Verhältnissen des Ökologischen Landbaus

A field trial with carrots was carried out in 1998 at two sites in Hesse (North: loamy soil in Neu-Eichenberg; East: sandy soil in Queck) to compare 6 open pollinating and 6 F1 hybrids under an Organic Farming regime. Characteristics of cultivation, harvest, quality, and longevity were measured. Of the parameters of cultivation and harvest the hybrids showed a more intensive foliage growth, higher marketable yields (plus 29 and 25%), and more homogeneous taproots than the open pollinating cultivars. Picture forming methods clearly separated the samples into the two groups of breeding methods. The open pollinating cultivars were characterized by higher degrees of form intensity and ripeness and a stable vitality. The hybrids of the sandy site had a better keeping quality after 6½ months storage, only the open pollinating cultivar ‘Rodelika’ had a very high ranking similar to the hybrids ‘Kardame F1’ and ‘Bolero F1’

Bestimmung der N-Fixierung unterschiedlicher Wintererbsengenotypen im Vergleich zu einer Sommererbse in Rein- und Gemengesaat

In organic farming the cultivation of leguminous crops is one of the most important sources of nitrogen (N). However, regarding the amount of N fixed, there are hardly any published data for winter peas. Therefore, the N fixation of five regular leafed winter peas types and one semi-leafless spring pea cultivar in single and mixed cropping (with winter rye spring cereals respectively) was measured in four successive growing seasons (2003/04 – 2006/07) at the experimental farm of the University of Kassel and in two consecutive vegetation periods (2005/06 - 2006/07) at the experimental farm of the University of Applied Science in Osnabrueck. The amount of N fixed was calculated according to the extended difference method at the beginning of flowering and at grain harvest. N fixation was usually higher for winter peas than for spring pea. At the beginning of flowering the amount of N fixed in pure stands was with a mean value of 92 kg ha-1 for winter peas and 29 kg ha-1 for the spring pea higher than in mixture with a mean value of 42 and 15 kg ha-1 respectively. At grain harvest the amount of N fixed for the spring pea in pure stands was higher than in mixtures with a mean of 65 and 33 kg ha-1 respectively. On the other hand the N fixation for winter peas was usually comparable in pure and mixed stands with a mean of 100 and 86 kg ha-1 respectively. This was a consequence of the higher pea grain yield in mixture than in pure stands and of a reduced biomass (leaves) loss in mixtures. Therefore, regular leaf winter peas can contribute to the N supply of the crop rotation better than spring peas

Semi- and Non-relativistic Limit of the Dirac Dynamics with External Fields

We show how to approximate Dirac dynamics for electronic initial states by semi- and non-relativistic dynamics. To leading order, these are generated by the semi- and non-relativistic Pauli hamiltonian where the kinetic energy is related to $\sqrt{m^2 + \xi^2}$ and $\xi^2 / 2m$, respectively. Higher-order corrections can in principle be computed to any order in the small parameter v/c which is the ratio of typical speeds to the speed of light. Our results imply the dynamics for electronic and positronic states decouple to any order in v/c << 1. To decide whether to get semi- or non-relativistic effective dynamics, one needs to choose a scaling for the kinetic momentum operator. Then the effective dynamics are derived using space-adiabatic perturbation theory by Panati et. al with the novel input of a magnetic pseudodifferential calculus adapted to either the semi- or non-relativistic scaling.Comment: 42 page