Auswirkungen unterschiedlicher S Versorgungszustände auf den N Flächenertrag eines Luzerne-Kleegrasbestandes

Die Untersuchung zeigt den Effekt einer Schwefel-Düngung auf den Ertrag eines Luzerne-Kleegrasbestandes, angebaut auf dem Versuchsbetrieb Gladbacherhof. Die S-Düngung hat einen bis zu 70%igen (90kgN *ha-1) Ertragsanstieg des Gesamtgemenges induziert. Dieser Ertragsanstieg war das Resultat einer höheren N-Konzentration und einem höheren TS-Ertrag der Leguminosen

Einfluss von Schwefel- und Stickstoffdüngung auf den Kornertrag von Winterraps in ökologischem Anbau

Die Untersuchung zeigt Effekte von Schwefel- und Stickstoffgaben auf den Kornertrag von Winterraps

Benefit of Sulfate fertilisation in Alfalfa - and clover-grass mixtures in organic farming

The study shows the effect of sulfur (S) fertilization of an alfalfa clover-grass mixture, cultivated on the experimental farm Gladbachhof. Induced by the S fertilization the yield and N and S concentration were positiv influenced

Wirkung einer Schwefeldüngung zu einem Luzerne-Kleegras-Bestand auf den Kornertrag der Nachfrucht Winterweizen

In this study clover-grass was fertilized with MgSO4 (40 kg S*ha-1 and 80 kg S*ha-1) and CaSO4 (80 kg S*ha-1). The yield of the following crop winter wheat was clearly positive affected by fertilizing sulphur in the clover grass

The importance of nodule CO2 fixation for the efficiency of symbiotic nitrogen fixation in pea at vegetative growth and during pod formation

Nodule CO2 fixation is of pivotal importance for N2 fixation. The process provides malate for bacteroids and oxaloacetate for nitrogen assimilation. The hypothesis of the present paper was that grain legume nodules would adapt to higher plant N demand and more restricted carbon availability at pod formation through increased nodule CO2 fixation and a more efficient N2 fixation. Growth, N2 fixation, and nodule composition during vegetative growth and at pod formation were studied in pea plants (Pisum sativum L.). In parallel experiments, 15N2 and 13CO2 uptake, as well as nodule hydrogen and CO2 release, was measured. Plants at pod formation showed higher growth rates and N2 fixation per plant when compared with vegetative growth. The specific activity of active nodules was about 25% higher at pod formation. The higher nodule activity was accompanied by higher amino acid concentration in nodules and xylem sap with a higher share of asparagine. Nodule 13CO2 fixation was increased at pod formation, both per plant and per 15N2 fixed unit. However, malate concentration in nodules was only 40% of that during vegetative growth and succinate was no longer detectable. The data indicate that increased N2 fixation at pod formation is connected with strongly increased nodule CO2 fixation. While the sugar concentration in nodules at pod formation was not altered, the concentration of organic acids, namely malate and succinate, was significantly lower. It is concluded that strategies to improve the capability of nodules to fix CO2 and form organic acids might prolong intensive N2 fixation into the later stages of pod formation and pod filling in grain legumes

der Georg-August-Universität Göttingen

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