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N-Freisetzung durch Ölrettich- und Weizenwurzeln unter Bodenbedingungen

  • Annette Deubel
  • Wolfgang Merbach
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Abstract

Knowledge about net-N release of living plant roots is of great importance for balance nitrogen in agrarian ecosystems and for calculation of N fertilization. In order to quantify this process spring wheat (Triticum aestivum) and oil radish (Raphanus sativus) were grown for six weeks in pots containing a 1: 1 (w/w) mixture of soil and quartz sand. 15N was applied three times to the shoots as 15NH3 for three hours (100 ppm NH3 with 95 at.-% 15Nexc). Seven days after the last labelling period (tillering stage of wheat) first plants were harvested. Second harvest took place 18 days after last labelling (shooting stage). Total N and 15N were measured in shoots, roots, and soil compartments using an elemental analyzer coupled with an emission spectrometer.

Both plant species assimilated 55 % of the 15N offered. After one weak approximately 80% of the 15N incorporated by the plants were found in the shoots, 11...12 % in the roots and 6...7 % had been released in the soil. Net N release of wheat roots increased up to the second harvest significantly (11 %) while root portion declined to 8 %. In contrast in the case of oilradish, N distribution was almost the same in both development stages, e. g. the N release seems to be in balance with re-incorporation in this time.

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Literaturverzeichnis

  1. Gransee, A.; Wiitenmayer, L., 2000: Qualitative and quantitative analysis of water-soluble root exudates in relation to plant species and development. Journal of Plant Nutrition and Soil Science163, 381–385.CrossRefGoogle Scholar
  2. Janzen, H. H., 1990: Deposition of nitrogen into the rhizosphere by wheat roots. Soil Biology and Biochemistry22, 1155–1160.CrossRefGoogle Scholar
  3. Janzen, H. H.; Bruinsma, Y., 1989: Methodology for the quantification of root and rhizosphere nitrogen dynamics by exposure of shoots to nitrogen-15 labelled ammonia. Soil Biology and Biochemistry21, 189–196.CrossRefGoogle Scholar
  4. Merbach, W.; Mirus, E.; Jäger, R.; Remus, R.; Ruppel, S.; Russow, R.; Gransee, A., 1997: Freisetzung von C- und N-Verbindungen durch Pflanzenwurzeln und ihre mögliche ökologische Bedeutung. Mitteilungen der Deutschen Bodenkundlichen Gesellschaft85, 695–698.Google Scholar
  5. Merbach, W.; Mnws, E.; Knot, G.; Remus, R.; Ruppel, S., Russow, R.; Gransee, A.; Schulze, J., 1999: Release of carbon and nitrogen compounds by plant roots and their possible ecological importance. Journal of Plant Nutrition and Soil Science162, 373–383.CrossRefGoogle Scholar
  6. Merbach, W.; Reining, E.; Knof, G., 1995: 15N-Freisetzung durch Weizenwurzeln in einen sandigen Boden Nordostdeutschlands. Mitteilungen der Deutschen Bodenkundlichen Gesellschaft76, 883–886.Google Scholar
  7. Merbach, W.; Ruppel, S., 1992: Influence of microbial colonization on 15CO2 assimilation and amounts of root-borne 15C compounds in soil. Photosynthetica26, 551–554.Google Scholar
  8. Merbach, W.; Schulze, J., 1998: 15N-Freisetzung durch Weizenwurzeln unter Bodenbedingungen. Mitteilungen der Gesellschaft für Pflanzenbauwissenschaften11, 231–232.Google Scholar
  9. Merbach, W.; Schulze, J.; Richert, M.; Rroço, E.; Mengel, K., 2000: A comparison of different 15N application techniques to study the N net rhizodeposition in the plant-soil system. Journal of Plant Nutrution and Soil Science163, 375–379.Google Scholar
  10. Ofosu-Budu, K. G.; Fujtta, K.; Ogata, J. J., 1990: Excretion of ureides and other nitrogenous compounds by the root system of soybeans at different growth stages. Plant and Soil128, 135–142.CrossRefGoogle Scholar
  11. Reinig, E.; Merbach, W.; Knof, G., 1995: 15N distribution in wheat and chemical fractionation of root-borne 15N in the soil. Isotopes in Environmental and Health Studies31, 345–349.CrossRefGoogle Scholar

Copyright information

© B. G. Teubner GmbH, Stuttgart/Leipzig/Wiesbaden 2001

Authors and Affiliations

  • Annette Deubel
    • 1
  • Wolfgang Merbach
    • 1
  1. 1.Institut für Bodenkunde und PflanzenernährungMartin-Luther-Universität Halle-WittenbergHalle/SaaleDeutschland

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