Description: When organic material is available, soil microorganisms may either take up simple organic molecules directly and release the surplus nitrogen (N) into the soil in the form of ammonium (NH4+), or they may mineralize organic N first and take it up in the form of NH4+. The route of N uptake has implications for the competition for N between microorganisms and plants and therefore for the N nutrition of crops. The objective of the proposed study is to gain a better understanding of the factors controlling the relative importance of the two N utilization routes by soil microorganisms. In a first step, an assay to determine the extent of the extracellular deamination of amino acids in soil shall be developed and tested. In a second step, the new assay shall be applied in laboratory incubations in combination with other methods, namely gross N mineralization, mineralization of amino acid-N, and natural 15N abundance of the microbial biomass, to determine the factors affecting the relative importance of the two N uptake routes. In a third step, the same methods shall be applied in a field study, which will focus of the temporal effects of fertilization management, including organic and mineral fertilizers, and the interactions with crops.
SupportProgram
Origins: /Bund/UBA/UFORDAT
Tags: Ammonium ? Mineraldünger ? Stickstoff ? Bodenkunde ? Bodenmikroorganismen ? Pflanzenernährung ? Studie ? Mikroorganismen ? Biomasse ?
Region: Hessen
Bounding boxes: 9° .. 9° x 50.55° .. 50.55°
License: cc-by-nc-nd/4.0
Language: Englisch/English
Time ranges: 2011-01-01 - 2025-08-16
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