caa a22 4500 477109985 CHVBK 20180405111606.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF00011295 doi (NATIONALLICENCE)springer-10.1007/BF00011295 Mengel K. Institute of Plant Nutrition of the Justus Liebig University, Südenlage, 35390, Giessen, Germany aut Turnover of organic nitrogen in soils and its availability to crops [Elektronische Daten] [K. Mengel] Major known fractions of soil nitrogen are amino nitrogen (proteins, peptides), polymers of amino sugars, and NH4 + fixed in interlayers of 2:1 minerals. Only a small percentage of the total soil organic N is easily mineralizable and contributes to the pool of mineral soil N. Predominant sources of mineralization are amino-N and polymers of amino sugars present in the soil microbial biomass. Influx into this pool occurs with the application of organic matter (green manure, straw), organic carbon released by plant roots, N2 assimilation by leguminous species and inorganic nitrogen. Microbial metabolization of green manure proteins results in a partial mineralization of the applied organic N, microbial metabolization of straw in the assimilation (immobilization) of inorganic nitrogen. Microbial biomass is characterized by a narrow C/N ratio (proteins, peptidoglycans, polymers of amino sugars). Its metabolization therefore is associated with a partial mineralization of the attacked organic nitrogen compounds. Nitrogen mineralization consists of a sequence of enzymatic processes for which the living microbial biomass provides the enzymes and the dead microbial biomass the substrate. Kluwer Academic Publishers, 1996 amino sugars nationallicence fixed NH4+ nationallicence immobilization nationallicence mineralization nationallicence nitrogen nationallicence proteins nationallicence Plant and Soil Kluwer Academic Publishers; gopher://gopher.wkap.nl 181/1(1996-04-01), 83-93 0032-079X 181:1<83 1996 181 11104 https://doi.org/10.1007/BF00011295 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00011295 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Mengel K. Institute of Plant Nutrition of the Justus Liebig University, Südenlage, 35390, Giessen, Germany aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers; gopher://gopher.wkap.nl/ 181/1(1996-04-01), 83-93 0032-079X 181:1<83 1996 181 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer