Nitrogen transformation in arable soils of North-West Germany during the cereal growing season |
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Authors: | R Nieder E Neugebauer A Willenbockel K C Kersebaum J Richter |
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Institution: | (1) Institut für Geographie und Geoökologie, Technische Universität Carolo Wilhemina, Langer Kamp 19c, D-38106 Braunschweig, Germany;(2) Institut für Ökosystem-und Prozeßmodellierung, ZALF, Eberswalder Strasse 84, D-15374 Müncheberg, Germany |
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Abstract: | In 1991, field experiments on loess (with winter wheat) and sandy soils (with summer barley) were conducted to study N dynamics in the microbial biomass and non-exchangeable NH
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. The measurements showed a mass change in microbial N, with a maximum increase of 100 kg N ha-1 30 cm-1 from March to July in the loess soil, and a change for only 1 month (May) in the sandy soil. Plots treated with conventional levels of N fertilizer (213 kg N ha-1 on a loess soil to winter wheat and 130 kg ha-1 on the sandy soil to summer barley), reduced levels of N (83% and 62% of the conventional N application), or no N showed no consistent fertilizer N effect on microbial biomass N. From March to July, non-exchangeable NH
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in loess soils under winter wheat decreased by 110 kg N ha-1 30 cm-1 in conventionally fertilized plots and by 200 kg N ha-1 30 cm-1 in a plot with no N fertilizer. After harvest, the pool of non-exchangeable NH
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increased due to increasing mineral N concentrations in the soil. |
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Keywords: | Microbial N Immobilization Remobilization NH
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fixation Exchangeable NH
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