Simulating the soil phosphorus dynamics of four long-term field experiments with a novel phosphorus model |
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Authors: | S. Anton A. Gasser Kerstin Nielsen Bettina Eichler-Löbermann Martin Armbruster Ines Merbach Uwe Franko |
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Affiliation: | 1. Helmholtz Centre for Environmental Research GmbH – UFZ, Halle (Saale), Germany;2. Lebenswissenschaftliche Fakultät, Institut für Agrar-und Stadtökologische Projekte an der Humboldt-Universität zu Berlin (IASP), Berlin, Germany;3. Agronomy and Crop Science, University of Rostock, Rostock, Germany;4. Agricultural Analytical and Research Institute Speyer (LUFA Speyer), Speyer, Germany |
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Abstract: | Phosphorus is a nonrenewable resource, which is required for crop growth and to maintain high yields. The soil P cycle is very complex, and new model approaches can lead to a better understanding of those processes and further guide to research gaps. The objective of this study was to present a P-submodel, which has been integrated in the existing Carbon Candy Balance (CCB) model that already comprises a C and N module. The P-module is linked to the C mineralization and the associated C-pools via the C/P ratio of fresh organic material. Besides the organic P cycling, the module implies a plant-available P-pool (Pav), which is in a dynamic equilibrium with the nonavailable P-pool (Pna) that comprises the strongly sorbed and occluded P fraction. The model performance was tested and evaluated on four long-term field experiments with mineral P fertilization, farmyard manure as organic fertilizer and control plots without fertilization. The C dynamics and the Pav dynamics were modelled with overall good results. The relative RMSE for the C was below 10% for all treatments, while the relative RMSE for Pav was below 15% for most treatments. To accommodate for the rather small variety of available P-models, the presented CNP-model is designed for agricultural field sites with a relatively low data input, namely air temperature, precipitation, soil properties, yields and management practices. The CNP-model offers a low entry threshold model approach to predict the C-N and now the P dynamics of agricultural soils. |
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Keywords: | CNP-model soil P dynamics soil process modelling total P and available P |
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