Soil Variability and Biogeochemical Fluxes: Toward a Better Understanding of Soil Processes at the Land Surface

Core Ideas Pattern recognition techniques can help explain biogeochemical flux variability. Dynamic factors and their impact on biogeochemical flux variability need better identification. Controls on biogeochemical fluxes are time and space scale dependent. Soil biogeochemical fluxes in the vadose zone are characterized by a large degree of variability in space and time. This fact leads to the need for the development and application of appropriate methodologies to better understand the high nonlinearity and complex feedback mechanisms responsible for such fluxes. In this sense, there still exists a lack of knowledge in topics such as the scale dependence of the spatial and temporal variability of the controls on soil moisture and biodegradation rates and the dynamic behavior of flow and transport model parameter, and its association with the presence of roots. Knowledge of the variability of biogeochemical fluxes is needed for assorted applications ranging from natural hazards and environmental pollution risk assessment to agricultural production and water resources management. The contributions to this special section epitomize the ongoing effort toward the characterization, quantification, modeling, and understanding of biogeochemical fluxes in the vadose zone at several spatial and temporal scales. The main progress has been the identification of different controls on soil moisture and biodegradation rates depending on the scale of the study as well as the important dependence of the spatial and temporal variability of biogeochemical fluxes on dynamic properties such as vegetation and weather variables

Charakterisierung der Zusammenset-zung organischer Bodensubstanz an Oberflächen von präferentiellen Fließ-wegen mit DRIFT Spektroskopie

Organische Bodensubstanz (OBS) auf Oberflächen präferentieller Fließwege be-einflusst maßgeblich deren Benetzungs-, Sorptions- und Transporteigenschaften. Die räumliche Verteilung der OBS-Eigenschaften auf intakten Oberflächen von Gefügeelementen wie organo-mineralischen Überzügen, Regenwurm-gängen und Wurzelbahnen ist weitgehend unbekannt. Mittels DRIFT-mapping wird die OBS auf Fließwegen kleinräumig er-fasst. Zur Charakterisierung dient das Ver-hältnis hydrophober zu hydrophiler Grup-pen, das die Hydrophobizität der OSB und damit die potentielle Benetzbarkeit der Oberflächen mit Wasser widerspiegelt, die mit Kontaktwinkelmessungen getestet wird. Die Ergebnisse zeigen räumliche Unter-schiede hinsichtlich Zusammensetzung, Verteilung und Benetzbarkeit der OBS auf Überzüge präferentieller Fließwegoberflä-chen. Dies kann sich auf den präferentiel-len Wasserfluss und die Verlagerung reak-tiver Stoffe auswirken

Frontiers in Hydropedology: Interdisciplinary Research from SoilArchitecture to the Critical Zone

This preface for the special section provides a brief background on hydropedology as an emerging interdisciplinary science. The 10 articles included in this special section stem from presentations given at the third International Conference on Hydropedology held in August 2016 in Beijing, China, which highlighted the importance of soil architecture and preferential flow, soil moisture and hillslope hydrology, hydrologic flux and soil structure interactions at different scales, soil biophysical and biochemical complexity, and Critical Zone science

On the role of hydrologic processes in soil and landscape evolution modeling : concepts, complications and partial solutions

The ability of water to transport and transform soil materials is one of the main drivers of soil and landscape development. In turn, soil and landscape properties determine how water is distributed in soil landscapes. Understanding the complex dynamics of this co-evolution of soils, landscapes and the hydrological system is fundamental in adapting land management to changes in climate. Soil-Landscape Evolution Models (SLEMs) are used to simulate the development and evolution of soils and landscapes. However, many hydrologic processes, such as preferential flow and subsurface lateral flow, are currently absent in these models. This limits the applicability of SLEMs to improve our understanding of feedbacks in the hydro-pedo-geomorphological system. Implementation of these hydrologic processes in SLEMs faces several complications related to calculation demands, limited methods for linking pedogenic and hydrologic processes, and limited data on quantification of changes in the hydrological system over time. In this contribution, we first briefly review processes and feedbacks in soil-landscape-hydrological systems. Next, we elaborate on the development required to include these processes in SLEMs. We discuss the state-of-the-art knowledge, identify complications, give partial solutions and suggest important future development. The main requirements for incorporating hydrologic processes in SLEMs are: (1) designing a model framework that can deal with varying timescales for different sets of processes, (2) developing and implementing methods for simulating pedogenesis as a function of water flow, (3) improving and implementing knowledge on the evolution and dynamics of soil hydraulic properties over different timescales, and (4) improving the database on temporal changes and dynamics of flow paths.</p

Neue Techniken zur Kompostierung. Teilvorhaben 10/2: Modellgestuetzte Abschaetzung der Stickstoff- und Humusdynamik zur Optimierung von Bodenzustand und Nitratauswaschung bei langfristiger Kompostanwendung auf ackerbaulich genutzten Standorten. T. 1: Sensitivitaetsanalysen, Modellkalibrierung, Basiszenarien Abschlussbericht

SIGLEAvailable from TIB Hannover: F99B1588 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman