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The European Commission has set targets for a reduction in nutrient losses by at least 50% and a reduction in fertiliser use by at least 20% by 2030 while ensuring no deterioration in soil fertility. Within the mandate of the European Joint Programme EJP Soil ‘Towards climate-smart sustainable management of agricultural soils’, the objective of this study was to assess current fertilisation practices across Europe and discuss the potential for harmonisation of fertilisation methodologies as a strategy to reduce nutrient loss and overall fertiliser use. A stocktake study of current methods of delivering fertilisation advice took place across 23 European countries. The stocktake was in the form of a questionnaire, comprising 46 questions. Information was gathered on a large range of factors, including soil analysis methods, along with soil, crop and climatic factors taken into consideration within fertilisation calculations. The questionnaire was completed by experts, who are involved in compiling fertilisation recommendations within their country. Substantial differences exist in the content, format and delivery of fertilisation guidelines across Europe. The barriers, constraints and potential benefits of a harmonised approach to fertilisation across Europe are discussed. The general consensus from all participating countries was that harmonisation of fertilisation guidelines should be increased, but it was unclear in what format this could be achieved. Shared learning in the delivery and format of fertilisation guidelines and mechanisms to adhere to environmental legislation were viewed as being beneficial. However, it would be very difficult, if not impossible, to harmonise all soil test data and fertilisation methodologies at EU level due to diverse soil types and agro-ecosystem influences. Nevertheless, increased future collaboration, especially between neighbouring countries within the same environmental zone, was seen as potentially very beneficial. This study

SuMaNu Interreg BSR Platform Project

Due to higher proportions of labile carbon (C) compounds the suitability of biochar produced by hydrothermal carbonization (HTC) for C sequestration is questionable. We hypothesized that pre-treatment with water would reduce the biological decay of hydrochar from sewage sludge. Unwashed and washed feedstock and hydrochar were incubated in a short-term experiment. The kinetics of the biological decomposition of the materials was calculated on the basis of a double exponential model and the C sequestration potential using the CANDY Carbon Balance (CCB) model. Biological decomposition of the carbonized materials was governed by the percentage of labile C compounds. Mean residence time of a fast (MRTfast) and slow decay pool (MRTslow) of unwashed hydrochars varied clearly (MRTfast: 0.8 – 5.0 months and the MRTslow: 5.0 – 18.6 months). The pre-treatment with water removed labile hydrochar C and reduced the biological accessibility. MRTfast and MRTslow was increased by intensive washings (MRTfast: 5.0 – 7.4 months and the MRTslow: 14.9 months). High synthesis coefficients suggest that hydrochar C was humified and transferred into stabilized SOC. The results clearly show that once adsorbed components were eliminated, and as compared to pyrolysed biochar hydrochar from sewage sludge may also be useful for soil C sequestration.

Electrical resistivity tomography (ERT) is one method for mapping and monitoring of the vadose zone. However the relation between the sensed physical properties (e.g., resistivity) and the soil parameter of interest is ambiguous and often not or only poorly understood. This study was carried out to quantify soil properties and the distribution of roots in a soil profile under field conditions at different time steps during the vegetation period. In our abstract we will focus on the investigation of pedogeophysical relationships between soil physical and plant physiological properties and electrical resistivity. The relationship with soil water content varies with the time (root growth). At both time steps we find a nearly constant medium correlation of electrical resistivity and root parameters.

Electrical resistivity tomography (ERT) is one method for mapping and monitoring of the vadose zone. However the relation between the sensed physical properties (e.g., resistivity) and the soil parameter of interest is ambiguous and often not or only poorly understood. This study was carried out to quantify soil properties and the distribution of roots in a soil profile under field conditions at different time steps during the vegetation period. In our abstract we will focus on the investigation of pedogeophysical relationships between soil physical and plant physiological properties and electrical resistivity. The relationship with soil water content varies with the time (root growth). At both time steps we find a nearly constant medium correlation of electrical resistivity and root parameters.

Humus-balancing methods are simple tools for the assessment of interactions between agriculturalland use and soil organic matter (SOM). Aside from this commonality, approaches forhumus balancing differ considerably with regard to their specific aim, scope, and methodicalapproach. The term “humus balance” covers both simple models to quantify SOM change in arablesoils, or soil organic C (SOC) change in particular, and models that refer to the optimizationof soil productivity in arable soils by calculating organic-fertilizer demand, without quantifyingSOM or SOC change. This situation naturally has caused much discussion and misunderstandings.Against this background, the aim of this review is to systematically explore the differentmethodical approaches to humus balancing in order to contribute to a more sophisticated discussionof this model family, its opportunities, and limitations. As humus balancing has long historyas well as special actual relevance in Germany, and, lately Switzerland, we focus on thesecountries and discuss the different approaches that are presently available and applied there.We argue that humus balances can be roughly categorized into “ecological” and “agronomical”approaches based on their specific concepts and methodology. Ecological humus balancescomprise a strong link to quantitative SOM change, while humus balances of the agronomicalfamily refer to the maintenance of soil productivity without a quantitative link to SOM change.Lately, some models have been presented that link the two concepts. However, we identify thathumus-balancing methods often are insufficiently validated, partly because the validation ofagronomical humus balances is not easily possible without a very comprehensive field-experimentalbasis. Further, the comparability of different approaches even within the two conceptfamilies is low at present, indicating the need for a comparative model evaluation for a properassessment of the methods.

Can you imagine what happens underneath your feet when you walk across a meadow ? Can you describe how it looks like underground ? What is the structure of the soil, how do the plant roots disperse in the dark ? How is the water distributed within the pore system, which in turn determines matter transformation in soil ? All these questions might be answered when you use the potential of X-ray computed tomography to look into, visualize and quantitatively analyze the soil.For that purpose, you must have soil samples first, and not only one, but a statistically relevant large number of samples! You better have a machine for the non-destructive sampling of soil. Here, we describe the setup and the application of such a machine and show the first macro- and micro-CT scans which we achieved with this method.

Giant spoil dumps originate in the course of open-cast mining. The initial properties of Triassic spoil as well as pedogenesis are characterized by weathering processes. Due to the poor conditions in dump spoil a natural succession of plants or a re-vegetation is a lengthy process. The Chinh Bac field experiment (Ha Long City, Quang Ninh province, Vietnam) was planned to investigate the possible impacts of three amendments – charred rice straw, power station ashes and fine material originating from the mining area in combination with sieved spoil of substrate quality – to enhance plant growth. The main focus of this study was directed towards the impact of added amendments on spoil chemical parameters. The investigations demonstrated that simply sieving the spoil leads to better substrate conditions. It increases the fine material which in turn leads to easier plantation conditions. At the same time oxidative processes and leaching acid products are stimulated which raises the pH values afterwards. The application of charred rice straw increased the amount of alkaline cations, in particular potassium, boosting the pH value. This led to an enhanced supply of nutrients for the plants in comparison to the other amendment variations which were very poor in nutrient availability. Adding power station ash resulted in a short-term pH value increase, however potential pollution caused by heavy metals cannot be ruled out. The pyrite containing fine material was identified as the poorest amendment. It may allow vegetation to grow quickly, however the proceeding weathering processes cause a strong acidification. This mobilizes heavy metal and aluminum ions which prevent healthy plant growth.

Ackerflächen, Wälder, Straßen, Industriegebiete und Städte – sie alle haben gemein, dass ein Flächenbedarf an wertvollem Boden besteht. Boden mit all seinen Funktionen ist uns eine selbstverständliche Lebensgrundlage, die kaum wahrgenommen wird. Erst wenn der Raum rar und das Nutzungsinteresse vielfältiger wird, fokussiert sich unsere Aufmerksamkeit auf ihn. Insbesondere Flächen, die derzeit von Nutzungen ausgeschlossen sind, wie zum Beispiel Brachflächen oder Abraumhalden, werden interessanter. Wie können diese wieder nutzbar gemacht werden? Neben der Staubminderung und dem Erosionsschutz ist die zentrale Aufgabe, einen Beitrag zur Erhaltung der Biodiversität zu leisten. Im Folgenden wird an einem Fallbeispiel in Vietnam dargestellt, was Rekultivierung bodenspezifisch bedeutet und was sie bewirken kann.

Geophysical methods are progressive, non-destructive but indirect techniques for characterization of soil properties and mapping of soil heterogeneities. Geophysical surveys for soil mapping lead generally to ambiguous results since geophysical parameters are influenced by several soil properties, e.g., organic content, clay content and bulk density.The investigations presented here focus on the effect of different stages of organic content on DC-geoelectrics and electromagnetic induction (EMI) at a long-term fertilization experiment. This experiment gives, after 105 years running,,in excellent opportunity to study the correlations between electrical resistivity, apparent electrical conductivity and soil parameters. Results from DC-geoelectrical measurements (profile length 80-160 m, electrode distance 0.5 m) twice, in August after harvest and in January during black fallow period, are presented. Additionally electromagnetical investigations were conducted in January. Correlations of resistivity and carbon input into the soil are significant and very strong; especially in January with r=-0.89 but contradictive in summer and winter. The analysis of resistivity and apparent electrical conductivity is critical since bulk density and water storage capacity is influenced by fertilization and plant growth. Interpretation of a combination of DC-geoelectrics and electromagnetical techniques on agricultural areas has to be clone with respect to management aspects.

Quantitative soil organic carbon (SOC) models are required for a better understanding of C sequestration in soils and for prognoses at different scenarios. However, it is unclear whether the major C-stabilization mechanisms are included adequately. Objectives were (1) to test the performance of the CIPS (Carbon turnover In Pore Space) model and the Rothamsted Carbon (RothC) Model for a prediction of the SOC dynamics at the long-term experiments at Halle (Germany) and (2) to compare the model structures of the quantitative models and a conceptual model in order to identify shortcomings of the quantitative models. Both quantitative models had a similar prediction performance: the C dynamics was predicted satisfactorily for the Halle sites under continuous rye with NPK fertilization or without any fertilization (1878-1953), but larger deviations between modeled and measured C contents were observed for the continuous rye and maize in the entire period from 1878 to 1996. The comparison of the conceptual model with the quantitative models revealed that the neglect of the black C dynamics and the interactions of SOC with mineral surfaces are not included explicitly. Site-specific calibrations are required where these processes have a significant impact on soil organic matter dynamics. Furthermore, the number of pools and mechanisms in the conceptual model is higher than in the quantitative models independent of their level of abstraction. Despite the neglect of some important mechanisms in the quantitative models, it has to be noted that they reproduce the SOC data generally well in agricultural surface soils. Moreover, they need only few inputs which are generally easily obtainable.

Three soil carbon models (RothC, CANDY and the Model of Humus Balance) were used to estimate the impacts of climate change on agricultural mineral soil carbon stocks in European Russia and the Ukraine using detailed spatial data on land-use, future land-use, cropping patterns, agricultural management, climate and soil type. Scenarios of climate were derived from the Hadley Centre climate Version 3 (HadCM3) model; future yields were determined using the Soil-Climate-Yield model, and land use was determined from regional agricultural and economic data and a model of agricultural economics. The models suggest that optimal management, which entails the replacement of row crops with other crops, and the use of extra years of grass in the rotation could reduce Soil organic carbon (SOC) loss in the croplands of European Russia and the Ukraine by 30-44% compared to the business-as-usual management. The environmentally sustainable management scenario (SUS), though applied for a limited area within the total region, suggests that much of this optimisation could be realised without damaging profitability for farmers.

A new modelling approach has been developed for carbon turnover in arable soils. The rationale for the new model is based on the hypothesis that long-term stabilization of carbon in soil is mainly a function of its accessibility or its localisation within the soil pore space. The main assumption of the new Carbon turnover In Pore Space (CIPS) model is that the biological activity is not evenly distributed through the whole pore space. Because of the poor aeration in the micro-pores they show very low biological activity leading to a strong protection of the carbon localized in this pore space. In the CIPS model four pools of organic matter are defined: - fresh organic matter (FOM) of plant residues and organic fertilizers,- active organic matter (AOM) associated with microbial biomass,- refractory organic matter (ROM) of decomposing carbon and- dissolved organic matter (DOM).The initial carbon distribution between pore size classes is tied to their surface area. DOM serves as an exchange medium between the pore size classes. Model parameters were determined by means of two incubation experiments and for field conditions adapted using data of the long-term agro ecosystem experiment 'Static fertilisation experiment' Bad Lauchstaedt. The CIPS model has been validated with data of the long-term agro ecosystem experiment 'Plant nutrition and fertilisation experiment - Field B' Prague Ruzyn. The model achieved a good fit of calculated versus observed data. By relating carbon turnover to soil architecture and thus to accessibility, the new CIPS model provides a means to relate soil carbon turnover to physical, measurable features of the system. The combination of quality controlled primary stabilization processes (recalcitrance of organic matter) and soil structure dependent stabilization processes (location of turnover) is paving the way towards a new generation of global carbon turnover models.

The CANDY model has been qualitatively assessed for simulating long-term dynamics of soil organic carbon and tested against different long-term experiments representing various land uses and geographical sites, but never before against conditions of the Former Soviet Union (FSU). Our goal was to simulate long-term trends in soil organic carbon for the long-term experiments of Barybino (Moscow region, Russia), Grakov (Kharkow region, Ukraine) and Yachenka (Minsk region, Belarus) representing the predominant arable soil types, climate conditions and typical management strategies for the investigated arable areas. The fit of modelled results to the observed data was evaluated to assess the suitability of the model for further applications in the FSU. The crop parameters of the CANDY model had to be adapted to the low yields observed under the Russian site conditions resulting in a higher sensitivity to crop-derived carbon input as a function of yield. The results show that the approach of treating the organic carbon situated in micro pores as inert, is an applicable solution for simulating soil carbon dynamics under Russian conditions. This evaluation of CANDY, against long-term experiments from Russia, gives confidence for its wider application in this region.

Almost all soil organic carbon turnover models rely on a partitioning of total organic carbon into an inert and a decomposable pool. The quantification of these pools has a large impact on modelling results. In this study several methods to estimate inert carbon in soils, based either on total soil organic matter or physical protection, were assessed with the objectives of (1) minimising errors in carbon and nitrogen dynamics and (2) ensuring usability for sites with marked differences in site conditions. CANDY simulations were carried out by varying solely the method for calculating the size of the inert carbon pool used to initialise the model. Experimental data from Bad Lauchstädt and Müncheberg were used for the simulation. The data were made available for modellers at a workshop held at Müncheberg (Germany) in 2004. The results concerning not only carbon but also nitrogen dynamics were analysed by applying selected statistical methods. It was shown that even in short-term simulations model initialisation procedure may influence the simulation results considerably. Three methods of estimating inert carbon were identified as being the most appropriate. These methods are either based on soil texture or pore-space classes and therefore account for the physical protection of soil organic matter. Thus, physical protection seems to be of major importance. By extending the scope of the investigation into nitrogen dynamics, additional support for the applicability of a selected method was obtained.

Traditionelle Kohlenstoff-Umsatz-Modelle verwenden gewöhnlich drei oder mehr funktionelle Pools, die durch verschiedene Geschwindigkeiten des Kohlenstoff-Umsatzes gekennzeichnet sind. Es handelt sich dabei hauptsächlich um konzeptionelle Pools, die nicht mit den beobachteten Eigenschaften des Bodens verbunden sind. Diese Tatsache schränkt den Wert von Vorhersagen der Größe und des Abbauverhaltens des passiven Kohlenstoff-Pools ein, welche auf der Grundlage von Simulationsrechnungen für künftige Umweltveränderungen getroffen werden. Für den Kohlenstoff-Umsatz in urbaren Böden ist ein neuer Modellierungsansatz entwickelt worden. Das Grundprinzip für das neue Modell beruht auf der Hypothese, dass die langfristige Stabilisierung von Kohlenstoff im Boden hauptsächlich eine Funktion seiner Zugänglichkeit oder seiner Lokalisierung innerhalb des Boden-Porenraums ist. Die Hauptannahme des neuen Carbon turnover In Pore Spaces (CIPS) Modells ist, dass die biologische Aktivität durch den ganzen Porenraum nicht gleich verteilt ist. Wegen der schlechten Durchlüftung in den Mikroporen herrscht in diesen eine niedrige biologische Aktivität vor, die zu einem starken Schutz des in diesem Porenraum lokalisierten Kohlenstoffs führt. Im CIPS-Modell werden vier Pools der organischen Substanz definiert: * frische organische Substanz (FOM) von Pflanzenrückständen und organischen Düngern * aktive organische Substanz (AOM) assoziiert mit der mikrobiellen Biomasse * refraktäre organische Substanz (ROM) Rückstand von dem sich zersetzendem Kohlenstoff und * gelöste organische Sache (DOM) Die anfängliche Kohlenstoff-Verteilung auf die Porengrößen-Klassen erfolgt nach dem Anteil der Porenoberfläche einer Klasse an der Gesamtporenoberfläche. DOM dient als Austauschmedium zwischen den Porengröße-Klassen. Die Parameter des CIPS-Modells resultieren aus der Anpassung der Simulationsergebnisse an die Experimentaldaten von Laborinkubationsversuchen, unter Verwendung von Parametern aus der Literatur als