In the last decades agricultural policy has gained increasingly in complexity. Nowadays it influences the food and agricultural sector from the global market down to the farm level. Widespread research questions, like the impact of the WTO negotiations on the farm structure, most often require comprehensive modeling frameworks. Thus, different types of models are utilized according to their comparative advantages and combined in a strategically useful way to more accurately represent micro and macro aspects of the food and agricultural sector. Consequently, in recent years we have seen an increase in the development and application of model linkages. Given this background, the overall objective of this subproject is a systematic sensitivity analysis of model linkages that gradually involves more and more characteristics of the linkage and the corresponding transfer of results between models. In addition, the project aims to answer the following specific question: How does structural change at the farm level influence aggregate supply and technical progress? Under which conditions is it possible to derive macro-relationships from micro-relationships? How does the aggregation level influence the model results and how can possible problems be overcome? This procedure is used to quantify the effects and to derive conditions for optimal interaction of the connected models. The analysis is based on the general equilibrium model GTAP (Global Trade Analysis Project) and the farm group model FARMIS (Farm Modelling Information System) which are employed in conjunction to analyze the effects of WTO negotiations on the farm level.
In many plant species, FLOWERING LOCUS T and related proteins are the mobile signal that communicates information on photoperiod from the leaves to the shoots, where the transition to flowering is realized. FT expression is tightly controlled at the transcriptional level so that it is restricted to leaves, occurs only in appropriate photoperiods, and integrates ambient temperature and developmental cues, as well as information on biotic and abiotic stress. We previously established that FT transcription in the model plant Arabidopsis thaliana requires proximal promoter cis-elements and a distal enhancer, both evolutionary conserved among Brassicacea species. In addition, FT transcription is blocked prior vernalization in biannual accessions and vernalization-dependency of FT is controlled through a CArG-box located in the first intron that binds the transcriptional repressor FLOWERING LOCUS C (FLC). Chromatin-mediated repression by the Polycomb Group (PcG) pathway is required for photoperiod-dependent FT regulation and participates in FT expression level modulation in response to other cues.In this project, I propose to explore the available sequence data from the 1001 genome project in Arabidopsis to evaluate how often changes in regulatory cis-elements at FT have occurred and how these translate into an adaptive value. Allele-specific FT expression pattern will be measured in F1 hybrids of different accessions in response to varying environmental conditions. FT alleles that show cis-regulatory variation will be further analyzed to pinpoint the causal regulatory changes and study their effect in more detail. The allotetrapolyploid species Brassica napus is a hybrid of two Brassiceae species belonging to the A- and C-type genome, which are in turn mesopolyploid due to a genome triplication that occurred ca. 10x106 years ago. We will determine allele-specific expression of FT paralogs from both genomes of a collection of B. napus accessions. The plants will be grown in the field in changing environmental conditions to maximize the chance to detect expression variation of the paralogs. We will compare the contribution of the founder genomes to the regulation of flowering time and asses variation in this contribution. A particular focus will be to study the impact of chromatin-mediated repression on allele selection in B. napus.
Chlorinated ethylenes are prevalent groundwater contaminants. Numerous studies have addressed the mechanism of their reductive dehalogenation during biodegradation and reaction with zero-valent iron. However, despite insight with purified enzymes and well-characterized chemical model systems, conclusive evidence has been missing that the same mechanisms do indeed prevail in real-world transformations. While dual kinetic isotope effect measurements can provide such lines of evidence, until now this approach has not been possible for chlorinated ethylenes because an adequate method for continuous flow compound specific chlorine isotope analysis has been missing. This study attempts to close this prevalent research gap by a combination of two complementary approaches. (1) A novel analytical method to measure isotope effects for carbon and chlorine. (2) A carefully chosen set of well-defined model reactants representing distinct dehalogenation mechanisms believed to be important in real-world systems. Isotope trends observed in biotic and abiotic environmental dehalogenation will be compared to these model reactions, and the respective mechanistic hypotheses will be confirmed or discarded. With this hypothesis-driven approach it is our goal to elucidate for the first timdehalogenation reactions.
Dairy farming across Germany displays diverse production systems. Factor endowment, management, technology adoption as well as competitive dynamics in the local or regional land, agribusiness and dairy processing sectors contribute to this differentiation on farm level. These differences impact on the ability of dairy farms and regional dairy production systems to successfully respond to pressures arising from future market and policy changes. The overall objective of the research activities of which this project is a part of, is to develop a thorough understanding of the processes that govern the spatial dynamics of dairy farm development in different regions in Germany. The central hypothesis of this research project is that management system and technological choices differ systematically across local production and market conditions. The empirical approach will focus on the estimation of farm specific nonparametric cost functions for dairy farms located in across Germany differentiated by time and location. A spatially differentiated data base with information on input use, resource availability, as well as local market conditions for land and output markets will be compiled. The nonparametric approach is specifically suited to disclose a more accurate representation of dairy production system heterogeneity across locations and time compared to parametric concepts as it provides the necessary flexibility to accommodate non-linearities relevant for a wide domain of explanatory variables. The methodology employed goes beyond the state of the art of the literature as it combines kernel density estimation with a Bayesian sampling approach to provide theory consistent parameters for each farm in the data sample.The specific methodological hypothesis is that the nonparametric approach is superior to current parametric techniques and this hypothesis is tested using statistical model evaluation. Regarding the farm management and technological choices, we hypothesize that land suitability for feed production determines the farm intensity of dairy production and thus management and technological choices. With respect to the ability of farms to successfully respond to market pressures we hypothesize that farms at the upper and lower tail of the intensity distribution both can generate positive returns from dairy production. These last two hypotheses will be tested using the estimated spatially differentiated farm specific costs and marginal costs.The expected outcomes are of relevance for the agricultural sector and the food supply chain economy as a whole as fundamental market structure changes in the dairy sector are ongoing due to the abolition of the quota regulation in the years 2014/2015. Thus, exact knowledge about differences and development of dairy cost heterogeneity of farms within and between regions are an important factor for the actors involved in the market as well as the political support of this process.
Organic matter (OM) composition and dynamic in subsoils is thought to be significantly different from those in surface soils. This has been suggested by increasing apparent 14C ages of bulk soil OM with depth suggesting that the amount of fresh, more easily degradable components is declining. Compositional changes have been inferred from declining ä13C values and C/N ratios indicative for stronger OM transformation. Beside these bulk OM data more specific results on OM composition and preservation mechanisms are very limited but modelling studies and results from incubation experiments suggest the presence and mineralization of younger, 'reactive carbon pool in subsoils. Less refractory OM components may be protected against degradation by interaction with soil mineral particles and within aggregates as suggested by the very limited number of more specific OM analysis e.g., identification of organic compound in soil fractions. The objective of this project is to characterize the composition, transformation, stabilization and bioavailability of OM in subsurface horizons on the molecular level: 1) major sources and compositional changes with depth will be identified by analysis of different lipid compound classes in surface and subsoil horizons, 2) the origin and stabilization of 'reactive OM will be revealed by lipid distributions and 14C values of soil fractions and of selected plant-specific lipids, and 3) organic substrates metabolized by microbial communities in subsoils are identified by distributional and 14C analysis of microbial membrane lipids. Besides detailed analyses of three soil profiles at the subsoil observatory site (Grinderwald), information on regional variability will be gained from analyses of soil profiles at sites with different parent material.
Comprehension of belowground competition between plant species is a central part in understanding the complex interactions in intercropped agricultural systems, between crops and weeds as well as in natural ecosystems. So far, no simple and rapid method for species discrimination of roots in the soil exists. We will be developing a method for root discrimination of various species based on Fourier Transform Infrared (FTIR)-Attenuated Total Reflexion (ATR) Spectroscopy and expanding its application to the field. The absorbance patterns of FTIR-ATR spectra represent the chemical sample composition like an individual fingerprint. By means of multivariate methods, spectra will be grouped according to spectral and chemical similarity in order to achieve species discrimination. We will investigate pea and oat roots as well as maize and barnyard grass roots using various cultivars/proveniences grown in the greenhouse. Pea and oat are recommendable species for intercropping to achieve superior grain and protein yields in an environmentally sustainable manner. To evaluate the effects of intercropping on root distribution in the field, root segments will be measured directly at the soil profile wall using a mobile FTIR spectrometer. By extracting the main root compounds (lipids, proteins, carbohydrates) and recording their FTIR-ATR spectra as references, we will elucidate the chemical basis of species-specific differences.
The aim of P2 within the Research Unit 'The Forgotten Part of Carbon Cycling: Organic Matter Storage and Turnover in Subsoils (SUBSOM)' is to contribute to the understanding of the different sources and stabilization processes of subsoil organic matter. This will be achieved by the analysis of the soil organic matter composition in topsoil versus subsoil by 13C NMR spectroscopy in bulk soils as well as organo-mineral associations. This will be done on a number of soil profiles differing in parent material and mineralogy and therefore also in the relevance of organo-mineral associations for subsoil C stabilization. In addition, a specific sampling approach will allow to differentiate three zones associated with the dominating effect of (1) leaching of DOC (the 'bulk soil' between trees), (2) root litter decomposition (the 'root-affected zone'), and (3) direct rhizodeposition of root exudates (the 'rhizosphere' sensu strictu). The contribution of above-ground versus below-ground litter is differentiated by the analysis of cutin and suberin biomarkers. Organic matter derived from microbial sources will be identified by the microbial signature of polysaccharides in the subsoil through the analysis of neutral sugars and amino sugars. Organo-mineral associations will be further characterized by N2-BET analyses to delineate the coverage of the mineral phase with organic matter. With these analyses and our specific analytical expertise at the submicron scale (nanoSIMS) we will participate in selected joint experiments of the research unit.
Subproject 3 will investigate the effect of shifting from continuously flooded rice cropping to crop rotation (including non-flooded systems) and diversified crops on the soil fauna communities and associated ecosystem functions. In both flooded and non-flooded systems, functional groups with a major impact on soil functions will be identified and their response to changing management regimes as well as their re-colonization capability after crop rotation will be quantified. Soil functions corresponding to specific functional groups, i.e. biogenic structural damage of the puddle layer, water loss and nutrient leaching, will be determined by correlating soil fauna data with soil service data of SP4, SP5 and SP7 and with data collected within this subproject (SP3). In addition to the field data acquired directly at the IRRI, microcosm experiments covering the broader range of environmental conditions expected under future climate conditions will be set up to determine the compositional and functional robustness of major components of the local soil fauna. Food webs will be modeled based on the soil animal data available to gain a thorough understanding of i) the factors shaping biological communities in rice cropping systems, and ii) C- and N-flow mediated by soil communities in rice fields. Advanced statistical modeling for quantification of species - environment relationships integrating all data subsets will specify the impact of crop diversification in rice agro-ecosystems on soil biota and on the related ecosystem services.
The sorption of anions in geotechnical multibarrier systems of planned high level waste repositories (HLWR) and of non-ionic and organic pollutants in conventional waste disposals are in the center of recent research. In aquatic systems, persistent radionuclides such as 79Se, 99Tc, 129I exist in a form of anions. There is strongly increasing need to find materials with high sorption capacities for such pollutants. Specific requirements on barrier materials are long-term stability of adsorbent under various conditions such as T > 100 C, varying hydrostatic pressure, and the presence of competing ions. Organo-clays are capable to sorb high amounts of cations, anions and non-polar molecules simultaneously having selectivity for certain ions. This project is proposed to improve the understanding of sorption and desorption processes in organo-clays. Additionally, the modification of material properties under varying chemical and thermal conditions will be determined by performing diffusion and advection experiments. Changes by sorption and diffusion will be analyzed by determining surface charge and contact angles. Molecular simulations on models of organo-clays will be conducted in an accord with experiments with aim to understand and analyze experimental results. The computational part of the project will profit from the collaboration of German partner with the group in Vienna, which has a long standing experience in a modeling of clay minerals.
Magnetic properties of ferrimagnetic minerals depend on their crystal lattice, anisotropy, chemical composition and grain size. The latter parameter is strongly controlled by microstructures, which are significant for the interpretation of the magnetic properties of shocked magnetic minerals. Fracturing and lattice defects are the main causes for magnetic domain size reduction and generate an increase in coercivity and the suppression of magnetic transitions (e.g. 34 K transition in pyrrhotite, Verwey transition in magnetite).Especially for an adequate investigation of shock-induced modifications in ferromagnetic minerals, a combination of microstructural and magnetic measurements is therefore essential.This project focusses on two significant aspects of extreme conditions - the consequence of shock waves on natural material on Earth and on the magnetic mineralogy of exotic magnetic minerals in iron meteorites. In order to obtain general correlations between deformation structures and magnetic properties, the specific magnetic properties and carriers as well as microstructures of samples from two impact structures in marine targets (Lockne and Chesapeake Bay) will be compared with shocked magnetite ore and magnetite-bearing target lithologies from outside the crater (Lockne) as well as from undeformed megablocks within the crater (Chesapeake Bay). We will test the hypothesis if shock-related microstructures and associated magnetic properties can significantly be overprinted by postshock hydrothermal alteration. We especially want to focus on the Verwey transition (TV) as lower TVs are described for shocked impact lithologies. Hence, the main focus of this study lies on magneto-mineralogical investigations which combine low- and high-temperature magnetic susceptibility and saturation isothermal remanent magnetization with mineralogical and microstructural investigations. The same methods will then be used for the investigation of iron meteorites, whose magnetic properties are often controled by exotic magnetic minerals like cohenite, schreibersite and daubreelite in addition to the metal phases. Magnetic transition temperatures of those phases are poorly documented in relation to their chemical composition as well as to their crystallographic and microstructural configuration. For a general understanding of shock-related magnetization processes in extraterrestrial and terrestrial material, however, it is crucial to obtain a general correlation between the initial 'unshocked' state and the subsequent shock- and alteration-related overprints.
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