Browsing by Subject "Boden-Landnutzungs-Informations-System"

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Regionale Darstellung der Umweltbelastungen durch klimarelevante Gase in der Agrarlandschaft Kraichgau - Das Boden-Landnutzungs-Informations-System für Treibhausgasemissionen
(2003) Rohierse, Andrea; Doluschitz, Reiner
Summary Goals The goals of the doctoral thesis were to determine at regional level the environmental impacts in the form of greenhouse gas emissions from the agricultural landscape of the Kraichgau region, to produce a method for projecting greenhouse gas emissions from agriculture and to subject appropriate prevention scenarios to an impact analysis. To attain these goals, a geographic information system (GIS) was used to build an environmental information system for greenhouse gases titled ?Soil and Land Use Information System for Greenhouse Gas Emissions?. Results Spatial presentation of the geodata bank Besides generation of a map of potential soil moisture for the Kraichgau region, the geodata basis developed here can be used to produce numerous thematic maps, such as fertilization maps and emissions maps of the greenhouse gases nitrous oxide and methane, as well as a map of the CO2 equivalent inventory. This can visualize the locations of centres of high or low emissions in the Kraichgau region. The findings of the evaluation of land-use maps generated from satellite images of the year 2000 show that the method of supervised classification used there and the multitemporal satellite image evaluation provide sufficient accuracy for a regional determination of greenhouse gas emissions from agriculture, as they were on average able to classify correctly 72% of arable land uses typical of the Kraichgau region. Forecast projection of greenhouse gas emissions from agriculture The environmental information system thus established allowed spatial quantification of Kraichgau-specific emissions. For this physiographic region, average total nitrous oxide emissions of 3.2 kg N2O-N / ha*a according to IPCC (2000b) were determined, taking the 22 Kraichgau municipalities into consideration. The average calculated maximum nitrous oxide emission potential from agriculturally utilized soils of the 2000 reference system at municipal level figures 4.1 kg N2O-N / ha*a, while the minimum figures 2.2 kg N2O-N / ha*a. Using Global Warming Potential (GWP) indexes, the CO2 equivalent inventory was calculated according to IPCC (2001) for the soils of the Kraichgau region. This was found to average 1.5 t CO2 equivalent / ha*a (GWP 100). The knowledge-based approach yielded a CO2 equivalent inventory around 1.1 t CO2 equivalent / ha*a (GWP 100). Overall, modelling found the Kraichgau physiographic region and arable farming region to represent a source of greenhouse gases. This was determined strongly by the high GWP of nitrous oxide compared to that of methane and carbon dioxide, and the circumstance that nitrogen inputs are relatively high in the intensively managed agricultural landscape. Impact analysis The results of the impact analysis show that if total nitrogen inputs are reduced by 20%, then some 6% of greenhouse gas emissions can be saved. If then, in land management, current fertilization guidance such as provided by the nitrate information service is complied with, this resulted in the GIS model in a roughly 10% reduction of CO2 equivalent emissions for the Kraichgau region. In a further prevention scenario, land uses were changed from intensively cultivated field crops (root crops) to extensively cultivated field crops or summer crops (malting barley), these being representative of other extensively cultivated crop varieties. At the same time, arable land was converted to low-intensity grassland areas, preferentially in zone III water protection zones. This reduced the CO2 equivalent inventory in the soil and land use system by about one third. Implementation of further measures and conversion of agriculturally utilized areas to organic management ? which, besides different fertilization practices, involves different cropping structures, a shift from short rotations to multiple rotations, and extensive grassland use ? even produce a reduction of greenhouse gas emissions by about two thirds in the model. The prevention scenarios ? involving reduced nitrogen inputs, compliance with current fertilization guidance across the whole region, and a range of land-use changes through to the conversion of farming practices to organic management ? show that climate protection goals can indeed be achieved in agriculture. This necessitates, besides reducing mineral as well as organic fertilizer inputs, changes in cropping structures, in rotations, in the choice of field crops as well as general changes to management methods and land-use changes. If this package of measures developed in the prevention scenarios were implemented in the production practices of farm holdings, with specific focuses depending upon the specific type of holding, climate protection in agriculture could be promoted greatly.