Browsing by Subject "GIS"

Now showing 1 - 5 of 5

Entwicklung eines GIS-gestützten schlagbezogenen Führungsinformationssystems für die Zuckerwirtschaft
(2005) Laudien, Rainer; Doluschitz, Reiner
The European Union aspires the GIS-based documentation of every agricultural area under cultivation from the year 2005 onwards. With this in mind, this thesis aims to design and develop a user-friendly Management Information System (MIS) for the sugar beet industry, which processes, visualizes, archives and documents geographical, remote sensing and attribute data. To meet the EU requirements the design of this "'Sugar beet Management Information System"' (SuMIS) is targeted at a GIS-based, modular, field-based approach which reflects the whole sugar beet supply chain. Therefore, the user of SuMIS will be able to geo-track and -trace every step from soil sampling to the beet delivery (fff = "from farm to factory"). By including and integrating GIS- and remote sensing data, SuMIS is a comprehensive System which can also be used as a Decision Support System within the Supply Chain Management. Due to the modular process-oriented design of SuMIS the potential of the system can be used by different users of the Supply Chain e.g. the field based documentation on the part of the farmer or the GIS-based decision making on the part of the sugar company. The design of SuMIS is based on the geo-datasets of two areas under investigation: Gemmingen/Kraichgau (area 1) and Plattling/Niederbayern (area 2). The dataset of area 1 represents the main part of the relational SuMIS geo-database and includes operational and external geo-data. The sugar beets in this area do not show plant diseases in general. Therefore, multi- and hyperspectral reflectance data of selected fields of area 2 is used to detect biotic growth-anomalies, general stress indicators and differences concerning plant vitalities and to create the respective spatial cognition. In order to collect the field data, a hyperspectral spectroradiometer (FieldSpec Handheld) is mounted stationary on a developed measurement device. This data is stored in a HTML-based spectral library. Besides that, multitemporal tractor- and airborne hyperspectral spectroradiometer measurements (GVIS, AVIS) are included to validate the ground based data. The reflection measurements are utilized to differentiate between healthy and unhealthy plants by using multispectral and hyperspectral vegetation indices. SuMIS includes new components which are developed and embedded by using the developer software "'Visual Basic"'. These are combined with existing functionalities in order to meet the EU GIS-requirements. Beside the functionalities which are used to analyze the hyperspectral data, two land-use classification methods are presented, applied and compared. Therefore, an object oriented (by using ERDAS Imagine® and a pixel based approach (by using eCognition) is employed to differentiate sugar beets from other crops in a simple and time efficient manner. QuickBird high resolution satellite form the basis for the accurate land use map. By applying the SuMIS functionalities and tools presented in this thesis, the users will be able to digitize their field data without any knowledge about GIS or geo-databases. Furthermore, storing and visualizing alphanumeric geodata is also possible by using these tools. Because of the information-specific structure of the geodata and its storage in several information layers, SuMIS is able to generate for instance mathematic calculations, clip-, merge- and join-procedures. This can be used for the spatial analysis or for creating new information layers. In this thesis such spatial GIS-results are shown in the context of a case study. The results of this case study indicate that the approaches developed lead to plausible results. Besides the description of the design of SuMIS and it's functionalities, the acceptance and survey of the expected individual benefits by potential selected users has been tested. Concerning the utility and value of SuMIS for the sugar beet industry, the functionalities are evaluated. The investigated results are discussed and perspectives for a broad application are described.
Grasping the complexity of intercropping - developing and testing an integrated decision support system for vegetable production in the North China Plain
(2010) Feike, Til; Claupein, Wilhelm
This cumulative dissertation consists of six papers published, accepted or submitted to international high standard journals or books. To detect and describe the status quo of vegetable intercropping in the North China Plain (NCP), a survey was conducted from autumn 2007 to spring 2008. The results of the interviews with researchers, extensionists and farmers embedded in the first article revealed a huge variety of intercropping systems being practiced by farmers in the region. The first article furthermore elaborated farmers? underlying motives and concepts and described the knowledge transfer systems involved. When evaluating the prevailing systems against the background of the rapidly changing socio-economic frame conditions for farming in rural China, it became obvious that a great proportion of the systems practiced nowadays are prone to extinction in a long run. Therefore the second article discussed possible adjustments of the intercropping systems to fit the demands of modern agriculture, while maintaining their potential agronomic and environmental benefits. To enable mechanization, it was suggested to either adjust the machinery to the traditional row intercropping systems, or adjust the cropping system to the prevailing and available machinery. The latter approach was then followed throughout the thesis, using an agronomic modeling approach. The combination of Chinese cabbage and maize was selected, as it is a traditional intercropping system, with strong interspecific effects. In the course of this study, the two crops were strip intercropped in four field experiments at three sites in Germany and in China in 2008 and 2009. To understand, explain and predict plant behavior under the impact of complex cropping structures, crop growth models present a viable and powerful tool. However, two constrains had to be overcome within the framework of this thesis i) Chinese cabbage is not integrated in the common process-oriented crop growth models, ii) a method had to be developed to quantify resource competition and simulate intercropping. Therefore the integration of Chinese cabbage, the number one field vegetable of China, into the CROPGRO model constituted the first step for the simulation of intercropping systems in China. Two greenhouse experiments, testing crop growth and development under different temperature regimes, served as the data base for the accurate parameterization of Chinese cabbage and built the baseline for the third article. Cardinal temperatures of Chinese cabbage were identified by correlating mean relative growth rates and mean leaf appearance rates to temperature. Minimum growth temperature was identified at 0 °C, optimum temperature ranges between 14 °C and 24 °C, and maximum temperature is 34 °C. The further adjustment and testing of the model, which was executed on up to six independent data sets, is presented in the fourth article. The key to successfully simulate intercropping systems is the knowledge on changes in resource availability compared to monocropping. Therefore, a method was developed to quantify the availability of the most crucial growth factor solar radiation at any location within a Chinese cabbage strip, presented in the fifth article. The method was extended in the sixth and final article to enable the estimation of available radiation in Chinese cabbage strips of different widths. The ?environmental modifications? option of CROPGRO was employed to simulate the effects of the estimated reduction in incoming radiation in Chinese cabbage strips of different width. Simulations were conducted over up to thirty years of weather data of 12 locations throughout the NCP, and were additionally tested on different soil texture types. The results were extended over the entire NCP by linking them to a GIS-system. The developed approach constitutes a reliable decision support for the optimization of the spatial arrangements in Chinese cabbage strip intercropping systems, according to local soil and climate conditions. The described approach can be extended to develop a comprehensive decision support system that allows testing of various intercrop combinations under a wide range of climate and especially radiation environments. The presented thesis is a valuable contribution to the development of sustainable vegetable production systems in the NCP. A new method to quantify availability of solar radiation in strip intercropping was developed, which can be applied in various other intercropping systems. The integration of Chinese cabbage into CROPGRO, offers great opportunities not only for studying intercropping systems, but also for improving input levels and resource use efficiency in Chinese cabbage production in China and throughout the world. Understanding farmers? concepts and estimating the production potential of intercropped Chinese cabbage created additional value, which substantially contributes to realizing the potential of intercropping in the NCP.
Modeling the influence of coastal vegetation on the 2004 tsunami wave impact
(2014) Laso Bayas, Juan Carlos; Cadisch, Georg
A tsunami causes several effects once it reaches inland. Infrastructure damage and casualties are two of its most severe consequences being mostly determined by seaquake intensity and offshore properties. Nevertheless, once on land, the energy of the wave is attenuated by gravity (elevation) and friction (land cover). Despite being promoted as ‘bio-shields’ against wave impact, proposed tree-belt effects lacked quantitative evidence of their performance in such extreme events, and have been criticized for creating a false sense of security. The current study analyzed some of the land uses in sites affected by the 2004 tsunami event, especially in coastal areas close to the coast of Indonesia, more specifically on the west coast of Aceh, Sumatra as well as on the Seychelles. Using transects perpendicular to the coast, the influence of coastal vegetation on the impact of the 2004 tsunami, particularly cultivated trees, was modeled. A spatial statistical model using a land cover roughness coefficient to account for the resistance offered by different land uses to the wave advance was developed. The coefficient was built using land cover maps, land use characteristics (stem diameter, height, and planting density), as well as a literature review. The spatial generalized linear mixed models used showed that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties, in the case of Aceh, by an average of 5%. Despite this positive effect of coastal vegetation in front of a settlement, it was also found that dense vegetation behind villages endangered human lives and increased structural damage in the same case, most likely due to debris carried by the backwash. The models initially developed in Aceh were adapted and tested for the effects that the same tsunami event caused in the Seychelles, where the intensity of the event was a tenth of that in Aceh. These new models suggested no direct effect of coastal vegetation, but they indicated that vegetation maintained dunes decreased the probability of structural damage. Additionally, using satellite imagery with higher resolution than that of the first study and/or from different years before the tsunami, corresponding land roughness coefficients were developed and tested with the existing models. The new models showed no signs of further increase of goodness of fit (AIC). Nevertheless, weather conditions at the acquisition dates as well as coverage and lack of image availability diminished the predictive power of these models. Overall, more than advocating for or against tree belts, a sustainable and effective coastal risk management should be promoted. This planning should acknowledge the location (relative to the sea) of settlements as the most important factor for future coastal arrangements. Nevertheless, it should also consider the possible direct and indirect roles of coastal vegetation, determined by its spatial arrangement as shown in the study models. Sustainability of these measures would only occur when coastal vegetation is regarded as a livelihood provider rather than just as a bio-shield. Practical examples could include, e.g. rubber plantations or home gardens in front of settlements, while leaving escape routes or grasslands and coconut plantations behind these. Therefore, the enforcement of educational programs, the setup and maintenance of effective warning systems and the adequate spatial allocation of coastal vegetation bringing tangible short and mid term benefits for local communities, as well as its adaption to local customs should be considered.
Numerische Modellierung und Simulation der räumlichen und zeitlichen Variabilität von Lachgasemissionen aus Agrarökosystemen
(2005) Huber, Stefan; Doluschitz, Reiner
The aim of this dissertation is to characterize the spatial and temporal variability of nitrous oxide emissions from agroecosystems by means of linking mathematical simulation models to Geographical Information-Systems (GIS). Specifically, this study tries to accomplish a methodological goal and a thematic goal. A general software framework for the linkage of agroecosystem-modells and GIS by employing object-oriented and component-based concepts is developed. As an example for the implementation of this framework, the agroecosystem-modell DNDC, the two-dimensional soil water model SWMS2d, and GIS are integrated to the new model Spatial DNDC. This new model is applied to the study of the spatial and temporal variability of nitrous oxide emissions from agroecosystems at different scales. The simulation of the emissions at 281 independent soil profiles from a 40 ha field in Michigan/USA for nine years shows a large temporal and spatial variability ranging from 0.35 to 4.21 kg N2O-N/ha/a. Except for three years the yearly emissions are always lognormal distributed. While comparing simulated and measured daily emissions cannot be regarded as satisfactorily, it can be shown that the median of the daily N2O-emission rates can be employed as a characteristic measure for the given site. The influence of lateral soil water movement on the emission of N2O is studied by employing SpatialDNDC on a dataset from Scheyern/Bavaria, which comprises measurement data for five sites along hill-slope transect for the year 1997. The simulated daily emission rates are very similar for the five sites and are in good agreement with the measurements. The temporal variability of the daily emission rates is largely shaped by the occurrence of nitrogen fertilization-events and following precipitation events. By looking at the yearly emissions a distinct, downslope-directed gradient can be seen with the highest emission of 6.87 kg N2O-N/ha/a at the highest hill position, and the lowest emission of 6.37 kg N2O-N/ha/a at the lowest hill position. This gradient can be explained by the soil water household which is largely influenced by a dry period in spring. Due to lateral water movement plants growing at lower positions have more water available for early-spring growth leading to higher water extraction during the dry period. Therefore the average soil water content, which is a major impact factor for N2O-emissions in SpatialDNDC, lower at the downslope positions as compared to the upslope positions. The modelling of N2O from agroecosystems in the North-China-Plain can merely be regarded as a test case for application of SpatialDNDC to larger regions and whole nations, respectively, since detailed input and validation data are missing. The three simulation studies show distinctively the two main problems of the regional usage of agroecosystem models: On the one hand detailed input data are missing leaving for the modeller only the option to make simplifying assumptions and thereby introducing great uncertainty into simulation results. On the other hand regional calibration and validation data are missing, which are crucial to the realistic depiction of variability within large study regions.
Reducing irrigation water supply to accomplish the goal of designing sustainable cropping systems in the North China plain
(2007) Binder, Jochen; Claupein, Wilhelm
An International Research Training Group (IRTG) of the University of Hohenheim and the China Agricultural University, entitled ?Modeling Material Flows and Production Systems for Sustainable Resource Use in the North China Plain? was launched in 2004. The major hypothesis was ?that adjustments in cropping systems and management practices provided potential for sustainable resource protection on a high yield level?. The research program was conducted in one of the most important economic and agricultural regions in China, the North China Plain (NCP). The NCP is one of the major maize (Zea mays L.) and wheat (Triticum aestivum L.) growing areas. A literature review indicated that over the last two decades yields for wheat and maize increased by more than 20%, which had mainly been achieved by augmenting the amount of irrigation water and fertilizer. Besides the positive effects on yield an increasing amount of these input factors leads to many environmental problems. Field experiments were carried out to compare different cropping systems. Currently, the double cropping of winter wheat and summer maize is the common cultivation system in the NCP. It consists of growing two crops mostly winter wheat and summer maize in one year. The winter wheat production depends on a supplemental irrigation, because rainfall is concentrated in the summer months during the maize growing season. An alternative to the intensive double cropping system could be the single cultivation of spring maize. Relative less irrigation water is required for spring maize production, because the rainy season coincides with the main part of the maize growing season. Due to the longer growing season spring maize normally realises higher yields in comparison to summer maize. However, the total yield of a double copping system of wheat and maize is higher. The evaluated system three harvests in two years (winter wheat and summer maize in the first year followed by spring maize in the second year) forms a balance between the double cropping system and the single cropping of spring maize. Due to the fact that three crops are grown in two years total yield is higher in comparison to single cropping of spring maize (two harvests in two years) but lower in comparison to the traditional double cropping system (four harvests in two years). However the lower cropping index in contrast to the double cropping of wheat and maize results in a lower demand of the input factors irrigation water and N-fertilizer whereas in comparison to the single cropping of spring maize a higher amount of input factor is required. Besides the conduction of field experiments for the collection of empirical datasets, the CERES-Maize and CERES-Wheat models were used to quantify the effects of different irrigation management practices on crop growth, productivity and sustainability of agricultural production. Results indicated that there is a considerable potential for reducing the irrigation amount for winter wheat. However, the results also showed that a supplemental irrigation at critical growth stages seems to be essential to maintain high yields and to ensure an adequate gross margin. In a more complex approach the CERES-Maize model was used to simulate the yield of summer maize and spring maize across the NCP. The spatial and temporal climate variability was taken into account by using up to 30 years of weather data from 14 meteorological stations. The simulated results were linked to a Geographic Information System (GIS). Results indicated that the yield distinction between summer maize and spring maize was partially very low as a result of water shortage at flowering stage. A delay in sowing and the use of adapted cultivars with a later flowering date could help to increase spring maize yields. Summarizing, the results of this study indicate that water is one of the most limiting factors for crop production in the NCP. Further, the reduction of total water consumption will become more and more important with water becoming increasingly scarce and thus costly. Consequently agriculture has to undergo and is already undergoing dramatic changes. The results of this study indicated that there are several possibilities optimize cropping systems in the NCP, focussing on a more sustainable use of water while maintaining high yields. In this context, crop models are valuable tools for e.g. irrigation planning or evaluating different cropping designs in the NCP.