Thesis (doctoral)--Universität, Hohenheim, 2005. / Includes bibliographical references (p. 114-124).

This research was carried out to test the potential of combining unmanned aerial vehicle (UAV) and remote sensing (RS) to support precision mapping of irrigation systems for paddy land. The study area is an urban/agricultural area of Central Vietnam. The Sentinel-2A imagery acquired on 30 June 2018 was interpreted according an object-based classification method aiming to map paddy land and irrigation systems for the Hoa Vang district; the total accuracy was 91.33% with a Kappa coefficient of 0.87. However, with the spatial resolution from the Sentinel-2A images (20 meters x 20 meters) it was difficult to classify paddy land and water from other objects within small and scattered parcel areas. This research was designed on five experimental flying zones, collecting 2,085 images by the UAV. With the very high spatial resolution data of the UAV, it was possible to clearly identify the boundaries of paddy land parcels, water sources such as rivers and lakes, and other objects such as canals and concrete irrigation systems. This classification derived from the orthogonal images from the five experimental zones using an object-based classification method, correcting the interpretation results of the Sentinel 2A images. Outcomes indicate that, the combination of UAV and RS can be applied to support precision mapping of irrigation systems for paddy land in urban agricultural areas. / Nghiên cứu này được thực hiện nhằm thử nghiệm khả năng kết hợp giữa UAV với viễn thám trong hỗ trợ độ chính xác của bản đồ hệ thống nước tưới cho đất trồng lúa ở vùng nông nghiệp đô thị tại Miền trung Việt Nam. Ảnh viễn thám Sentinel- 2A thu nhận vào 30/6/2018 đã được giải đoán bằng phương pháp định hướng đối hướng để thành lập bản đồ hệ thống nguồn nước tưới cho huyện Hòa Vang vào năm 2018, với kết quả độ chính xác tổng số là 91,33% và hệ số kappa là 0,87. Mặc dù với kết quả giải đoán có độ chính xác cao nhưng với độ phân giải không gian của ảnh Sentinel-2A là 20m x 20m rất khó để phân loại được các vùng đất lúa có diện tích nhỏ và phân bố phân tán. Nghiên cứu này đã thiết kế 5 khu vực bay thử nghiệm với 2.085 ảnh để thu thập dữ liệu từ UAV. Có thể thấy rằng dữ liệu ảnh từ UAV với độ phân giải siêu cao có thể nhận diện và phân biệt được một cách rõ ràng không chỉ ranh giới của các thửa đất lúa, hệ thống nguồn nước như sông hồ, mà còn cả những đối tượng kênh mương thủy lợi nhỏ. Kết quả giải đoán các ảnh bay chụp bằng UAV sử dụng dụng phương pháp định hướng đối tượng, nghiên cứu này đã hiệu chỉnh được kết quả giải đoán ảnh Sentinel 2A. Kết quả cho thấy việc kết hợp dữ liệu viễn thám với UAV là hoàn toàn có khả năng sử dụng để hỗ trợ độ chính xác thành lập bản đồ hệ thống nguồn nước cho đất trồng lúa ở vùng nông nghiệp đô thị.

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Ökologischer Landbau hat insbesondere in den vergangenen zwanzig Jahren weltweit an Bedeutung zugenommen. Im Zusammenhang mit Ernährungssicherung, ressourcenschonender Landwirtschaft und Umweltschutz ist die Entwicklung und Förderung dieses Bewirtschaftungssystems in vielen Ländern der Erde auf der Agenda. Landwirte, Verbraucher und Politiker verbinden damit die Hoffnung, Landnutzung nachhaltiger betreiben zu können und durch die Kenntnis der naturwissenschaftlichen Zusammenhänge, den Umgang mit pflanzlichen und tierischen Organismen in der landwirtschaftlichen Produktion wesensgemäßer gestalten zu können. Gleichzeitig entsprechen sie damit der Forderung von Konsumenten nach gesunden, nicht belasteten Lebensmitteln und einer intakten Umwelt. Obwohl wir weltweit die Einführung und Etablierung des Bewirtschaftungssystems ökologischer Landbau beobachten können, ist festzustellen, dass die Gründe, Wurzeln und Erscheinungsformen in den einzelnen Ländern unterschiedlich sind. Deshalb sind länderspezifische Analysen und Bewertungen notwendige Beiträge zur Theoriebildung zum ökologischen Landbau. In diesen Kontext ist die vorliegende Arbeit zu stellen. Gegenstand der Arbeit war die Analyse des gegenwärtigen Entwicklungsstandes des ökologischen Landbaus in Südkorea in den Bereichen, wie Entwicklungsgeschichte, Konzeptionen, Institutionen, Produktion und Vermarktung sowie Zertifizierung und Förderungspolitik. In einer Fallstudie wurden ausgewählte ökologisch (Yuki)-wirtschaftende Betriebe analysiert. Es werden damit Lösungsansätze zur Weiterentwicklung des ökologischen Landbaus in Südkorea dargestellt. / Organic farming has increased in meaning world-widely in particular in the past two decades. In relation to securing food supply, resource-preserving farming and environmental protection are the development and promotion of this management system in many countries on the agenda. Organic farming made it possible that farmers, consumers and politicians hope to manage land in a sustainable way, and achieve the handling of vegetable and animal organisms in the agricultural production in a suitable way. At the same time it corresponds to the need of con-sumers for healthy, not polluted food and intact environment. Although we can observe the introduction and establishment of the management system of organic farming in many countries, it needs to specify that that the reasons, roots and manifestations of organic farming in each country are different. Therefore, individual analysis and evaluation for each country necessarily contribute to build their own theory of organic farming. This work has to be viewed in this respect. The purpose of this work is to clarify: - the basic conditions of the organic farming in South Korea, - the practical change of organic farming based on the case study of organic rice cultivation and - the ideas for developing strategy of organic farming in South Korea.

Das übergeordnete Ziel dieser Studie ist es, die Auswirkungen des Eindringens von Salzwasser auf den Reisanbau bei unterschiedlichen Salzgehalten zu analysieren und zu untersuchen, wie Veränderungen in den Reissortenoptionen innerhalb der nördlichen zentralen Küstenregion Vietnams dazu beitragen können, diese Auswirkungen zu reduzieren. Auf Böden mit hohem Salzgehalt, die für den Reisanbau nicht mehr geeignet sind, werden geeignetere Anpassungsstrategien gefordert, indem die Präferenz der Landwirte für verschiedene Anbaufolgen und die Faktoren, die ihre Präferenzen im Zusammenspiel mit verschiedenen Salzgehaltsstufen beeinflussen, untersucht werden. Die Studie untersuchte die Auswirkungen des Salzgehalts auf den Mittelwert und die Variabilität der Reiserträge in vier Gemeinden der Provinz und untersuchte mögliche Änderungen im Portfolio der Reissorten, die Erträge zu steigern und gleichzeitig die Ertragsvariabilität zu verringern. Außerdem wurden die Auswirkungen des Salzwassereinbruchs auf die Produktivität und die technische Effizienz der Reisfarmen im Untersuchungsgebiet bewertet. Im Gegensatz zu bestehenden Studien wurden in dieser Untersuchung die Auswirkungen der Bodenversalzung analysiert. Salztolerante Reissorten können die Erträge sichern, solange der Salzgehalt moderat ist, sind aber ungeeignet, sobald der Salzgehalt hoch ist. Dies führte zur Durchführung eines dritten methodischen Ansatzes, der mit Hilfe eines Choice-Experiments Informationen über die Präferenzen und Motivationen der Reisbauern für die Wahl zwischen dem Portfolio der lokal möglichen adaptiven und transformativen Optionen generierte. Die Adoptionsergebnisse der Befragten bei verschiedenen Versalzungsgraden wurden ebenfalls simuliert. Die Ergebnisse zeigen, dass sich der Salzgehalt negativ auf die Reiserträge auswirkt, zu einer Erhöhung der Variabilität der Erträge beiträgt und die technische Effizienz von Reis in Abhängigkeit von den Reissorten verringert. / The overall objective of this study is to analyze the impact of saltwater intrusion on rice cultivation at different salinity levels and it also explores how changes in the rice cultivar options within the north central coastal region of Vietnam can help to reduce these impacts. In soils with high salinity levels which are no longer suitable for rice cultivation, more suitable adaptation strategies are called upon through examining farmers’ preference for different crop sequences and the factors affecting their preferences in the interaction with various levels of salinity. The study investigated impacts of salinity on mean and variability of rice yields in four communes of Thua Thien Hue Province and looked at possible changes in the portfolio of rice cultivars, which would offer farmers the potential to increase yields and decrease yield variability simultaneously. I also evaluated the impact of saltwater intrusion on the productivity and technical efficiency of rice farms in the study area. Contrasting to existing studies, this research analyzed season-differentiated impact of soil salinity. Salt tolerant rice varieties can secure yields as long as salinity levels are moderate but are inappropriate once salinity becomes severe. This led to the conduct of third methodological approach that generated information about rice farmers’ preferences and motivations for choosing among the portfolio of locally feasible adaptive and transformative options using a choice experiment. The respondents’ adoption outcomes at different salinity levels were also simulated. The results showed that salinity has negative impact on rice yields, contributes to an increase in variability of yields and reduces rice technical efficiency depending on rice varieties.