京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第19346号 / 地環博第139号 / 新制||地環||28(附属図書館) / 32348 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 舟川 晋也, 准教授 真常 仁志, 准教授 西前 出 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

No description available.

Sandy soils make up more than 205,000 ha in the coastal area of the North Central region of Vietnam. Thua Thien Hue province lying in the south of this region has predominantly sandy soils that cover almost 47,000 ha out of the 84,000 ha of cultivated land. Most of the population lives in the coastal area and people’s livelihoods are largely dependent on crop farming in these inherently poor soils. The objectives of this study were to provide extensive information on the soil and organic resources (including agricultural and aquatic sources) in the coastal area of Thua Thien Hue province, to assess the fertilization capacity of various organic materials when applied at different rates to soils for different crops and to make a diagnosis of the balance of main plant nutrients within the farms to assess possible risks of depletion in soils or of release to the environment. Soil characteristics were measured from a survey of 300 cultivated plots in seven villages scattered in the coastal area. All these light-textured soils are acidic and are very poor in organic C. Consequently, the cation exchange capacity is very low. Soil properties are linked significantly to the different cropping patterns. Farmers in the studied area use wide diversify of organic materials for various purposes. Very large variations in the content of major elements (C, N, P, K, Ca, and Mg) are observed in the organic samples. Crop yield and soil fertility increased following the rate of farmyard manure and organic amendment application. Organic amendments brought higher profit for rice and peanut growers in coastal sandy area. The highest fertilization efficiency was observed for pig manure in case of growing rice and peanut and goat manure for sweet potato. The most frequently used species of aquatic plants by local farmers are Najas indica, Vallisneria spiralis, Potamogeton malaianus plus various algae species. Najas Indica and Hydrilla verticillata showed the highest fertilization capacity. At farm level, the N, P, K balances in 10 studied farms were positive. More detailed N-P-K balances in 9 field plots indicated that N balance was largely positive for rice and sweet potato plots. P imports exceeded P exports in all studied plots, whereas K balance was always negative in 4 cropping systems.

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第18437号 / 地環博第119号 / 新制||地環||24(附属図書館) / 31295 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 ショウ ラジブ, 教授 清野 純史, 准教授 小林 広英 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第19349号 / 地環博第142号 / 新制||地環||28(附属図書館) / 32351 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)准教授 小林 広英, 教授 岡﨑 健二, 准教授 深町 加津枝 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM

No description available.

Human trafficking crime is rising globally at an alarming rate, and Vietnam is one of the nations with the highest prevalence of trafficking female victims for forced sex services and forced marriages. This study explored human trafficking awareness in remote communities of central Vietnam and the factors for young girls dropping out of school for work at an early age. The study also investigated the link between gender inequality and the child labor problem in these communities. There is no extant empirical research pertaining to human trafficking awareness in the remote communities of central Vietnam. This research fills this gap and highlights the importance of awareness strategies to combat human trafficking. Gender inequality, human motivation theory, vulnerability, and victimology provided theoretical constructs to explain the findings of this research study. The data collection process was conducted through semistructured face-to-face interviews with 19 villagers, mothers of the child labor victims, teachers, human services workers, members of the Vietnam Women's Union, and village leaders in the research sites. The coding technique was used for the data analysis process. Participants had (a) little knowledge about human trafficking crime; (b) no awareness of the ramifications; and (c) the effects of a culture of gender inequality on the lives of people in the remote communities of central Vietnam. Findings of this study have implications for assisting policy makers and law enforcement officials and offer guidance that may help to protect people in the communities and bring offenders to justice. The findings also encourage the Vietnamese government to bridge the gender inequality divide so that young girls in these remote communities can achieve an equal voice and equal justice that they deserve.

This study aims to create a flood extent map with Sentinel imagery and to evaluate impacts on agricultural land in the lagoon region of central Vietnam. In this study, remote sensing images, obtained from 2017 to 2019, were used to simultaneously map the land cover status of a flood in the Quang Dien district. This study highlights flooded areas from Sentinel-2 images by calculating some indicators such as the Land Surface Water Index (LSWI) and the Enhanced Vegetation Index (EVI). Comparisons between the floodplain samples (GPS point-based) and flood mapping results, with the ground-truth data, indicate that the overall accuracy and Kappa coefficients were 97.9% and 0.62 respectively for 2017; the values for 2019 were 95.7% and 0.77 for the same coefficients. Land use maps overlying the flood-affected maps show that approximately 11% of the agriculture land area was affected by floods in 2019 comparison to a 10% in 2017. Wet rice was the most affected crop with the flooded area accounting for more than 70% of the district under each flood event. The most affected communes are: Quang An, Quang Phuoc and Quang Thanh. This study provides valuable information for flood disaster planning, mitigation and recovery activities in Vietnam. / Mục tiêu của nghiên cứu là lập bản đồ phân bố ngập lụt với hình ảnh vệ tinh Sentinel và đánh giá ảnh hưởng ngập lụt đến sử dụng đất nông nghiệp ở vùng đầm phá miền Trung, Việt Nam. Trong nghiên cứu này, ảnh viễn thám thu nhận giai đoạn 2017-2019 được sử dụng để xây dựng bản đồ hiện trạng sử dụng đất tại thời điểm bị ngập nước trên địa bàn huyện Quảng Điền. Nghiên cứu đã xác định được vùng ngập lụt ở huyện Quảng Điền bằng phương pháp phân loại chỉ số mặt nước (Land Surface Water Index – LSWI) và chỉ số khác biệt thực vật (Enhanced Vegetation Index-EVI) từ ảnh Sentinel-2. Xác định vùng nước lũ bị che khuất bởi mây bằng mô hình số hóa độ cao (DEM). Kết quả phân loại vùng ngập lụt được so sánh với giá trị tham chiếu mặt đất cho thấy độ chính xác tổng thể và hệ số Kappa đạt được trong năm 2017 là 97,9% và 0,62; trong khi năm 2019 đạt 95,7% và 0.77. Bản đồ sử dụng đất chồng lên bản đồ lũ lụt cho thấy khoảng 11% diện tích đất nông nghiệp bị ảnh hưởng bởi lũ lụt năm 2019 so với 10% năm 2017. Cây lúa nước là cây trồng bị ảnh hưởng nặng nề nhất, với diện tích bị ngập lụt chiếm hơn 70% diện tích lúa của huyện. Các xã bị ngập lớn là xã Quảng An, Quảng Phước và Quảng Thành. Nghiên cứu này cung cấp thông tin có giá trị cho các hoạt động lập kế hoạch, giảm nhẹ và phục hồi thiên tai lũ lụt ở Việt Nam.

This research focuses on clarifying the local and scientific knowledge about flooding adaptations, the interaction between local knowledge and scientific information in the low-lying area of Central Vietnam is analyzed. Data was obtained using three techniques including: semi-structured interviews, direct observation and household surveys. Responses indicate that the villagers have accumulated and inherited this type of knowledge in their society for a long time. The level of local knowledge is affected by gender, occupation and house location. This implies that the villagers’ social roles and their everyday interactions with the natural environment have nurtured an accumulated local knowledge. Scientific information is provided by the National Committee for Flood and Storm Control and National Center for Hydrometeorology Prediction. It contains information regarding disaster type, intensity, risk level and directions. The information is transferred to local people through mass media, social networks and official documents. However, local people are credulous toward scientific information given by the state. It was found that many villagers are not likely to follow the official guideline, especially the villagers with a high level of local knowledge. / Nghiên cứu tập trung làm rõ kiến thức bản địa và khoa học về thích ứng lũ lụt cũng như mối tương tác của chúng ở vùng trũng thấp miền Trung Việt Nam. Dữ liệu được thu thập bằng cách sử dụng kết hợp ba phương pháp bao gồm phỏng vấn bán cấu trúc, quan sát trực tiếp và khảo sát hộ gia đình. Các kết quả nghiên cứu chỉ ra rằng người dân đã tích lũy và kế thừa kiến thức bản địa từ xã hội của họ trong một thời gian dài. Mức độ kiến thức bản địa bị ảnh hưởng bởi giới tính, nghề nghiệp và vị trí nhà ở. Vai trò xã hội và những tương tác hàng ngày của người dân với môi trường tự nhiên đã nuôi dưỡng và tích lũy kiến thức bản địa. Thông tin khoa học được cung cấp bởi Ủy ban Phòng chống lụt bão Quốc gia và Trung tâm Dự báo Khí tượng Thủy văn Quốc gia. Các thông tin về loại thiên tai, cường độ, mức độ rủi ro và hướng chỉ dẫn được thông báo. Thông tin này được chuyển đến người dân thông qua các phương tiện thông tin đại chúng, mạng xã hội và các văn bản chính thức. Tuy nhiên, người dân địa phương chủ quan trước những thông tin khoa học do cơ quan nhà nước đưa ra. Nhiều người dân không tuân theo các hướng dẫn chính thức của chính quyền địa phương, đặc biệt là những người có mức độ kiến thức bản địa được đánh giá cao.

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.