ネパール山岳地域における気候変動がもたらす食糧安全保障と生業への影響評価～ラムジュン郡の事例から～

付記する学位プログラム名: グローバル生存学大学院連携プログラム京都大学0048新制・課程博士博士(地球環境学)甲第20540号地環博第161号新制||地環||32(附属図書館)京都大学大学院地球環境学舎地球環境学専攻(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 StudiesKyoto UniversityDFA

The Relationships between Climate Variability and Crop Yield in a Mountainous Environment: A Case Study in Lamjung District, Nepal

Several studies have concluded that mountainous countries such as Nepal are more vulnerable to climate change; thus, a changing climate should have a significant impact on crop yields. This work aims to explore the impact of climate change on major crop yields in the mountainous parts of Nepal and to determine their relationships based on a regression model between historical climatic data and yield data for food crops. The study starts with an analysis of the last 30 years of climatic data from Lamjung district. Mann-Kendall and Sen’s Slope methods have been used for the trend analysis and quantification. The results showed an increase in temperature of approximately 0.02 °C to 0.07 °C per year in different seasons and a mixed trend in precipitation. Although there was no significant impact of the climate variables on the yields of all crops, the regression analysis revealed negative relationships between maize yield and summer precipitation and between wheat yield and winter minimum temperature, and a positive relationship between millet yield and summer maximum temperature

Household perceptions about the impacts of climate change on food security in the mountainous region of Nepal

This study tried to understand the mountainous households' perception of climate change and its impacts on food security in the Lamjung district of Nepal. The study attempted to find out changes in households food security and daily activities in the face of climate change for the last twenty years. The study started with the 150 household surveys along with participatory rural appraisal to understand the climate change perception of local people and its impact on dimensions of food security. Households expressed different levels of perception in terms of climate change on food security. The result shows that most of the mountainous households experienced increased temperature, less rainfall in winter, an increasing number of natural disasters and the emergence of insects for the last twenty years. They perceived the role of climate change in decreased crop production, decreased dairy products and increased household work. The situation of food security is likely to be more vulnerable to climate change in the future. It was also observed that households have been using different autonomous adaptation measures, such as high yielding crop varieties, enhanced irrigation systems and fertilizers, to cope with the changing climate. Finally, the study recommended policy instruments to enhance food security in the mountainous region amidst changing climate

Evaluation of different insecticides against Liriomyza sativae (Diptera: Agromyzidae) on cucumber plants

Liriomyza sativae (Diptera: Agromyzidae) is a cosmopolitan, polyphagous pest of horticultural crops and many are resistant to insecticides. Cucumber producers in the Katahari, Biratnagar in the Eastern region of Nepal, have been facing severe challenges in recent years due to infestations by the leafminer. This pest has emerged as a major concern for local cucumber farmers, adversely affecting plant health, yield, and economic viability. The objective of this study is to investigate the efficacy of various insecticides for controlling Liriomyza and the impact of these treatments on the growth, yield, and economic aspects of cucumber cultivation. Research plots were sprayed with profenophos + cypermethrin, emamectin, chlorantraniliprole, Btk + S. spinosa, spinetoram, azadirachtin, and a water spray control. Insecticide efficacy was monitored by examining the collected leaf samples for leafminer stings, larval mines, larvae number, and rate of injury. Chlorantraniliprole and spinetoram significantly reduced the number of leafminer stings, larval mines, and the average number of larvae, resulting in lower injury rates compared to the water spray control. The insecticide treatments exhibited varying effects on plant height, number of leaves per plant, male and female flower counts, and the sex ratio. Likewise, chlorantraniliprole application led to the highest fruit number per plant, resulting in the highest yield. Other treatments also influenced these parameters but to a lesser extent. The economic analysis revealed that chlorantraniliprole had the highest total cost of cultivation but also generated the highest gross return, net return, and benefit-cost ratio. Overall, this study demonstrates that chlorantraniliprole exhibited the most promising results in terms of pest control, plant growth, yield parameters, and economic returns. These findings provide valuable insights for cucumber farmers and can aid in developing effective strategies for managing cucumber leafminers

High-resolution mapping of seasonal crop pattern using sentinel imagery in mountainous region of Nepal: A semi-automatic approach

Sustainable agricultural management requires knowledge of where and when crops are grown, what they are, and for how long. However, such information is not yet available in Nepal. Remote sensing coupled with farmers’ knowledge offers a solution to fill this gap. In this study, we created a high-resolution (10 m) seasonal crop map and cropping pattern in a mountainous area of Nepal through a semi-automatic workflow using Sentinel-2 A/B time-series images coupled with farmer knowledge. We identified agricultural areas through iterative self-organizing data clustering of Sentinel imagery and topographic information using a digital elevation model automatically. This agricultural area was analyzed to develop crop calendars and to track seasonal crop dynamics using rule-based methods. Finally, we computed a pixel-level crop-intensity map. In the end our results were compared to ground-truth data collected in the field and published crop calendars, with an overall accuracy of 88% and kappa coefficient of 0.83. We found variations in crop intensity and seasonal crop extension across the study area, with higher intensity in plain areas with irrigation facilities and longer fallow cycles in dry and hilly regions. The semi-automatic workflow was successfully implemented in the heterogeneous topography and is applicable to the diverse topography of the entire country, providing crucial information for mapping and monitoring crops that is very useful for the formulation of strategic agricultural plans and food security in Nepal

Map of Study area.

South Asian countries face a disproportionate impact from disasters due to their unique topography, poverty, low literacy rates, and socio-economic status. Human activities, such as unplanned urbanization and poorly designed rural road networks, have further contributed to disasters in the region. The article explores the potential of nature-based solutions (NbS) as a means of addressing these challenges through the integration of green, blue, and grey infrastructure. The analysis evaluates the significance of NbS and examines policies and regional cooperation in Bangladesh, Bhutan, India, Nepal, and Sri Lanka, highlighting the importance of incorporating NbS into national policies and promoting collaboration among these countries. The study identifies the current low implementation of NbS in South Asia, with limited research in this area. While there are existing policy tools related to coastal zone management, water, forest, and urban development, policies related to NbS should be coherent, connected, and integrated with natural resources, climate change, disaster risk reduction, and socio-economic growth to achieve sustainable development in the region. Overall, the article emphasizes the need for effective policy implementation and research to enhance resilience to climate change and promote sustainable development in South Asia.</div

Supplementary information for Table 1 and Table 2.

These files include the list of literatures reviewed while writing this paper. (DOCX)</p

Policy and nature based solution linkages.

South Asian countries face a disproportionate impact from disasters due to their unique topography, poverty, low literacy rates, and socio-economic status. Human activities, such as unplanned urbanization and poorly designed rural road networks, have further contributed to disasters in the region. The article explores the potential of nature-based solutions (NbS) as a means of addressing these challenges through the integration of green, blue, and grey infrastructure. The analysis evaluates the significance of NbS and examines policies and regional cooperation in Bangladesh, Bhutan, India, Nepal, and Sri Lanka, highlighting the importance of incorporating NbS into national policies and promoting collaboration among these countries. The study identifies the current low implementation of NbS in South Asia, with limited research in this area. While there are existing policy tools related to coastal zone management, water, forest, and urban development, policies related to NbS should be coherent, connected, and integrated with natural resources, climate change, disaster risk reduction, and socio-economic growth to achieve sustainable development in the region. Overall, the article emphasizes the need for effective policy implementation and research to enhance resilience to climate change and promote sustainable development in South Asia.</div