1. Full name:     Nguyen Le Trang                                   2. Sex: Female

3. Date of birth: 22/11/1987                                            4. Place of birth: Hanoi

5. Admission decision number: No 4374/QD-DHKHTN, dated on 20/11/2015 by Rector of VNU University of Science

6. Changes in academic process: Extended time by decision No 3154/QD-DHKHTN, dated on 03/10/2019 by Rector of  VNU University of Science.

7. Official thesis title: Study greenhouse gas emissions in paddy rice cultivation in Nam Dinh province and propose mitigation measures

8. Major: Environmental Sciences                                  9. Code: 9440301.01

10. Supervisors: Assoc.Prof.Dr. Mai Van Trinh and Assoc.Prof.Dr. Nguyen Manh Khai     

11. Summary of the new findings of the thesis

-  Investigated, surveyed and assessed the status of rice production and fertilizer usage in Nam Dinh province, built up natural conditions data (soil, climate, irrigation…) and rice cultivation to calculate and simulate emissions at two pilot sites and throughout the province.

- DNDC model when applied to calculate the amount of GHG emissions in paddy rice cultivation is highly correlated when compared with actual field measurement data in Nghia Hung and Hai Hau, so it is suitable for emission simulation for similar soils with other climatic conditions throughout Nam Dinh province.

- Observed and simulated emissions of CH4 and N2O from paddy rice cultivation in Nam Dinh. The amount of GHGs emission in rice cultivation greatly depends on the characteristics of the soils. In particular, alluvial soil has a light mechanical composition for the highest emissions, an average of more than 27,000 kgCO2e/ha/year, heavy alluvial component has the lowest emissions, an average of about 12,000 kgCO2e/ha /year.

- Use urea-slowly fertilized fertilizer 46A + (orange urea) or urea + NEB26 (green urea) with the dosage equal to 75% and 50% of the conventional fertilizer without reducing the rice yield on the alluvial and alluvial soil saline water in the Red River Delta, thus indirectly reducing the cost of nitrogen fertilizer use by farmers. The slow-release nitrogen fertilizer did not significantly reduce the CH4 emission in rice cultivation but significantly reduced the N2O emission, especially Urea 46+, down 1.2 to 1.4 times the normal nitrogen in the alluvial saline soil in spring crop and 42.7% in the summer crop.

- Mixed NPK fertilizer with compost and biochar has higher yield than NPK (control) formula from 0.72 to 1.01 tons/ha (13.0 - 17.4%) for the summer crop and increase from 0.26 to 0.44 tons/ha (3.6 - 4.7%) for the spring crop. Organic materials increase GHGs emission, especially CH4, however, when combined with biochar, it will reduce the emission of organic fertilizer. In the direction of developing the organic agriculture, the use of organic fertilizer is an integral part, but it means that the GHGs emission will be increased in rice production. Therefore, biochar is a combined option to reduce emission in organic farming, while increasing productivity and improving soil quality.

12. Practical applicability, if any:

- Nam Dinh paddy rice cultivation is shifting towards high intensification, inorganic fertilizers are still mainly used very much, even higher than recommended. It causes waste and environmental pollution, while applied organic fertilizer is very limited and increasingly reduced both in the percentage of households applying and fertilizing. Understanding the impact of climate change on local rice production, most people are ready to receive new scientific and technological measures to adapt and mitigate climate change.

- The study applied the DNDC model to calculate the amount of GHGs emission in wet rice cultivation on a provincial scale and integrated with the geographic information system to build a GHGs emission map for Nam Dinh province, which can be verified. clearly identify the emission level from rice cultivation in each district and commune. From this map, scientists and management can propose appropriate measures to reduce GHGs emission.

- Slow-released nitrogen fertilizer did not support much to reduce CH4 emission in rice fields in both experimental crops, but significantly reduced N2O emission. Using fertilizer slowly soluble with a protein dose 25% lower than conventional farmers use but does not reduce productivity, demonstrating the role of inhibitors of urease enzyme activity, it could not only save money for farmers, but also have reduced GHGs emission and pollution of surface water and groundwater.

- Applying organic materials (compost, biochar) has a clear effect on GHGs emission, however, when applied in combination with biochar, will increase the efficiency of organic fertilizer and improve quality. Soil and emissions are reduced compared to using only organic fertilizer

13. Further research directions, if any

- Continuing studies on GHGs emission for the Red River Delta.

- Application of DNDC model in simulation of emission for other fertilizer and irrigation regimes to find the optimal farming method

14. Thesis-related publications:

1. Ngo Duc Minh, Mai Van Trinh, Reiner Wassmann, Bjorn Ole Sander, Tran Dang Hoa, Nguyen Le Trang, Nguyen Manh Khai (2015), “Simulation of Methane Emission from Rice Paddy Fields in Vu Gia-Thu Bon River Basin of Vietnam with the DNDC Model: Field Validation and Sensitivity Analysis”, VNU Journal of Science: Earth and Environmental Sciences 31(1), pp. 36-48.

2. Ngo Duc Minh, Mai Van Trinh, Tran Dang Hoa, Hoang Trong Nghia, Nguyen Manh Khai, Nguyen Le Trang, Bjorn Ole Sander, Reiner Wassmann (2016), “Modelling N2O emission from rice field in impacts of farming practices: A case study in Duy Xuyen district, Quang Nam province (Central Vietnam)”, Journal of Vietnamese Environment (J. Viet. Env) – Special Issue 8(4), pp.223-228. DOI: 10.13141/jve.vol8.no4.pp223-228. Published online by Technische Universität Dresden. ISSN 2193-6471. https://oa.slub-dresden.de/ejournals/jve.

3. Nguyen Van Bo, Mai Van Trinh, Bui Thi Phuong Loan, Le Quoc Thanh, Pham Anh Cuong, Nguyen Le Trang (2016), “UREA-AGROTAIN and greenhouse gases emission”. The second National Confence on Crop Sciences, Can Tho August 11-12, 2016, Vietnam Academy of Agricultural Science, Agicultural Publisher, pp. 80-85.

4. Mai Van Trinh, Bui Thi Phuong Loan, Vu Duong Quynh, Vu Đinh Tuan, Luc Thi Thanh Them, Nguyen Le Trang (2016), “Initial research the effect of different organic fertilizers on greenhouses emission in paddy rice fields, fluvisols and salic fluvisols in Nam Dinh province”. Science and Technology Journal of Agriculture and Rural Development 10, pp. 71-78

5. Luc Thi Thanh Them, Nguyen Le Trang, Mai Van Trinh (2016) “Application of DNDC model for simulating Green House Gases emission from lowland rice field on fluvisols and salic fluvisols in Nam Dinh province”, Journal of Vietnam Agricultural Science and Technology 10(71), pp. 82-87

6. Nguyen Le Trang, Bui Thi Phuong Loan, Mai Van Trinh, Nguyen Van Bo, Nguyen Thu Thuy (2018), “Influence of different organic materials and slow released chemical fertilizer to the greenhouse gases emission and paddy rice yield cultivated on saline fluvial soil in Nghia Hung district, Nam Dinh province”,  Journal of Vietnam Agricultural Science and Technology 6(91), pp. 100-105.

7. Nguyen Le Trang, Bui Thi Thu Trang, Mai Văn Trinh, Nguyen Tien Sy, Nguyen Manh Khai (2019), “Application of DNDC Model for Mapping Greenhouse Gas Emission from Paddy Rice Cultivation in Nam Dinh Province”, VNU Journal of Science: Earth and Environmental Sciences 35(2), pp. 23-32