1. Full name: Nguyen Thi Hong Thinh                             2. Sex: Female

3. Date of birth: 17/4/1978                                              4. Place of birth: Ha Nam

5. Admission decision number: No 4860/QD-DHKHTN dated on 24/11/2014 by Rector of VNU University of Science.

6. Changes in academic process:

Decision No. 2409/QD-DHKHTN dated on 11/7/2017 by the Rector of the VNU University of Science on the change of thesis title and the supervisors of the doctoral thesis.

7. Official thesis title: Studying on ¹³C/¹²C isotope ratio and organic carbon sequestration potential of some Fluvisol soils in the Red River Delta

8. Major: Environmental Science                                        9. Code: 9440301.01

10. Supervisors:            Assoc. Prof. Nguyen Van Vuong

                                    Dr. Trinh Van Giap

11. Summary of the new findings of the thesis

- In the present thesis, the author improved and further developed the procedure that allows a complete removal of inorganic carbon for the analysis of stable isotope composition, ¹³C, in Soil Organic Carbon (SOC) and applied to evaluate the ability of soil carbon sequestration.

- The thesis identified the correlation of SOC with ¹³C and the main soil physical and chemical properties for the soil depth of 0-30 cm of the Eutric Fluvisols and Dystric Fluvisols in the Red River Delta. The thesis also elucidated the change of ¹³C in the soil in relation to annual crop model changing from 2 maize crops-1 rice crop to 2 rice crops-1 maize crop model for two scenarios: without plant residue recycling and with plant residue recycling after harvesting. The present work determined the origin and contribution of plant residues to SOC and proved that the farming models have greatly influenced on the soil C storage capacity.

12. Practical applicability, if any:

The ¹³C isotope composition is an indicator that clearly reflects the origin of SOC and can be applied in practice to assess the ability of C storage in the soil of the current rice-maize crop models and indicate appropriate cultivation practices to maintain SOC, reduce greenhouse gas emissions, and contribute to environmental protection.

13. Further research directions, if any:

- Continue to study the dynamics of SOC in the soil and possible factors that may affect the decomposition and accumulation of SOC in the maize-rice cultivation systems in Vietnam.

- Expanding research of SOC for different soil uses and agroecosystems towards sustainable management and use of soil resources in Vietnam.

14. Thesis-related publications:

Nguyen Thi Hong Thinh, Vu Hoai,   Ha Lan Anh, Trinh Van Giap, Nguyen Van Vuong (2018), “A procedure of determining carbon-13 composition in soil organic carbon on an Isotope Ratio Mass- Spectrometer”, Nuclear Science and Technology, Vol.8, No. 1, pp. 23-28.

Nguyen Thi Hong Thinh, Vu Hoai, Ha Lan Anh, Vo Thi Anh, Truong Viet Chau, Trinh Van Giap, Tran Minh Tien (2019), “Study the Changes in Soil Organic Carbon of Rice-Maize Cropping System in the Top Layer of Alluvisol Soil in Dan Phuong: A Study of C-13 Stable Isotope Composition (δ13C)”, Journal of Environmental Protection, 10, 1361-1372.

Minh N. Nguyen, Andy A. Meharg, Manus Carey, Stefan Dultz, Federica Marone, Sarah B. Cichy, Chinh T. Tran, Giang H. Le, Nga T. Mai, Thinh T.H. Nguyen (2019), “Fern, Dicranopteris linearis, derived phytoliths in soil: Morphotypes solubility and content in relation to soil properties” , European Journal of Soil Science,; 70:507–517.

Thu T.T. Tran, Thao T. Nguyen, Van T. Nguyen, Huong T.H.Huynh, Thinh T.H. Nguyen, Minh N. Nguyen (2019), “Copper encapsulated in grass-derived phytoliths: Characterization, dissolution properties and the relation of content to soil properties”,  Journal  of  Environmental  Manage  Science,  249 109423.