Southeast Asian University Consortium for Graduate Education in Agriculture and Natural Resources (UC)

The Education and Collective Learning Department (ECLD) conducted a Special Graduate Seminar on 29 April 2022 with Dr. Nguyen Thanh Trung from the Department of Soil Science and Plant Nutrition, Faculty of Natural Resources and Environment, Vietnam National University of Agriculture (VNUA). Dr. Trung shared his PhD research on Enhancing Soil Fertility and Sustainable Agricultural Production Using Legume-based Intercropping in Northern Mountainous Areas of Vietnam. Dr. Trung is an alumnus under the SEARCA Full MS/PhD research scholarship. He earned his PhD in Tropical Agriculture from Kasetsart University, Thailand in 2021.

Dr. Trung’s preliminary investigation in 2017 for his research.Dr. Trung’s preliminary investigation in 2017 for his research.

Dr. Trung talked about the importance of Cassava in Vietnam, specifically in the strategy of the country’s food security. However, soil erosion continues to threaten the production of Cassava as it removes the highly fertile topsoil, decreases soil water infiltration capacity, leads to waterlogging and water scarcity, reduces rooting depth, causes off-site soil and water pollution, and damages infrastructures. The monocropping systems on steep slopes also contribute to severe erosion. The overall impacts of soil erosion have led to a decline in cassava production of 31% in the Northern Mountainous Areas of Vietnam.

Through research funding from SEARCA, CIAT-Asia, CIRAD, and the ACTAE project funded by the French Agency of Development, Dr. Trung embarked on his study to address the issues of low agricultural production and economic benefit, and poor soil fertility in Vietnam through sustainable agroecological practices, specifically, the intercropping of legumes.

Dr. Trung’s field inoculation experiment in 2018.Dr. Trung’s field inoculation experiment in 2018.

Intercropping has its share of advantages and disadvantages. It boosts crop production, maximizes land use, controls pests, diseases, and weeds, maintains soil fertility, decreases soil runoff, emits a considerably lower amount of greenhouse gases, gives higher profit to cash crops, and promotes functional diversity of the soil microbial communities. However, intercropping also provides limited possibilities for different cultural practices, production mechanization and harvesting, competes for soil resources, and decreases yields as the crops differ in their competitive abilities.

Dr. Trung’s screening of native rhizobia strains under greenhouse condition at VNUA in 2018.Dr. Trung’s screening of native rhizobia strains under greenhouse condition at VNUA in 2018.

Dr. Trung’s study looked into assessing the effects of the cassava-cowpea intercropping system on soil and nutrient losses, crop yields and economic returns to smallholders and the potential strains for effective rhizobia inoculants and the scaling-up of production through farmer associations. Results of the study showed that the Cassava-cowpea intercropping in the Northern Mountainous Areas of Vietnam exhibited potential that may be considered a highly appropriate strategy for sustainable agricultural production. Research results showed the presence of effective rhizobia and its potential as an efficient inoculant for further scaling-up production in the fields. Results also include improved soil covering level, reduced soil erosion, and nutrient loss. And that more importantly, it maintained cassava yield and significantly improved the income of local farmers.

Dr. Trung’s on-farm erosion experiment in 2018.Dr. Trung’s on-farm erosion experiment in 2018.

Dr. Trung also shared his experience as a SEARCA scholar during the seminar. He learned about the opportunity through his colleagues at VNUA. He also highlighted the avenues that opened for him as a SEARCA scholar and even received multiple organizations’ support for his PhD research.

Dr. Trung’s thesis defense was conducted online due to pandemic restrictions.Dr. Trung’s thesis defense was conducted online due to pandemic restrictions.

SEARCA’s Special Graduate Seminar is held once every semester and highlights outstanding research by scholars from their graduate thesis. Hosting the seminar is the Center's way to support the scholars' academic milestones and recognize their capacity to produce quality research that has a great impact on agriculture and rural development.

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