Vietnam shares intercropping strategy

LOS BAÑOS, Laguna: Vietnam National University of Agriculture (VNUA) has introduced intercropping in a Special Graduate Seminar conducted by the Education and Collective Learning Department (ECLD) of the Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA) here.

During the seminar on April 29, 2022, Dr. Nguyen Thanh Trung from the VNUA Department of Soil Science and Plant Nutrition, Faculty of Natural Resources and Environment, shared his Ph.D. research on Enhancing Soil Fertility and Sustainable Agricultural Production Using Legume-based Intercropping in Northern Mountainous Areas of Vietnam (NMAV).

Also an alumnus under the SEARCA Full MS/Ph.D. research scholarship earning his Ph.D. in Tropical Agriculture from Kasetsart University, Thailand in 2021, Trung talked about the importance of cassava in Vietnam, specifically in the strategy of the country's food security.

However, he noted that 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, and causes off-site soil and water pollution, and damages infrastructures.

Trung said the monocropping systems on steep slopes also contribute to severe erosion, noting that the overall impacts of soil erosion have led to a decline in cassava production of 31 percent in the northern mountainous areas of Vietnam.

According to SEARCA, 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.

Trung explained that intercropping has its share of advantages and disadvantages.

He said 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.

On the other hand, Trung said 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.

Trung also noted that his 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.

SEARCA said the results of Trung's study showed that the cassava-cowpea intercropping in the NMAV exhibited potential that may be considered a highly appropriate strategy for sustainable agricultural production.

It said research results showed the presence of effective rhizobia and its potential as an efficient inoculant for further scaling-up production in the fields, including improved soil covering level, reduced soil erosion and nutrient loss. More importantly, it maintained cassava yield and, significantly, improved the income of local farmers.

SEARCA said it funded Trung's research, together with the International Center for Tropical Agriculture (or CIAT-Asia from its Spanish-language name Centro Internacional de Agricultura Tropical), Cirad which is the French Agricultural Research Centre for International Development, and the ACTAE project funded by the French Agency of Development.

Trung shared his experience as a SEARCA scholar during the seminar and that 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 Ph.D. research.

SEARCA Director Glenn Gregorio said the Special Graduate Seminar is held once every semester and highlights outstanding research by scholars from their graduate thesis.

Gregorio noted that hosting the seminar is SEARCA'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.