The role of biological nitrogen fixation in increasing crop production and soil fertility in Vietnam

BNF has a positive effect on growth and yield of most agricultural crops and on soil in Vietnam. The field test of BNF inoculants showed that rhizobial inoculants increased grain yield of groundnut 13.8%-17.5% in North and Central Vietnam and 22% in South Vietnam. Depending on the fertilizer status and nutrition content of soil, BNF inoculants increased rice yield by 4.07-19.59%, tea by 9.1-26.7% and maize by 9.4-10.2%. In addition, inoculants improved plant resistance to some pathogen diseases. Mixed culture of nitrogen fixing, phosphate solubilizing, and plant growth promoting microorganisms had a positive effect on growth and yield of different crops and increased profits. It increased the yield of rice 15.2-15.7%, and of soybean 16.3-19.5%. BNF also has a positive effect on the growth of forestry trees. The paper discusses various constraints of BNF application in Vietnam, and possible solutions to these.