In order to boost grain yield of soybeans by cultural practices, an experiment was carried out with two most promising soybean varieties in Mekong Delta , VN. The experimental design is split plot design with three replicates . Plot size is 6. 5m x 2m , with and/or without nutrient foliar spraying in main plots , and seeding rate is in subplots with four different seeding treatments: 40 x 20 cm, 40 x 5 cm, 30 x 10 cm and 30 x 5 cm that is, from 25 plants per square meter to 66 plants per square meter .