Of course, the best type of soil for growing soybean (Glycine max (L.) Merrill) is a light textured soil, rich in humus, and its acidity is around neutral (not acid). Such a soil may be neither influenced by saline water nor under flooded condition. But in South Vietnam, especially in the Mekong Delta and in favorable weather conditions, soybean is able to grow and de-velop well and give a high seed yield on relatively heavy clay with pH over 4.5 There, soybean can be grown without land tillage; this has been clari-fied by experimental data in cormnercial scale.
Tran, Tuan Thuong and Chu, Huu Tin
"Research Notes : Nontillage is a technique in growing soybean,"
Soybean Genetics Newsletter: Vol. 9
, Article 52.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol9/iss1/52