Only a small quantity of manganese is essential for plant growth however under certain soil conditions even this is not available to the plant. Depending on severity, manganese deficiency will retard plant growth and may drastically decrease yields. A deficiency of manganese will affect the photosynthesis system of the plant. The visual symptoms of a manganese deficiency on soybeans is interveinal chlorosis of the leaves. The veins remains green until the chlorosis nears the white stage then they also lose their color.
Murdock, Lloyd W.; Miller, Harold F.; Peaslee, Doyle; and Frye, Wilbur, "Manganese Fertilization of Soybeans" (1977). Agronomy Notes. 111.