Part 1, Section 6: Soybean
Soybean
NUTRITIONAL REQUIREMENTS
Determine lime and fertilizer needs by soil test. Soybean in rotation can make use of fertilizer applied to the previous crop; however, this does not eliminate the need for a sound fertility program. Maintain pH between 6.0 and 6.5. In the absence of a soil test, refer to the most recent soil test available for the field, and adjust rates according to values listed in Table 1.2-5 for soybeans. Apply fertilizer before seeding or band at least 2 inches to the side of seed at planting. Do NOT drill fertilizer with the seed or use “pop-up” fertilizer.
Soybean that has been properly inoculated with nitrogen-fixing bacteria rarely respond to nitrogen fertilization. If the previous year’s crop was not soybeans, inoculate seed with fresh, viable, nitrogen-fixing bacteria immediately before planting. Recent research results indicate a 70% chance for a 2.0 bushel-per-acre yield increase when inoculating seed planted into fields growing soybean every other year. Triple the inoculant rate if soybeans have not been grown previously in the field. For more information, see Agronomy Facts #11, Inoculation of Forage and Grain Legumes.
If pH is below 6.0 and is not to be corrected with lime, apply molybdenum as a seed treatment at planting. This helps to ensure proper nitrogen fixation.