In order to maximize yields, nitrogen still must be added. However, the key is the amount that needs to be applied. Using biological nitrogen fixation greatly decreases the amount of industrial fertilizer needed. Crop producers should identify the degree of successful nodulation in their crop in the seedlings. Soybean plants are considered to be well-nodulated if they have ten to twenty nodules per plant a month after planting.
Active nodules appear pink to the naked eye, indicating active hemoglobin.
Producers should recognize the following factors in relation to nitrogen fixation. This is a common form that can be applied either directly to the dry seed in the seed box or to seed moistened with a sticky syrup such as honey or molasses. These can be applied to the soil close to the seed in the seedbed. These have the potential of greatly increasing Rhizobial numbers in the seed vicinity and have particular value on the new fields or on fields known to have a nodulation problem. Granular inoculants are applied to the soil in the seedbed along with the seed.