Healthy nodules on soybean root.
Rhizobia growth, health, and activity depend on the initial population of bacteria and soil conditions that can favor or hinder their development. Several factors can reduce activity of these bacteria:
Soybean field not previously planted to soybeans.
Dark green strips were inoculated with rhizobia.
Reduced nodulation can lead to nitrogen deficiency symptoms in soybeans if residual nitrogen is not available.
Field not previously planted to soybeans shows symptoms of nitrogen deficiency.
Yellowing is not always due to reduced nodulation. Other possible causes of soybean yellowing include:
Field areas show N deficiency due to poor nodulation.