Dynamic Response of Nitrogen Content to Moisture Variation in Soybean during the Whole Growth Period

Background: Soybeans are the main sources of oil and protein for most of the global population. As the population grows, so does the demand for soybeans. However, drought is a major factor that limits soybean growth. Methods: The nitrogen content in different parts of the soybean under drought stress and rehydration was investigated using the soybean cultivars, HN44 and HN65, at different growth stages (vegetative growth, parallel period of vegetative growth and reproductive growth and reproductive growth). Result: During the vegetative growth stage, drought decreased the plant’s nitrogen content. After rehydration, all the organs showed different degrees of compensatory effects. During the parallel period of vegetative and reproductive growth, drought decreased the nitrogen content of the leaves. After rehydration, the nitrogen content was partially restored. During the reproductive growth period, drought affected the translocation of nitrogen to the sink. After rehydration, the nitrogen content increased in the pods and decreased in other parts. In summary, rehydration after drought during the vegetative growth period of soybean can lead to nitrogen accumulation, but the reproductive growth phase differs from earlier; therefore, this period should avoid drought stress.