Sole and combined effects of drought and phosphorus application on soybean

Abstract

Phosphorus is one of the most important macronutrients for plant development, and although it might be present in relatively high concentrations in the soil, yet the readily-available amounts can be much lower because it presents in forms of soil complexes. P application can help plants tolerate drought stress, which is increasingly reported and predicted in soybean main cultivation areas. An experiment was carried out in 2018 and 2019 in Debrecen, Hungary to investigate the sole and combined effects of P fertilization and drought stress on two soybean cultivars. Results showed that leaf area, relative chlorophyll content and, to a higher extent, stomatal conductance and plant height of both cultivars were negatively affected by both P and water deficits. Pod number/plant and seed yield were also decreased as a result of drought and lack of P. Moreover, oil concentration in the produced seeds was measurably decreased under drought stress and significantly increased with P application, whereas protein concentration was not measurably affected by P application, but increased under drought stress conditions. It could be concluded that the high rate of P fertilizer is not recommended in the study area as it did not have noticeable effects compared to the lower rate.

Keywords

• fertilization
• seed quality
• soybean
• water deficit
• yield