Phosphorus And Zinc Effects On Soybean Glycine Max L Merrill Yield And Agronomic Efficiency

Phosphorus (P) and zinc (Zn) are required for the growth and development of soybean (Glycine max (L.) Merrill). However, their interactions may affect the uptake of each nutrient and soybean growth, development, and yield. The objective of this research study was to identify possible interactions of P and Zn and determine the effect upon soybean nutrient status, yield, and agronomic efficiency. This study was conducted at the Illinois State University Farm at Lexington and Normal in 2020. The experimental design was a 4 x 4 factorial arranged in a randomized complete block design with four blocks at each location. Phosphorus was applied as mono-ammonium phosphate (MAP) at 0, 33, 67, 100 kg P ha-1 and zinc was applied as zinc sulfate (ZnSO4) at 0, 5, 11, 16 kg Zn ha-1. Fully developed trifoliate leaves from the top three nodes were collected at R2 and seed samples were taken at R6 for analysis of P and Zn. Phosphorus fertilization had no effect on the P concentration of leaves but increased the P concentration of the seeds. The P concentration of the seeds for the highest rate (100 kg P ha-1) was greater than the control (0 kg P ha-1) and the lowest P rate (33 kg P ha-1). Zinc application had no effect on Zn concentration of soybean leaves and seeds. Neither P nor Zn affected soybean yield components and yield. Phosphorus and zinc agronomic efficiency did not improve with P and Zn application, respectively.There was no soil P-Zn interaction that affected soybean growth and yield. However, there was a weak inverse correlation between leaf P concentration and seed Zn concentration (r = -0.43), and between leaf Zn concentration and seed P concentration (r = -0.30). This study revealed that soybean yield and agronomic efficiency do not respond positively to P and Zn application when the soil test indicates P and Zn are sufficient.