Developing environmentally friendly alternative technologies to improve weed control and optimize Phosphorus fertilizer use is crucial for sustainable agriculture. In this project, we evaluated the use of the PTXD (phosphite oxidoreductase)/Phosphite system to sustain Phosphorus (P) fertilization and weed control for soybean cultivation. This system relies on using an alternative P-fertilizer (Phosphite, Phi) and plants expressing the ptxD gene, and we previously demonstrated that it is highly effective for cotton cultivation. We performed multiple greenhouse experiments to investigate the phenotypic, physiological, and biochemical features of ptxD-soybean plants compared to the non-transformed controls (WT) when fertilized with Phi. We demonstrated that ptxD-plants effectively use Phi as the only P source and that the PTXD/Phi technology is an effective dual system that provides P-fertilization and weed control for soybean cultivation. Our analyses of phenotype characterization, hyperspectral images, and biochemical analysis suggest that ptxD-plants fertilized with Phi are less subjected to stress as compared to the WT plants in low Pi soils, and that Phi might enhance stress and plant defense responses. This might provide further advantages to the soybean plants over the traditional agricultural schemes, which deserves further investigation to understand better the changes induced by the PTXD/Phi system. We also assessed the control of Phi over six different weeds that affect soybean cultivation, including Johnson grass, morning glory, palmer amaranth (glyphosate-resistant), and velvet leaf. Our research revealed that Phi is very effective at controlling these weeds even when grown in 20 ppm-P soil. This indicates Phi's potential as an effective weed control tool in both sub-optimal-Pi and low-Pi conditions when applied as a foliar treatment. This approach aligns with sustainable agriculture practices by reducing reliance on traditional herbicides and promoting responsible Phi use in field conditions.