Synergistic effect of nano-iron phosphide and wood vinegar on soybean production and grain quality†

Abstract

Phosphorus fertilizer (PF) is an important nutrient for crop growth, but it can be easily immobilized in the soil by oxides of aluminum, iron, and calcium, resulting in its reduced bioavailability. In our study, we demonstrated that iron phosphide nanomaterials (FeP-NMs) effectively enhance phosphorus utilization in plants. Specifically, with the addition of wood vinegar (WV), soybeans required only 20% of the standard PF dose to achieve maximum yield. Application of 20% FeP-NMs with WV significantly increased soybean yield by 54% compared to the control group. This reduction in PF input by 80% in future agriculture not only conserves phosphate rock resources but also promotes the reuse of agricultural waste, such as WV. Furthermore, the application of FeP-NMs and WV improved the nutritional quality of soybeans, increasing flavonoid, protein, and amino acid contents in seeds by 13%, 17.5%, and 32%, respectively. These improvements can be attributed to enhanced photosynthesis (12.4%) and increased stability of the antioxidant enzyme system (reduced by 8–45%) following the application of FeP-NMs and WV. Additionally, phosphorus in FeP-NMs was more efficiently converted to soil-available and inorganic forms, thereby enhancing plants' phosphorus absorption and utilization efficiency. Our study addresses a knowledge gap concerning the potential utilization of transition metal phosphide NMs as PF in agriculture. It provides significant support for the future development of nano-agriculture, highlighting the important role of FeP-NMs in optimizing crop yield and seed quality.