Amino acid enhanced phosphorus fertilizers enhance wheat yield and efficiency by optimizing soil phosphorus pools in...

Developing amino acid-based biostimulant-enhanced phosphate fertilizers can help improve fertilizer use efficiency and reduce environmental emissions. However, under the background of phosphorus (P) risk management, the mechanism by which amino acid-enhanced phosphate fertilizers affect the transformation characteristics of soil P remains unclear. This study aimed to explore the effects of amino acid addition on soil P pools, crop yield, and phosphate fertilizer utilization through a soil column experiment. Five treatments were set up: (1) no fertilizer control (CK), (2) no phosphate fertilizer control (NK), (3) application of diammonium phosphate (P), (4) application of 0.5% amino acid-enriched diammonium phosphate (AP0.5), and (5) application of 5% amino acid-enriched diammonium phosphate (AP5), with six replicates for each treatment. The results showed that amino acid-enriched phosphate fertilizers promoted the absorption and utilization of P by wheat, and improved the yield and PUE, with the most significant effect in the AP0.5 treatment. Compared with the P treatment, the soil Olsen-P and Labile-P in the AP0.5 and AP5 treatments increased by 29.76% - 33.45% and 4.49% - 5.11%, respectively, with significant differences. However, there were no significant differences in the above indicators among treatments with different amino acid addition amounts. Path analysis between different P fractions and Olsen-P showed that H₂O-P, NaHCO₃-P_i and NaOH-P_i had the greatest direct effects on Olsen-P; while NaHCO₃-Po and NaOH-Po may contribute indirectly to Olsen-P through their mineralization to NaHCO₃-P_i and NaOH-P_i, respectively. The research results indicated that amino acid-enriched phosphate fertilizers can not only increase the yield but also do not increase the risk of P leaching, and have good environmental benefits compared with ordinary phosphate fertilizers. The addition of amino acids will promote the transformation of soil organic P to inorganic P to maintain the soil Olsen-P level. This study deepens the understanding of the effects of amino acid-enriched phosphate fertilizers on soil P pool characteristics, thus providing a basis for the development of new phosphate fertilizers.