Ammonium Polyphosphate Promotes Maize Growth and Phosphorus Uptake by Altering Root Properties

Phosphorus (P) is an essential nutrient for maize growth, significantly affecting both yield and quality. Despite the typically high concentration of available P in black soils, the efficiency of crop uptake and utilization remains relatively low. This study aimed to evaluate the effects of different P fertilizers on maize yield, root growth parameters, and P use efficiency to identify strategies for optimizing P management in black soil regions. Field experiment results indicated that the combination of ammonium polyphosphate (APP) with other P fertilizers led to variations in yield and P fertilizer absorption efficiency. Various P fertilizers were tested, including diammonium phosphate (DAP), ammonium polyphosphate (APP), fused calcium magnesium phosphate (FCMP), a combination of DAP and FCMP (DAP+FCMP), and a control with no phosphate (CK). The results indicated that P application significantly increased maize yield, with APP (171.8 g/plant) outperforming other P application treatments. Different P fertilizer types significantly affect soil P content and the composition of P fractions. APP significantly increased both the total P (TP) and the proportion of inorganic P (Pi). Furthermore, APP application significantly improved root length (RL), surface area (SAR), and root activity (RA) compared to CK, leading to enhanced nutrient absorption. APP also significantly increased P uptake and utilization (REp, FPp, AEp, PHI, and PAC). In summary, by optimizing plant biomass and P uptake, APP can directly and indirectly influence maize yield. Improving rhizosphere properties through the selection of suitable fertilizer types can enhance fertilizer use efficiency and increase maize production.