Agronomic Modulation of Maize Starch Functionality through Phosphorus Management: A Proof-of-Concept Field Study

High Resolution Image Download MS PowerPoint Slide This proof-of-concept field study investigated whether different phosphorus fertilizer sources (soluble diammonium phosphate (DAP) and slow-release struvite) and application methods (broadcast or near-root placement) can modify maize starch properties for biobased applications. Placement increased shoot P content but decreased starch P/PO 4 3– levels relative to broadcast. Struvite produced smaller starch granules than DAP, and broadcast treatments led to smaller granules than placement─especially with struvite. FTIR (1047/1022 cm –1 ) revealed contrasting trends in starch structural order depending on the fertilizer type and application method. These structural changes resulted in higher gelatinization onset (T 0 ) and peak (T p ) temperatures in DAP-broadcast and reduced water absorption in DAP-placement. Broadcast and struvite treatments showed higher modulus (G′ and G″ values) with temperature dynamics than placement and DAP, respectively. DAP-placement showed the slowest hydrolysis rates among all treatments, consistent with starch P/PO 4 3– levels. These results indicate a potential route to tailor the starch structure and functionality through P management.