Changes in soil phosphorus forms affect soil zinc availability in distinct paddy rice soil textures under long-term phosphate fertilization

The interaction between phosphorus (P) and zinc (Zn) significantly impacts crop yield and nutrient availability in agricultural systems. This study examines how long-term P fertilization in paddy rice affects soil P forms and Zn dynamics across three distinct soil textures (sand, loam, and clay) over 20 years (2003–2022) in a long-term experimental field. Long-term P fertilization increased total P (TP), Olsen-P, and various P fractions, with clay soils showing the highest increases in TP (201.13 mg kg⁻¹) and total inorganic P (77.46 mg kg⁻¹). P fertilizer application enhanced available Zn content (AZn) and the available index of Zn (AIZn) while total Zn (TZn) decreased in loam, clay and sand soils. Changes in AZn and AIZn content were positively correlated with alterations in soil Olsen-P and specific P fractions content (CaCl₂-P, Ca₂-P, and water-soluble P). Grain removed Zn content (△Grain RZn) ranged from 0.023 to 0.045 kg hm⁻², with significantly increases in clay and sand soils linked to soil storage Olsen-P (△SOlsen-P), while it decreased in loam soils with increasing △SOlsen-P. Redundancy analysis identified changes in soil storage AZn, Ca₂-P, and water soluble P as significant factors influencing changes in grain removed Zn and P content (△Grain RZn and △Grain RP). This study highlights the complex interactions between P forms and Zn availability in different soil textures, with important implications for long-term phosphate fertilization practices in paddy fields.