Effects of Different Novel Fertilizer Applications on Phosphorus Loss from Surface and Seepage Water in Paddy Fields in the Chaohu Lake Watershed
Phosphorus (P) loss from paddy fields contributes to eutrophication in Chaohu Lake. This study evaluated the effects of novel fertilizers and P reduction on P loss and rice yield. Seven treatments were established: no P (CK), rice-specific fertilizer (ZYF), slow-release blended fertilizer (SRF), Xinjutian compound fertilizer (XJT), enhanced loss-controlled fertilizer (CRF), CRF with 10% P reduction (CRF-10P%), and CRF with 30% P reduction (CRF-30P%). Results showed that novel fertilizers and P reduction significantly reduced concentrations of total phosphorus (TP), dissolved phosphorus (DP), and particulate phosphorus (PP) in surface water and leachate. The first 5 days after basal fertilization and heavy rainfall were high-risk periods for P loss. Rainfall increased TP concentrations by 417.74%–432.86% and 94.85%–351.35% in surface water and leachate, respectively; DP increased by 120.80%–322.44%, and PP by 280.66%–501.77% and 80.23%–297.55%. Compared with ZYF, SRF, XJT, and CRF reduced TP loss by 15.43%–33.95%, with SRF showing the lowest loss. Under P reduction, CRF-10P% and CRF-30P% reduced TP loss by 31.48% and 37.04%, respectively, with CRF-30P% achieving the lowest loss. Notably, CRF-10P% increased rice yield by 22.37% relative to ZYF, indicating that moderate P reduction with enhanced loss-controlled fertilizer can maintain or increase yield while reducing environmental risk. The study concludes that CRF-10P% offers a promising strategy for sustainable rice production in the Chaohu Lake watershed.