Drip fertigation with treated municipal wastewater and soil amendment with composted sewage sludge for sustainable protein-rich rice cultivation

Abstract

Rice paddy farming is threatened by global water scarcity, necessitating the adoption of novel water-saving cultivation practices. The purpose of this study is to determine the effects of drip fertigation with treated municipal wastewater (TWW) on a rice–soilsystem that is amended with composted sewage sludge (CSS). The treatments included flood irrigation with tap water (Control; T1), flood irrigation with TWW (T2), drip irrigation (DI) with TWW at 86% water consumption (T3), DI with TWW at 75% water consumption (T4), DI with TWW at 69% water consumption (T5), and DI with tap water at 86% water consumption (T6). The control was administered mineral fertilizers, and all other treatments received the same N amount (260 kg ha −1 ) from CSS. The results indicated that TWW drip fertigation had a significant beneficial effect on rice production by increasing (59.7 g pot −1 , T3) or maintaining (51.4 g pot −1 , T4) grain yield while conserving up to 25% of water when compared to conventional flood irrigation and mineral fertilizer application (52.9 g pot −1 ). In comparison to conventional farming, TWW drip fertigation in conjunction with CSS amendment significantly increased grain protein and Cu content while reducing As accumulation by 50%. Both CSS and TWW are effective at retaining soil fertility while avoiding unfavorable accumulation of As, Pb, Cd, Cu, and Zn. The novel cultivation techniques described herein have the potential to significantly improve the sustainability of rice farming in water-stressed areas, as well as integrated wastewater management strategies aimed at achieving sustainable development goals. • Rice farming can benefit from treated wastewater (TWW) and composted sludge (CSS). • TWW drip fertigation greatly increased rice yield and conserved up to 25% of water. • CSS and TWW reuse increased protein while lowering As contents by 50% in grains. • The practices effectively preserved soil fertility without toxic element buildup.