PARTIAL SUBSTITUTION OF MINERAL FERTILIZERS WITH CATTLE DUNG COMPOST IMPROVES GRAIN YIELD WHILE REDUCING GREENHOUSE GAS EMISSIONS IN IRRIGATED LOWLAND RICE SYSTEMS

The growing dependence on mineral fertilizers in irrigated rice (Oryza sativa L.) production has raised production costs and increased greenhouse gas emissions, creating a need for more sustainable fertilization practices. This study explored whether part of the mineral fertilizer requirement could be replaced with cattle dung compost without reducing rice productivity or increasing greenhouse gas emissions. To address this objective, twelve fertilization strategies combining different rates of cattle dung compost, NPK fertilizer, and urea were compared under irrigated lowland conditions. Rice grain yield, together with CH4, CO2, and N2O emissions, was monitored throughout the cropping cycle. Pearson's correlation and principal component analyses were then applied to better understand the links between crop performance and greenhouse gas emissions. Fertilization treatments significantly affected grain yield and greenhouse gas emissions (P < 0.001). The highest grain yield (9.60 t ha-1) was achieved when 30 t ha-1of cattle dung compost was used together with complete substitution of NPK fertilizer and a 67% reduction in urea application.