Ratoon rice-duck co-culture maintains rice grain yield and decreases greenhouse gas emissions in central China

Abstract

Both ratoon rice monoculture and rice-duck co-culture systems are gaining growing popularity in China. However, it remains unclear whether integration of ducks into ratoon rice field can reduce the inputs, and how it affects the crop productivity and greenhouse gas emissions amid resource scarcity and climate change. Here, a two-year field experiment was conducted in Hubei Province of central China in 2020 and 2021 to evaluate rice grain yield, global warming potential (GWP), and GWP intensity (GWPi) from both main and ratoon seasons of ratoon rice monoculture system and ratoon rice-duck co-culture system. The four treatments including ratoon rice monoculture system with traditional fertilizer and pesticide management (RR), ratoon rice-duck co-culture system with traditional fertilizer management and no pesticide application (RRD-P0), ratoon rice-duck co-culture system with traditional fertilizer management and reduced pesticide by 88% (RRD-P1), and ratoon rice-duck co-culture system with reduced fertilizer by 15% and pesticide by 88% (RRD-F1P1) were carried out with three replications under field conditions. On average, the treatments of RRD-P1 and RRD-F1P1 showed significantly lower emissions of CH4 and CO2, and therefore lower GWP than RR. Compared with RR, RRD-P1 and RRD-F1P1 significantly decreased GWP by 19–25% and GWPi by 22–32% without sacrificing rice grain yield on an annual basis while RRD-P0 caused a GWPi increase primarily due to rice grain yield reduction. Overall, ratoon rice-duck co-culture system with reduction of 88% pesticide could decrease the 15% fertilizer and reduce greenhouse gas emissions, while maintaining rice productivity in ratoon rice production. Our findings propose a feasible technical approach to balance rice grain yield and lower environmental cost using rice-duck co-culture farming system.