Unraveling the dual-acting effects of 2-cyclopenten-1-one (CCO): Yield increase and gaseous emission mitigation via microbial regulation

Abstract

Conventional inhibitors, such as N-Butylthiophosphoric triamide (NBPT) and 3,4-Dimethylpyrazol phosphate (DMPP), have been widely used to mitigate nitrogen loss, but their long-term environmental impacts remain a concern. Previous studies have indicated that 2-cyclopenten-1-one (CCO), a plant-derived compound, exhibits a dual-acting of suppressing urease activity and inhibiting nitrification. This unique property endows CCO with the potential to be developed into an eco-friendly and highly efficient novel inhibitor. In light of these findings, a field experiment was carried out to comprehensively assess the yield-increasing and emission-decreasing effects of this novel inhibitor and to explore the underlying microbial mechanisms. The experiment involved four treatments, each with three replicates: (i) Control (no fertilizer application); (ii) chemical fertilizer (NPK); (iii) NPK with NBPT and DMPP (NPK+ND), and (iv) NPK with CCO (NPK+CCO).

The results demonstrated that both CCO and ND treatments effectively increased yield and reduced emissions. Compared to NPK treatment, the CCO treatment significantly decreased NH₃, N₂O, and CO₂ emissions by 11.4 %, 9.9 %, and 12.8 %, respectively, and enhanced CH₄ uptake 27.32 g ha⁻¹. Furthermore, the ND treatment efficiently regulated the relative abundance and structure of microbial communities associated with genes such as amoB, nirS, and nisK. In contrast, CCO treatment acted more specifically on genes like norB and nirD. CCO significantly impacted target microorganisms, including Nocardioides and Nitrospira, by elevating bacterial abundance and intensifying community competition. Consequently, soil microbial metabolism, especially denitrification, was inhibited, reducing greenhouse gases (GHGs) emissions and enhancing maize yields. These findings provide valuable insights for evaluating nutrient-retention mechanisms of novel inhibitors and strategies to mitigate the greenhouse effect.