Rice plant consumption of atmospheric nitrous oxide and temporal dynamics in paddy soil

Rice cultivation under submerged conditions has great potential to act as a sink rather than a source of nitric oxide (N₂O) emissions under high nitrogen (N) fertilization. The study aimed to investigate whether rice plants under paddy soil conditions have the potential to influence N₂O emissions and its temporal dynamics. We employed the closed static chambers with rice transplanted inside using ¹⁵N₂O injection and included five treatments, each with three replicates and ¹⁵N₂O injection: N0 (0 kg N ha^-1), N45 (45 kg N ha^-1), N90 (90 kg N ha^-1), N180 (180 kg N ha^-1) and WN90 (90 kg N ha^-1 without ¹⁵N₂O injection).

The results demonstrated that minimum N₂O concentration (10.66 ppm at 30 min) was recorded at booting stage (44 days) with the treatment N90 showing 97.88% reduction in concentration compared to the initial concentration (502.02 ppm). Negative correlation (r = -0.77, P < 0.05) between N treatments and N₂O reduction was reported, referring to decreased reduction at high N levels, whereas a positive correlation (r = 0.52, P < 0.05) between soil ¹⁵N and nosZ was observed. Without added N, nosZ gene activity was low and denitrification was limited; however, plant N₂O recovery was observed to be higher.

Overall, our results suggest that the N90 treatment is the most effective strategy for optimizing nosZ activity and enhancing N₂O reduction at the same time as ensuring a balanced recovery of N₂O in plant tissues. This approach also facilitates the conversion of N₂O to environmentally friendly N₂, providing a sustainable strategy for rice cultivation. © 2026 Society of Chemical Industry.