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

BACKGROUND Rice cultivation under submerged conditions has great potential to act as a sink rather than a source of nitric oxide (N 2 O) emissions under high nitrogen (N) fertilization. The study aimed to investigate whether rice plants under paddy soil conditions have the potential to influence N 2 O emissions and its temporal dynamics. We employed the closed static chambers with rice transplanted inside using 15 N 2 O injection and included five treatments, each with three replicates and 15 N 2 O 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 15 N 2 O injection). RESULTS The results demonstrated that minimum N 2 O 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 N 2 O reduction was reported, referring to decreased reduction at high N levels, whereas a positive correlation ( r = 0.52, P < 0.05) between soil 15 N and nosZ was observed. Without added N, nosZ gene activity was low and denitrification was limited; however, plant N 2 O recovery was observed to be higher. CONCLUSION Overall, our results suggest that the N90 treatment is the most effective strategy for optimizing nosZ activity and enhancing N 2 O reduction at the same time as ensuring a balanced recovery of N 2 O in plant tissues. This approach also facilitates the conversion of N 2 O to environmentally friendly N 2 , providing a sustainable strategy for rice cultivation.